Patent Publication Number: US-10331324-B1

Title: Measurement and testing system

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This is a continuation-in-part of U.S. Nonprovisional patent application Ser. No. 14/953,505, entitled “Force Measurement System”, filed on Nov. 30, 2015, which is a continuation-in-part of U.S. Nonprovisional patent application Ser. No. 14/556,656, entitled “Measurement And Testing System”, filed on Dec. 1, 2014, now U.S. Pat. No. 9,200,897; which is a continuation-in-part of U.S. Nonprovisional patent application Ser. No. 14/042,332, entitled “Measurement And Testing System”, filed on Sep. 30, 2013, now U.S. Pat. No. 8,902,249; which is a continuation-in-part of U.S. Nonprovisional patent application Ser. No. 13/726,065, entitled “Measurement And Testing System”, filed on Dec. 22, 2012, now U.S. Pat. No. 8,643,669; the disclosure of each of which is hereby incorporated by reference as if set forth in their entirety herein. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not Applicable. 
     NAMES OF THE PARTIES TO A JOINT RESEARCH AGREEMENT 
     Not Applicable. 
     INCORPORATION BY REFERENCE OF MATERIAL SUBMITTED ON A COMPACT DISK 
     Not Applicable. 
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     The invention generally relates to a measurement and testing system. More particularly, the invention relates to a measurement and testing system that may be in the form of a force measurement system. 
     2. Background 
     Measurement and testing systems are utilized in various fields to detect and analyze many different measurable quantities. For example, in biomedical applications, measurement and testing systems are used for gait analysis, assessing balance and mobility, evaluating sports performance, and assessing ergonomics. However, conventional measurement and testing systems have numerous limitations and drawbacks. 
     In order to properly execute certain tests utilizing measurement and testing systems, it is often necessary to utilize a large measurement surface area. However, conventional measurement and testing systems with large measurement surface areas have no means by which to separately analyze the movement of the individual legs of the subject walking thereon. Also, conventional measurement and testing systems with large measurement surface areas are difficult to install, and are not easily adaptable to different space configurations in a building. 
     Therefore, what is needed is a measurement and testing system with a large measurement surface area that enables the movement of the individual legs of the subject disposed thereon to be separately analyzed. Moreover, what is needed is a measurement and testing system that includes a data acquisition and processing device which is specially programmed to determine the movement generated by each of the legs separately. Furthermore, a need exists for a measurement and testing system in the form of a force measurement system with a modular configuration that is easy to install, and is readily adaptable to different building space configurations. In addition, what is needed is a measurement and testing system that is capable of combining data channels from various devices with different sampling rates into a single time-synced channel collection. 
     BRIEF SUMMARY OF EMBODIMENTS OF THE INVENTION 
     Accordingly, the present invention is directed to a measurement and testing system that substantially obviates one or more problems resulting from the limitations and deficiencies of the related art. 
     In accordance with one or more embodiments of the present invention, there is provided a measurement and testing system comprising a plurality of force measurement assemblies, each of the plurality of force measurement assemblies includes a force measurement surface for receiving at least one portion of a body of a subject and at least one force transducer, the at least one force transducer configured to sense one or more measured quantities and output one or more first signals that are representative of the one or more measured quantities; an input device, the input device configured to output a second signal comprising input data indicative of which of the plurality of force measurement assemblies are to be combined with one another; and a data processing device operatively coupled to the input device and each of the force transducers of each of the force measurement assemblies, the data processing device configured to receive the second signal outputted by the input device and to form a virtual force measurement assembly comprising a subset of the plurality of force measurement assemblies based upon the input data of the second signal, and the data processing device further configured to receive each of the one or more first signals that are representative of the one or more measured quantities for the subset of the plurality of force measurement assemblies, and to convert the one or more first signals into load output data. 
     In a further embodiment of the present invention, the input device comprises at least one of: (i) a mouse, (ii) a keyboard, and (iii) a touchscreen user interface. 
     In yet a further embodiment, the measurement and testing system further comprises a visual display device having an output screen, the visual display device configured to display one or more images on the output screen so that the one or more images are viewable by a system user. In this further embodiment, the input device comprises a keyboard configured to output the second signal in response to a manipulation of the keyboard by the system user, and the data processing device is further configured to generate a dialog box on the output screen of the visual display device for enabling the system user to specify designated ones of the plurality of force measurement assemblies forming the virtual force measurement assembly using the keyboard. 
     In still a further embodiment, the measurement and testing system further comprises a visual display device having an output screen, the visual display device configured to display one or more images on the output screen so that the one or more images are viewable by a system user. In this further embodiment, the input device comprises a mouse configured to output the second signal in response to a manipulation of the mouse by the system user; and the data processing device is further configured to generate a graphical representation of a layout of the plurality of force measurement assemblies on the output screen of the visual display device for enabling the system user to specify designated ones of the plurality of force measurement assemblies forming the virtual force measurement assembly by allowing the system user to select the force measurement assemblies on the output screen of the visual display device using the mouse. 
     In yet a further embodiment, the measurement and testing system further comprises a visual display device having an output screen, the visual display device configured to display one or more images on the output screen so that the one or more images are viewable by a system user. In this further embodiment, the input device comprises a touchscreen user interface of the visual display device configured to output the second signal in response to a manipulation of the touchscreen user interface by the system user, and the data processing device is further configured to generate a graphical representation of a layout of the plurality of force measurement assemblies on the output screen of the visual display device for enabling the system user to specify designated ones of the plurality of force measurement assemblies forming the virtual force measurement assembly by allowing the system user to select the force measurement assemblies on the output screen of the visual display device using the touchscreen user interface. 
     In still a further embodiment, the data processing device is configured to form the virtual force measurement assembly using the input data of the second signal from the input device prior to generating the load output data from the one or more first signals. 
     In yet a further embodiment, the data processing device is further configured to generate the load output data by combining the one or more first signals of the subset of the plurality of force measurement assemblies forming the virtual force measurement assembly into a single time-synced synthetic channel. 
     In still a further embodiment, the input device and the data processing device are each part of a single digital device. 
     In yet a further embodiment, the single digital device comprises one of: (i) a laptop computing device, (ii) a tablet computing device, and (iii) a smartphone. 
     In accordance with one or more other embodiments of the present invention, there is provided a measurement and testing system comprising a first measurement device having a first sampling rate, the first measurement device configured to sense one or more measured quantities and output one or more first measurement signals that are representative of the one or more measured quantities, the one or more first measurement signals comprising a first plurality of data values with corresponding first timestamps associated with each of the first plurality of data values; a second measurement device having a second sampling rate that is different than the first sampling rate of the first measurement device, the second measurement device configured to sense one or more measured quantities and output one or more second measurement signals that are representative of the one or more measured quantities, the one or more second measurement signals comprising a second plurality of data values with corresponding second timestamps associated with each of the second plurality of data values; and a data processing device operatively coupled to the first measurement device and the second measurement device, the data processing device configured to receive the one or more first measurement signals from the first measurement device and the one or more second measurement signals from the second measurement device, the data processing device further configured to synchronize each of the first plurality of data values with each of the second plurality of data values by determining which of the first timestamps correspond to the second timestamps. 
     In a further embodiment of the present invention, the second sampling rate of the second measurement device is greater than the first sampling rate of the first measurement device, or the second sampling rate of the second measurement device is less than the first sampling rate of the first measurement device. 
     In yet a further embodiment, the first measurement device is in the form of a force plate and the second measurement device is in the form of an inertial measurement unit, and wherein the second sampling rate of the inertial measurement unit is variable over time. 
     It is to be understood that the foregoing general description and the following detailed description of the present invention are merely exemplary and explanatory in nature. As such, the foregoing general description and the following detailed description of the invention should not be construed to limit the scope of the appended claims in any sense. 
    
    
     
       BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
       The invention will now be described, by way of example, with reference to the accompanying drawings, in which: 
         FIG. 1  is a diagrammatic perspective view of a measurement and testing system according to an embodiment of the invention; 
         FIG. 2  is a block diagram of constituent components of the measurement and testing system, according to an embodiment of the invention; 
         FIG. 3  is a block diagram illustrating data manipulation operations carried out by the measurement and testing system, according to an embodiment of the invention; 
         FIG. 4  is a diagrammatic perspective view of one measurement assembly used in the measurement and testing system, according to an embodiment of the invention, wherein the measurement assembly is in the form of a dual force plate; 
         FIG. 5  is a diagrammatic top view of one measurement assembly used in the measurement and testing system with exemplary coordinate axes superimposed thereon, according to an embodiment of the invention, wherein the measurement assembly is in the form of a dual force plate; 
         FIG. 6  is a diagrammatic perspective view of another measurement assembly used in the measurement and testing system, according to an embodiment of the invention, wherein the measurement assembly is in the form of a single force plate; 
         FIG. 7  is a diagrammatic top view of another measurement assembly used in the measurement and testing system with exemplary coordinate axes superimposed thereon, according to an embodiment of the invention, wherein the measurement assembly is in the form of a single force plate; 
         FIG. 8  is a first screenshot displayed on the operator visual display device of the measurement and testing system illustrating the timeline bar feature, according to an embodiment of the invention; 
         FIG. 9  is a second screenshot displayed on the operator visual display device of the measurement and testing system illustrating the timeline bar feature, according to an embodiment of the invention; 
         FIG. 10  is a partial flowchart illustrating a manner in which the timeline bar is generated by the measurement and testing system, according to an embodiment of the invention; 
         FIG. 11  is a continuation of the flowchart of  FIG. 10 , which illustrates additional steps of the timeline bar generation procedure, according to an embodiment of the invention; 
         FIG. 12  is a continuation of the flowchart of  FIG. 11 , which illustrates additional steps of the timeline bar generation procedure, according to an embodiment of the invention; 
         FIG. 13  is a continuation of the flowchart of  FIG. 12 , which illustrates additional steps of the timeline bar generation procedure, according to an embodiment of the invention; 
         FIG. 14  depicts an exemplary portion of software program code and exemplary tabular data for illustrating the manner in which session records are sorted during the timeline bar generation procedure; 
         FIG. 15  is a first screenshot displayed on the operator visual display device of the measurement and testing system illustrating the mode change notification feature, according to an embodiment of the invention; 
         FIG. 16  is a second screenshot displayed on the operator visual display device of the measurement and testing system illustrating the mode change notification feature, according to an embodiment of the invention; 
         FIG. 17  is a flowchart illustrating the procedure by which the dynamic population feature of the measurement and testing system is carried out, according to an embodiment of the invention; 
         FIG. 18  is a screenshot displayed on the operator visual display device of the measurement and testing system illustrating the signal loss alert feature, according to an embodiment of the invention; 
         FIG. 19  is a flowchart illustrating the procedure by which the signal loss alert feature of the measurement and testing system is carried out, according to an embodiment of the invention; 
         FIG. 20  is a continuation of the flowchart of  FIG. 19 , which illustrates additional steps of the procedure by which the signal loss alert feature of the measurement and testing system is carried out, according to an embodiment of the invention; 
         FIG. 21  is a partial screenshot displayed on the operator visual display device of the measurement and testing system illustrating a first plurality of global/progress reports that a system user is able to select, according to an embodiment of the invention; 
         FIG. 22  is a partial screenshot displayed on the operator visual display device of the measurement and testing system illustrating a second plurality of global/progress reports that a system user is able to select, according to an embodiment of the invention; 
         FIG. 23  is a screenshot displayed on the operator visual display device of the measurement and testing system illustrating an exemplary global/progress report generated by the measurement and testing system, according to an embodiment of the invention; 
         FIG. 24  is a partial flowchart illustrating a manner in which global/progress reports are generated by the measurement and testing system, according to an embodiment of the invention; 
         FIG. 25  is a continuation of the flowchart of  FIG. 24 , which illustrates additional steps of the global/progress report generation procedure, according to an embodiment of the invention; 
         FIG. 26  is a partial screenshot displayed on the operator visual display device of the measurement and testing system illustrating a group of tests that are available when a first type of measurement assembly is connected to the data acquisition and processing device, according to an embodiment of the invention; 
         FIG. 27  is a partial screenshot displayed on the operator visual display device of the measurement and testing system illustrating a group of tests that are available when a second type of measurement assembly is connected to the data acquisition and processing device, according to an embodiment of the invention; 
         FIG. 28  is a partial screenshot displayed on the operator visual display device of the measurement and testing system illustrating a group of tests that are available when a third type of measurement assembly is connected to the data acquisition and processing device, according to an embodiment of the invention; 
         FIG. 29  is a partial screenshot displayed on the operator visual display device of the measurement and testing system illustrating a group of tests that are available when both the second and third types of measurement assemblies are connected to the data acquisition and processing device, according to an embodiment of the invention; 
         FIG. 30  is a partial screenshot displayed on the operator visual display device of the measurement and testing system illustrating a pop-up window that allows a system user to manually select the type of measurement assembly is connected to the data acquisition and processing device, according to an embodiment of the invention; 
         FIG. 31  is a partial screenshot displayed on the operator visual display device of the measurement and testing system illustrating a pop-up window that allows a system user to manually select the type of measurement assembly that he or she wants to utilize for performing a particular test, according to an embodiment of the invention; 
         FIG. 32  is a partial flowchart illustrating a manner in which the availability of tests are determined based on the type of measurement assembly that is connected to the data acquisition and processing device, according to an embodiment of the invention; 
         FIG. 33  is a continuation of the flowchart of  FIG. 32 , which illustrates additional steps of the procedure by which the availability of tests are determined based on the type of measurement assembly that is connected to the data acquisition and processing device, according to an embodiment of the invention; 
         FIG. 34  is a flowchart illustrating the procedure by which output data from two measurement assemblies is combined by the data acquisition and processing device, according to an embodiment of the invention; 
         FIG. 35  is a partial screenshot displayed on the operator visual display device of the measurement and testing system illustrating a pop-up window that is used to determine the arrangement of a plurality of measurement assemblies that are connected to the data acquisition and processing device, according to an embodiment of the invention; 
         FIG. 36  is a perspective view of a plurality of measurement assemblies used in the measurement and testing system, according to an embodiment of the invention, wherein the measurement assemblies are combined as a single virtual measurement assembly with two measurement surfaces, and wherein a plurality of local and absolute coordinate axes are superimposed on each of the two measurement surfaces; and 
         FIG. 37  is a perspective view of a plurality of measurement assemblies used in the measurement and testing system, according to an embodiment of the invention, wherein the measurement assemblies are combined as a single virtual measurement assembly with a single measurement surface, and wherein a plurality of local and absolute coordinate axes are superimposed on the single measurement surface; 
         FIG. 38  is a perspective view of a measurement and testing system comprising a force plate array that utilizes virtual force plates, according to another embodiment of the invention; 
         FIG. 39  is a top view of another force plate array of an alternative measurement and testing system that illustrates the manner in which distances are computed between the varying subject&#39;s center of pressure over time, according to yet another embodiment of the invention; 
         FIG. 40  is a graph illustrating a magnitude of a vertical force being applied to each of the force plates in the force plate array of  FIG. 39  by a subject; 
         FIG. 41  is another graph illustrating a magnitude of a vertical force being separately applied by a right foot and a left foot of a subject during a gait cycle; 
         FIG. 42  is a top view of yet another force plate array of another alternative measurement and testing system that illustrates the manner in which distances are computed between the centers of pressure for each foot of the subject, according to still another embodiment of the invention; 
         FIG. 43  is another top view of the force plate array of  FIG. 42  illustrating the manner in which a cluster computational analysis is applied to the centers of pressure for each foot of the subject, according to yet another embodiment of the invention; 
         FIG. 44  is a perspective view of a force plate module of a force measurement system, according to yet another embodiment of the invention; 
         FIG. 45  is a side elevational view of the force plate module of  FIG. 44 ; 
         FIG. 46  is an end elevational view of the force plate module of  FIG. 44 ; 
         FIG. 47  is a top plan view of the force plate module of  FIG. 44 ; 
         FIG. 48  is a partially exploded perspective view of the force plate module of  FIG. 44 ; 
         FIG. 49  is a perspective view of a force measurement system comprising a plurality of force plate modules of  FIG. 44  connected together; 
         FIG. 50  is a schematic diagram illustrating one configuration for the electrical subassembly of the force plate module of  FIG. 44 , according to one embodiment of the invention; 
         FIG. 51  is another schematic diagram illustrating an alternative configuration for the electrical subassembly of the force plate module of  FIG. 44 , according to another embodiment of the invention; 
         FIG. 52A  is a schematic diagram illustrating a series power connection configuration for electrically coupling a plurality of force plate modules to one another, according to one embodiment of the invention; 
         FIG. 52B  is a schematic diagram illustrating an alternative power connection configuration for electrically coupling a plurality of force plate modules to one another, according to another embodiment of the invention; 
         FIG. 53A  is a schematic diagram illustrating a series data connection configuration for electrically coupling a plurality of force plate modules to one another, according to one embodiment of the invention; 
         FIG. 53B  is a schematic diagram illustrating an alternative data connection configuration for electrically coupling a plurality of force plate modules to one another, according to another embodiment of the invention; 
         FIG. 54  is a screenshot displayed on the operator visual display device of the measurement and testing system illustrating a graphical representation of a force plate array so that force plates of the array forming a virtual force plate may be selected by a user, according to an embodiment of the invention; 
         FIG. 55  is a flowchart illustrating the procedure by which output data from selected force plates forming the virtual force plate of the force plate array is combined by the data processing device; and 
         FIG. 56  illustrates an example of data time-syncing carried out by the measurement and testing system described herein, according to an embodiment of the invention. 
     
    
    
     Throughout the figures, the same parts are always denoted using the same reference characters so that, as a general rule, they will only be described once. 
     DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION 
     The present invention is described herein, in an exemplary manner, with reference to hardware components, computer system architecture, and flowcharts that illustrate exemplary processes carried out by the computer system. In a preferred embodiment, functional blocks of the flowchart illustrations can be implemented by computer system instructions. These computer program instructions may be loaded directly onto an internal data storage device of a computing device (e.g., a hard drive of a computer). Alternatively, these computer program instructions could be stored on a portable computer-readable medium (e.g., a flash drive, a floppy disk, a compact disk, etc.), and then subsequently loaded onto a computing device such that the instructions can be executed thereby. In other embodiments, these computer program instructions could be embodied in the hardware of the computing device, rather than in the software thereof. It is also possible for the computer program instructions to be embodied in a combination of both the hardware and the software. Also, in the disclosure, when a reference is made to a computing device that is “configured to”, “arranged to” and/or “configured and arranged to” perform a specific function (e.g., a data acquisition/data processing device  104  configured and arranged to perform a specific function), it is to be understood that, in one or more embodiments of the invention, this means that the computing device is specially programmed to carry out the particular function (e.g., the data acquisition/data processing device  104  being specially programmed to perform a specific function). 
     This description describes in general form the computer program(s) required to carry out the various features of the invention. Any competent programmer in the field of information technology could develop a functioning system using the description set forth herein. 
     For the sake of brevity, conventional computer system components, conventional data networking, and conventional software coding will not be described in detail herein. Also, it is to be understood that the connecting lines shown in the block diagram(s) included herein are intended to represent functional relationships and/or operational couplings between the various components. Similarly, connecting lines are also used between the elements of the flowcharts in order to illustrate the functional relationships therebetween. In addition to that which is explicitly depicted, it is to be understood that many alternative or additional functional relationships and/or physical connections may be incorporated in a practical application of the system. 
     An exemplary embodiment of the measurement and testing system is seen generally at  100  in  FIG. 1 . In the illustrative embodiment, the measurement and testing system  100  generally comprises a measurement assembly  102  (e.g., a force measurement assembly) that is operatively coupled to a data acquisition/data processing device  104  (i.e., a data acquisition and processing device or computing device that is capable of collecting, storing, and processing data), which in turn, is operatively coupled to a subject visual display device  106  and an operator visual display device  130 . As illustrated in  FIG. 1 , the force measurement assembly  102  is configured to receive a subject  108  thereon, and is capable of measuring the forces and/or moments applied to its measurement surfaces  114 ,  116  by the subject  108 . 
     As shown in  FIG. 1 , the data acquisition/data processing device  104  includes a plurality of user input devices  132 ,  134  connected thereto. Preferably, the user input devices  132 ,  134  comprise a keyboard  132  and a mouse  134 . In addition, the operator visual display device  130  may also serve as a user input device if it is provided with touch screen capabilities. While a desktop type computing system is depicted in  FIG. 1 , one of ordinary of skill in the art will appreciate that another type of data acquisition/data processing device  104  can be substituted for the desktop computing system such as, but not limited to, a laptop or a palmtop computing device (i.e., a PDA). In addition, rather than providing a data acquisition/data processing device  104 , it is to be understood that only a data acquisition device could be provided without departing from the spirit and the scope of the claimed invention. 
     As illustrated in  FIG. 1 , force measurement assembly  102  is operatively coupled to the data acquisition/data processing device  104  by virtue of an electrical cable  118 . In one embodiment of the invention, the electrical cable  118  is used for data transmission, as well as for providing power to the force measurement assembly  102 . Various types of data transmission cables can be used for cable  118 . For example, the cable  118  can be a Universal Serial Bus (USB) cable or an Ethernet cable. Preferably, the electrical cable  118  contains a plurality of electrical wires bundled together, with at least one wire being used for power and at least another wire being used for transmitting data. The bundling of the power and data transmission wires into a single electrical cable  118  advantageously creates a simpler and more efficient design. In addition, it enhances the safety of the testing environment when human subjects are being tested on the force measurement assembly  102 . However, it is to be understood that the force measurement assembly  102  can be operatively coupled to the data acquisition/data processing device  104  using other signal transmission means, such as a wireless data transmission system. If a wireless data transmission system is employed, it is preferable to provide the force measurement assembly  102  with a separate power supply in the form of an internal power supply or a dedicated external power supply. 
     Referring again to  FIG. 1 , it can be seen that the force measurement assembly  102  of the illustrated embodiment is in the form of a dual force plate assembly. The dual force plate assembly includes a first plate component  110 , a second plate component  112 , at least one measurement device (e.g., force transducer) associated with the first plate component  110 , and at least one measurement device (e.g., force transducer) associated with the second plate component  112 . In the illustrated embodiment, a subject  108  stands in an upright position on the force measurement assembly  102  and each foot of the subject  108  is placed on the top surfaces  114 ,  116  of a respective plate component  110 ,  112  (i.e., one foot on the top surface  114  of the first plate component  110  and the other foot on the top surface  116  of the second plate component  112 ). The at least one force transducer associated with the first plate component  110  is configured to sense one or more measured quantities and output one or more first signals that are representative of forces and/or moments being applied to its measurement surface  114  by the left foot/leg  108   a  of the subject  108 , whereas the at least one force transducer associated with the second plate component  112  is configured to sense one or more measured quantities and output one or more second signals that are representative of forces and/or moments being applied to its measurement surface  116  by the right foot/leg  108   b  of subject  108 . 
     In illustrated embodiment, the at least one force transducer associated with the first and second plate components  110 ,  112  comprises four (4) pylon-type force transducers  154  (or pylon-type load cells) that are disposed underneath, and near each of the four corners (4) of the first plate component  110  and the second plate component  112  (see  FIG. 4 ). Each of the eight (8) illustrated pylon-type force transducers has a plurality of strain gages adhered to the outer periphery of a cylindrically-shaped force transducer sensing element for detecting the mechanical strain of the force transducer sensing element imparted thereon by the force(s) applied to the surfaces of the force measurement assembly  102 . 
     In an alternative embodiment, rather than using four (4) pylon-type force transducers  154  on each plate component  110 ,  112 , force transducers in the form of transducer beams could be provided under each plate component  110 ,  112 . In this alternative embodiment, the first plate component  110  could comprise two transducer beams that are disposed underneath, and on generally opposite sides of the first plate component  110 . Similarly, in this embodiment, the second plate component  112  could comprise two transducer beams that are disposed underneath, and on generally opposite sides of the second plate component  112 . Similar to the pylon-type force transducers  154 , the force transducer beams could have a plurality of strain gages attached to one or more surfaces thereof for sensing the mechanical strain imparted on the beam by the force(s) applied to the surfaces of the force measurement assembly  102 . 
     Rather, than using four (4) force transducer pylons under each plate, or two spaced apart force transducer beams under each plate, it is to be understood that the force measurement assembly  102  can also utilize the force transducer technology described in commonly-owned U.S. Pat. No. 8,544,347, the entire disclosure of which is incorporated herein by reference. 
     In other embodiments of the invention, rather than using a measurement assembly  102  having first and second plate components  110 ,  112 , it is to be understood that a force measurement assembly  102 ′ in the form of a single force plate may be employed (see  FIG. 6 ). Unlike the dual force plate assembly illustrated in  FIGS. 1 and 4 , the single force plate comprises a single measurement surface on which both of a subject&#39;s feet are placed during testing. Although, similar to the measurement assembly  102 , the illustrated single force plate  102 ′ comprises four (4) pylon-type force transducers  154  (or pylon-type load cells) that are disposed underneath, and near each of the four corners (4) thereof for sensing the load applied to the surface of the force measurement assembly  102 ′. 
     Also, as shown in  FIG. 1 , the force measurement assembly  102  is provided with a plurality of support feet  126  disposed thereunder. Preferably, each of the four (4) corners of the force measurement assembly  102  is provided with a support foot  126  (e.g., mounted on the bottom of each pylon-type force transducer or on the bottom of a base). In one embodiment, each support foot  126  is attached to a bottom surface of a force transducer. In another embodiment, one or more of the force transducers could function as support feet (e.g., if pylon-type force transducers are used, the first and second plate components  110 ,  112  could be supported on the force transducers). In one preferred embodiment, at least one of the support feet  126  is adjustable so as to facilitate the leveling of the force measurement assembly  102  on an uneven floor surface. 
     Now, turning to  FIG. 2 , it can be seen that the data acquisition/data processing device  104  (i.e., the local computing device) of the measurement and testing system  100  comprises a microprocessor  104   a  for processing data, memory  104   b  (e.g., random access memory or RAM) for storing data during the processing thereof, and data storage device(s)  104   c , such as one or more hard drives, compact disk drives, floppy disk drives, flash drives, or any combination thereof. As shown in  FIG. 2 , the force measurement assembly  102 , the subject visual display device  106 , and the operator visual display device  130  are operatively coupled to the data acquisition/data processing device  104  such that data is capable of being transferred between these devices  102 ,  104 ,  106 , and  130 . Also, as illustrated in  FIG. 2 , a plurality of data input devices  132 ,  134  such as the keyboard  132  and mouse  134  shown in  FIG. 1 , are operatively coupled to the data acquisition/data processing device  104  so that a user is able to enter data into the data acquisition/data processing device  104 . In some embodiments, the data acquisition/data processing device  104  can be in the form of a desktop computer, while in other embodiments, the data acquisition/data processing device  104  can be embodied as a laptop computer. 
     Referring again to  FIG. 2 , it can be seen that the measurement and testing system  100  can also include a remote computing device  136 . Like the data acquisition/data processing device  104  (i.e., the local computing device) described above, the remote computing device  136  also comprises a microprocessor for processing data, memory (e.g., random access memory or RAM) for storing data during the processing thereof, and data storage device(s), such as one or more hard drives, compact disk drives, floppy disk drives, flash drives, or any combination thereof. As shown in  FIG. 2 , in the illustrated embodiment, the remote computing device  136  can be operatively coupled to the data acquisition/data processing device  104  (i.e., the local computing device) by means of a network connection  138 . In some embodiments, the network connection  138  is an encrypted network connection so that data can be securely transferred between the local computing device  104  and the remote computing device  136 . The network connection  138  between the computing devices  104 ,  136  can be a conventional hard-wired connection (e.g., utilizing an Ethernet cable or any other type of suitable data transmission cable), or alternatively, can utilize wireless data transmission technology (e.g., a wireless local area network, commonly referred to as Wi-Fi technology). Alternatively, the network connection  138  between the computing devices  104 ,  136  can be an Internet-based connection. 
     In the illustrated embodiment of the invention, the local computing device  104  is disposed at a first location, while the remote computing device  136  is disposed at a second location. Also, in one or more embodiments, the first location is geographically remote from the second location, and the first and second locations are separated from one another by a predetermined distance (e.g., by at least one mile). 
     With reference again to  FIG. 1 , the visual display devices  106 ,  130  of the measurement and testing system  100  will be described in more detail. In the illustrated embodiment, each visual display device  106 ,  130  is in the form of a flat panel monitor. Those of ordinary skill in the art will readily appreciate that various types of flat panel monitors having various types of data transmission cables  120 ,  140  may be used to operatively couple the visual display devices  106 ,  130  to the data acquisition/data processing device  104 . For example, the flat panel monitors employed may utilize a video graphics array (VGA) cable, a digital visual interface (DVI or DVI-D) cable, a high-definition multimedia interface (HDMI or Mini-HDMI) cable, or a DisplayPort digital display interface cable to connect to the data acquisition/data processing device  104 . Alternatively, in other embodiments of the invention, the visual display devices  106 ,  130  can be operatively coupled to the data acquisition/data processing device  104  using wireless data transmission means. Electrical power is supplied to the visual display devices  106 ,  130  using a separate power cord that connects to a building wall receptacle. 
     Those of ordinary skill in the art will appreciate that the visual display devices  106 ,  130  can be embodied in various forms. For example, if the visual display devices  106 ,  130  are in the form of flat screen monitors as illustrated in  FIG. 1 , they may comprise a liquid crystal display (i.e., an LCD display), a light-emitting diode display (i.e., an LED display), a plasma display, a projection-type display, or a rear projection-type display. Although, it will be appreciated that the subject visual display device  106  may take other forms as well, such as a head-mounted display, a heads-up display, or a 3-dimensional display. Each of the visual display devices  106 ,  130  may also be in the form of a touch pad display. For example, the visual display devices  106 ,  130  may comprise multi-touch technology which recognizes two or more contact points simultaneously on the surface of the screen so as to enable users of the device to use two fingers for zooming in/out, rotation, and a two finger tap. 
       FIG. 3  graphically illustrates the acquisition and processing of the load data carried out by the exemplary measurement and testing system  100 . Initially, as shown in  FIG. 3 , a load L is applied to the force measurement assembly  102  by a subject disposed thereon. The load is transmitted from the first and second plate components  110 ,  112  to its respective set of pylon-type force transducers or force transducer beams. As described above, in one embodiment of the invention, each plate component  110 ,  112  comprises four (4) pylon-type force transducers  154  disposed thereunder. Preferably, these pylon-type force transducers are disposed near respective corners of each plate component  110 ,  112 . In a preferred embodiment of the invention, each of the pylon-type force transducers includes a plurality of strain gages wired in one or more Wheatstone bridge configurations, wherein the electrical resistance of each strain gage is altered when the associated portion of the associated pylon-type force transducer undergoes deformation resulting from the load (i.e., forces and/or moments) acting on the first and second plate components  110 ,  112 . For each plurality of strain gages disposed on the pylon-type force transducers, the change in the electrical resistance of the strain gages brings about a consequential change in the output voltage of the Wheatstone bridge (i.e., a quantity representative of the load being applied to the measurement surface). Thus, in one embodiment, the four (4) pylon-type force transducers  154  disposed under each plate component  110 ,  112  output a total of four (4) analog output voltages (signals). In some embodiments, the four (4) analog output voltages from each plate component  110 ,  112  are then transmitted to a preamplifier board (not shown) for preconditioning. The preamplifier board is used to increase the magnitudes of the transducer analog voltages, and preferably, to convert the analog voltage signals into digital voltage signals as well. After which, the force measurement assembly  102  transmits the force plate output signals S FPO1 -S FPO8  to a main signal amplifier/converter  144 . Depending on whether the preamplifier board also includes an analog-to-digital (A/D) converter, the force plate output signals S FPO1 -S FPO8  could be either in the form of analog signals or digital signals. The main signal amplifier/converter  144  further magnifies the force plate output signals S FPO1 -S FPO8 , and if the signals S FPO1 -S FPO8  are of the analog-type (for a case where the preamplifier board did not include an analog-to-digital (A/D) converter), it may also convert the analog signals to digital signals. Then, the signal amplifier/converter  144  transmits either the digital or analog signals S ACO1 -S ACO8  to the data acquisition/data processing device  104  (computer  104 ) so that the forces and/or moments that are being applied to the surfaces of the force measurement assembly  102  can be transformed into output load values OL. In addition to the components  104   a ,  104   b ,  104   c , the data acquisition/data processing device  104  may further comprise an analog-to-digital (A/D) converter if the signals S ACO1 -S ACO8  are in the form of analog signals. In such a case, the analog-to-digital converter will convert the analog signals into digital signals for processing by the microprocessor  104   a.    
     When the data acquisition/data processing device  104  receives the voltage signals S ACO1 −S ACO8 , it initially transforms the signals into output forces and/or moments by multiplying the voltage signals S ACO1 -S ACO8  by a calibration matrix. After which, the force F L  exerted on the surface of the first force plate by the left foot of the subject, the force F R  exerted on the surface of the second force plate by the right foot of the subject, and the center of pressure for each foot of the subject (i.e., the x and y coordinates of the point of application of the force applied to the measurement surface by each foot) are determined by the data acquisition/data processing device  104 . Referring to  FIG. 5 , which depicts a top view of the measurement assembly  102 , it can be seen that the center of pressure coordinates (x P     L   , y P     L   ) for the first plate component  110  are determined in accordance with x and y coordinate axes  142 ,  144 . Similarly, the center of pressure coordinates (x P     R   , y P     R   ) for the second plate component  112  are determined in accordance with x and y coordinate axes  146 ,  148 . If the force transducer technology described in pending, commonly-owned U.S. patent application Ser. No. 13/348,506 is employed, it is to be understood that the center of pressure coordinates (x P     L   , y P     L   , x P     R   , x P     R   ) can be computed in the particular manner described in that application. 
     As explained above, rather than using a measurement assembly  102  having first and second plate components  110 ,  112 , a force measurement assembly  102 ′ in the form of a single force plate may be employed (see  FIGS. 6 and 7 , which illustrate a single force plate). As discussed hereinbefore, the single force plate comprises a single measurement surface on which both of a subject&#39;s feet are placed during testing. As such, rather than computing two sets of center of pressure coordinates (i.e., one for each foot of the subject), the embodiments employing the single force plate compute a single set of overall center of pressure coordinates (x P , y P ) in accordance with x and y coordinate axes  150 ,  152 . 
     In one exemplary embodiment, the data acquisition/data processing device  104  determines the vertical forces F Lz , F Rz  exerted on the surface of the first and second force plates by the feet of the subject and the center of pressure for each foot of the subject, while in another exemplary embodiment, the output forces of the data acquisition/data processing device  104  include all three (3) orthogonal components of the resultant forces acting on the two plate components  110 ,  112  (i.e., F Lx , F Ly , F Lz , F Rx , F RY , F Rz ). In yet other embodiments of the invention, the output forces and moments of the data acquisition/data processing device  104  can be in the form of other forces and moments as well. 
     Now, specific functionality of the exemplary measurement and testing system  100  will be described in detail. It is to be understood that the aforedescribed functionality of the measurement and testing system  100  can be carried out by the data acquisition/data processing device  104  (i.e., the local computing device) utilizing software, hardware, or a combination of both hardware and software. For example, the data acquisition/data processing device  104  can be specially programmed to carry out the functionality described hereinafter. In one embodiment of the invention, the computer program instructions necessary to carry out this functionality may be loaded directly onto an internal data storage device  104   c  of the data acquisition/data processing device  104  (e.g., on a hard drive thereof) and subsequently executed by the microprocessor  104   a  of the data acquisition/data processing device  104 . Alternatively, these computer program instructions could be stored on a portable computer-readable medium (e.g., a flash drive, a floppy disk, a compact disk, etc.), and then subsequently loaded onto the data acquisition/data processing device  104  such that the instructions can be executed thereby. In one embodiment, these computer program instructions are embodied in the form of a measurement and testing software program executed by the data acquisition/data processing device  104 . In other embodiments, these computer program instructions could be embodied in the hardware of the data acquisition/data processing device  104 , rather than in the software thereof. It is also possible for the computer program instructions to be embodied in a combination of both the hardware and the software. 
     According to one aspect of the illustrative embodiment, referring to  FIGS. 8 and 9 , the data acquisition/data processing device  104  of the measurement and testing system  100  is configured and arranged to generate a screen image  200  that includes a timeline bar  202  disposed proximate to a top of the output screen of the operator visual display device  130 . As shown in  FIGS. 8 and 9 , the illustrated timeline bar  202  includes a plurality date icons  204 ,  206 ,  208  for accessing subject testing output data. The data acquisition/data processing device  104  is additionally configured to assign the subject testing output data to a selected one of the plurality of date icons  204 ,  206 ,  208  in accordance with the date on which the subject testing output data was generated. In addition, as illustrated in  FIGS. 8 and 9 , the data acquisition/processing device  104  is further configured to generate a subject (patient) information icon  210  in the timeline bar  202  that includes information about a particular test subject for which output data was generated by the measurement and testing system  100 . In  FIG. 9 , it can also be seen that the data acquisition/processing device  104  is further configured to generate a drop-down menu  212  for at least one of the plurality of date icons (e.g., date icon  204 ), wherein the drop-down menu  212  comprises output data collected at a plurality of different times on the date (e.g., Jun. 18, 2009) displayed on the associated date icon  204 . As shown in  FIG. 9 , the data acquisition/processing device  104  is preferably configured to arrange the output data listed in the drop-down menu  212  in accordance with the time at which the output data was collected. In particular, the output data collected at the plurality of different times is arranged by the data acquisition/processing device  104  in one of ascending or descending order based upon the time at which it was collected ( FIG. 9  illustrates an example of arrangement in ascending order, i.e., listing morning (AM) times before afternoon (PM) times). Also, referring to  FIG. 9 , it can be seen that the data acquisition/processing device  104  is configured to generate a visual indicator  214  (e.g., a small triangle) in a lower corner of the date icon  204  containing the drop-down menu  212 . Similarly, the other date icons  206 ,  208 , which also contain drop down menus, are provided with visual indicators (e.g., small triangles) in the lower corners thereof. 
     Referring to  FIG. 8 , it can be seen that, similar to the plurality of date icons  204 ,  206 ,  208 , the subject (patient) information icon  210  also contains a drop-down menu  216 . The patient or subject drop-down menu  216  includes several different items that may be selected by the user of the system  100 , such as general patent information, patient progress reports, and data exporting options. Also, like one or more of the plurality of date icons  204 ,  206 ,  208 , the subject (patient) information icon  210  has a visual indicator  218  (e.g., a small triangle) in a lower corner thereof in order to inform users of the system  100  that the subject (patient) information icon  210  contains a drop-down menu  216 . 
     Now, the specific attributes of the timeline bar  202 , which can be embodied in a measurement and testing software program(s), will be described in more detail. As illustrated in  FIGS. 8 and 9 , the items (e.g., subject testing results) in the timeline bar  202  are organized by date, and additionally sorted by time. The measurement and testing software program executed by the data acquisition/data processing device  104  also groups tests performed during a particular session together. In one embodiment of the invention, a session is defined as a series of tests that are performed in succession without exiting the test series. As such, test results, which are a form of output data generated from the measurement device signals of the measurement assembly  102 , are grouped into session records (i.e. session records can comprise a collection of output data from the measurement assembly  102 , as well as other types of data). Although, a session could be defined in a different manner in other embodiments of the invention. For example, in other embodiments, a session could be determined in accordance with predetermined window of time (e.g., 10 minutes) as set by a user, or a session could be defined as a specific block of tests that are specified by the user to comprise a session. In the drop-down menu  212  (see  FIG. 9 ), it can be seen that eight Standing Stability tests (the quantity of tests is indicated by the parenthetical number) are separated from two Standing Stability tests by a separating line  220 . The eight Standing Stability tests were performed during the same session, while the two Standing Stability tests were performed during a different, subsequent session. The separating line  220  separates the two distinct sessions from one another. 
     The dynamic population feature of the measurement and testing software program, as will be described hereinafter, drives the content of the timeline bar  202 . For example, suppose three Standing Stability tests are performed in the same session. The measurement and testing software will combine these into a single report when the testing data is entered into the program. 
     In accordance with this aspect of the illustrative embodiment, a flowchart illustrating the functionality of the timeline bar feature of the measurement and testing system  100  is set forth in  FIGS. 10-13 . All of the steps described below with reference to the flowcharts of  FIGS. 10-13  are carried out by the data acquisition/processing device  104 . In particular, the flowcharts graphically illustrate the manner in which the data acquisition/processing device  104  generates the timeline bar, as well as the manner in which output data is assigned to elements of the timeline bar. Referring initially to  FIG. 10 , the procedure commences at  300  when a patient record is selected on the screen by a system user, and in step  302 , the timeline bar  202  is emptied and reset to the initial condition by the data acquisition/processing device  104  in response to the user input (i.e., the contents of the timeline bar  202  are deleted). After the timeline bar  202  is emptied and reset, a database (e.g., a patient database) is queried for all session records pertaining to a particular patient (step  304 ). For example, the patient database can be searched for all records containing the same patient globally unique identifier (GUID), which identifies a particular patient. Then, once all records having the same patient GUID are isolated, the resulting record set is sorted by date (see e.g., table  340  in  FIG. 14 ). Depending on the particular configuration that is desired, this sorting order can be oldest-to-newest or newest-to-oldest. 
     As an example of the operations performed in step  304 , reference is made to the exemplary query string  338  in  FIG. 14 . The “SELECT” statement in this query string  338  creates a resulting data set from the combination of two tables: (i) a first table, entitled “Sessions”, which contains, for example, reference identifiers to the test results; and (ii) a second table, entitled “TestResults”, which includes, for example, the weight of the subject, the height of the subject, and computed values for a particular test (TestResults.SessionGUID=Sessions.GUID). The “WHERE” clause in the query string  338  only returns results for a matching patient identifier (i.e., patent GUID “4f6 . . . a5d”—the middle characters of the GUID have been omitted to facilitate the explanation thereof, as indicated by the use of the ellipses), while the “ORDER” clause will order the result set by the StartTime, which is a field in the TestResults table. The “SELECT DISTINCT Sessions.*” clause only returns fields from the Sessions table (otherwise, columns would be obtained from both tables, which is not desirable). Using the “DISTINCT” keyword ensures that only distinct results are returned (i.e., duplicate rows are filtered out). Advantageously, the use of “Sessions.*”, rather than just “*”, ensures that only unique rows from the Sessions table are returned, rather unique rows from both the Sessions table and the TestResults table. The main benefit of executing the “INNER JOIN” command in the query string  338  of  FIG. 14  is that any sessions, which contain no data (i.e., sessions that are empty), are removed from the record lists. As a result, the timeline bar is not populated with sessions having no data. 
     Turning again to  FIG. 10 , in step  306 , each session record is read and then, in decision block  308 , it is determined whether the date field in the session record exists in the existing timeline bar  202  for that particular patient. For example, the session record may have a “start time” field associated therewith (see  FIG. 14 ) that contains the time and date on which the test was performed. If the date field does not exist in the timeline bar  202 , then a new session group is created as a visual icon (e.g.,  204 ,  206 ,  208 ,  222 ) in the timeline bar  202  (step  310 ). Next, in decision block  312  of  FIG. 11 , it is determined if the date field contains a year that is different from those presently included in the timeline bar  202 . If the year in the date field is different from those presently included in the timeline bar  202  (e.g., the year 2008, which is not included in the timeline bar  202  of  FIGS. 8 and 9 ), the spacing between the existing date icons and the added date icon(s) is increased (i.e., a noticeable gap is created by year groupings—see step  314  of  FIG. 11 ). Also, in step  314 , a visual border is created around date icon(s) from the same year. For example, see the added date icon  222  in  FIG. 9  (Dec. 10, 2008), which has been illustrated using dashed lines in order to signify that it has been added to the timeline bar  202 . However, if it is determined in decision block  308  of  FIG. 10  that the date field in the session record exists in the existing timeline bar  202  for the particular patient, an existing session group visual icon is used (e.g., icon  204 ), and a visual line (e.g., dashed separating line  226  in  FIG. 9 ) is created in the drop-down menu  212  to indicate multiple sessions on this same date (in step  316 ). For example, refer to the added session test  224  in  FIG. 9  (i.e., mCTSIB test), which has been outlined with dashed lines in order to signify that it has been added to the drop-down menu  212 . 
     In decision block  312  of  FIG. 11 , if it is determined that the date field contains a year that is the same as one of those presently included in the timeline bar  202  (e.g., the year 2009, which is included in the timeline bar  202  of  FIGS. 8 and 9 ), then an iteration through the test results in the session record is performed in step  318 . In the session record, each test result is identified using a unique GUID as the record identifier, which is used to identify and locate record (sessions and records of other types are also identified using unique GUIDs as well). After which, in decision block  320  of  FIG. 11 , it is determined whether, in accordance with the report rules from the dynamic population process, if the results for the particular test are to be combined with other similar or same test results in the session. For example, suppose the report rules comprise the following lines of code:
         &lt;!REPORTXML name=“Standing Stability Report” type=“TestReport”   testobject=“BalanceTests.NSEO”   testobject=“BalanceTests.NSEC”   testobject=“BalanceTests.PSEO”   testobject=“BalanceTests.PSEC”   reportcombines=“*testobject*” reportcombinedtitle=“Standing Stability”&gt;
 
This example illustrates that the “Standing Stability Report” is to be used for the following test objects: BalanceTests.NSEO, BalanceTests.NSEC, BalanceTests.PSEO, and BalanceTests.PSEC. The keyword “reportcombines” is set with a special shorthand text “*testobject*” to instruct the system  100  to use the declared testobject keyword values; the code could also have been written as “reportcombines=BalanceTests.NSEO; BalanceTests.NSEC; BalanceTests.PSEO; and BalanceTests.PSEC”, and the result would have been the same. As such, the reports generated from test results of the different types of balance tests are combined with the title “Standing Stability”. In one embodiment, test reports comprise test results presented in a form that is readily ascertainable to a user (e.g., in graphical form).
       

     If the results for the particular test are to be combined with other similar or the same test results in the session, then in decision block  322 , it is further determined if the same or similar test results already exist in the drop-down menu (e.g.,  212 ) for the visual icon (e.g., date icon  204 ) as described above. If the same or similar test results do not exist in the drop-down menu  212 , then the name of the test report for this test from the dynamic population process will be added as a drop-down menu item entry (e.g., “mCTSIB” test  224  in drop-down menu  212 ) in the visual icon (e.g., date icon  204 ) and it will be linked to this test result record (step  324 ). The name of the test report for this test also will be added as a drop-down menu item entry if, in decision block  320 , it is determined that, according to the report rules from dynamic population process, the results for the particular test are not to be combined with other similar or same test results in the session (refer to  FIG. 11 ). 
     In decision block  322 , if it is determined that the same or similar test results already exist in the drop-down menu (e.g.,  212 ) for the visual icon (e.g., date icon  204 ), then additional internal data is added to an existing entry in the drop-down menu item (see step  326  in  FIG. 12 ). In some embodiments, the text of the menu item can be changed per the dynamic population template rules (e.g., a parenthetical number may be placed next to the entry in the drop-down menu  212 —see  FIG. 9 ). Next, in decision block  328  of  FIG. 12 , it is determined whether there are any additional test results for this session record. If there are any additional test results for this session record, then the process reverts back to step  318  in  FIG. 11 , wherein an iteration through the test results that are in the session record is performed. If there are not any additional test results for this session record, then the process proceeds to decision block  330 , wherein it is determined if there are any additional session records that are to be processed. If it is determined in decision block  330  that there are additional session records that require processing, then the process reverts back to step  306  in  FIG. 10 , wherein each session record is read. However, if it is determined at decision block  330  that there are not any additional session records that need to be processed, then the process proceeds to decision block  332 . 
     Referring to decision block  332  in  FIG. 12 , it is next determined whether, according to the dynamic population templates and rules gathered, if there are global reports for the timeline bar  202 . If there are global reports for the timeline bar  202 , then, in step  334  of  FIG. 13 , those global report(s) are gathered and placed in the first timeline visual icon (e.g., patient information icon  210 ) as a set of drop-down menu icons with a unique representational symbol in the timeline item, and the process ends at  336 . In contrast, if it is determined in decision block  332  that there are no global reports for the timeline bar  202 , the process ends at step  336  in  FIG. 13 . 
     According to another aspect of the illustrative embodiment, with reference to  FIGS. 15 and 16 , the data acquisition/data processing device  104  of the measurement and testing system  100  is configured and arranged to generate a screen image  400  with a plurality of mode selection tabs  402 ,  406 ,  408  and a side bar menu  410  on the operator visual display device  130 . When a user switches from a current mode of operation (e.g., patient data entry mode) to another mode of operation (e.g., assessment mode) by selecting one of mode selection tabs (e.g.,  406 ) indicative of the another mode utilizing the user input device (e.g., keyboard  132  or mouse  134  by moving pointer  414  thereon), the data acquisition/data processing device  104  is configured to automatically displace the side bar menu  410  to an edge of the screen image  400 . The displacement of the side bar menu  410  is a visual indicator of a system or process state change that is used to draw attention that a significant mode of operation has changed for the user that may otherwise happen without the user noticing it. In the illustrated embodiment of  FIG. 15 , the plurality of mode selection tabs  402 ,  406 ,  408  is disposed proximate to a top of the screen image  400  and the side bar menu  410  is disposed proximate to a lateral side of the screen image  400 . When the data acquisition/data processing device  104  automatically displaces the side bar menu  410  to the edge of the operator visual display device  130 , the side bar menu  410  is replaced by a new sidebar menu  412  (see  FIG. 16 ) associated with the another mode (e.g., the assessment mode). When the data acquisition/processing device  104  automatically displaces the side bar menu  410  to the edge of the operator visual display device  130 , an inner edge  410   a  (see  FIG. 15 ) of the side bar menu  410  is gradually dragged towards an outer peripheral edge of the operator visual display device  130  in a continuous manner until the sidebar menu  410  is no longer visible to the user. The inner edge  410   a  of the side bar menu  410  remains generally parallel to the outer peripheral edge of the operator visual display device  130  as it dragged towards the outer peripheral edge thereof. Advantageously, the displacement of the side bar menu  410  off the output screen alerts the user of the measurement and testing system  100  that he or she is switching operational modes (i.e., switching the functional content of the software program). Otherwise, without the notification effect created by the displacement of the side bar menu  410 , a user of the system  100  may not be readily unaware that he or she is switching modes. 
     Now, the specific functionality of the side bar menu displacement feature will be described in more detail. Initially, the data acquisition/data processing device  104  is programmed to take a graphical snapshot (e.g., a bitmap grab) of the screen image (e.g., screen image  400 ) on the operator visual display device  130  that is changing or switching contexts (i.e., when a user selects one of the tabs  402 ,  406 ,  408 ). The bitmap image is then placed into a top-level window container as the entire surface to be used. This top-level container (i.e., top-level meaning that it is above everything else) is displaced so as to be disposed almost exactly over top of where the source area is currently located, or was previously located. The operation mode is then changed, which results in the area that was made into a visual bitmap being erased and replaced with something else. Once this has occurred, the system notifies the animation routine to begin moving the bitmap image off the screen. In one embodiment, the graphical snapshot is animated so that it appears as if the side bar menu  410  is sliding off the output screen. For example, every 30 frames per second, the measurement and testing software program executed by the data acquisition/data processing device  104  moves the bitmap image across the output screen of the operator visual display device  130  and forces the area to redraw. After the animation has been completed (i.e., by the bitmap image moving completely off the screen), the bitmap and the top-level container are both discarded. 
     According to yet another aspect of the illustrative embodiment, the remote computing device  136 , which is disposed at a first location, is specially programmed to generate one or more testing routines based upon input by a first system user. The data acquisition/data processing device  104  is configured to read the one or more testing routines generated by the remote computing device  136  and to integrate the one or more testing routines into the measurement and testing software program loaded thereon and executed thereby (i.e., dynamically populate the software program with new tests that are remotely generated). In other words, the one or more testing routines generated by the remote computing device  136  operate as an automatic plug-in to the measurement and testing software program (e.g., like a macro). The data acquisition/data processing device  104  of the measurement and testing system  100  is further configured to enable a second system user to utilize the one or more testing routines in the measurement and testing software program while data is acquired from a subject undergoing testing on the measurement assembly. Advantageously, this dynamic population feature of the measurement and testing software program allows the tests performed by the measurement and testing system  100  to be created and/or updated easily off-site, thereby obviating the need for the system end user to develop his or his own tests. Because the testing routines are typically written in a specific program code (e.g., HTML), and system end users are rarely trained software programmers, the dynamic population feature enables the measurement and testing software to be regularly updated without the need for system end users trained in software programming. Also, if end users of the measurement and testing software need to make only minor changes to the testing routines, they are able to change cosmetic features of test report output by utilizing a basic text editor, such as Microsoft® Notepad, for making changes to data labeling, and the like, in the program code. 
     Initially, the dynamic population feature of the measurement and testing software program reads a specific set of directories, and looks for a specific pattern of filenames (e.g., the software looks for HTML files under a specific set of directories). After which, the measurement and testing software program reads the content of the specific identified files, and looks for specific patterns of text. The patterns of text in the specific identified files inform the measurement and testing software program on the data acquisition/data processing device  104  how to organize the tests, the test reports, and the test outputs. For example, the first line of text in an exemplary HTML file may contain the following information: (i) the name of the test (e.g., Forward Lunge), (ii) the tab under which the test is to be located in the measurement and testing software program (e.g., Assessment), (iii) the grouping within the tab, if applicable (e.g., the “Training” tab includes groups, such as “Closed Chain”, “Mobility”, “Quick Training”, “Seated”, and “Weight Shifting”), and any predefined or custom options. 
     In accordance with this aspect of the illustrative embodiment, a flowchart illustrating the functionality of the dynamic population feature of the measurement and testing system  100  is set forth in  FIG. 17 . All of the steps described below with reference to the flowchart of  FIG. 17  are carried out by the data acquisition/processing device  104 . Referring to this figure, the procedure commences at  500 , and in step  502 , a list of files from a defined set of folders is gathered. For example, the testing software program looks for a specific file pattern (e.g., a specific extension) in a particular directory (e.g. a “Reports” directory) using a regular expression search routine (regex). After which, in step  504 , each file is read and, at decision block  506 , it is determined if the particular file contains report rules or a matching template definition pattern (e.g., with one or more key pairs). If the file does not contain a definition matching template pattern, the process proceeds to step  512 , wherein it is determined if there are any more files. If the file does contain a definition matching template, the template information is processed from the file in step  508 , which includes matching any key fields with stored database objects and caching off file identifiers for later matching and organization. The file identifiers (i.e., file names) are stored internally in the cache memory of the data acquisition/data processing device  104  so that the file identifiers do not have to be repeatedly read from a directory, thereby resulting in a performance advantage. As an example of how template information is processed from a file in step  508 , suppose that the following three (3) files exist:
         file #1: the test file:   &lt;!TESTXML name=“Limits of Stability” type=“Assessment” testobject=“#LimitsOfStability”&gt;   file #2: the report file:   &lt;!REPORTXML name=“Limits of Stability” type=“Assessment” testobject=“#LimitsOfStability” reportcombines=“*testobject*” reportcombinedtitle=“Limits of Stability”&gt;   file #3: the patient screen file:   &lt;!PATIENTTESTXML name=“Limits of Stability” type=“Assessment” testobject=“#LimitsOfStability”&gt;
 
In the above example, the “test file” (i.e., file #1) determines the content on the operator visual display device  130 , the “report file” (i.e., file #2) determines how the results of the tests are presented to a user, while the “patient screen file” (i.e., file #3) determines the content on the subject visual display device  106 . The entries ‘testobject=“#LimitsOfStability” ’ in the above files call up a subroutine for performing additional functionality (e.g., acting as a plug-in). In this example, a record with an associated record identifier (e.g., a number) is placed in a master database listing of tests, wherein the record indicates that the LimitsOfStability test is called “Limits of Stability” and is an “Assessment” type of test (as opposed to, for example, a “Training” or “Diagnostic” test. In other words, the “Limits of Stability” test would be entered under the “Assessments” tab  406  in  FIG. 16 . The record identifier in the master database listing of tests will then be used to locate the test file and test result processing code, as needed later on. The fields above, e.g., the name, type, test object, report title, and what the report combines, etc., are all stored in an internal object in the database. The end result being that there are three collections of data, which include: (i) a report collection, (ii) a test collection, and (iii) an optional patient screen collection. If the test does not have a matching patient screen, then it will default to using the existing test file (i.e., the patient screen will match the test screen on the operator visual display device  130 ). In addition, certain keywords such as “grouping” can be used to organize the tests into a visual collection of similar items, whereas keywords such as “package” and “series” can be used to define a predetermined series of tests that can be called up by the user by name. Also, tests that contain options, which may be set by a user, can additionally have an “option” keyword with additional text fields that determine the content of the options. Moreover, any other keywords can be processed by the system  100  as expansion needs arise.
       

     In step  508 , key fields (e.g., name=“Limits of Stability”, type=“Assessment”, and testobject=“#LimitsOfStability” in the above example) are matched with stored database objects using a heuristic routine that looks for loaded results from the file system, and scans the database for existing records matching the type and test object. If the type and test object are found, then the name in the database is updated (e.g., if needed, the test is renamed). Conversely, if the database does not contain the type and test object, the system searches for a matching name. If the matching name is found, for example, the stored test object and type is updated (e.g., if the functionality of the test changed). If the database does not contain the test object or the name, then this is presumed to be a new test and the records for this new test are added in the database. Also, once the database has been scanned, any tests that existed before in the database, but do not presently have any matching files, are marked as inactive (because the system can no longer process the tests or show reports for them, but this could be a transient problem that reinstalling the test will fix, so nothing is deleted). For example, the tests or reports could have been inadvertently deleted by a system user. 
     Then, referring again to  FIG. 17 , in step  510 , each template result is sorted into an appropriate list (e.g., global reports, focused testing, test result reports, etc.). For example, a global report may contain general patient information that is not associated with any particular test. If the report type is “global”, then there is no test object assigned to this report, and it will be placed in the patient information icon (i.e., icon  210  in  FIGS. 8 and 9 ). Next, at decision block  512 , it is determined if there are any more files. If it is determined at step  512  that there are more files, then the process reverts back to step  504 . If it is determined that there are no more files in step  512 , the process ends at  514 . 
     According to still another aspect of the illustrative embodiment, the data acquisition/data processing device  104  of the measurement and testing system  100  is configured and arranged to alert the user of the system when the one or more signals from the at least one transducer of the measurement assembly  102  are no longer detected by generating a quasi-instantaneous visual indicator on the operator visual display device  130 . In general, in order to implement this feature, a specially programmed timing routine is incorporated in the force plate driver. If the specially programmed timing mechanism does not receive data from the force measurement assembly  102  in a predetermined amount of time, it will signal to the primary application program (i.e., a higher level software program) that the force measurement assembly  102  has been disconnected or has failed. In one embodiment, the predetermined amount of time ranges from approximately 100 milliseconds to approximately 3 seconds (or from 100 milliseconds to 3 seconds). The specially programmed timing routine is embodied in steps  704 ,  714 , and  720  described below with respect to the flowchart of  FIGS. 19 and 20 . The high end of the range is intended to give a user of the measurement and testing system  100  enough time to reconnect the force measurement assembly  102  to the data acquisition/data processing device  104  (i.e., enough time to reconnect electrical cable  118 ). 
     Referring to  FIG. 18 , the manner in which the quasi-instantaneous visual indicator is displayed on the operator visual display device  130  will be explained. Preferably, the visual indicator displayed on the operator visual display device  130  comprises a change in a background color of a screen image  600 . More particularly, the change in the background color of the screen image  600  comprises changing the top border  602  and the bottom border  604  of the screen image  600  from a first color to a second color. In  FIG. 18 , because this is a black-and-white image, the change in the color of the top and bottom border  602 ,  604  is indicated through the use of a hatching pattern (i.e., a diagonal hatching pattern). In one embodiment of the invention, the first color of the top and bottom border  602 ,  604  is dark blue, while the second color of the top and bottom border  602 ,  604  is bright red. Bright red is chosen for the second color because it readily attracts the attention of the user so that corrective measures may be immediately taken thereby. 
     In accordance with this aspect of the illustrative embodiment, a flowchart illustrating the functionality of the measurement assembly disconnect/failure alert feature of the measurement and testing system  100  is set forth in  FIGS. 19 and 20 . The process described herein assumes that the USB communication system has already been established with the measurement assembly  102  (i.e., force plate), in accordance with the hardware chipset provider&#39;s specifications. In general, this requires the opening of a USB connection and looking for specific device signatures. All of the steps described below with reference to the flowcharts of  FIGS. 19 and 20  are carried out by the data acquisition/processing device  104 . Referring to this figure, the procedure commences at  700 , and in step  702 , an attempt is made to read a block of data (i.e., transmitted in one or more signals) from the one or more measurement devices (i.e., one or more force transducers) of the force measurement assembly  102 . After which, at decision block  704 , it is determined whether the data is able to be read in a predetermined amount of time (e.g., a predetermined timeout of 100 milliseconds). If the data is able to be read in a predetermined amount of time, then, in step  706 , the received data is decoded and a checksum analysis is performed. The checksum analysis is performed in order to ensure the integrity of the raw data from the force measurement assembly  102 . For example, the checksum analysis may utilize a particular cyclic redundancy check (CRC), such as a CRC-16. Conversely, if the data is not able to be read in the predetermined time period, the bad or empty packet counter is incremented in step  714 . A bad packet is indicative of a bad checksum, whereas an empty packet counter signifies the receipt of empty data. 
     After the checksum analysis is performed in step  706 , at decision block  708 , it is determined whether the decoded checksum is valid. If the decoded checksum is determined to be valid, the bad or empty packet counter is reset in step  710 . Then, in step  712  of  FIG. 20 , the decoded data is passed up to the higher level processor (i.e., a high level software program, such as the measurement and testing software program, which is a type of data collection and analysis software program), and the process ends at step  718 . However, if the decoded checksum is determined to be invalid in step  708 , the data block is discarded and the bad or empty packet counter is incremented in step  716 . 
     Referring again to  FIG. 19 , if the bad or empty packet counter has been incremented in either step  714  or  716 , it is determined, in decision block  720  of  FIG. 20 , whether or not the bad or empty packet counter has reached the configured threshold (e.g., a predetermined number of packets of data). The predetermined number of packets of data can be set based upon the amount of noise that is tolerable in the system  100 . The predetermined number of packets of data may also set in accordance with the type of measurement assembly (e.g., force measurement assembly  102 ) that is operatively coupled to the data acquisition/data processing device  104 . For example, if a complex force measurement assembly  102  (e.g., having a large number of separate plates or measurement surfaces) is connected to the data acquisition/data processing device  104 , then a small predetermined number of packets may be set (e.g., 2 packets). In contrast, if a simpler force measurement assembly  102  is coupled to the data acquisition/data processing device  104 , then a larger predetermined number of packets may be tolerable (e.g., 15 packets). If the bad or empty packet counter has not reached the configured threshold, the process ends at step  718 . Otherwise, if the bad or empty packet counter has reached the configured threshold in step  720 , the application and the other high-level processors (e.g., the measurement and testing software program) are signaled by an agreed-upon mechanism in step  722 , which indicates that there is a problem with the force measurement assembly  102  and that it has probably either been disconnected or failed in some manner. After completing step  722 , the process ends, and a condition is set to reset the USB subsystem at  725 . 
     According to yet another aspect of the illustrative embodiment, referring to  FIGS. 21-25 , the data acquisition/data processing device  104  of the measurement and testing system  100  is configured and arranged to generate one or more subject global or progress reports (see e.g., the Forward Lunge Progress Report in  FIG. 23 ) utilizing the output data acquired during one or more of the plurality of sessions, generate a subject information icon on the output screen of the visual display device, and assign the one or more subject global reports to the subject information icon. In this embodiment, the output data is arranged in a plurality of sessions, and output data that is acquired during the performance of a successive series of tests is arranged in a single session of the plurality of sessions. In general, the global/progress reports collect information (e.g., output data) from individual sessions and display the aggregate results in one overall report (e.g., the exemplary report illustrated in  FIG. 23 ). As such, the information contained in a typical global/progress report is based upon output data collected on a plurality of different dates (i.e., the typical global/progress report spans across multiple days). While the global/progress reports may contain less detailed information than that which is available by accessing the reports for individual sessions themselves (i.e., by using the date icons of the timeline bar), the global/progress reports enable a system user to get an overall look at a particular subject&#39;s test performance over a period of time (e.g., over several days) without the need to laboriously click on each and every individual session in the date icons of the timeline bar. As such, the global/progress reports advantageously allow a system user to more quickly ascertain a subject&#39;s overall performance during a certain test by simply clicking on a single entry in a drop-down menu. 
     With particular reference to  FIG. 21 , it can be seen that the data acquisition/data processing device  104  of the measurement and testing system  100  is configured and arranged to generate a screen image  800  that includes a timeline bar  802  with a subject (patient) information icon  804  having a plurality of entries  808 - 816  arranged in a drop-down menu  806 . Specifically, as shown in the exemplary screenshot of  FIG. 21 , the entries in the drop-down menu  806  include: (i) patient information  808  (e.g., background information regarding the patient, such as height, weight, home address, contact information, name of physician, etc.), (ii) a first global/progress report  810  for a mCTSIB test (i.e., mCTSIB Progress Report), (iii) a second global/progress report  812  for a rhythmic weight shift test (i.e., Rhythmic Weight Shift Progress), (iv) a third global/progress report  814  for a unilateral stance test (i.e., Unilateral Stance Progress), and (v) a fourth global/progress report  816  for a weight bearing squat test (i.e., Weight Bearing Squat Progress). As shown in  FIG. 21 , each of the plurality of subject global/progress reports in the drop-down menu  806  is vertically spaced apart from the other reports included therein. 
     Another exemplary screenshot  800 ′ is depicted in  FIG. 22 . Similar to the screenshot  800  illustrated in  FIG. 21 , the screenshot  800 ′ of  FIG. 22  includes a timeline bar  802 ′ with a subject (patient) information icon  804  having a plurality of entries  808 ′ and  818 - 832  arranged in a drop-down menu  806 ′. The drop-down menu  806 ′ in the screenshot  800 ′ contains significantly more global/progress report entries  818 - 832  than that illustrated in the screenshot  800  of  FIG. 21 . Specifically, in addition to the patient information  808 ′, the drop-down menu  806 ′ includes the following entries: (i) a first global/progress report  818  for a forward lunge test (i.e., Forward Lunge Progress), (ii) a second global/progress report  820  for a mCTSIB test (i.e., mCTSIB Progress Report), (iii) a third global/progress report  822  for a rhythmic weight shift test (i.e., Rhythmic Weight Shift Progress), (iv) a fourth global/progress report  824  for a sit to stand test (i.e., Sit to Stand Progress), (v) a fifth global/progress report  826  for a step, quick turn test (i.e., Step, Quick Turn Progress), (vi) a sixth global/progress report  828  for a step up, over test (i.e., Step Up, Over Progress), (vii) a seventh global/progress report  830  for a tandem walk test (i.e., Tandem Walk Progress), and (viii) an eighth global/progress report  832  for a walk across test (i.e., Walk Across Progress). 
     Next, with reference to  FIG. 23 , the content of an exemplary global/progress report will be described. In  FIG. 22 , if a system user were to click on the “Forward Lunge Progress” entry  818  in the drop-down menu  806 ′, a report similar to that illustrated in  FIG. 23  would be displayed on the screen. As shown in  FIG. 23 , the exemplary report  834  (i.e., the Forward Lunge Progress Report) contains a plurality of graphs  836 - 850  (i.e., eight (8) graphs arranged in four (4) rows and two (2) columns). Each of these graphs  836 - 850  includes output data that was acquired during a plurality of sessions on a plurality of days (e.g., February 26th, April 4th, April 11th, and April 12th). In each of the graphs  836 - 850 , it can be seen that February 26th and April 4th are only listed once along the x-axis, while April 11th is listed twice, and April 12th is listed three times. This is because only a single session of the forward lunge test was performed on both February 26th and April 4th, while two sessions of the test were performed on April 11th, and three sessions of the test were performed on April 12th. The graphs disposed in the left-hand column of  FIG. 23  include results for both the right and left legs of the subject or patient. The results for the right leg of the subject are differentiated from the results for the left leg of the subject by placement of a small circle  852  at the top of the bars pertaining to the right leg output results. 
     As illustrated by the exemplary report  834  of  FIG. 23 , the data acquisition/data processing device  104  is further configured and arranged to automatically alert a system user when one or more test results displayed in the one or more subject global reports are outside a predetermined range, below a normal value (e.g., below an average value for healthy subjects within a particular age group), or above a baseline value by generating a first visual indicator on the output screen of the visual display device. In general, the measurement and testing system  100  indicates that test results are outside a predetermined range, below a normal value, or above a baseline value by using a red color to display those results on the output screen of the visual display device. Although, because  FIG. 23  is a black-and-white image, test results that are outside a predetermined range, below a normal value, or above a baseline value are indicated through the use of a first hatching pattern (i.e., a diagonal hatching pattern, to indicate those results that would appear in “red” on the output screen). For example, referring to graph  836  in  FIG. 23  (entitled Distance (% Body Height)), it can be seen that all of the bars in this graph are denoted with the diagonal hatching pattern  854  to indicate that they are all below a normal value (i.e., 40%) indicated by the indicator line  856  extending generally horizontally across the graph  836  at the 40% value on the y-axis of the graph. The results displayed in the graph  836  indicate that the patient or subject performing the forward lunge test did not lunge forward the normal percentage distance for a person his or her age during any of the testing sessions. The 40% value (i.e., lunge distance as a percentage of body height), which is denoted using threshold line  856 , represents the normal value for a person who is approximately the subject&#39;s same age (e.g., based on an average value for healthy subjects). As another example, referring to graph  844  in  FIG. 23  (entitled Distance (% Difference)), it can be seen that all of the bars in this graph are denoted with the diagonal hatching pattern  854  to indicate that they are all outside a predetermined range or band (i.e., as indicated by the bounding lines  858 ,  860  extending generally horizontally across the graph  844 ). The results displayed in the graph  844  indicate that the patient or subject performing the forward lunge test had an abnormal percent difference in the distance achieved by his or her right leg as compared to his or her left leg for all of the testing sessions. The distance, expressed as a percent difference between the two legs, should have fallen within the band bounded by lines  858 ,  860  if the subject had results in the normal range. In general, it can be seen that the graphs  836 - 842  on the left-hand side of the report  834  are concerned with whether or not the patient or subject is above or below a single normal value, while the graphs  844 - 850  on the right-hand side of the report  834  are concerned with whether or not the patient or subject is within a normal percentage band of difference between the right and left legs. That is, each of the graphs  844 - 850  on the right-hand side of the report  834  focuses on the percentage difference between the two legs of the subject. 
     As also illustrated by the exemplary report  834  of  FIG. 23 , the data acquisition/data processing device  104  is additionally configured and arranged to automatically alert the user of the system when one or more test results displayed in the one or more subject global reports are within a predetermined range, above a normal value (e.g., above an average value for healthy subjects within a particular age group), or below a baseline value by generating a second visual indicator on the output screen of the visual display device, which is distinct from the first visual indicator. In general, the measurement and testing system  100  indicates that test results are within a predetermined range, above a normal value, or below a baseline value by using a green color to display those results on the output screen of the visual display device. Although, because  FIG. 23  is a black-and-white image, test results that are within a predetermined range, above a normal value, or below a baseline value are indicated through the use of second and third hatching patterns (i.e., a criss-cross and horizontal line style hatching patterns, to indicate those results that would appear in “green” on the output screen). For example, referring to graph  838  in  FIG. 23  (entitled Impact Index (% Body Weight)), it can be seen that the bars in this graph for the sessions occurring on February 26th and April 4th are denoted with a criss-cross style hatching pattern  862  (i.e., for the left foot of the subject) and a horizontal line style hatching pattern  863  (i.e., for the right foot of the subject) to indicate that they are all above a normal value (e.g., approximately 15%) indicated by the indicator line  864  extending generally horizontally across the graph  838  at the approximately 15% value on the y-axis of the graph. The results displayed in the graph  838  indicate that, on both February 26th and April 4th, the patient or subject performing the forward lunge test had an impact index that exceeded the normal value for a person who is approximately the subject&#39;s same age. As another example, referring to graph  840  in  FIG. 23  (entitled Contact Time (sec)), it can be seen that the bars in this graph for the sessions occurring on February 26th and April 4th are denoted with the criss-cross style hatching pattern  862  (i.e., for the left foot of the subject) and the horizontal line style hatching pattern  863  (i.e., for the right foot of the subject) to indicate that they are below a baseline value (e.g., approximately 1.5 seconds) indicated by the indicator line  866  extending generally horizontally across the graph  840  at the approximately 1.5 second value on the y-axis of the graph. The results displayed in the graph  840  indicate that, on both February 26th and April 4th, the patient or subject performing the forward lunge test had a contact time that was below the baseline value for a person who is approximately the subject&#39;s same age. As yet another example, referring to graph  846  in  FIG. 23  (entitled Impact Index (% Difference)), it can be seen that the bars in this graph for the sessions occurring on February 26th and April 4th are denoted with the criss-cross style hatching pattern  862  to indicate that they are both within a predetermined range or band (i.e., as indicated by the bounding lines  868 ,  870  extending generally horizontally across the graph  846 ). The results displayed in the graph  846  indicate that the patient or subject performing the forward lunge test had a normal percent difference in the impact index achieved by his or her right leg as compared to his or her left leg for the testing sessions performed on February 26th and April 4th. On these two days, the impact index, expressed as a percent difference between the two legs, fell within the normal band bounded by lines  868 ,  870  for results in a normal range. 
     In accordance with this aspect of the illustrative embodiment, a flowchart illustrating the functionality of the global/progress reports feature of the measurement and testing system  100  is set forth in  FIGS. 24 and 25 . All of the steps described below with reference to the flowcharts of  FIGS. 24 and 25  are carried out by the data acquisition/processing device  104 . Referring to this figure, the procedure commences at  900 , and in step  902 , reports of a “Global” type are selected from a master list. In step  902 , a list of files is dynamically built by the measurement and testing software program (e.g., when the program is started by a user). Beginning with step  904  in  FIG. 24 , each report from the list is processed by the data acquisition/processing device  104 . Initially, at decision block  906 , it is determined whether the particular report that is being processed requires a specific test result type or condition. If the particular report being processed does not require a specific test result type or condition, then, in step  912 , the report is added to the subject (patient) information icon  804  in  FIGS. 21 and 22 . For example, referring to the screenshots of  FIGS. 21 and 22 , the Patient Information report  808 ,  808 ′ is always generated by the measurement and testing software program, and displayed under the subject (patient) information icon  804 . As explained above, an exemplary Patient Information report  808 ,  808 ′ comprises background information regarding the patient, such as height, weight, home address, contact information, name of physician, etc. Because the Patient Information report  808 ,  808 ′ contains general information about the subject or patient that is not specific to any particular test, there is no need to apply a filter to this report. Conversely, if it is determined in decision block  906  that the particular report being processed does require a specific test result type to be present or a condition to be satisfied, then, in step  908 , the requisite specific test type(s) or condition(s) are checked (i.e., conditions such as the data range, etc.). For example, a data range condition may stipulate that a particular report may only be displayed when test results exist for a predetermined date range (e.g., from May 4th to May 11th). Advantageously, the use of conditions allows the measurement and testing software program to filter the reports that are displayed under subject (patient) information icon  804 . 
     Now, several exemplary conditions that are checked by the measurement and testing software program will be explained. Initially, each report file informs the system  100  of what it wants or needs. This starts out with a list of test GUIDs (e.g., BESS assessment test) that are grouped into the following lists, any or all of which can be empty or contain values: (i) Must Have List; (ii) Must Not Have List; (iii) Can Have List. In the Must Have List, the report is shown only if all of test GUIDs contained in this list exist in the overall list of test results that the subject or patient has performed. For example, suppose the report file comprises the following lines of code:
         list=report:: mustHaveTheseGuids( )   if (list is not empty)   then
           if (resultsTestGuids contains all values in list)   then
               return true # this will indicate do show report   
               else
               return false # this will indicate do not show report
 
In the above example, if the file, entitled resultsTestGuids, contains all of the GUID values in the list, then the report will be shown. However, if the file, entitled resultsTestGuids, does not contain all of the GUID values in the list, then the report will not be shown. For example, for a particular report to be displayed, it may be required that results from both a Limits of Stability (LOS) test and a Forward Lunge test are available. In the Must Not Have List, the report is not shown if one or more of these test GUIDs contained in this list exist in the overall list of test results that the subject or patient has performed. For example, suppose the report file comprises the following lines of code:
   
               
           list=report::mustNOThaveTheseGuids( )   if (list is not empty)   then
           if (resultsTestGuids contains any value in list)   then
               return false # this will indicate do not show report
 
In the above example, if the file, entitled resultsTestGuids, contains any of the GUID values in the list, then the report will not be shown. However, if the file, entitled resultsTestGuids, does not contain any of the GUID values in the list, then the report will be shown. For example, for a particular report to be displayed, it may be required that results for a Limits of Stability (LOS) test are not contained within the same session as results for a Forward Lunge test. In the Can Have List, the report is shown only if one or more of these Test GUIDs exist in the list of test results that the subject or patient has performed. For example, suppose the report file comprises the following lines of code:
   
               
           list=report::canHaveTheseGuids( )   if (list is not empty)   then
           if (resultsTestGuids contains any values in list)   then
               return true # this will indicate do show report   
               else
               return false # this will indicate do not show report   
               
           return true # no list of anything, the report is always shown
 
In the above example, if the file, entitled resultsTestGuids, contains any of the GUID values in the list, then the report will be shown. However, if the file, entitled resultsTestGuids, does not contain any of the GUID values in the list, then the report will not be shown. If the file does not contain a list of anything, then the report is always shown (e.g., the Patient Information report). As one example, the results from a Limits of Stability (LOS) test could be combined with the results from a Standing Stability test in a single report. Considering the three exemplary conditions described above, the Must Not Have List trumps the other two conditions.
       

     In addition, the measurement and testing software program preferably has the following additional flags that determine how the above lists (i.e., conditions) are used: (i) tests must be in the same session, and (ii) tests must be in the same day. If it is true that the tests must be in the same session, then the abovedescribed three filtering lists (i.e., filtering conditions) are applied only to groups of test results that occur within the same session (a collection of test results that were performed logically together). For example, suppose that the above three rules state that both BESS and LOS are required (i.e., must-haves), then the report is only shown if both the Balance Error Scoring System (BESS) and Limits of Stability (LOS) test results are available in the same session. If the BESS test was done in one session, and the LOS test in another session, then the report is not available. If it is true that the tests must be in the same day, then the abovedescribed three filtering lists are applied only to groups of test results that occur within the same calendar day—this implies same session, but can be separate sessions in the same day. For example, suppose that the above three rules state that both BESS and LOS are required (i.e., must-haves), then the report is only shown if both BESS and LOS results are available in the same day. If BESS was done on one day, and LOS on another day, then the report is not available. If neither the Same Session or Same Day flags are set, then the abovedescribed three filtering lists are used without regard to the session or calendar day grouping. That is, the entire list of tests performed by the patient is used when examining each condition (i.e., each of the three lists). 
     In another alternative embodiment, the reports could be filtered in accordance with numerical values that are contained within the test results themselves. In this embodiment, a particular report could be displayed only when a subject&#39;s score for a particular test exceeds a certain predetermined value (e.g., when a subject&#39;s score is 50 or greater). Also, one or more reports could require two or more sessions of test results to exist before being displayed (e.g., results from BESS tests performed in two or more sessions). In addition, in some embodiments, the conditions described above could be combined with another (e.g., a particular report could only be displayed if test results for both a BESS test and Tandem Walk test exist but not those for a mCTSIB test. 
     Referring back to  FIG. 24 , at decision block  910 , it is determined whether the condition is satisfied (i.e., one of the conditions described above). If the condition is satisfied, then, in step  912 , the report is added to the subject (patient) information icon  804  in  FIGS. 21 and 22 . However, if the condition is not satisfied, then the process proceeds to step  914 , wherein it is determined if there are additional reports from the list to process. If there are not additional reports from the list to process, the process ends at step  918  (see  FIG. 25 ). However, if there are additional reports from the list to process, the process proceeds to step  916 , wherein the data acquisition/processing device  104  continues to the next report from the list. As shown in  FIGS. 24 and 25 , after step  916 , the process reverts back to step  904  in which the next report from the list is processed. It is to be understood that the procedure illustrated in  FIGS. 24 and 25  will continue in the manner described above until all of the reports from the list have been processed. Advantageously, as a result of the filtering process described above, the measurement and testing software program does not generate any empty global/progress reports (i.e., global/progress reports that do not contain any numerical test results). 
     According to still another aspect of the illustrative embodiment, referring to  FIGS. 26-33 , the data acquisition/data processing device  104  of the measurement and testing system  100  is configured and arranged to automatically filter the tests that are available in accordance with the type of measurement assembly or assemblies  102  that are connected to the data acquisition/data processing device  104 . In general, according to this aspect of the illustrative embodiment, the data acquisition and processing device  104  is configured and arranged to (i) assemble a list of tests that are capable of being performed utilizing the at least one measurement assembly  102 ; (ii) determine, for each of the tests in the list, whether the execution of each particular test in the list requires the use of a specific measurement assembly and/or requires that a predetermined condition be satisfied (i.e., requires the use of a specific measurement assembly, or that a predetermined condition be satisfied, or both the use of a specific measurement assembly and that a predetermined condition be satisfied); (iii) when it is determined that the execution of the particular test in the list requires the use of a specific measurement assembly and/or requires that a predetermined condition be satisfied, determine whether the at least one measurement assembly  102  comprises the specific measurement assembly that is required and/or whether the predetermined condition has been satisfied; and (iv) when it is determined that the at least one measurement assembly is the specific measurement assembly that is required and/or the predetermined condition has been satisfied, add the test name or icon for the particular test to a listing of available test names or icons that are displayed on the at least one visual display device  130  so that a system user is able to select the particular test. Advantageously, the measurement and testing software program loaded on, and executed by the data acquisition and processing device  104  automatically determines the test protocols that are available based on the type of measurement assembly  102  connected to the system  100 . 
     Initially, referring to  FIG. 26 , it can be seen that the data acquisition/data processing device  104  of the measurement and testing system  100  is configured and arranged to generate a screen image  1000  that includes a plurality of mode selection tabs  1002 ,  1004 , and  1006 . When a user selects the Assessments tab  1004 , a plurality of test icons  1008 - 1016  are displayed on the visual display device  130 . As shown in the screenshot of  FIG. 26 , these test icons include a first icon  1008  for a Limits of Stability (LOS) test, a second icon  1010  for a Rhythmic Weight Shift test, a third icon  1012  for a Unilateral Stance test, a fourth icon  1014  for a Weight Bearing Squat test, and a fifth icon  1016  for a mCTSIB test. In order to execute a particular test, a user merely selects the appropriate test icon (e.g., by clicking on one of the icons  1008 - 1016 ). In the illustrative embodiment, when a first type of measurement assembly  102  is connected to the data acquisition/data processing device  104 , this group of tests is displayed. For example, the first type of measurement assembly  102  may comprise a dual force plate assembly having a particular footprint (e.g., a static dual force plate having a 18″×20″ overall footprint). The test icons  1008 - 1016  in  FIG. 26  represent the tests that are capable of being effectively performed using the first type of measurement assembly  102 . The tests that are not capable of being performed using the first type of measurement assembly  102  are filtered out by the measurement and testing software program so they are not displayed on the visual display device  130 , and thus, are not available for selection by a system user when the first type of measurement assembly  102  is connected. 
     It is to be understood that certain tests can only be effectively performed using certain measurement assemblies  102 . For example, a particular test may require a measurement assembly  102  that has a minimum footprint size (i.e., dimensional area). Thus, if a measurement assembly  102  having a footprint size that is smaller than the minimum footprint size is the only one connected to the data acquisition/data processing device  104 , the tests requiring the minimum footprint size would not be displayed on the visual display device  130 . As another example, a particular test may require the measurement assembly to have dynamic functionality (e.g., the measurement assembly  102  comprises a force plate that is rotated, or translated, or both rotated and translated). Consequently, if a measurement assembly  102  which does not have the requisite dynamic functionality is the only one connected to the data acquisition/data processing device  104 , the tests requiring the dynamic functionality would not be displayed on the visual display device  130 . 
     Another exemplary screenshot  1000 ′ is depicted in  FIG. 27 . Similar to the screenshot  1000  illustrated in  FIG. 26 , the screenshot  1000 ′ of  FIG. 27  includes a plurality of mode selection tabs  1002 ,  1004 , and  1006 . However, when a user selects the Assessments tab  1004 , a greater number of test icons  1008 - 1028  are displayed on the visual display device  130 , as compared to that displayed in the screenshot of  FIG. 26 . As shown in the screenshot of  FIG. 27 , the test icons include an icon  1008  for a Limits of Stability (LOS) test, an icon  1010  for a Rhythmic Weight Shift test, an icon  1012  for a Unilateral Stance test, an icon  1014  for a Weight Bearing Squat test, an icon  1016  for a mCTSIB test, an icon  1018  for a Forward Lunge test, an icon  1020  for a Sit to Stand test, an icon  1022  for a Step, Quick Turn test, an icon  1024  for a Step Up, Over test, an icon  1026  for a Tandem Walk test, and an icon  1028  for a Walk Across test. As described above, in order to execute a particular test, a user merely selects the appropriate test icon (e.g., by clicking on one of the icons  1008 - 1028 ). In the illustrative embodiment, when a second type of measurement assembly  1402 ,  1404  (see  FIGS. 36 and 37 ) is connected to the data acquisition/data processing device  104 , this group of tests is displayed. For example, the second type of measurement assembly  1402 ,  1404  may comprise a dual force plate assembly having an overall footprint that is larger than the first type of measurement assembly (e.g., a static dual force plate having 20″×60″ overall footprint). The test icons  1008 - 1028  in  FIG. 27  represent the tests that are capable of being effectively performed using the second type of measurement assembly  1402 ,  1404 . The tests that are not capable of being performed using the second type of measurement assembly  1402 ,  1404  are filtered out by the measurement and testing software program so they are not displayed on the visual display device  130 , and thus, are not available for selection by a system user when the second type of measurement assembly  1402 ,  1404  is connected. 
     In  FIG. 28 , yet another exemplary screenshot  1000 ″ is shown Like the screenshots  1000 ,  1000 ′ illustrated in  FIGS. 26 and 27 , the screenshot  1000 ″ of  FIG. 28  includes a plurality of mode selection tabs  1002 ,  1004 , and  1006 . However, when a user selects the Assessments tab  1004 , a different group of test icons  1008 - 1016  and  1030 - 1034  are displayed on the visual display device  130 , as compared to that displayed in the screenshots of  FIGS. 26 and 27 . As shown in the screenshot of  FIG. 28 , the test icons include an icon  1008  for a Limits of Stability (LOS) test, an icon  1010  for a Rhythmic Weight Shift test, an icon  1012  for a Unilateral Stance test, an icon  1014  for a Weight Bearing Squat test, an icon  1016  for a mCTSIB test, an icon  1030  for an Adaption Test, an icon  1032  for a Motor Control Test, and an icon  1034  for a Sensory Organization Test (SOT). As explained above, in order to execute a particular test, a user merely selects the appropriate test icon (e.g., by clicking on one of the icons  1008 - 1016 ,  1030 - 1034 ). In the illustrative embodiment, when a third type of measurement assembly (e.g., a dynamic measurement assembly) is connected to the data acquisition/data processing device  104 , this group of tests is displayed. For example, the third type of measurement assembly may comprise a dynamic force plate assembly, wherein a dual force plate is capable of being rotated, translated, or both rotated and translated while a subject or patient is disposed thereon. The dynamic force plate assembly may have a dual force plate that has a footprint similar to the first type of measurement assembly  102  (e.g., a dual force plate having a 18″×20″ overall footprint). The test icons  1008 - 1016  and  1030 - 1034  in  FIG. 28  represent the tests that are capable of being effectively performed using the third type of measurement assembly (i.e., the dynamic force measurement assembly). The tests that are not capable of being performed using the third type of measurement assembly are filtered out by the measurement and testing software program so they are not displayed on the visual display device  130 , and thus, are not available for selection by a system user when the third type of measurement assembly is connected. 
     With reference to  FIG. 29 , still another exemplary screenshot  1000 ′″ is illustrated. Like the screenshots  1000 ,  1000 ′,  1000 ″ shown in  FIGS. 26, 27, and 28 , respectively, the screenshot  1000 ′ of  FIG. 29  includes a plurality of mode selection tabs  1002 ,  1004 , and  1006 . Although, when a user selects the Assessments tab  1004 , a larger group of test icons  1008 - 1034  are displayed on the visual display device  130 , as compared to that displayed in the screenshots of  FIGS. 26-28 . As shown in the screenshot of  FIG. 29 , the test icons include an icon  1008  for a Limits of Stability (LOS) test, an icon  1010  for a Rhythmic Weight Shift test, an icon  1012  for a Unilateral Stance test, an icon  1014  for a Weight Bearing Squat test, an icon  1016  for a mCTSIB test, an icon  1018  for a Forward Lunge test, an icon  1020  for a Sit to Stand test, an icon  1022  for a Step, Quick Turn test, an icon  1024  for a Step Up, Over test, an icon  1026  for a Tandem Walk test, and an icon  1028  for a Walk Across test, an icon  1030  for an Adaption Test, an icon  1032  for a Motor Control Test, and an icon  1034  for a Sensory Organization Test (SOT). As described above, in order to execute a particular test, a user merely selects the appropriate test icon (e.g., by clicking on one of the icons  1008 - 1034 ). In the illustrative embodiment, when both the second and third type of measurement assembly are connected to the data acquisition/data processing device  104 , this group of tests is displayed. In other words, the test icons  1008 - 1034  depicted in the screenshot of  FIG. 29  are representative of the combined set of tests that are available when both the static dual force plate with a 20″×60″ overall footprint, and the dynamic force plate assembly, are both operatively coupled to the data acquisition/data processing device  104 . The test icons  1008 - 1034  in  FIG. 29  represent the tests that are capable of being effectively performed using at least one of the second and third types of measurement assemblies (i.e., at least one of the 20″×60″ static dual force plate  1402 ,  1404  and the dynamic force measurement assembly). The tests that are not capable of being performed using one of these two types of measurement assemblies are filtered out by the measurement and testing software program so they are not displayed on the visual display device  130 , and thus, are not available for selection by a system user when these measurement assemblies are connected. 
     When a measurement assembly (e.g.,  102 ) is initially connected to the data acquisition/data processing device  104 , the data acquisition/data processing device  104  reads the serial number from the firmware installed on the measurement assembly  102 . If the serial number from the measurement assembly  102  is recognized by the data acquisition/data processing device  104 , the measurement and testing software program automatically filters the tests that are displayed on the visual display device  130  in accordance with the type of device that is connected (e.g., if a particular serial number is already is associated with a 20″×60″ static dual force plate, and this is the only plate in the system  100 , then the measurement and testing software program automatically filters out all of the tests that cannot be performed on this plate). However, if the serial number from the measurement assembly  102  is not recognized by the data acquisition/data processing device  104  (e.g., because this is the first time that the plate has ever been connected to the data acquisition/data processing device  104 ), the data acquisition/data processing device  104  generates the pop-up window  1036  illustrated in  FIG. 30 . The pop-up window  1036  prompts the system user to manually select the type of measurement assembly  102  that is connected to the data acquisition/data processing device  104  by clicking on the appropriate one of the plate icons  1038 ,  1040 , or  1042 , and then, by pressing the “OK” button  1044  to complete his or her selection. Alternatively, if the user inadvertently selected the incorrect icon  1038 ,  1040 , or  1042 , he or she can always revise the selection by pressing the “Cancel” button  1046 . Once the user manually selects the type of measurement assembly  102  that is connected to the data acquisition/data processing device  104  using the pop-up window  1036 , the data acquisition/data processing device  104  equates the serial number of the connected device to the type of measurement assembly  102  that is operatively coupled to the data acquisition/data processing device  104  (e.g., Ser. No. 67899882 is a 18″×20″ Essential force plate assembly because a user selected the Essential force plate icon  1040  in the pop-up window  1036 ). Once the serial number of the connected device has been equated to a particular type of measurement assembly  102 , the pop-up window  1036  will not be subsequently displayed to the system user. Rather, after reading the recognized serial number from the firmware installed on the measurement assembly  102 , the measurement and testing software program automatically filters the tests that are available for the connected device. 
     In another embodiment of the invention, rather than prompting the user to select the type of a newly connected device by displaying the pop-up window  1036 , the data acquisition/data processing device  104  is specially programmed to automatically determine the type of the device by reading the force plate dimensional data from the firmware installed on the measurement assembly  102  (e.g., an 18″×20″ footprint of the force plate assembly is embedded in the firmware). In this alternative embodiment, after retrieving the dimensional data from the firmware of the plate, the data acquisition/data processing device  104  is further configured to equate the dimensional data with a particular plate type (e.g., the data acquisition/data processing device  104  references tabular data that equates this dimensional data with an Essential-type force plate). Thus, in this embodiment, it is not necessary for the user to manually identify the type of plate that has been connected to the data acquisition/data processing device  104  when it is first utilized in the measurement and testing system  100 . 
     Whenever two or more measurement assemblies  102  are connected to the data acquisition/data processing device  104 , and a particular test is capable of being performed on each of these measurement assemblies  102 , a user is automatically prompted to select which measurement assembly  102  is to be used for the particular test before the test is started. Specifically, the data acquisition/data processing device  104  is configured and arranged to generate the pop-up window  1048  illustrated in  FIG. 31 , which requires a user to select the type of device (i.e., force plate) that he or she wishes to use for the test. Initially, the user selects the radio button that is next to the desired device (e.g., radio button  1050  for a Dynamic force plate assembly with a displaceable force plate or radio button  1052  for a Functional static force plate with a 20″×60″ overall footprint). After selecting the appropriate radio button  1050 ,  1052 , the user then presses the “OK” button  1054  to complete his or her selection. Alternatively, if the user inadvertently selected the incorrect radio button  1050  or  1052 , he or she can always revise the selection by pressing the “Cancel” button  1056 . Once the user has selected the type of device that he or she wishes to utilize for performing the test, the user can then proceed with performing the desired test. 
     In accordance with this aspect of the illustrative embodiment, a flowchart illustrating the functionality of the device test filter feature of the measurement and testing system  100  is set forth in  FIGS. 32 and 33 . All of the steps described below with reference to the flowcharts of  FIGS. 32 and 33  are carried out by the data acquisition/processing device  104 . Referring initially to  FIG. 32 , the procedure commences at  1100 , and in step  1102 , device (i.e., measurement assembly  102 ) attachment or removal is detected during the startup of the measurement and testing software program. That is, the data acquisition/processing device  104  reads the serial number of the device (e.g., a known or recognized measurement assembly  102 ) that is connected from the firmware of the device. Next, in step  1104 , a list of the available tests are assembled by the data acquisition/processing device  104  (e.g., by reading a database list or a list of test files). Beginning with step  1106  in  FIG. 32 , each test from the list is processed by the data acquisition/processing device  104 . Initially, at decision block  1108 , it is determined whether the particular test that is being processed requires a specific type of device (i.e., type of measurement assembly  102 ) and/or whether it requires a certain condition to be satisfied. If the particular test that is being processed does not require a specific type of device or a condition to be satisfied, then, in step  1114 , the test icon is added to the visual display of available tests that the user may select (e.g., as illustrated under the Assessments tab  1004  in  FIGS. 26-29 ). For example, referring to the screenshots of  FIGS. 26-29 , the Limits of Stability (LOS) test, the Rhythmic Weight Shift test, the Unilateral Stance test, and the Weight Bearing Squat test are always available regardless of the type of device that is connected to the data acquisition/processing device  104 , and thus, are always displayed under the Assessments tab  1004  in  FIGS. 26-29 . As such, these tests do not require any type of filtering. Conversely, if it is determined in decision block  1108  that the particular test being processed does require a specific device type or a condition to be satisfied, then, in step  1110 , the requisite device type is evaluated or the requisite condition(s) is checked (i.e., conditions such as the size of the force plate, device capabilities, etc.). For example, a particular test may require a force plate with a minimum footprint (i.e., a minimum plate surface area) so that the subject or patient has adequate room to perform the test protocol (e.g., Forward Lunge test or Step Up, Over test). As another example, a certain test may require that the device is capable of displacing the force plate surface with the patient or subject disposed thereon while the test is being executed (e.g., Adaption Test, Motor Control Test, or Sensory Organization Test (SOT)). Advantageously, the use of conditions allows the measurement and testing software program to automatically filter the tests that cannot be effectively performed with the device or devices (i.e., measurement assembly or assemblies  102 ) that are connected to the data acquisition/processing device  104 . 
     Referring again to the flowchart in  FIG. 32 , at decision block  1112 , it is determined whether the condition is satisfied (e.g., one of the exemplary conditions described above). If the condition is satisfied, then, in step  1114 , the test icon is added to the visual display of available tests that the user may select (e.g., as illustrated under the Assessments tab  1004  in  FIGS. 26-29 ). However, if the condition is not satisfied, then the process proceeds to step  1116 , wherein it is determined if there are additional tests from the list to process. If there are not additional tests from the list to process, the process ends at step  1120 . However, if there are additional tests from the list to process, the process proceeds to step  1118 , wherein the data acquisition/processing device  104  continues to the next test from the list. As shown in  FIGS. 32 and 33 , after step  1118 , the process reverts back to step  1106  in which the next test from the list is processed. It is to be understood that the procedure illustrated in  FIGS. 32 and 33  will continue in the manner described above until all of the tests from the list have been processed. Advantageously, as a result of the filtering process described above, the measurement and testing software program only permits a system user to select tests that can be effectively performed with the type of device (i.e., measurement assembly  102 ) that is connected to the data acquisition/processing device  104  (all other tests are filtered out by the abovedescribed process). Thus, inaccurate test results resulting from the use of an improper device are thereby automatically prevented by the measurement and testing system  100 . 
     According to yet another aspect of the illustrative embodiment, referring to  FIGS. 34-37 , the data acquisition/data processing device  104  is configured and arranged to mathematically combine the output for a plurality of measurement assemblies  1402 ,  1404 —see  FIGS. 36 and 37  (e.g., for a plurality of force plates) so as to create a virtual measurement assembly (e.g., a virtual force plate). Also, the data acquisition/data processing device  104  is configured and arranged to automatically correct the local coordinate system of one of the measurement assemblies  102  (e.g., one of the plurality of force plates) in order to account for the actual orientation of the measurement assembly  102  (e.g., force plate) relative to the other measurement assembly  102  (e.g., force plate). For example, in one particular arrangement, two measurement assemblies  102  (e.g., force plates) are placed in an end-to-end arrangement, wherein one of the two force plates is rotated 180 degrees relative to the other of the two force plates. 
     In accordance with this aspect of the illustrative embodiment, a flowchart illustrating the functionality of the virtual measurement assembly feature of the measurement and testing system  100  is set forth in  FIG. 34 . All of the steps described below with reference to the flowchart of  FIG. 34  are carried out by the data acquisition/processing device  104 . Referring to  FIG. 34 , the procedure commences at  1200 , and in step  1202 , collected data from a plurality of measurement assemblies or devices  102  (e.g., a plurality of force plates) is processed by the data acquisition/processing device  104 . In one exemplary embodiment, two measurement assemblies  102  (e.g., force plates) are used to collect data from a subject or patient disposed thereon. In this embodiment, after the data acquisition/data processing device  104  receives a plurality of voltage signals (i.e., a plurality of channels of data) from the two measurement assemblies  102 , it initially transforms the signals into output force and moment components by multiplying the voltage signals by a calibration matrix. For example, the voltage output signals received from the first force plate assembly are transformed into the vertical force component F ZL1  exerted on the left plate of the assembly by the left foot of the subject, the vertical force component F ZR1  exerted on the right plate of the assembly by the right foot of the subject, the moment component about the x axis M XL1  exerted on the left plate of the assembly by the left foot of the subject, the moment component about the x axis M XR1  exerted on the right plate of the assembly by the right foot of the subject, the moment component about the y axis M YL1  exerted on the left plate of the assembly by the left foot of the subject, and the moment component about the y axis M YR1  exerted on the right plate of the assembly by the right foot of the subject. Similarly, the voltage output signals received from the second force plate assembly are transformed into the vertical force component F ZL2  exerted on the left plate of the assembly by the left foot of the subject, the vertical force component F ZR2  exerted on the right plate of the assembly by the right foot of the subject, the moment component about the x axis M XL2  exerted on the left plate of the assembly by the left foot of the subject, the moment component about the x axis M XR2  exerted on the right plate of the assembly by the right foot of the subject, the moment component about the y axis M YL2  exerted on the left plate of the assembly by the left foot of the subject, and the moment component about the y axis M YR2  exerted on the right plate of the assembly by the right foot of the subject. 
     Next, at decision block  1204 , it is determined whether the current subject or patient test wants or requires the two measurement assemblies  102  (e.g., force plates) to be combined as one virtual measurement assembly (e.g., one virtual force plate). If the particular test that is being performed does not want or require the two measurement assemblies  102  (e.g., force plates) to be combined as one virtual measurement assembly, the resultant separate force and moment components (F ZL1 , F ZR1 , M XL1 , M XR1 , M YL1 , M YR1 , F ZL2 , F ZR2 , M XL2 , M XR2 , M YL2 , M YR2 ) are returned in step  1210 . It is noted that, prior to returning the final computed result in step  1210 , the separate force and moment components (F ZL2 , F ZR2 , M XL2 , M XR2 , M YL2 , M YR2 ) for the second, rotated measurement assembly  102  (e.g., second force plate) are corrected in order to account for the actual orientation of the measurement assembly  102  (e.g., force plate) relative to the other measurement assembly  102  (e.g., force plate), as described hereinafter. 
     Conversely, if it is determined in decision block  1204  that the particular test that is being performed does want or requires the two measurement assemblies  1402 ,  1404  (e.g., force plates) to be combined as one virtual measurement assembly (e.g., one virtual force plate), the output signals (i.e., channels) are summed from both of the measurement assemblies  1402 ,  1404  (e.g., force plates) into a synthetic channel in step  1206 , using matrix rotation to correct for the actual orientation of the second, rotated measurement assembly  1404  (e.g., force plate). 
     Initially, with reference to  FIG. 36 , the corrections that are performed for the second, rotated force plate  1404  will be explained. As shown in  FIG. 36 , two force plates  1402 ,  1404  are arranged end-to-end so as to form one overall force measurement assembly  1400  (or one virtual force plate  1400 ). The first force plate  1402 , which is typically the force plate disposed closest to the data acquisition/processing device  104  and the operator visual display device  130 , is disposed in a standard, non-rotated position. However, the second force plate  1404 , which is typically the force plate disposed furthest from the data acquisition/processing device  104  and the operator visual display device  130 , is disposed in a non-standard, rotated position (i.e., the second force plate  1404  is rotated 180 degrees relative to the first force plate  1402 ). As a result of the rotated orientation of the second force plate  1404 , the left and right vertical force components F ZL2 , F ZR2  must be swapped, the left and right moment components about the x axis W XL2 , M XR2  must be swapped, and the left and right moment components about the y axis M YL2 , M YR2  must be swapped. Also, in order to account for the 180 degree rotation of the second force plate  1404 , the sign of the left and right moment components about the x axis M XL2 , M XR2  must be flipped (e.g., −1 becomes +1), and the sign of the left and right moment components about the y axis M YL2 , M YR2  must be flipped (e.g., −1 becomes +1). This sign change in the moment components M XL2 , M XR2 , M YL2 , M YR2  for the second force plate  1404  can be generally explained with reference to the following rotation matrix: 
                   R   =     [           cos   ⁢           ⁢   θ             -   sin     ⁢           ⁢   θ               sin   ⁢           ⁢   θ           cos   ⁢           ⁢   θ           ]             (   1   )               
In equation (1), when the angle θ is equal to 180 degrees, then the rotation matrix R is equal to:
 
                   R   =     [           -   1         0           0         -   1           ]             (   2   )               
Thus, when the original values of the moment components M XL2 , M XR2 , M YL2 , M YR2  are multiplied by a similar rotation matrix, wherein angle θ is equal to 180 degrees, the sign of the moment component values must be flipped.
 
     Now, the manner in which the output signals from the individual force plates  1402 ,  1404  are summed in order to obtain the overall output values for the single virtual force plate  1400  with left and right measurement surfaces  1406 ,  1408  will be described (see  FIG. 36 ). As illustrated in  FIG. 36 , the origin of the absolute coordinates axes  1412 ,  1414 ,  1416  for the left measurement surface  1406  is disposed between the two force plates  1402 ,  1404 , and is centered in a lateral direction on the virtual left plate surface. Similarly, as also illustrated in  FIG. 36 , the origin of the absolute coordinates axes  1418 ,  1420 ,  1422  for the right measurement surface  1408  is disposed between the two force plates  1402 ,  1404 , and is centered in a lateral direction on the virtual right plate surface. Initially, the overall left and right vertical force components F ZL   _   VP , F ZR   _   VP  for the virtual force plate  1400  are obtained as follows:
 
 F   ZL   _   VP   =F   ZL1   +F   ZR2   (3)
 
 F   ZR   _   VP   =F   ZR1   +F   ZL2   (4)
         where:   F ZL1 : vertical force component exerted on the surface of the first force plate by the left foot of the subject;   F ZR1 : vertical force component exerted on the surface of the first force plate by the right foot of the subject;   F ZL2 : vertical force component exerted on the surface of the second force plate by the right foot of the subject (left and right force component values are switched for the second plate, i.e., plate signal for F ZL2  actually measures F ZR2 ); and   F ZR2 : vertical force component exerted on the surface of the second force plate by the left foot of the subject (left and right force component values are switched for the second plate, i.e., plate signal for F ZR2  actually measures F ZL2 ).
 
The overall vertical force F Z   _   VP  for the virtual force plate  1400  can be obtained from the following summation equation:
 
 F   Z   _   VP   =F   ZL   _   VP   +F   ZR   _   VP   (5)
 
When the left and right vertical force components F ZL   _   VP , F ZR   _   VP  are summed in equation (5), the virtual force plate  1400  is considered to have a single measurement surface  1410  (see  FIG. 37 ), without distinguishing between the vertical forces exerted by left and right legs of the subject or patient.
       

     For the virtual force plate  1400 , the overall left and right moment components about the x axis M XL   _   VP , M XR   _   VP  are obtained from the following equations:
 
 M   XL   _   VP   =M   XL1 ( F   ZL1   ·−d )+(− M   XR2 )+( F   ZR2   ·d )  (6)
 
 M   XR   _   VP   =M   XR1 ( F   ZR1   ·−d )+(− M   XL2 )+( F   ZL2   ·d )  (7)
         where:   M XL1 : moment component about the x-axis exerted on the surface of the first force plate by the left foot of the subject;   M XR1 : moment component about the x-axis exerted on the surface of the first force plate by the right foot of the subject;   M XL2 : moment component about the x-axis exerted on the surface of the second force plate by the right foot of the subject (left and right moment component values are switched for the second plate, i.e., plate signal for M XL2  actually measures M XR2 );   M XR2 : moment component about the x-axis exerted on the surface of the second force plate by the left foot of the subject (left and right moment component values are switched for the second plate, i.e., plate signal for M XR2  actually measures M XL2 ); and   d: distance (e.g., in meters) equal to one-half the length of the first force plate or one-half the length of the second force plate (illustrated force plates  1402 ,  1404  are the same physical size—see  FIG. 37 ).
 
In equations (6) and (7) above, the parenthetical terms containing the distance value d are required in order to correct for the shifted position of the coordinate axes of the virtual force plate surfaces. Because the virtual plate coordinate axes (i.e., left surface coordinates axes  1412 ,  1414 ,  1416  and right surface coordinate axes  1418 ,  1420 ,  1422 —see  FIG. 36 ) are located between the first and second plates, rather than in the middle of the respective first and second plates, the computed values for the moment components about the x-axis must adjusted accordingly. In particular, as shown in  FIG. 36 , the origin of the local coordinate axes  1424 ,  1426 ,  1428  for the left plate surface of the first force plate  1402  is disposed in the center thereof, while the origin of the local coordinate axes  1430 ,  1432 ,  1434  for the right plate surface of the first force plate  1402  is disposed in the center thereof. As discussed above, the second force plate  1404  is rotated 180 degrees relative to the first force plate  1402 . Consequently, the physical left and right measurement surfaces of the second force plate  1404  are flipped relative to the first force plate  1402 . Referring again to  FIG. 36 , the origin of the local coordinate axes  1436 ,  1438 ,  1440  for the left plate surface of the second force plate  1404  is disposed in the center thereof, while the origin of the local origin of the coordinate axes  1442 ,  1444 ,  1446  for the right plate surface of the second force plate  1404  is disposed in the center thereof. In order to correct for the 180 degree rotation of the second force plate  1404 , the x and y axes ( 1436 ,  1438  and  1442 ,  1444 ) of the left and right measurement surfaces, respectively, must be rotated by the angle θ (i.e., 180 degrees) such that respective corrected x′ and y′ axes ( 1437 ,  1439  and  1443 ,  1445 ) are obtained. The parenthetical terms containing the distance value d in equations (6) and (7) transform the plate output values measured in accordance with the local coordinate systems of the left and right plate surfaces of each force plate  1402 ,  1404  into output values based upon the absolute left and right coordinate systems disposed between the two force plates  1402 ,  1404  (see  FIG. 36 ). The overall moment component about the x-axis M X   _   VP  for the virtual force plate  1400  can be obtained from the following summation equation:
 
 M   X   _   VP   =M   XL   _   VP   +M   XR   _   VP   (8)
 
The overall moment component about the x-axis M X   _   VP  in equation (8) is defined relative to the absolute coordinate axes  1450 ,  1452 ,  1454  in  FIG. 37 . When the first force plate  1402  is treated as a separate, single measurement surface, the moments acting thereon are defined relative to the local coordinate axes  1456 ,  1458 ,  1460  in  FIG. 37 . Similarly, when the second force plate  1404  is treated as a separate, single measurement surface, the moments acting thereon are defined relative to the local coordinate axes  1462 ,  1464 ,  1466  in  FIG. 37  (with the corrected, rotated coordinate axes  1463 ,  1465  shown using dashed lines).
       

     For the virtual force plate  1400 , the overall left and right moment components about the y axis M YL   _   VP , M YR   _   VP  are obtained from the following equations:
 
 M   YL   _   VP   =M   YL1 +(− M   YR2 )  (9)
 
 M   YR   _   VP   =M   YR1 +(− M   YL2 )  (10)
         where:   M YL1 : moment component about the y-axis exerted on the surface of the first force plate by the left foot of the subject;   M YR1 : moment component about the y-axis exerted on the surface of the first force plate by the right foot of the subject;   M YL2 : moment component about the y-axis exerted on the surface of the second force plate by the right foot of the subject (left and right moment component values are switched for the second plate, i.e., plate signal for M YL2  actually measures M YR2 ); and   M YR2 : moment component about the y-axis exerted on the surface of the second force plate by the left foot of the subject (left and right moment component values are switched for the second plate, i.e., plate signal for M YR2  actually measures M YL2 ).
 
The overall moment component about the y-axis M Y   _   VP  for the virtual force plate  1400  can be obtained from the following summation equation:
 
 M   Y   _   VP   =M   YL   _   VP   +M   YR   _   VP   (11)
 
Similar to that described above for equation (8), the overall moment component about the y-axis M Y   _   VP  in equation (11) is defined relative to the absolute coordinate axes  1450 ,  1452 ,  1454  in  FIG. 37 .
       

     Once the overall vertical force and moment components F Z   _   VP , M X   _   VP , M Y   _   VP  are computed for the virtual force plate  1400 , the center of pressure of the vertical force can be computed as follows: 
     
       
         
           
             
               
                 
                   
                     x 
                     P_VP 
                   
                   = 
                   
                     
                       - 
                       
                         M 
                         Y_VP 
                       
                     
                     
                       F 
                       Z_VP 
                     
                   
                 
               
               
                 
                   ( 
                   12 
                   ) 
                 
               
             
           
         
       
     
     
       
         
           
             
               
                 
                   
                     y 
                     P_VP 
                   
                   = 
                   
                     
                       - 
                       
                         M 
                         X_VP 
                       
                     
                     
                       F 
                       Z_VP 
                     
                   
                 
               
               
                 
                   ( 
                   13 
                   ) 
                 
               
             
           
         
       
         
         
           
             where: 
             x P   _   VP , y P   _   VP : coordinates of the point of application for the vertical force (i.e., center of pressure) on the virtual force plate.
 
In addition, the data acquisition/data processing device  104  may also determine x and y values for the center-of-gravity (COG) of the subject or patient using the computed center of pressure (COP) values from equations (12) and (13). In one embodiment, the data acquisition/data processing device  104  converts the computed center of pressure (COP) to a center of gravity (COG) for the subject using a Butterworth filter. For example, in this embodiment, a second-order Butterworth filter with a 0.75 Hz cutoff frequency is used. In another embodiment, the center-of-gravity (COG) can be computed in the manner described in pending, commonly-owned U.S. patent application Ser. No. 14/015,535, the entire disclosure of which is incorporated herein by reference.
 
           
         
       
    
     Now, returning to the flowchart in  FIG. 34 , after the output signals (i.e., channels) from both measurement assemblies  1402 ,  1404  (e.g., force plates) are summed in step  1206 , the number of recorded channels from multiple devices (e.g., multiple measurement assemblies  1402 ,  1404  in the form of force plates) are reduced to a single device (e.g., a single measurement assembly in the form of a virtual force plate) in step  1208 . Once the final computed result (e.g., the overall vertical force and moment components F Z   _   VP , M X   _   VP , M Y   _   VP ) is returned in step  1210 , the process ends at step  1212 . 
     In order to execute the calculations described above in equations (1)-(13), the data acquisition/data processing device  104  must be able to identify each of the two measurement assemblies  1402 ,  1404  that are connected thereto (i.e., the data acquisition/data processing device  104  must be able to distinguish the first force plate from the second force plate). If the data acquisition/data processing device  104  is not able to differentiate between the first and second force plates (e.g., because this is the first time that the first and second force plates have ever been connected to the data acquisition/data processing device  104 ), the data acquisition/data processing device  104  generates the pop-up window  1300  illustrated in  FIG. 35 . As diagrammatically indicated by the downwardly-directed arrow  1312 , the pop-up window  1300  prompts the system user to manually select the force plate  1304  that is located furthest away from the operator computer system  1306  by standing on the surface of the force plate  1304 . When the user stands on the surface of the force plate  1304 , the data acquisition/data processing device  104  detects a positive weight in excess of a set value (e.g., 1 Newton) for a predetermined number of seconds (e.g., 2 seconds). After standing on the plate  1304 , the user is then instructed to press the “OK” button  1308  to complete his or her selection, and confirm the proper plate order. Alternatively, if the user inadvertently selected the incorrect force plate (e.g., force plate  1302 , which is closest to the operator computer system  1306 ), he or she can always revise the selection by pressing the “Cancel” button  1310 . Once the user manually selects the force plate  1304  that is located furthest from the operator computer system  1306  using the pop-up window  1300 , the data acquisition/data processing device  104  designates the force plates  1302 ,  1304  as the first and second force plates, respectively, for the purpose of the calculations described above in equations (1)-(13). Thus, because the second force plate  1304  is rotated 180 degrees relative to the designated standard orientation of the plate coordinate axes, the matrix rotation calculations explained above are performed on the output values from the second force plate  1304  in order to compensate for its rotated position. Once the furthest force plate  1304  has been configured as the second force plate  1304  by the data acquisition/data processing device  104  (e.g., by equating its serial number with the second force plate designation), the pop-up window  1300  will not be subsequently displayed to the system user when the system user utilizes the measurement and testing software program at a later date or time. 
     It is readily apparent that the embodiments of the measurement and testing system  100  described above offer numerous advantages and benefits. In one or more embodiments, the measurement and testing system  100  discussed herein employs inventive filtering techniques in order to create a single, easily understandable report from data acquired on a plurality of different dates, thereby facilitating the analysis of the data by a user of the system. Moreover, in one or more embodiments, the measurement and testing system  100  includes a data acquisition and processing device which is specially programmed to automatically regulate the availability of tests in accordance with the type of measurement assembly or assemblies that is being utilized in the measurement system by filtering the tests that cannot be executed properly on a particular measurement assembly or assemblies. Furthermore, in one or more embodiments, the measurement and testing system  100  has a data acquisition and processing device which is specially programmed to create one or more virtual measurement assemblies from a plurality of physical measurement assemblies that are operatively coupled thereto in different orientations, such that the system is capable of having a large measurement surface area, while still being readily portable. 
     According to still another aspect of the illustrative embodiment, with initial reference to  FIG. 38 , the data acquisition/data processing device is specially programmed to determine one or more subsets of a plurality of measurement assemblies experiencing a load from one or more body portions of the subject, to construct one or more virtual measurement assemblies from the one or more respective subsets, and to determine output forces and/or moments for the one or more virtual measurement assemblies using the signals from the measurement devices of the measurement assemblies in the one or more subsets. 
     An illustrative embodiment of a measurement and testing system utilizing virtual force plates is seen generally at  1500  in  FIG. 38 . The force plate system  1500  generally comprises a force plate array  1502  operatively coupled to a data acquisition and processing device  1504  by virtue of an electrical cable  1522 . In one or more embodiments, the electrical cable  1522  is used for data transmission, as well as for providing power to the force plates of the force plate array  1502 . Preferably, the electrical cable  1522  contains a plurality of electrical wires bundled together, with at least one wire being used for power and at least another wire being used for transmitting data. The bundling of the power and data transmission wires into a single electrical cable  1522  advantageously creates a simpler and more efficient design. In addition, it enhances the safety of the testing environment when human subjects are being tested on the force plate array  1502 . However, it is to be understood that the force plate array  1502  can be operatively coupled to the data acquisition and processing device  1504  using other signal transmission means, such as a wireless data transmission system. If a wireless data transmission system is employed, it is preferable to provide the force plate array  1502  with a separate power supply in the form of an internal power supply or a dedicated external power supply. 
     Referring again to  FIG. 38 , it can be seen that the force plate array  1502  according to the illustrated embodiment of the invention includes a plurality of measurement assemblies in the form of force plates  1506  that are disposed adjacent to one another, and each being separated by a narrow gap  1510 . As depicted in  FIG. 38 , each force plate  1506  of the force plate array  1502  is preferably provided with at least four (4) measurement devices (i.e., force transducers  1508  thereunder). Also, each force plate  1506  has a measurement surface (i.e., top surface  1516 ) that is configured to receive at least one portion of a body of a subject (e.g., a foot/leg of a subject). In one or more embodiments, a subject stands in an upright position on the force plate array  1502  and each foot of the subject is placed on one or more top surfaces  1516  of one or more force plates  1506  in the force plate array  1502  (e.g., in  FIG. 38 , the left foot  1520  of the subject, as represented by the first hatched area, is disposed on the top surfaces  1516  of force plate nos.  2 ,  3 ,  7 ,  8 , whereas the right foot  1518  of the subject, as represented by the second hatched area, is disposed on the top surfaces  1516  of force plate nos.  11 ,  12 ,  16 ,  17 ). In  FIG. 38 , each force plate  1506  of the force plate array  1502  is identified by a corresponding identification number  1532  (i.e., force plate no.  1 ,  2 ,  3 ,  4 ,  5 , etc.). 
     As shown in  FIG. 38 , the data acquisition and processing device  1504  (e.g., in the form of a laptop digital computer) generally includes a base portion  1524  with a central processing unit (CPU) disposed therein for collecting and processing the data that is received from the force plate array  1502 , and a plurality of devices  1526 - 1530  operatively coupled to the central processing unit (CPU) in the base portion  1524 . Preferably, the devices that are operatively coupled to the central processing unit (CPU) comprise user input devices  1526 ,  1528  in the form of a keyboard  1526  and a touchpad  1528 , as well as a graphical user interface in the form of a laptop LCD screen  1530 . While a laptop type computing system is depicted in the embodiment of  FIG. 38 , one of ordinary skill in the art will appreciate that another type of data acquisition and processing device  1504  can be substituted for the laptop computing system such as, but not limited to, a palmtop computing device (i.e., a PDA) or a desktop type computing system having a plurality of separate, operatively coupled components (e.g., a desktop type computing system including a main housing with a central processing unit (CPU) and data storage devices, a remote monitor, a remote keyboard, and a remote mouse, as depicted in  FIGS. 1 and 35 ). The laptop computing system  1504  in  FIG. 38  comprises the same constituent hardware components as those described above with regard to data acquisition and processing device  104  (e.g., a microprocessor  104   a  for processing data, memory  104   b  (e.g., random access memory or RAM) for storing data during the processing thereof, and data storage device(s)  104   c ). 
     As diagrammatically illustrated in  FIG. 38 , the data acquisition and processing device  1504  is specially programmed to determine a first subset of the plurality of measurement assemblies (i.e., force plates nos.  11 ,  12 ,  16 ,  17 ) experiencing a load (e.g., vertical force F ZR ) from a first portion of the body of the subject (i.e., right foot/leg  1518 ) and a second subset of the plurality of measurement assemblies (i.e., force plates nos.  2 ,  3 ,  7 ,  8 ) experiencing a load (e.g., vertical force F ZL ) from a second portion of the body of the subject (i.e., left foot/leg  1520 ). The data acquisition and processing device  1504  is further specially programmed to construct a first virtual measurement assembly  1512  from the first subset (i.e., force plates nos.  11 ,  12 ,  16 ,  17 ) and a second virtual measurement assembly  1514  from the second subset (i.e., force plates nos.  2 ,  3 ,  7 ,  8 ), and to determine respective output forces and moments for the first and second virtual measurement assemblies  1512 ,  1514  using the respective signals from the measurement devices of the measurement assemblies (i.e., force plates) in the first and second subsets. Also, the data acquisition and processing device  1504  may be specially programmed to compute a load center of pressure for each of the first and second virtual measurement assemblies  1512 ,  1514  using the respective signals from the measurement devices of the measurement assemblies (i.e., force plates) in the first and second subsets. The output forces and moments for the virtual measurement assemblies  1512 ,  1514  may be determined in a manner similar to that described above with regard to equations (3), (4), (6), (7), (9), and (10) by mathematically combining the individual forces and moments for force plates nos.  11 ,  12 ,  16 ,  17 , and by mathematically combining the individual forces and moments for force plates nos.  2 ,  3 ,  7 ,  8 . The load centers of pressures for the virtual measurement assemblies  1512 ,  1514  may be determined in a manner similar to that described above with regard to equations (12) and (13). 
     As shown in  FIG. 38 , each of the measurement surfaces  1516  of the plurality of measurement assemblies  1506  has a footprint that is substantially equal to the first and second feet  1518 ,  1520  of the subject such that each of the first and second feet  1518 ,  1520  generally lands on a different one of the measurement surfaces  1516  of the plurality of measurement assemblies  1506  when the subject traverses the force plate array  1502  comprising the plurality of measurement assemblies  1506 . In another embodiment, each of the measurement surfaces of the plurality of measurement assemblies may have a footprint that is smaller than each of the first and second feet  1518 ,  1520  of the subject so that each foot of the subject also generally lands on a different one of the measurement surfaces  1516  of the plurality of measurement assemblies  1506  when the subject traverses the force plate array  1502 . 
     In an illustrative embodiment, with reference to the top view of the force plate array  1502 ″ of  FIG. 42 , the data acquisition and processing device  1504  is specially programmed to use a calculated distance between load centers of pressure in order to determine whether each measurement assembly  1506 ″ in a pair of measurement assemblies (i.e., a pair of force plates) is to be assigned to a same one of the first and second subsets or a different one of the first and second subsets. Initially, the data acquisition and processing device  1504  is specially programmed to compute a local load center of pressure (i.e., points  1534  in  FIG. 42 ) for each measurement assembly (i.e., force plates  1 C,  1 D,  2 A,  2 B,  2 C,  2 D,  3 A,  3 B) in the plurality of measurement assemblies (i.e., force plate array  1502 ″) experiencing a load from the subject. In  FIG. 42 , it can be seen that the right foot  1518 ″ of the subject exerts a load (i.e., a force and/or moment) on force plates  1 C,  1 D,  2 C,  2 D, while the left foot  1520 ″ of the subject exerts a load (i.e., a force and/or moment) on force plates  2 A,  2 B,  3 A,  3 B. In the manner described above, the local load center of pressure is computed individually for each of the force plates  1 C,  1 D,  2 A,  2 B,  2 C,  2 D,  3 A,  3 B experiencing a load from either the subject&#39;s right foot  1518 ″ or the subject&#39;s left foot  1520 ″ relative to the force plate&#39;s local coordinate axes (i.e., the origins of the local coordinate axes may be disposed in the middle of each force plate). Then, the local center of pressure coordinates determined for each of the force plates  1 C,  1 D,  2 A,  2 B,  2 C,  2 D,  3 A,  3 B are converted to global center of pressure coordinates. As shown in  FIG. 42 , the origin  1540  of the x-axis  1536  and the y-axis  1538  of the global coordinate system of the force plate array  1502 ″ may be disposed in the middle of the array  1502 ″, and at the corners of force plates  2 B,  2 C,  3 B,  3 C. Once all of the local center of pressure coordinates have been converted to global center of pressure coordinates by the data acquisition and processing device  1504 , the data acquisition and processing device  1504  is specially programmed to calculate distances between the load centers of pressure. For example, referring again to  FIG. 42 , the distance x 1  is computed between the load center of pressure points on force plates  3 A and  3 B, the distance x 2  is computed between the load center of pressure points on force plates  2 B and  2 C, and the distance x 3  is computed between the load center of pressure points on force plates  1 C and  1 D. Similarly, distance y 1  is computed between the load center of pressure points on force plates  2 A and  3 A and the distance y 2  is computed between the load center of pressure points on force plates  1 D and  2 D. After which, as will be explained hereinafter, the data acquisition and processing device  1504  uses the calculated distances x 1 , x 2 , x 3 , y 1 , y 2  between the load centers of pressure  1534  in order to determine whether each measurement assembly  1506 ″ in a pair of measurement assemblies is to be assigned to a same one of the first and second subsets (i.e., a same one of virtual force plates  1512 ′,  1514 ′) or a different one of the first and second subsets (i.e., a different one of virtual force plates  1512 ′,  1514 ′). 
     Referring again to  FIG. 42 , in the illustrated embodiment, the data acquisition and processing device  1504  is specially programmed to compare the calculated distances x 1 , x 2 , x 3 , y 1 , y 2  between the load centers of pressure  1534  to at least one foot size parameter (i.e., a foot width of the subject or foot length) of the subject in order to determine whether each measurement assembly  1506 ″ in a pair of measurement assemblies is to be assigned to a same one of the first and second subsets (i.e., a same one of virtual force plates  1512 ′,  1514 ′) or to a different one of the first and second subsets (i.e., a different one of virtual force plates  1512 ′,  1514 ′). For example, suppose the subject has a foot width of approximately 3.5 inches and a foot length of approximately 11.0 inches. Also, suppose, for example, that the distance x 1  is approximately equal to 2.75 inches, the distance x 2  is approximately equal to 4.3 inches, the distance x 3  is approximately equal to 2.85 inches, the distance y 1  is approximately equal to 9.0 inches, and the distance y 2  is approximately equal to 9.25 inches. Using these exemplary numerical values, the data acquisition and processing device  1504  determines that the center of pressure coordinates  1534  that are located on force plates  3 A and  3 B each correspond to a load generated by the same foot (i.e., the left foot  1520 ″) of the subject because the distance x 1  between these two center of pressure points is approximately equal to 2.75 inches, which is less than the approximate foot width of the subject, namely 3.5 inches. Similarly, the data acquisition and processing device  1504  determines that the center of pressure coordinates  1534  that are located on force plates  1 C and  1 D each correspond to a load generated by the same foot (i.e., the right foot  1518 ″) of the subject because the distance x 3  between these two center of pressure points is approximately equal to 2.85 inches, which is less than the approximate foot width of the subject, namely 3.5 inches. In contrast, the data acquisition and processing device  1504  determines that the center of pressure coordinates  1534  that are located on force plates  2 B and  2 C each correspond to a load generated by different feet of the subject, namely the right and left feet  1518 ″,  1520 ″, because the distance x 2  between these two center of pressure points is approximately equal to 4.3 inches, which is significantly greater than the approximate foot width of the subject (i.e., 3.5 inches), and thus, the respective loads corresponding to these two points must have been applied by separate feet. In addition, the data acquisition and processing device  1504  determines that the center of pressure coordinates  1534  that are located on force plates  2 A and  3 A each correspond to a load generated by the same foot (i.e., the left foot  1520 ″) of the subject because the distance y 1  between these two center of pressure points is approximately equal to 9.0 inches, which is less than the approximate foot length of the subject, namely 11.0 inches. Similarly, the data acquisition and processing device  1504  determines that the center of pressure coordinates  1534  that are located on force plates  1 D and  2 D each correspond to a load generated by the same foot (i.e., the right foot  1518 ″) of the subject because the distance y 2  between these two center of pressure points is approximately equal to 9.25 inches, which also is less than the approximate foot length of the subject, namely 11.0 inches. Because the intent of creating the virtual force plates  1512 ′,  1514 ′ in the force plate array  1502 ″ is to track the change in the center of pressure for each of the subject&#39;s feet  1518 ″,  1520 ″ independently from one another, when load center of pressure points disposed on a subset of force plates are created by the same foot, each of these force plates in the subset will be assigned to a single virtual plate by the data acquisition and processing device  1504 . In the illustrated example described above with reference to  FIG. 42 , force plates  1 C and  1 D and force plates  2 C and  2 D will be assigned to the same virtual force plate  1512 ′ because the loads acting thereon are all applied by the right foot  1518 ″ of the subject. Similarly, force plates  2 A and  2 B and force plates  3 A and  3 B will be assigned to the same virtual force plate  1514 ′ because the loads acting thereon are all applied by the left foot  1520 ″ of the subject. In contrast, the force plates  2 B and  2 C will be assigned to different virtual force plate  1512 ′,  1514 ′ because the loads acting thereon are applied by different feet  1518 ″,  1520 ″ of the subject. 
     Also, in the illustrated embodiment of  FIG. 42 , the data acquisition and processing device  1504  is specially programmed to additionally compare the calculated distances x 1 , x 2 , x 3 , y 1 , y 2  between the load centers of pressure  1534  to at least one step size parameter (i.e., the step width or the step length) of the subject in order to determine whether each measurement assembly  1506 ″ in a pair of measurement assemblies is to be assigned to a same one of the first and second subsets (i.e., a same one of virtual force plates  1512 ′,  1514 ′) or to a different one of the first and second subsets (i.e., a different one of virtual force plates  1512 ′,  1514 ′). For example, suppose the subject has a step width of approximately 4.35 inches and a step length of approximately 30.0 inches. Also, as described above, suppose the distance x 1  is approximately equal to 2.75 inches, the distance x 2  is approximately equal to 4.3 inches, the distance x 3  is approximately equal to 2.85 inches, the distance y 1  is approximately equal to 9.0 inches, and the distance y 2  is approximately equal to 9.25 inches. Using these exemplary numerical values, the data acquisition and processing device  1504  determines that the center of pressure coordinates  1534  that are located on force plates  3 A and  3 B each correspond to a load generated by the same foot (i.e., the left foot  1520 ″) of the subject because the distance x 1  between these two center of pressure points is approximately equal to 2.75 inches, which is less than the approximate step width of the subject, namely 4.35 inches. Similarly, the data acquisition and processing device  1504  determines that the center of pressure coordinates  1534  that are located on force plates  1 C and  1 D each correspond to a load generated by the same foot (i.e., the right foot  1518 ″) of the subject because the distance x 3  between these two center of pressure points is approximately equal to 2.85 inches, which is less than the approximate step width of the subject, namely 4.35 inches. In contrast, the data acquisition and processing device  1504  determines that the center of pressure coordinates  1534  that are located on force plates  2 B and  2 C each correspond to a load generated by different feet of the subject, namely the right and left feet  1518 ″,  1520 ″, because the distance x 2  between these two center of pressure points is approximately equal to 4.3 inches, which is significantly greater than the approximate foot width of the subject (i.e., 3.5 inches) and approximately equal to the average step width of the subject of 4.35 inches, and thus, the respective loads corresponding to these two points must have been applied by separate feet. In the illustrated example described above, with reference to  FIG. 42 , force plates  1 C and  1 D will be assigned to the same virtual force plate  1512 ′ because the loads acting thereon are all applied by the right foot  1518 ″ of the subject. Similarly, force plates  3 A and  3 B will be assigned to the same virtual force plate  1514 ′ because the loads acting thereon are all applied by the left foot  1520 ″ of the subject. In contrast, the force plates  2 B and  2 C will be assigned to different virtual force plate  1512 ′,  1514 ′ because the loads acting thereon are applied by different feet  1518 ″,  1520 ″ of the subject. 
     In the illustrated embodiment, with reference to the top view of the force plate array  1502 ″ of  FIG. 43 , the data acquisition and processing device  1504  is specially programmed to compare each of the computed load centers of pressure to one another using a cluster computational method so as to determine whether particular measurement assemblies  1506 ″ are to be assigned to a same one of the first and second subsets or to a different one of the first and second subsets. As described above, the data acquisition and processing device  1504  initially is specially programmed to compute a local load center of pressure (i.e., points  1534  in  FIG. 43 ) for each measurement assembly (i.e., force plates  1 C,  1 D,  2 A,  2 B,  2 C,  2 D,  3 A,  3 B) in the plurality of measurement assemblies (i.e., force plate array  1502 ″) experiencing a load from the subject. In  FIG. 43 , it can be seen that the right foot  1518 ″ of the subject exerts a load (i.e., a force and/or moment) on force plates  1 C,  1 D,  2 C,  2 D, while the left foot  1520 ″ of the subject exerts a load (i.e., a force and/or moment) on force plates  2 A,  2 B,  3 A,  3 B. In the manner described above, the local load center of pressure is computed individually for each of the force plates  1 C,  1 D,  2 A,  2 B,  2 C,  2 D,  3 A,  3 B experiencing a load from either the subject&#39;s right foot  1518 ″ or the subject&#39;s left foot  1520 ″ relative to the force plate&#39;s local coordinate axes (i.e., the origins of the local coordinate axes may be disposed in the middle of each force plate). Then, the local center of pressure coordinates determined for each of the force plates  1 C,  1 D,  2 A,  2 B,  2 C,  2 D,  3 A,  3 B are converted to global center of pressure coordinates. As shown in  FIG. 43 , the origin  1540  of the x-axis  1536  and the y-axis  1538  of the global coordinate system of the force plate array  1502 ″ may be disposed in the middle of the array  1502 ″, and at the corners of force plates  2 B,  2 C,  3 B,  3 C. Once all of the local center of pressure coordinates have been converted to global center of pressure coordinates by the data acquisition and processing device  1504 , the data acquisition and processing device  1504  is specially programmed to carry out a cluster computational method (e.g., a k-means cluster computational method). 
     Referring to  FIG. 43 , it can be seen that there are total of eight (8) sets of load center of pressure coordinates  1534  that are to be organized into two groups (i.e., one for the right foot of the subject  1518 ″ and one for the left foot of the subject  1520 ″) using the cluster computation method. For example, based upon the absolute coordinates axes  1536 ,  1538  in  FIG. 43 , the load center of pressure coordinates  1534  are (3, −3), (5, −3), (3, −6), (5, −6), (−3, 1), (−5, 1), (−3, −2), (−5, −2). First of all, the data acquisition and processing device  1504  determines an initial best-guess for the coordinate values of each of the centroids for the two groups. For example, suppose that the first two load center of pressure coordinates, namely (3, −3), (5, −3), are used by the data acquisition and processing device  1504  as the first guesses for the centroids (i.e., C 1 =(3, −3), C 2 =(5, −3)). After initial values of the centroids are established, the data acquisition and processing device  1504  computes the distance between each of the cluster/group centroids C 1 , C 2  and each of the load center of pressure coordinates  1534  using the following distance formula: 
     
       
         
           
             
               
                 
                   d 
                   = 
                   
                     
                       
                         
                           ( 
                           
                             
                               x 
                               2 
                             
                             - 
                             
                               x 
                               1 
                             
                           
                           ) 
                         
                         2 
                       
                       + 
                       
                         
                           ( 
                           
                             
                               y 
                               2 
                             
                             - 
                             
                               y 
                               1 
                             
                           
                           ) 
                         
                         2 
                       
                     
                   
                 
               
               
                 
                   ( 
                   14 
                   ) 
                 
               
             
           
         
       
         
         
           
             where: 
             x 2 : x-coordinate of the centroid; 
             x 1 : x-coordinate of the load center of pressure; 
             y 2 : y-coordinate of the centroid; and 
             y 1 : y-coordinate of the load center of pressure.
 
After computing the distance between each of the cluster/group centroids C 1 , C 2  and each of the load center of pressure coordinates  1534  using equation (14) above, the data acquisition and processing device  1504  assigns each of the load center of pressure coordinates  1534  to either the first group or the second group based upon whether the minimum distance was computed for the first centroid or the second centroid. For example, based upon the first guesses for the centroids above, the load center of pressure coordinates (3, −3), (3, −6), (−3, 1), (−5, 1), (−3, −2), and (−5, −2) are closer to the first centroid C 1 =(3, −3), and thus are assigned to the first group (i.e., Group I). Conversely, based upon the first guesses for the centroids above, the load center of pressure coordinates (5, −3), (5, −6), are closer to the second centroid C 2 =(5, −3), and thus are assigned to the second group (i.e., Group II). Now that the members of each group have been determined by the data acquisition and processing device  1504 , the new centroids for each group are computed based upon these new group memberships. The first group has six members, and thus the first centroid is computed as follows:
 
           
         
       
    
                       C   1     =     (       (       3   +   3   +     (     -   3     )     +     (     -   5     )     +     (     -   3     )     +     (     -   5     )       6     )     ,     (         (     -   3     )     +     (     -   6     )     +   1   +   1   +     (     -   2     )     +     (     -   2     )       6     )       )       ⁢     
     ⁢           ⁢       C   1     =       (       (       -   10     6     )     ,     (       -   11     6     )       )     =     (       -   1.67     ,     -   1.83       )                 (   15   )               
The second group has two members, and thus the second centroid is computed as follows:
 
                     C   2     =       (       (       5   +   5     2     )     ,     (         (     -   3     )     +     (     -   6     )       2     )       )     =       (       (     10   2     )     ,     (       (     -   9     )     2     )       )     =     (     5   ,     -   4.5       )                 (   16   )               
After the new centroids are computed, the data acquisition and processing device  1504  is specially programmed to use equation (14) above in order to compute the distance between each of the new cluster/group centroids C 1 , C 2  and each of the load center of pressure coordinates  1534 . Then, the data acquisition and processing device  1504  once again assigns each of the load center of pressure coordinates  1534  to either the first group or the second group based upon whether the minimum distance was computed for the first centroid or the second centroid. After the data acquisition and processing device  1504  determines the revised members of each group, the new centroids for each group are once again computed based upon these new group memberships. These same series of steps described above are iterated until the members of each group remain constant (i.e., none of the load center of pressure coordinates  1534  move from one group to the other). After the load center of pressure coordinates  1534  no longer switch groups, the computation of the k-means clustering has reached its stability and no more iterations are needed. At this point, the data acquisition and processing device  1504  determines the final groupings and the final centroids for each group. In the illustrated embodiment, referring again to  FIG. 43 , the load center of pressure coordinates (3, −3), (5, −3), (3, −6), and (5, −6) are assigned to the first group (i.e., group I), which has a centroid located at point  1542  (i.e., the centroid for group I is (4, −4.5)). The load center of pressure coordinates (−3, 1), (−5, 1), (−3, −2), and (−5, −2) are assigned to the second group (i.e., group II), which has a centroid located at point  1544  (i.e., the centroid for group I is (−4, −0.5)). The diagonal dividing line  1546  is used to diagrammatically separate the two groups of load center of pressure coordinates in  FIG. 43 .
 
     As such, based upon the results of the cluster computational method described above, the data acquisition and processing device  1504  determines that the center of pressure coordinates (3, −3), (5, −3), (3, −6), and (5, −6), which are located on force plates  2 C,  2 D,  1 C, and  1 D respectively, each correspond to a load generated by the same foot (i.e., the right foot  1518 ″) of the subject because each of these center of pressure coordinates  1534  are members of the same group (i.e., group I). Similarly, the data acquisition and processing device  1504  determines that the center of pressure coordinates (−5, 1), (−3, 1), (−5, −2), and (−3, −2), which are located on force plates  3 A,  3 B,  2 A, and  2 B respectively, each correspond to a load generated by the same foot (i.e., the left foot  1520 ″) of the subject because each of these center of pressure coordinates  1534  are members of the same group (i.e., group II). In the illustrated example described above, with reference to  FIG. 43 , force plates  1 C,  1 D,  2 C, and  2 D will be assigned to the same virtual force plate  1512 ′ because the loads acting thereon are all applied by the right foot  1518 ″ of the subject. Similarly, force plates  2 A,  2 B,  3 A, and  3 B will be assigned to the same virtual force plate  1514 ′ because the loads acting thereon are all applied by the left foot  1520 ″ of the subject. 
     Also, with reference again to  FIG. 38 , the illustrated embodiment of the measurement and testing system  1500  utilizing virtual force plates may further include a motion capture system. As shown in  FIG. 38 , the motion capture system includes a plurality of motion capture devices (i.e., video cameras  1548 ) that capture the motion of the first body portion of the subject (i.e., right foot/leg  1518 ) and the second body portion of the subject (i.e., left foot/leg  1520 ). The video cameras  1548  of the motion capture system generate motion capture data representative of the captured motion (i.e., video images) of the first body portion of the subject  1518  and the second body portion of the subject  1520 . While three (3) cameras  1548  are depicted in  FIG. 38 , one of ordinary skill in the art will appreciate that more or less cameras can be utilized, provided that at least two cameras  1548  are used. The motion capture data may be used by the data acquisition and processing device  1504  to make a supplementary determination of applied load positions on each of the measurement assemblies (i.e., force plates  1506 ) in the first and second subsets so as to correct for measurement errors resulting from a single measurement assembly  1506  experiencing loads from both the first and second limbs  1518 ,  1520  of the subject. That is, when a single force plate  1506  is experiencing loads from both the first and second limbs  1518 ,  1520  of the subject (i.e., double contact on the force plate  1506  by both limbs  1518 ,  1520 ), the motion capture data may be used by the data acquisition and processing device  1504  to determine the relative positions of the two limbs  1518 ,  1520  on that force plate  1506 . The data acquisition and processing device  1504  may also utilize the motion capture data in conjunction with the distance measurements and/or the cluster computational method described above in order to accurately determine the force plates  1506  that are being contacted by each limb  1518 ,  1520  of the subject. In addition, the motion capture data may be utilized by the data acquisition and processing device  1504  to determine whether a load that is being applied to the particular one of the plurality of measurement assemblies  1506  is being applied by the first body portion of the subject  1518  or the second body portion of the subject  1520 . 
     The motion capture system illustrated in  FIG. 38  is a markerless-type motion detection/motion capture system. That is, the motion capture system of  FIG. 38  uses a plurality of high speed video cameras to record the motion of a subject without requiring any markers to be placed on the subject. However, in another embodiment, a marker-based motion capture system is utilized. In this embodiment, the subject is provided with a plurality of markers disposed thereon. These markers are used to record the position of the limbs of the subject in 3-dimensional space. In this embodiment, the plurality of cameras  1548  are used to track the position of the markers as the subject moves his or her limbs in 3-dimensional space. For example, the subject may have a plurality of single markers applied to anatomical landmarks (e.g., the iliac spines of the pelvis, the malleoli of the ankle, and the condyles of the knee), or clusters of markers applied to the middle of body segments. As the subject executes particular movements on the force plate array  1502 , the data acquisition/data processing device  1504  calculates the trajectory of each marker in three (3) dimensions. Then, once the positional data is obtained using the motion capture system, the position of the subject&#39;s limbs  1518 ,  1520  may be determined, and inverse kinematics may be employed in order to determine the joint angles of the subject. Both of the aforementioned markerless and marker-based motion capture systems are optical-based systems. In one embodiment, the optical motion capture systems utilize visible light, while in another alternative embodiment, the optical motion capture system employs infrared light (e.g., the system could utilize an infrared (IR) emitter to project a plurality of dots onto objects in a particular space as part of a markerless motion capture system). For example, a motion capture device with one or more cameras, one or more infrared (IR) depth sensors, and one or more microphones may be used to provide full-body three-dimensional (3D) motion capture, facial recognition, and voice recognition capabilities. It is also to be understood that, rather than using an optical motion capture system, a suitable magnetic or electro-mechanical motion detection/capture system may also be employed in the measurement and testing system described herein, or a motion capture system that utilizes a plurality of inertial measurement units (IMUs) disposed on the limbs of the subject. 
     In a further embodiment of the measurement and testing system of  FIG. 38 , the data acquisition and processing device  1504  is specially programmed to use a predetermined time delay in order to determine whether each measurement assembly  1506  in a pair of measurement assemblies is to be assigned to a same one of the first and second subsets (i.e., a same one of virtual force plates  1512 ,  1514 ) or to a different one of the first and second subsets (i.e., a different one of virtual force plates  1512 ,  1514 ). For example, the predetermined time delay utilized by the data acquisition and processing device  1504  may constitute the average time duration (e.g., 0.30 seconds) of the right or left swing phase of the subject (i.e., from left toe off to left heel contact, or from right toe off to right heel contact). 
     In yet a further embodiment of the measurement and testing system of  FIG. 38 , the data acquisition and processing device  1504  is specially programmed to compute, by using the output data, a series of load centers of pressure  1534  for the subject (see  FIG. 39 ). In  FIG. 39 , the points  1534  represent the path of the subject&#39;s center of pressure over time as the subject traverses the force plate array  1502 ′. The force plate array  1502 ′ of  FIG. 39  comprises a plurality of measurement assemblies in the form of rectangular force plates  1506 ′ (i.e., force plates  1 A- 4 D) with identification numbers  1532 ′. As shown in  FIG. 39 , the subject&#39;s right foot  1518 ′ is disposed on force plates  1 C,  1 D,  2 C,  2 D, while the subject&#39;s left foot  1520 ′ is disposed on force plates  3 A,  3 B,  4 A,  4 B. In  FIG. 39 , the force plates  1 A- 4 D forming the force plate array  1502 ′ are being treated as a single overall virtual force plate with the progression of the subject&#39;s center of pressure over time being represented by the series of points or dots  1534 . When the points or the dots  1534  are close together (e.g., as those illustrated under the right foot  1518 ′ and the left foot  1520 ′ of the subject), there is a small change in the subject&#39;s center of pressure over time. Conversely, when the points or the dots  1534  are far apart (e.g., those spaced apart by distances d 1  and d 2 ), there is a large change in the subject&#39;s center of pressure over time. 
     The data acquisition and processing device  1504  is specially programmed to compare each of the computed load centers of pressure  1534  to one another so as to determine a substantial incremental increase in a magnitude of the computed load center of pressure that corresponds to double stance in a gait cycle of the subject. For example, with reference to  FIG. 39 , the data acquisition and processing device  1504  is specially programmed to compare the load centers of pressure  1534  separated by the large distances d 1  and d 2  to the load centers of pressure  1534  separated by only small distances between one another (e.g., distance d 3  in  FIG. 39 ) in order to determine the double stance phase of the subject&#39;s gait cycle. Because a rapid change in a person&#39;s center of pressure is experienced during the double stance phase of the gait cycle, the large distances d 1  and d 2  between the subject&#39;s centers of pressure on force plates  2 C and  3 B clearly indicates that the double stance phase of the subject&#39;s gait cycle is occurring during this time. The data acquisition and processing device  1504  is specially programmed to utilize the determined substantial incremental increase in the magnitude of the computed load center of pressure (e.g., as indicated by the large spacing distances d 1  and d 2  in  FIG. 39 ) in order to determine whether the load that is being applied to the particular one of the plurality of measurement assemblies  1506 ′ is being applied by the first body portion of the subject (i.e., right foot/leg  1518 ′) or the second body portion of the subject (i.e., left foot/leg  1520 ′). In addition, the data acquisition and processing device  1504  is specially programmed to compare each of the computed load centers of pressure  1534  to one another so as to determine differences in magnitude between successive computed load centers of pressure  1534  for a predetermined time increment, and to compare the determined differences in magnitude between successive computed load centers of pressure  1534  in order to determine whether the load that is being applied to the particular one of the plurality of measurement assemblies is being applied by the first body portion of the subject (i.e., right foot/leg  1518 ′) or the second body portion of the subject (i.e., left foot/leg  1520 ′). In particular, once the load center of pressure points  1534  corresponding to the double stance phase of the gait cycle are identified, the data acquisition and processing device  1504  determines that the closely spaced-apart points  1534  disposed on force plates  1 C and  2 C correspond to the same foot of the subject (i.e., the right foot  1518 ′ of the subject), whereas the closely spaced-apart points  1534  disposed on force plates  3 B and  4 B correspond to the same foot of the subject (i.e., the left foot  1520 ′ of the subject). Also, based upon the coordinate values of each load center of pressure point  1534 , the data acquisition and processing device  1504  determines that the closely spaced-apart points  1534  disposed on force plates  1 C and  2 C correspond to the right foot  1518 ′ of the subject, while the closely spaced-apart points  1534  disposed on force plates  3 B and  4 B correspond to the left foot  1520 ′ of the subject (i.e., the center of pressure points corresponding to the left foot  1520 ′ of the subject will have x-coordinate values that are either less than (if the x-axis is pointing to the right), or greater than (if the x-axis is pointing to the left) the x-coordinate values of the center of pressure points corresponding to the right foot  1518 ′ of the subject). 
     In still a further embodiment of the measurement and testing system, the data acquisition and processing device  1504  is specially programmed to compare, by using the output data for the force plates  1 A- 4 D in the force plate array  1502 ′, forces applied to measurement surfaces of respective ones of the plurality of measurement assemblies  1506 ′ as each of the plurality of measurement assemblies  1506 ′ are activated so as to determine whether the load that is being applied to the particular one of the plurality of measurement assemblies  1506 ′ is being applied by the first body portion of the subject (i.e., right foot/leg  1518 ) or the second body portion of the subject (i.e., left foot/leg  1520 ). In  FIG. 40 , the vertical forces (F z ) being applied to each of the active measurement assemblies (i.e., force plates  1506 ′) in the force plate array  1502 ′ of  FIG. 39  are plotted as function of time. As such, the y-axis  1602  of the graph  1600  of  FIG. 40  corresponds to the vertical reaction force (e.g., as listed in the percentage of the subject&#39;s weight), and the x-axis  1604  of the graph  1600  of  FIG. 40  corresponds to time (e.g., in seconds). In addition to the forces being applied to each of the active measurement assemblies (i.e., force plates  1506 ′) in the force plate array  1502 ′, the graph  1600  of  FIG. 40  also includes a curve  1606  of the total vertical force being applied to the force plates of the force plate array  1502 ′. 
     Now, with reference to  FIG. 40 , the manner in which the data acquisition and processing device  1504  determines whether the load is being applied by the first body portion of the subject (i.e., right foot/leg  1518 ′) or the second body portion of the subject (i.e., left foot/leg  1520 ′) will be explained. In  FIG. 40 , the right foot heel down position occurs at point  1620 , while the right foot heel up position occurs at point  1622 . Between these two points  1620 ,  1622 , force plates  1 C,  1 D,  2 C,  2 D of the force plate array  1502 ′ (see  FIG. 39 ) are experiencing a load. Turning again to  FIG. 40 , the left foot heel down position occurs at point  1624 , while the left foot heel up position occurs at point  1628 . Between these two points  1624 ,  1628 , force plates  2 C,  3 A,  3 B,  4 A,  4 B of the force plate array  1502 ′ (see  FIG. 39 ) are experiencing a load. In  FIG. 40 , the double stance phase  1630  of the gait cycle (i.e., when both feet of the subject are in contact with the force plate array  1502 ′) occurs between points  1624  and  1626 . By identifying the double stance phase of the gait cycle, the data acquisition and processing device  1504  determines that the vertical forces occurring prior to the double stance phase in time are associated with the first of the subject&#39;s two feet (i.e., between points  1620  and  1622  in  FIG. 40 ), and further determines that the vertical forces occurring after the double stance phase in time are associated with the second of the subject&#39;s two feet (i.e., between points  1626  and  1628  in  FIG. 40 ), because only a single foot of the subject is in contact with the force plate array surface during these two time increments. As explained above, the particular foot of the subject that is applying the forces before, and after the double stance phase of the gait cycle may be determined by comparing the x-coordinates of the load centers of pressure. 
     In addition, the data acquisition and processing device  1504  may be further specially programmed to compute, by using the output data, a summation of forces applied to measurement surfaces of respective ones of the plurality of measurement assemblies  1506 ′ as each of the plurality of measurement assemblies  1506 ′ are activated so as to determine whether the load that is being applied to the particular one of the plurality of measurement assemblies  1506 ′ is being applied by only a single foot of the subject or both feet of the subject. For example, referring again to  FIG. 40 , if the force curve associated with force plate  2 C is added to the force curve associated with force plate  3 B, the data acquisition and processing device  1504  determines that forces applied to these two force plates  2 C,  3 B must have been generated by two separate feet of the subject, rather only a single foot of the subject, because the summation of the peak forces applied to force plates  2 C,  3 B greatly exceeds the weight of the subject (i.e., when the force curves associated with the force plates  2 C,  3 B are added together, their peak summation greatly exceeds the value of the total force curve  1606  in  FIG. 40 ). 
     Now, turning to  FIG. 41 , a graphical illustration of force curves corresponding to the right and left foot of the subject will be explained. In  FIG. 41 , the separate vertical forces (F z ) being applied by the subject&#39;s feet are plotted as function of time. As such, the y-axis  1610  of the graph  1608  of  FIG. 41  corresponds to the vertical force, and the x-axis  1612  of the graph  1608  of  FIG. 41  corresponds to time (e.g., in seconds). The curve  1614  in  FIG. 41  illustrates the vertical force generated by the right foot of the subject on the force plate array, while the curve  1616  in  FIG. 41  illustrates the vertical force generated by the left foot of the subject on the force plate array (e.g., the force plate array of  FIG. 39 ). Similar to that described above for  FIG. 40 , the double stance phase of the gait cycle (i.e., when both feet of the subject are in contact with the force plate array  1502 ′) occurs in the region  1618  of  FIG. 41 . 
     It is apparent from the above detailed description that the measurement and testing systems  1500  with the force plate arrays  1502 ,  1502 ′,  1502 ″ significantly advance the field of human balance assessment and human gait analysis. For example, the measurement and testing systems  1500  with the force plate arrays  1502 ,  1502 ′,  1502 ″ described herein utilize a large measurement surface area that enables the movement of the individual legs of the subject disposed thereon to be separately analyzed. As another example, the measurement and testing systems  1500  with the force plate arrays  1502 ,  1502 ′,  1502 ″ described herein include a data acquisition and processing device that is specially programmed to determine the movement generated by each of the legs separately. As yet another example, the measurement and testing systems  1500  with the force plate arrays  1502 ,  1502 ′,  1502 ″ described herein have a data acquisition and processing device which is specially programmed to create one or more virtual measurement assemblies from one or more subsets of a plurality of measurement assemblies. As still another example, the measurement and testing systems  1500  with the force plate arrays  1502 ,  1502 ′,  1502 ″ described herein are capable of accurately producing force and moment output data for situations where the subject&#39;s feet are overlapping more than one of the separate measurement surfaces forming the overall large measurement surface area. As yet another example, the measurement and testing systems  1500  with the force plate arrays  1502 ,  1502 ′,  1502 ″ described herein may comprise a plurality of measurement assemblies that are dimensioned and sized to prevent both feet of the subject from landing on the same one of the separate measurement surfaces comprising the array, thereby enabling the separate analysis of the movement generated by each of the two legs to be accurately performed. 
     Another illustrative embodiment of a measurement and testing system in the form of a force measurement system is illustrated in  FIGS. 44-49 . Initially, referring to the perspective view of  FIG. 49 , it can be seen that, in the illustrative embodiment, the force measurement system may comprise a force plate array  1730  formed by a plurality of force plate modules  1700  connected to one another. Similar to that described above for the force plate system  1500 , the force plate modules  1700  of the force plate array  1730  may be operatively coupled to a data acquisition and processing device  1740  (i.e., a computing device  1740 ) by virtue of a plurality of electrical cables  1734  (see e.g.,  FIGS. 50 and 51 ). In one or more embodiments, the electrical cables  1734  are used for data transmission, as well as for providing power to the force plate modules  1700  of the force plate array  1730 . Preferably, the electrical cables  1734  contain a plurality of electrical wires bundled together, with at least one wire being used for power and at least another wire being used for transmitting data. The bundling of the power and data transmission wires into a single electrical cable  1734  to each force plate module  1700  advantageously creates a simpler and more efficient design. In addition, it enhances the safety of the testing environment when human subjects are being tested on the force plate array  1730 . However, it is to be understood that the force plate array  1730  can be operatively coupled to the data acquisition and processing device  1740  using other signal transmission means, such as a wireless data transmission system. If a wireless data transmission system is employed, it is preferable to provide the force plate array  1730  with a separate power supply in the form of an internal power supply or a dedicated external power supply. 
     Now, turning to  FIGS. 44-48 , it can be seen that, in the illustrative embodiment, each of the force plate modules  1700  of the force plate array  1730  includes a plurality of force plate assemblies in the form of force plates that are disposed adjacent to one another, and each being separated by a narrow gap  1722  (see  FIG. 44 ). As depicted in  FIGS. 44-45 , the plurality of force plate assemblies of the force plate module  1700  are supported on a common base component  1718 , which is in the form of a continuous base plate that extends underneath all of the module force plate assemblies in the illustrated embodiment. Also, in the illustrated embodiment, each of the force plate assemblies includes a top plate component  1702  having an upper surface, the upper surface of each top plate component  1702  forming a force measurement surface for receiving at least one portion of a body of a subject (e.g., a foot/leg of a subject). In addition, each of the illustrated module force plate assemblies is provided with a plurality of force transducers  1704  (e.g., a pair of transducer beams) disposed underneath, and supporting the top plate component  1702 . The force transducers of the force plate assemblies are configured to sense one or more measured quantities and output one or more signals that are representative of the one or more measured quantities (i.e., force and/or moments). In one or more embodiments, a subject stands in an upright position on the force plate array  1730  in  FIG. 49 , and each foot of the subject is placed on one or more top surfaces of the force plate modules  1700  in the force plate array  1730 . In  FIGS. 44, 47, and 48 , each force plate assembly of the force plate module  1700  is identified by a corresponding identification number (i.e., force plate no.  1 ,  2 ,  3 ,  4 ,  5 ,  6 ,  7 , and  8 ). 
     With reference primarily to  FIG. 48  of the illustrative embodiment, the force transducers  1704  of each force plate assembly of the force plate module  1700  will be described in detail. As shown in the exploded view of  FIG. 48 , each of the pair of force transducers  1704  is disposed proximate to one of the opposite longitudinal ends of the top plate component  1702  of each force plate assembly. Each of the force transducers  1704  generally comprises a central rectangular body portion  1706  with an upper standoff portion, first and second L-shaped transducer beam portions  1710 ,  1712  that wrap around a portion of the outer periphery of the rectangular body portion  1706 , and a beam connector portion  1714  that connects each of the first and second L-shaped transducer beam portions  1710 ,  1712  to a common side of the rectangular body portion  1706 . As shown in  FIG. 48 , each of the first and second L-shaped transducer beam portions  1710 ,  1712  is oppositely disposed with respect to one another, and, except for the connector portion  1714 , each of the first and second L-shaped transducer beam portions  1710 ,  1712  is spaced apart from the outer side surfaces of the rectangular body portion  1706  by a continuous narrow gap. Each of the L-shaped transducer beam portions  1710 ,  1712  comprises two transducer beam sections perpendicularly disposed relative to one another, namely a proximal beam section connected to the connector portion  1714  and a distal beam section with a lower standoff portion  1716 . The upper standoff portion (i.e., the raised top surface) of rectangular body portion  1706  elevates the top plate component  1702  above the top surfaces of the L-shaped transducer beam portions  1710 ,  1712  so as to create a gap between the top surfaces of the L-shaped transducer beam portions  1710 ,  1712  and the bottom surface of the top plate component  1702 , whereas the lower standoff portions  1716  of the distal beam sections elevate the bottom surfaces of the L-shaped transducer beam portions  1710 ,  1712  above the top surface of the base plate component  1718  so as to create a gap between the top surface of the base plate component  1718  and the bottom surfaces of the L-shaped transducer beam portions  1710 ,  1712 . As such, in the illustrative embodiment, the structural components  1702 ,  1718  to which the force transducers  1704  are mounted are connected only to the upper standoff portion of the rectangular body portion  1706  and the lower standoff portions  1716  of the distal beam sections so as to ensure that the total load applied to the force transducers  1704  is transmitted through the transducer beam portions  1710 ,  1712 . The compact structural configuration of the force transducers  1704  enables the force transducers  1704  to be effectively utilized in the force plate module  1700 , which comprises the plurality of small force plate assemblies (i.e., force plate nos.  1 ,  2 ,  3 ,  4 ,  5 ,  6 ,  7 , and  8 ). 
     In the illustrative embodiment, each of the L-shaped transducer beam portions  1710 ,  1712  may comprises a plurality of strain gages for detecting the deformation in the beam sections of the L-shaped transducer beam portions  1710 ,  1712  resulting from the applied load. For example, in the illustrative embodiment, the force transducers  1704  of each force plate assembly of the force plate module  1700  may be sensitive to the vertical force (F z ) and the moments in the x and y directions (M x , M y ). Alternatively, the force transducers  1704  of each force plate assembly of the force plate module  1700  may be sensitive to all six (6) force and moment components (F x , F y , F z , M x , M y , M z ). Because the manner in which the forces and/or moments are determined by the data acquisition and processing device  1740  from the output signals of the force transducers  1704  is generally the same as that described above with regard to  FIG. 3 , an explanation of this functionality does not need to repeated in conjunction with this embodiment. 
     Similar to the data acquisition/data processing device  104  described above with reference to  FIG. 2 , the data acquisition and processing device  1740  (i.e., computing device  1740 ) may comprise a microprocessor for processing data from the force plate modules  1700 , memory (e.g., random access memory or RAM) for storing data during the processing thereof, and data storage device(s), such as one or more hard drives, compact disk drives, floppy disk drives, flash drives, or any combination thereof. Also, the data acquisition and processing device  1740  may comprise user input devices in the form of a keyboard, mouse, and touchpad or touchscreen. 
     Turning again to the partially exploded perspective view of  FIG. 48 , it can be seen that the rectangular body portion  1706  of each force transducer  1704  is provided with a plurality of mounting apertures  1708  disposed therethrough (i.e., four (4) mounting apertures  1708  arranged in a rectangular configuration) for receiving fasteners (e.g., mounting screws) that secure the force transducer  1704  to the top plate component  1702 . Also, as shown in  FIG. 48 , it can be seen that the base plate component  1718  is provided with a plurality of mounting apertures  1720  disposed therethrough (i.e., four (4) mounting apertures  1720  corresponding to each force plate assembly) for receiving fasteners (e.g., mounting screws) that secure the lower standoff portions  1716  of the force transducers  1704  to the base plate component  1718 . 
     With combined reference to  FIGS. 44-46 and 48 , it can be seen that, in the illustrative embodiment, the force plate module  1700  comprises a plurality of alignment/securement devices  1724  (i.e., combination alignment and latching devices) for attaching and aligning the force plate module  1700  to the one or more additional force plate modules  1700  in the force plate array  1730  (as depicted in  FIG. 49 ). That is, each force plate module  1700  in the force plate array  1730  of  FIG. 49  is provided with a plurality of alignment/securement devices  1724  to connect the force plate module  1700  to one or more adjacent force plate modules  1700  in the modular force plate array  1730 . For example, as best shown in the perspective views of  FIGS. 44 and 48 , a pair of spaced-apart alignment/securement devices  1724  is provided on two (2) perpendicularly disposed sides of the base plate component  1718 . In the illustrative embodiment of  FIGS. 44-46 and 48 , each of the plurality of alignment/securement devices  1724  may comprise a cylindrical pin-like member (or cylindrical boss member) projecting outward from a side of the base plate component  1718 . Each of the pin-like alignment/securement devices  1724  may be received within a corresponding cylindrical bore or recess in an adjacent force plate module  1700  of the force plate array  1730 . As such, the adjacent force plate modules  1700  of the force plate array  1730  are capable of being both aligned with one another, and fixed relative to one another, by the mating engagement between the pin-like alignment/securement devices  1724  and their corresponding cylindrical bores or recesses. In the illustrative embodiment, the alignment/securement devices  1724  are configured to be removably engaged and disengaged without the use of any tools (e.g., no tools are required to engage the pin-like member with its corresponding cylindrical bore or recess). For example, the pin-like member may be spring-loaded so that it snaps into place within its corresponding cylindrical bore or recess. Also, in the illustrative embodiment, the alignment/securement devices  1724  of each force plate module  1700  may be top accessible so that a person disposed on the top surface of the force plate module  1700  may engage and disengage the pin-like members from their corresponding cylindrical bores or recesses without being required to access the bottom or side of the force plate module  1700 . The top accessibility of the alignment/securement devices  1724  greatly facilitates the installation of the force plate modules  1700  forming the force plate array  1730  because the sides and bottom of the force plate modules  1700  may be generally inaccessible in typical force plate array installations. 
     Advantageously, the modular configuration of the force measurement system allows the components of the individual force plate modules  1700  to be completely assembled at the factory in a closely-controlled manner, and then the individual force plate modules  1700  to be easily secured to one another on site using the alignment/securement devices  1724  so as to form the overall force plate array  1730 . For example, in one or more embodiments, the force plate modules  1700  may be assembled in an array on mounting surface, such as the floor of a building or a metal mounting plate. The modular construction of the force plate system allows the force plate array  1730  to be easily adapted to specific room configurations in a building (i.e., the individual force plate modules  1700  may be fastened together so as to form a myriad of different force plate array geometries. 
     Next, referring to  FIGS. 50 and 51 , illustrative embodiments of the electrical components and wiring of the force plate module  1700  will be explained. Initially, as shown in  FIG. 50 , it can be seen that, in this first illustrative embodiment, each of the force plate assemblies may comprise a dedicated digitizer and signal conditioner  1726  that is electrically coupled to each of the force transducers  1704  of the respective force plate assembly by electrical transducer wiring  1736 . Each digitizer and signal conditioner  1726  converts the analog voltage signals from the transducers  1704  of its respective force plate assembly into digital voltage signals, and may also perform other functions on the signals as well, such as amplification, filtering, etc. Referring again to  FIG. 50 , it can be seen that each force plate digitizer and signal conditioner  1726  is electrically coupled to an electrical interface  1728  of the force plate module  1700  by electrical wiring  1732  (e.g., by Universal Serial Bus (USB) cables). The electrical interface  1728  of the force plate module  1700  may comprise one or more electrical ports for receiving one or more respective wiring plug connectors of electrical cables that transfer data and/or power to, and from, the force plate module  1700 . For example, as shown in  FIG. 50 , the electrical interface  1728  of the force plate module  1700  is electrically coupled to the data acquisition and processing device  1740  by the electrical cable  1734  so that the signals from the force transducers  1704  of the force plate assemblies may be converted into output loads (i.e., into forces and/or moments). In  FIG. 50 , it can be seen that a plurality of other force plate modules  1700  are electrically connected to the data acquisition and processing device  1740  by electrical cables  1734  so that load data may be generated from these force plate modules  1700  as well. 
     In one or more embodiments, the electrical interface  1728  of the force plate module  1700  may comprise a plurality of electrical ports, which include a Universal Serial Bus (USB) port, an Ethernet port, a power over Ethernet (PoE) port, and an additional power input port. 
     Turning to  FIG. 51 , it can be seen that the second illustrative embodiment depicted in this figure is similar in many respects to the first illustrative embodiment of  FIG. 50  described above. However, unlike the embodiment of  FIG. 50 , each force plate assembly of the force plate module  1700  is not provided with a dedicated digitizer and signal conditioner  1726 . Rather, as shown in  FIG. 51 , the force transducers  1704  of the four (4) force plate assemblies of the force plate module  1700  are electrically coupled to a first digitizer and signal conditioner  1726  by electrical transducer wiring  1736 , and then the force transducers  1704  of the other four (4) force plate assemblies of the force plate module  1700  are electrically coupled to a second digitizer and signal conditioner  1726  by electrical transducer wiring  1736 . Then, each of the two (2) digitizers and signal conditioners  1726  are electrically coupled to the electrical interface  1728  of the force plate module  1700  by respective electrical cables  1732  (e.g., by Universal Serial Bus (USB) cables). Finally, as described above for the embodiment of  FIG. 50 , the electrical interface  1728  of the force plate module  1700  is electrically coupled to the data acquisition and processing device  1740  by the electrical cable  1734  so that the signals from the force transducers  1704  of the force plate assemblies may be converted into output loads (i.e., into forces and/or moments). And, as explained above for  FIG. 50 , it can be seen that a plurality of other force plate modules  1700  are electrically connected to the data acquisition and processing device  1740  so that load data may be generated from these force plate modules  1700  as well. 
     In one or more embodiments, one or more of the plurality of force plate modules  1700  of the force plate array  1730  may comprise a redundant power connection to a power source (e.g., a building wall receptacle) to provide a backup power supply, reduce power transmission losses in the force measurement system, and/or increase the power delivery capacity of the force measurement system. In particular, in the illustrative embodiment of  FIG. 52B , a plurality of force plate modules  1700  may comprise power connections to two or more other force plate modules  1700  so as to provide an auxiliary transmission path for electrical power and/or to reduce power transmission losses in the force measurement system. Initially, referring to  FIG. 52A , it can be seen that the electrical interfaces  1728  of the four (4) force plate modules  1700  are connected in series with one another by electrical power wiring  1738 . As such, in the wiring configuration of  FIG. 52A , the equivalent resistance for the electrical current path between electrical interface I 1  and electrical interface I 4  is R 4-1 =3R (i.e., between nodes  1  and  4 ). Although, in the alternative redundant wiring scheme of  FIG. 52B , the equivalent resistance for the electrical current path between electrical interface I 1  and electrical interface I 4  is reduced to R 4-1 =0.75R (i.e., between nodes  1  and  4 ). Thus, the addition of the electrical power wiring  1738  directly connecting electrical interface I 1  to electrical interface I 4  substantially reduces the equivalent resistance R 4-1 , thereby substantially reducing power transmission losses in the force measurement system. Moreover, the addition of the electrical power wiring  1738  directly connecting electrical interface I 1  to electrical interface I 4  also provides a redundant power connection for the system so as to compensate for the failure of one or more of the cables connecting the electrical interfaces  1728  of two force plate modules  1700  with one another (e.g., in  FIG. 52B , if the cable  1738  connecting the electrical interface I 2  to the electrical interface I 3  fails, power is still capable of being supplied to electrical interfaces I 3  and I 4  by the cable extending between the electrical interface I 1  and electrical interface I 4 ). 
     Also, in one or more embodiments, one or more of the plurality of force plate modules  1700  of the force plate array  1730  may comprise a redundant data connection to the data acquisition and processing device  1740  to provide an auxiliary data transmission path and/or to increase a data transfer rate in the force measurement system. In particular, in the illustrative embodiment of  FIG. 53B , a plurality of force plate modules  1700  may comprise data connections to two or more other force plate modules  1700  so as to provide an auxiliary data transmission path and/or to increase a data transfer rate in the force measurement system. Initially, referring to  FIG. 53A , it can be seen that the electrical interfaces  1728  of the four (4) force plate modules  1700  are connected in series with one another by data transmission wiring  1739 . As such, because the electrical interfaces  1728  of the force plate modules  1700  in  FIG. 53A  are electrically coupled to one another in series, the data from the four (4) force plate modules  1700  are combined with one another such that the data transmission wiring back to the data acquisition and processing device  1740  has an overall data transmission load of 4T. In the wiring configuration of  FIG. 53A , the data transmission load from electrical interface I 2  to electrical interface I 1  is 3T. Although, in the alternative redundant wiring scheme of  FIG. 53B , the data transmission load from electrical interface I 2  to electrical interface I 1  is reduced to 1.5T. In  FIG. 53B , the remaining 1.5T of the data transmission load is transmitted by the data transmission wiring  1739  extending between electrical interface I 4  and I 1 . Thus, the addition of the data transmission wiring  1739  directly connecting electrical interface I 4  to electrical interface I 1  reduces the maximum data transmission load between any two of the electrical interfaces in  FIG. 53B  down to 1.5T, thereby allowing a smaller wire size to be used between electrical interface I 3  and I 2 , and between electrical interface I 2  and I 1  (multiple smaller data transmission wires are more cost effective for the system than a single larger data transmission wire). Moreover, the addition of the data transmission wiring  1739  directly connecting electrical interface I 4  to electrical interface I 1  also provides a redundant data connection for the system so as compensate for the failure of one or more of the data cables connecting the electrical interfaces  1728  of two force plate modules  1700  with one another (e.g., in  FIG. 53B , if the cable  1739  connecting the electrical interface I 3  to the electrical interface I 2  fails, data is still capable of being transmitted from electrical interfaces I 3  and I 4  by the data cable  1739  extending between the electrical interface I 4  and electrical interface I 1 . 
     In one or more embodiments, electrical power may be provided to one or more of the plurality of force plate modules  1700  in the force plate array  1730  using a power over Ethernet connection. As such, a single cable or wire may be used both for plate module power and data transmission. Further, in one or more embodiments, both redundant data connections and redundant power connections may be utilized between the force plate modules  1700  so as to provide backup connections in the case of either a power failure or a data transmission failure (e.g., resulting from an inoperative connection to a particular force plate module  1700 ). 
     In one or more alternative embodiments, one or more of the plurality of force plate modules  1700  in the force plate array  1730  may comprise a wireless data interface and/or a wireless power interface so that electrical cables are not required for power and data transmission to the data acquisition and processing device  1740  (e.g., the electrical interfaces  1726  may include a wireless-type interface). In such a wireless arrangement, the same redundant power and data configurations described above for the wired connections may also be incorporated in the alternative wireless power and data configurations. 
     As discussed above with regard to  FIG. 53A , the electrical interfaces  1728  of the force plate modules  1700  may be electrically coupled to one another in series so that the data from a preceding force plate module  1700  is combined with data from one or more subsequent force plate modules  1700  in the force plate array  1730  (i.e., data combination on the “fly”). For example, the data from the plate assemblies of a plurality of force plate modules  1700  may be combined in one or more of the following ways: (i) data combined in the order received without fallback, (ii) the data of the oldest field is dropped first, (iii) additional data is added to an overflow field when the normal data fields are completely filled, and (iv) the lowest load is dropped by some metric. For data combination scheme (i) above, fields corresponding to particular load locations (e.g., force plate assemblies on force plate modules  1700 ) are consecutively filled by the force plate modules  1700  in series until there are no longer any empty fields. After there are no longer any empty fields that are capable of being filled, the data from subsequent force plate assemblies of the force plate modules  1700  are simply not included in the combined data collection. As such, the first data combination scheme does not have a fallback strategy (i.e., data fields are filled on a first come, first served basis without fallback). Fallback strategies are needed when there are more loaded, active elements (e.g., loaded force plate assemblies) than data fields. For data combination scheme (ii) above, the oldest field&#39;s data is dropped when no empty data fields are remaining. For example, when there are three (3) elements (e.g., force plate assemblies) that are consecutively loaded in series, and there are only two data fields that are capable of being filled, the data corresponding to the first (oldest) element (e.g., force plate assembly) in the series is dropped when the data corresponding to the third (newest) loaded element is added to the plurality of data fields. As such, in the data combination scheme (ii), only the data corresponding to the second and third loaded elements (e.g., second and third loaded force plate assemblies) remain in the data packet containing the data fields. For data combination scheme (iii) above, the data packet is provided with an overflow field, and any subsequent loaded elements (e.g., force plate assemblies) in the series that do not have an available data field are added to the overflow field. For example, the combined data packet being used in conjunction with four (4) loaded elements (e.g., force plate assemblies) connected in series may comprise two regular data fields and one overflow data field. The loads corresponding to the first two loaded elements (e.g., force plate assemblies) in the series respectively fill the first and second regular data fields in the data packet. Because there are no remaining regular data fields left after they are filled by the first two loaded elements (e.g., force plate assemblies) in the series, the loads corresponding to the last two loaded elements (e.g., force plate assemblies) in the series are additively combined in the overflow field. As such, the data of the last two loaded elements is still retained in the combined data packet. For data combination scheme (iv) above, the lowest load in the series is dropped based upon some metric. For example, the combined data packet being used in conjunction with three (3) loaded elements (e.g., force plate assemblies) connected in series may comprise two available data fields. The loads of the two elements (e.g., force plate assemblies) in the series having the two highest load values are retained, while the load of the element (e.g., force plate assembly) in the series having the lowest load value is dropped. As such, in the data combination scheme (iv), only the load data corresponding to the two highest load values is retained in the data packet, while the load data corresponding to the lowest of the load values is not retained in the data packet. A variety of different metrics may be used to determine the lowest load that is dropped. For example, the metric may comprise an overall vector magnitude or the magnitude of one element of the vector (magnitude of the x-component of the vector, magnitude of the y-component of the vector, etc.). 
     It is readily apparent that the embodiments of the force measurement system with the modular configuration described above offer numerous advantages and benefits. The aforedescribed modular force measurement system is easy to install, and is readily adaptable to different building space configurations (i.e., the force measurement system is easily scalable for different room sizes and geometries). Also, because the plurality of force measurement assemblies of the force plate module are mounted on a common base at the factory, the plurality of force measurement assemblies are capable of being accurately aligned with one another. As such, when installed on site, it is only necessary to attach the individual force plate modules to one another in order to form the overall force plate array (e.g., by using the alignment/securement devices described above). Thus, the force measurement system is capable of being easily deployed on site by simply attaching the individual force plate modules to one another. In addition, because the embodiments of the force measurement system described above incorporate redundant power and data connections, the reliability of the force measurement system is greatly increased. 
     In accordance with another illustrative embodiment of the measurement and testing system described herein, the measurement and testing system is configured and arranged so as to allow a system user to preselect force plates of a force plate array that form a virtual force plate prior to the collection of load output data using the force plate array. In this illustrative embodiment, the measurement and testing system includes a plurality of force measurement assemblies (e.g., the force plate assemblies described above in conjunction with  FIG. 38  and  FIGS. 44-49 ), one or more input devices (e.g., a mouse, keyboard, and/or touchscreen user interface), and a data processing device (e.g., the computing device  1740  described above) operatively coupled to the one or more input devices and each of the force transducers of each of the force plate assemblies. In this illustrative embodiment, the one or more input devices are configured to output one or more signals comprising input data indicative of which of the plurality of force plate assemblies are to be combined with one another, and the data processing device is configured and arranged to receive the one or more signals outputted by the one or more input devices and to form a virtual force measurement assembly comprising a subset of the plurality of force measurement assemblies based upon the input data of the one or more signals. Also, in this illustrative embodiment, the measurement and testing system further comprises a visual display device having an output screen (e.g., the visual display device  1530  described above in conjunction with  FIG. 38 ). The visual display device is configured to display one or more images on the output screen so that the one or more images are viewable by a system user. 
     With particular reference to  FIG. 54 , in the illustrative embodiment, it can be seen that the data processing device of the measurement and testing system is configured and arranged to generate a screen image  1800  on the visual display device that generally includes a graphical representation of a force plate array  1802  and a dialogue box  1810  for entering force plate identification numbers for the selected ones of the force plate assemblies. As shown in  FIG. 54 , the graphical representation of the force plate array  1802  comprises a plurality of individual force plates  1804  with identification numbers  1806  on each of the force plates  1804 . The subset of force plates  1804  selected by the system user to form the virtual force measurement assembly are encircled by a dashed outline  1808  in  FIG. 54 . 
     In the illustrative embodiment, the one or more input devices may include a keyboard (i.e., keyboard  1526  in  FIG. 38 ) configured to output one or more signals with the input data in response to a manipulation of the keyboard by the system user. As shown in the screenshot of  FIG. 54 , the dialog box  1810  enables the system user to specify designated ones of the plurality of force plate assemblies  1804  forming the virtual force measurement assembly  1808  by entering force plate numbers  1812  into the dialog box  1810  by using the keyboard. 
     In the illustrative embodiment, the one or more input devices also may include a mouse (i.e., mouse  134  in  FIG. 1 ) configured to output one or more signals with the input data in response to a manipulation of the mouse by the system user. As shown in the screenshot of  FIG. 54 , the graphical representation of the force plate array  1802  enables the system user to specify designated ones of the plurality of force plate assemblies  1804  forming the virtual force measurement assembly  1808  by manipulating the mouse so as to place the selector arrow  1814  on the desired ones of the force plate assemblies  1804 , and then selecting the force plate assemblies  1804  for inclusion in the virtual force measurement assembly  1808  by clicking one of the buttons on the mouse. 
     In the illustrative embodiment, the one or more input devices additionally may include a touchscreen user interface (i.e., a touchscreen user interface of the visual display device) configured to output one or more signals with the input data in response to a manipulation of the touchscreen user interface by the system user. As shown in the screenshot of  FIG. 54 , the graphical representation of the force plate array  1802  enables the system user to specify designated ones of the plurality of force plate assemblies  1804  forming the virtual force measurement assembly  1808  by touching the locations of the desired ones of the force plate assemblies  1804  on the output screen of the touchscreen user interface. 
     In the illustrative embodiment, the input device and the data processing device may each be part of a single digital device (e.g., a laptop computing device, a tablet computing device, or a smartphone). In one or more alternative embodiments, the data processing device and the input device may be separate components that are operatively coupled to one another (e.g., a desktop type computing system including a main housing with a central processing unit (CPU), a remote monitor, a remote keyboard, and a remote mouse, as depicted in  FIGS. 1 and 35 ). 
     In accordance with the aforedescribed illustrative embodiment, a flowchart illustrating the procedure by which output data from selected force plate assemblies  1804  forming the virtual force measurement assembly  1808  is combined will be described with reference to  FIG. 55 . All of the steps described below with reference to the flowchart of  FIG. 55  are carried out by the data processing device of the measurement and testing system. Referring to  FIG. 55 , the procedure commences at  1820 , and in step  1822 , the input data from the one or more input devices is processed by the data processing device so as to determine the selected devices forming the virtual force measurement assembly  1808 . In the illustrative embodiment, the data processing device is configured to form the virtual force measurement assembly  1808  using the input data of the one or more signals from the input device prior to generating the load output data from the measurement signals of the selected force plate assemblies  1804  so that load output from inactive force plate assemblies is not required to be generated by the data processing device. Then, in step  1824 , collected data from all connected, selected devices (i.e., selected force plate assemblies  1804 ) is processed by the data processing device. In one embodiment, selected force plate assemblies  1804  are used to collect data from a subject or patient disposed thereon. In this embodiment, after the data processing device receives a plurality of voltage signals (i.e., a plurality of channels of data) from the selected force plate assemblies  1804 , it initially transforms the signals into output force and moment components by multiplying the voltage signals by a calibration matrix. For example, the voltage output signals received from each of the selected force plate assemblies  1804  are transformed into the vertical force components F Z  exerted on the plates of the assembly by the feet of the subject, the moment component about the x axis M X  exerted on the plates of the assembly by the feet of the subject, and the moment component about the y axis M Y  exerted on the plates of the assembly by the feet of the subject. Next, with reference again to  FIG. 55 , it can be seen that, in step  1826 , any matrix and summation calculations are performed by the data processing device as needed by the synthetic virtual device (i.e., the virtual force measurement assembly  1808 ). For example, similar to those described above in conjunction with the embodiment of  FIGS. 34-37 , the channels of data from the selected force plate assemblies  1804  may be summed into a synthetic channel if required, and matrix rotation may be used to correct for the actual orientation of the selected force plate assemblies  1804  in the force plate array  1802 . Then, in step  1828  of  FIG. 55 , the device channels of the selected force plate assemblies  1804  may be combined into a single time-synced channel collection. That is, in the illustrative embodiment, the data processing device may be configured to generate the load output data by combining the signals of the subset of the plurality of force plate assemblies  1804  forming the virtual force measurement assembly  1808  by combining the signals of the subset of the plurality of force plate assemblies  1804  forming the virtual force measurement assembly  1808  into a single time-synced synthetic channel. The time-syncing of the output data will be described in further detail hereinafter. Once the final computed result (e.g., the overall vertical force and moment components F Z   _   VP , M X   _   VP , M Y   _   VP ) is returned in step  1830 , the process ends at step  1832 . 
     In accordance with yet another illustrative embodiment of the measurement and testing system described herein, the data processing device of the measurement and testing system is configured and arranged to synchronize data sets with different sampling rates or different sampling frequencies by using timestamp syncing. In this illustrative embodiment, the measurement and testing system includes a first measurement device (e.g., a force plate) and a second measurement device (e.g., an inertial measurement unit (IMU)). The first measurement device has a first sampling rate (e.g., 1,000 Hertz), and the first measurement device is configured to sense one or more measured quantities and output one or more first measurement signals that are representative of the one or more measured quantities. As illustrated in table  1834  of  FIG. 56 , the one or more first measurement signals comprise a first plurality of data values (i.e., vertical force values  1836  (F Z ) in table  1834 ) with corresponding first timestamps (i.e., timestamps  1838  in table  1834 ) associated with each of the first plurality of data values  1836 . The second measurement device has a second sampling rate (e.g., 100 to 250 Hertz) that is different than the first sampling rate of the first measurement device, and the second measurement device is configured to sense one or more measured quantities and output one or more second measurement signals that are representative of the one or more measured quantities. As illustrated in table  1840  of  FIG. 56 , the one or more second measurement signals comprise a second plurality of data values (i.e., x position values  1842  (R X ) in table  1840 ) with corresponding second timestamps (i.e., timestamps  1844  in table  1840 ) associated with each of the second plurality of data values  1842 . In this illustrative embodiment, the measurement and testing system further includes a data processing device (i.e., a computing device) operatively coupled to the first measurement device (i.e., the force plate) and the second measurement device (i.e., the IMU). The data processing device is configured to receive the one or more first measurement signals from the first measurement device (i.e., the force plate) and the one or more second measurement signals from the second measurement device (i.e., the IMU). As illustrated in  FIG. 56 , the data processing device further is configured to synchronize each of the first plurality of data values  1836  with each of the second plurality of data values  1842  by determining which of the first timestamps  1838  correspond to the second timestamps  1844 . In particular, as diagrammatically indicated by the arrows  1846 , the data values  1842  in table  1840  are aligned with the data values  1836  in table  1834  that correspond to the same point in time by matching the corresponding timestamps  1838 ,  1844  of the data values  1836 ,  1842 . 
     In the illustrative example of  FIG. 56 , the first sampling rate or frequency (i.e., 1,000 Hertz) of the force plate is greater than the second sampling rate or frequency (i.e., 100 to 250 Hertz) of the inertial measurement unit (IMU). Also, in the illustrative example of  FIG. 56 , the second sampling rate or frequency of the inertial measurement unit (IMU) is variable over time (i.e., the sampling frequency varies between 100 Hertz and 250 Hertz over time). In other alternative embodiments, the first measurement device may be in form of a different device with a sampling rate or frequency that is less than the sampling rate or frequency of the second measurement device. Also, the second measurement device may be in form of a different measurement device with a constant sampling frequency, rather than a variable sampling rate or frequency. 
     Although the invention has been shown and described with respect to a certain embodiment or embodiments, it is apparent that this invention can be embodied in many different forms and that many other modifications and variations are possible without departing from the spirit and scope of this invention. Moreover, while reference is made throughout this disclosure to, for example, “an illustrative embodiment”, “one embodiment” or a “further embodiment”, it is to be understood that some or all aspects of these various embodiments may be combined with one another as part of an overall embodiment of the invention. Also, the compound conjunction “and/or” is used throughout this disclosure to mean one or the other, or both. 
     In addition, while exemplary embodiments have been described herein, one of ordinary skill in the art will readily appreciate that the exemplary embodiments set forth above are merely illustrative in nature and should not be construed as to limit the claims in any manner. Rather, the scope of the invention is defined only by the appended claims and their equivalents, and not, by the preceding description.