Abstract:
A device for measuring the force-exerting ability of human muscle groups, comprising at least one pressing element which works together with a force-measuring unit which can measure the force exerted on at least one pressing element The pressing element, of which there is at least one in the force-measuring unit. being arranged so that its height can be adjusted and so that it can be fixed at a desired height. The force-measuring device having, in addition to the at least one pressing element working together with a force-measuring unit, at least one and preferably three additional pressing elements serving to hold certain parts of the test person&#39;s body in place, whose height can also be adjusted and which can be fixed at the desired height and are horizontally adjustable and can be fixed in the desired horizontal position.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention concerns a force-measuring device, in particular a device for measuring the force-exerting ability of human muscle groups, comprising at least one pressing element which works together with a force-measuring unit which can measure the force exerted onto at least one pressing element, with this pressing element (of which there is at least one) in the force-measuring unit being arranged so that its height can be adjusted and so that it can be fixed at a desired height. 
     2. The Background Art 
     Force-measuring devices of the type described at the beginning are known from the state of the art as described in U.S. Pat. No. 4,742,832. For example, when measuring the force-exerting ability of the arm muscles, the subject is placed in sitting position in the force-measuring device. A load-producing cushion unit is located in front of the subject. When the subject presses his hand against the load-producing cushion unit, a motion is produced for measuring the force. The arrangement according to U.S. Pat. No. 4,742,832 simultaneously measures the force contributions of other muscle groups along with the force exerted by the muscle group which is to be measured. This falsifies the measurement. 
     In addition, there are force-measuring devices described in PCT/US 87/01247 and PCT/US 88/01354, which make it possible to measure various muscle groups. These systems have a complicated structure and are expensive. These systems also take up a lot of space. Moreover, even these force-measuring devices are unable to perform force measurements on individual muscle groups without simultaneously measuring the contributions of other muscle groups which are not supposed to be measured. 
     Measuring the force-exerting ability of various muscle groups is especially important for controlling the training of preventive medicine training programs. This concerns especially the trunk-stabilizing muscles, which have a special influence on the spinal column. Preventing back pain requires avoiding muscular imbalances. Sports medicine investigations have shown that weak trunk muscles favor the occurrence of back pain. Information about the ability force-exerting ability of the trunk muscles which determine performance is important for preventive medicine back training. Such information can help fitness centers, physical therapists, and other rehabilitation devices formulate individual training programs for customers or patients and target diagnosed muscular weaknesses. Such measurement procedures have seldom been used up to now for cost reasons, since creating the known measurement systems mentioned above was economically not very attractive. 
     SUMMARY OF THE INVENTION 
     The problem on which this invention is based is to create a measurement device of the type mentioned at the beginning which makes it possible to measure the force-exerting ability of individual muscle groups and is simultaneously simple to construct. 
     This is accomplished according to the invention by the fact that the force-measuring device has, in addition to the at least one pressing element working together with a force-measuring unit, at least one, preferably three pressing elements serving to hold certain parts of the test person&#39;s body in place, whose height can also be adjusted and which can be fixed at the desired height and are horizontally adjustable and can be fixed in the desired horizontal position. The individual muscle groups can be measured one after the other, with each of the pressing elements, of which there are at least one, being fixed at the height suitable for it. 
     It is also advantageous if at least one pressing element and/or the force-measuring device is arranged so that it can pivot upward and/or downward. This makes it possible, for example, to measure forces exerted onto the pressing clement from above, so that the force-exerting ability of additional muscle groups can be determined. 
     It is preferable if the force-measuring device has two pressing elements, each working together with a force-measuring unit, with these two pressing elements being arranged so that they can be pushed horizontally, for example, against the breast and back of the subject at the same height. This makes it easy to measure the abdominal muscles and sacrospinal muscle one after the other, for example. 
     According to the invention, the force-measuring device can have, in addition to the at least one pressing element working together with a force-measuring unit, at least one, preferably three other pressing elements, which do not work together with a force-measuring unit and whose height can also be adjusted and which can be fixed at the desired height and preferably are also horizontally adjustable and which can be fixed in the desired position. These other pressing elements make it possible to hold the subject&#39;s body at certain places while other muscle groups are measured. 
     According to a preferred embodiment of this invention the force-measuring device comprises a frame with a top and two side frame pieces and a base plate from which the side frame pieces extend upward. Both sides of the side frame pieces which are turned toward one another can have a vertical adjustment strip arranged on them, on which vertical slides can move and be fixed, whose travel causes the height adjustment of the at least one pressing element. It is preferable if each of the vertical slides has a horizontal slide is fixed on it, in which a horizontal adjustment strip can move approximately in the direction toward the opposite vertical adjustment strip or away from it, with the movement of the horizontal adjustment strip causing the horizontal adjustment of the at least one pressing element. The frame construction with the horizontal and vertical adjustment strips and the vertical and horizontal slides assigned to them give the device a relatively uncomplicated structure, which nevertheless ensures that certain parts of the subject&#39;s body are fixed in an ideal manner for each muscle group and that the force is picked up in an ideal manner through the pressing elements. 
     The end of a horizontal adjustment strip turned toward the opposite vertical adjustment strip can have a force-measuring unit placed on it, on whose opposite end is placed the pressing element together with which it works. As an alternative to this, the end of a horizontal adjustment strip turned toward the opposite vertical adjustment strip can have a pressing element placed on it which does not work together with a force-measuring device. This makes it possible to move the pressing elements toward or away from the body of the subject by simply moving the horizontal adjustment strip horizontally. 
     According to a preferred embodiment of this invention, the force-measuring unit comprises a force transducer, which preferably has the shape of the letter “Z”. The force transducer can measure the force exerted onto it, for example by means of a wire strain gauge. It is advantageous for the force transducer to work according to the principle of measuring shear force transverse to the longitudinal axis. Such a force transducer is very sensitive and can determine the force exerted on it over a great range of forces. 
     It is advantageous for the force-measuring unit to comprise a pivoting element which has a pressing element fastened to it by suitable means of attachment, with the pivoting element being arranged in the force-measuring unit in such a manner that exerting a force on the pressing element in the direction toward the force-measuring unit presses the pivoting element against the force transducer, and thus exerts a measurable force on it. The previously mentioned arrangement is constructed in a simple but effective manner since the force exerted on the pressing element is passed directly to the force transducer. 
     The horizontal and vertical slides can be placed on the horizontal and vertical adjustment strips in a continuously adjustable and fixable manner. As an alternative to this, equidistant holes can be made in the vertical and horizontal adjustment strips, which make it possible to fix the vertical or horizontal slides, in which case the vertical and horizontal adjustment can only be made in steps corresponding to the distances between the holes. 
     A force-measuring device according to the invention can also comprise horizontal and vertical stay bars. In particular, a horizontally oriented stay bar can be oriented perpendicular to the horizontal adjustment strips and can be gripped by the hands of the subject so that he can pull himself toward the bar or press himself away from it. 
     The following description of the figures also gives an overview of the muscle groups which can be measured, for example with the force-measuring device according to the invention. More advantages and features of this invention will be made clear by the following description of preferred embodiments, which makes reference to the attached figures. The figures are as follows: 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front view of a force-measuring device according to the invention; 
     FIG. 2 is a perspective view of a force-measuring device according to the invention; 
     FIG. 3 is a perspective view of a force-measuring device according to the invention in an arrangement which is suitable for measuring the force-exerting ability of the abdominal muscles and the sacrospinal muscle; 
     FIG. 4 is a perspective view of a force-measuring device according to the invention in an arrangement which is suitable for measuring the force-exerting ability of the side trunk muscles; 
     FIG. 5 is a perspective view of a force-measuring device according to the invention in an arrangement which is suitable for measuring the force-exerting ability of the flexors of the cervical spine and the cervical muscles; 
     FIG. 6 is a perspective view of a force-measuring device according to the invention in an arrangement which is suitable for measuring the force-exerting ability of the upper back muscles and the triceps and pectoral muscles; 
     FIG. 7 is a perspective view of a force-measuring device according to the invention in an arrangement which is suitable for measuring the force-exerting ability of the abductor muscles. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     As can be seen in FIG. 1, a force-measuring device according to the invention comprises a frame made of a top frame piece  1  and side frame pieces  2 ,  3 . The bottoms of the side frame pieces  2 ,  3  are connected with a base plate  4  which give a secure upright position to the force-measuring device according to the invention. 
     The internal sides of the side frame pieces  2 ,  3  turned toward one another have vertical adjustment strips  5 ,  6  placed on them which lie against them. The vertical adjustment strips  5 ,  6  can be designed as square metal struts, as are the frame pieces  1 ,  2 ,  3 . In the sample embodiment shown, the vertical adjustment strips  5 ,  6  have equidistant holes  7  over their entire height, which, in the arrangement according to FIG. 1, pass through the adjustment strips  5 ,  6  from front to back and perpendicular to them. Each of the adjustment strips  5 ,  6  has several vertical slides  8  whose height can be adjusted, in particular which can slide up and down. The vertical slides  8  have a tightening knob  9  which makes it possible to fix the respective vertical slide  8  at the desired height as a function of the grid dimension of the holes  7  in adjustment strips  5 ,  6 . Of course it is also possible according to the invention for the vertical slides  8  to be adjustable in a continuous manner, instead of stepwise, with the minimum step size being determined by the holes  7 . In the sample embodiment shown, the left adjustment strip  5  has three vertical slides  8  arranged on it, while the right adjustment strip  6  only has two vertical slides  8 . 
     Each of the vertical slides  8  has a horizontal slide  10  fastened on it which is oriented perpendicularly to it and through which a horizontal adjustment strip  11  can be moved approximately in the direction toward the middle of the force-measuring device and away from it, that is toward the left and right in FIG.  1 . Each of the horizontal adjustment strips  11  has equidistant horizontal perpendicular holes  12  passing through the adjustment strip  11 , so that the horizontal adjustment strip  11  can be stopped at a desired position by means of a tightening knob  13  arranged on the horizontal slide  10 . 
     Each end of the two top horizontal adjustment strips  11  turned toward the middle of the force-measuring device has a force-measuring unit  14  according to the invention on it. This force-measuring unit  14  will be described in detail below. Each of the internal sides of the force-measuring device  14 , which are turned approximately toward the middle of the force-measuring device, have pressing elements  15  made in the form of cushions placed on their upper third. Such pressing elements  15  made in the form of cushions are also located on the internal ends of the middle and lower horizontal adjustment strips  11  turned approximately toward the middle of the force-measuring device. 
     The force-measuring devices  14  and/or the pressing elements  15  can be arranged so that they can pivot, for example by up to 90°, about at least one point of articulation on the respective horizontal adjustment strip  11 . This makes it possible to measure, for example, a force acting from above on the pressing element connected with a force-measuring device  14  after it is pivoted 90° counterclockwise. 
     FIG. 1 also shows another vertical stay bar  16  projecting upward from the base plate  4  and a horizontal stay bar  17  which is placed, in the sample embodiment shown, in the inside of the connection area of the top right vertical slide  8  with the associated horizontal slides  10 . The function of the horizontal stay bar  17  is also described in detail below. 
     The force-measuring device  14  shown in detail in FIG. 2 comprises an essentially cuboid housing  18  whose side turned toward the inside or the middle of the force-measuring device has a cushion holder  19  placed on it. On the housing side, the cushion holder  19  is held approximately at its geometric center by an upper outward-turned leg  20  of a flat piece of steel  21  mounted in the housing so that it can pivot. The top L-leg  20  of the flat piece of steel  21  projects outward through a opening  22  in the inside of the housing  18 , so that pressing on the pressing element  15  in the form of a cushion exerts a force through the cushion holder  19  onto the top L-leg  20  of the flat piece of steel  21 . The lower part of the flat piece of steel  21  is mounted so that it can pivot about a pivoting axis  23 . Starting from this pivoting axis  23 , the flat piece of steel  21  comprises an essentially vertically oriented long leg  24  and the outward-oriented top L-leg  20  lying against it. Pressing on the pressing element  15  exerts an inward-directed force on the top L-leg  20 , so that the essentially vertical leg  24  of the flat piece of steel  21  is also pressed inward. 
     The housing  18  also has a force transducer  25  placed in it, which is essentially Z-shaped. Each of the two outer right and left legs of the “Z” has a threaded hole  26 ,  27  in it. The threaded hole  26  makes it possible to fasten the force transducer  25  with a screw  28 , for example, on the outside of the housing, approximately opposite the opening  22 . In the sample embodiment shown in FIG. 2, the threaded hole  27  turned toward the inside holds an outward-facing screw  29  which runs to a point facing the vertical leg  24  of the flat piece of steel  21  and forming a pressure point for introducing force. An adjustment screw  32  makes it possible to adjust the distance between the vertical leg  24  of the flat piece of steel  21  and the pressure point of the screw  29  so as to minimize the play in the force-measuring unit  14 . 
     The middle leg of the essentially Z-shaped force transducer  25  has a wire strain gauge placed in it, which makes possible sensitive measurement of the force exerted on the pressure point. The force transducer  25  works according to the principle of measuring shear force transverse to the longitudinal axis. The application space for the wire strain gauge can be filled with a highly elastic substance and thus be protected from mechanical and chemical damage. For example, on the top a measurement output  30  exits from the force transducer  25  and passes upward out of the housing  18  of the force-measuring unit  14 , for example, as is shown in the sample embodiment. The measurement output  30  can be connected with a measurement device having an LCD display, for example. Such a measurement device can be powered by batteries or rechargeable batteries, for example, so that no external source of power is necessary. However, instead of being connected with a measurement device, the measurement output  30  can also be connected with a laptop computer, for example, or something like it, in order to store and further process the measurement data obtained. 
     FIG.  3  through FIG. 7 show sample applications of a force-measuring device according to the invention. The arrangement of the pressing elements  15  in the form of cushions shown in FIG. 3 is for measuring the force-exerting ability of the abdominal muscles and the sacrospinal muscle. In the sample embodiment shown the hip area of the subject  31  is fixed with the two middle pressing elements  15 . The two left and right top pressing elements  15 , each of which has a force-measuring unit  14 , lie against the back and breast area of the subject  31 . Pressing forward on the right force-measuring unit  14  measures the force-exerting ability of the abdominal muscles, while pressing backward on the left force-measuring unit  14  measures the force-exerting ability of the sacrospinal muscle. 
     In the design shown in FIG. 4, the hips of the subject are again fixed by the middle pressing elements  15 . The two top pressing elements  15 , each connected with force-measuring units  14 , lie against the top outside of the upper arms of the subject  31 . Pressing to the left or right on the respective pressing elements  15  connected with force-measuring units  14  determines the force-exerting ability of the side trunk muscles (lateral flexion). 
     In the arrangement shown in FIG. 5, the subject  31  is fixed approximately at breast height by the middle pressing elements  15 . The pressing elements  15  connected with the force-measuring units  14  lie approximately in the area of the back of the head and the forehead. Pressing the forehead against the pressing element  15  in the form of a cushion on the right side of the force-measuring device according to the invention determines the force-exerting ability of the flexors of the cervical spine. Pressing the back of the head against the pressing element  15  in the form of a cushion on the left side of the force-measuring device according to the invention determines the force-exerting ability of the cervical muscles (extensors of the cervical spine). 
     In the arrangement shown in FIG. 6, the lower left pressing element  15  made as a cushion serves as a sitting surface. The left pressing element  15  arranged above it stabilizes the lumbar spine of the subject  31 , and the top right pressing element  15  connected with a force-measuring unit  14  lies against the breast area of the subject  31 . The hands of the subject  31  grip the horizontal stay bar  17 . Pulling the breast or the upper body against the pressing element  15  made in the form of a cushion in the right part of the force-measuring device determines the force-exerting ability of the upper back muscles. As an alternative to the arrangement shown in FIG. 6, the upper left pressing element  15  connected with a force-measuring unit  14  can be laid against the area of the shoulder blades of the subject  31 . In such an arrangement if the arms are pressed forward against the stay bar  17 , then pressing the back against the pressing element  15  made in the form of a cushion can determine the force-exerting ability of the triceps and pectoral muscles. 
     In the arrangement shown in FIG. 7, the left middle pressing element  15  made in the form of a cushion lies in the outside area of the right thigh of the subject  31 . Approximately in the area of the opposite knee the right pressing element  15  connected with a force-measuring unit  14  lies against it on the outside. Pressing the left leg against the cushion set at knee height makes it possible to determine the force-exerting ability of the abductors. 
     In addition to the muscle groups shown in FIG.  3  and FIG. 7, the force-measuring device according to the invention, with its great variability, can determine the force-exerting ability of other muscle groups 
     
       
         
               
             
               
               
               
             
           
               
                   
               
               
                 List of Reference Numbers 
               
               
                   
               
             
             
               
                   
               
             
          
           
               
                   
                 1 
                 top frame piece 
               
               
                   
                 2, 3 
                 side frame piece 
               
               
                   
                 4 
                 base plate 
               
               
                   
                 5, 6 
                 vertical adjustment strip 
               
               
                   
                 7 
                 holes in 6 
               
               
                   
                 8 
                 vertical slide 
               
               
                   
                 9 
                 tightening knob on 8 
               
               
                   
                 1 
                 horizontal slide 
               
               
                   
                 11 
                 horizontal adjustment strip 
               
               
                   
                 12 
                 holes in 11 
               
               
                   
                 13 
                 tightening knob on 10 
               
               
                   
                 14 
                 force-measuring unit 
               
               
                   
                 15 
                 pressing element, cushion 
               
               
                   
                 16 
                 vertical stay bar 
               
               
                   
                 17 
                 horizontal stay bar 
               
               
                   
                 18 
                 housing 
               
               
                   
                 19 
                 cushion holder 
               
               
                   
                 20 
                 top L frame piece 
               
               
                   
                 21 
                 flat piece of steel 
               
               
                   
                 22 
                 opening 
               
               
                   
                 23 
                 pivoting axis 
               
               
                   
                 24 
                 vertical frame piece 
               
               
                   
                 25 
                 force transducer 
               
               
                   
                 26, 27 
                 threaded hole 
               
               
                   
                 28, 29 
                 screw 
               
               
                   
                 30 
                 measurement output 
               
               
                   
                 31 
                 subject 
               
               
                   
                 32 
                 adjustment screw