Patent Publication Number: US-10307641-B2

Title: Exercise tracker

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application claims priority to U.S. Ser. No. 14/972,312 filed on Dec. 17, 2015 and titled “Exercise Tracker,” the contents of which are hereby incorporated by reference in their entirety, and to U.S .Provisional Application Ser. No. 62/101,702 filed on Jan. 9, 2015and titled “Apparatus and Method for Tracking Exercise Equipment Usage,” the contents of which are hereby incorporated by reference in their entirety. 
    
    
     BACKGROUND 
     The advent of wearable monitors, such as pedometers and heart rate monitors, coupled with the increasing ease with which digital data can be recorded via wireless communication has led to a proliferation of technologies that allow users to track their physical fitness activities. Fitness trackers that communicate directly with a user&#39;s mobile phone or computer through Bluetooth®, for example, have become common. 
     Services that aggregate data from multiple monitoring devices and allow users to share data and “compete” with friends has increased the utility of the technologies by motivating individuals to achieve their wellness goals. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  illustrates an example exercise tracker mounted to a sample piece of exercise equipment. 
         FIG. 2  illustrates an example exercise tracker mounted to a cable of a sample piece of exercise equipment. 
         FIG. 3  illustrates example data collected by the force sensor incorporated into the exercise tracker. 
         FIGS. 4A-4B  are example free body diagrams illustrating forces acting on the exercise tracker. 
         FIG. 5  depicts example components of the exercise tracker. 
         FIG. 6  illustrates sample data collected by the exercise tracker. 
         FIG. 7  illustrates a graphical user interface for presenting the data collected by the exercise tracker. 
         FIGS. 8A-B  illustrate isometric and exploded views, respectively of another form factor for the exercise tracker. 
     
    
    
     DETAILED DESCRIPTION 
     Despite the increased interest in digitizing and recording users&#39; fitness activity, known fitness trackers do not adequately capture the activity performed on weight-lifting exercise equipment traditionally found in homes and private gyms. Thus, a device which can integrate this significant aspect of physical fitness into the expanding ecosystem of the “quantified self” would be beneficial. 
     One solution involves an exercise tracker that can detect repetitions performed on a piece of exercise equipment, especially one that requires a user to tension a cable to provide resistance. An example exercise tracker that can detect repetitions performed on exercise equipment includes a force sensor programmed to output a force signal representing a force applied to a cable associated with the piece of exercise equipment. The exercise tracker further includes a processing device programmed to receive the force signal and determine, from the force signal, exercise data including an amount of weight lifted and a number of repetitions performed. 
     The exercise data can be transmitted to and viewed by the user of the exercise equipment. In some instances, the exercise data may be transmitted to a remote server. The user can view the exercise data by accessing the data stored on the remote server via, e.g., a computing device such as a smartphone, tablet computer, a desktop computer, a laptop computer, or the like. 
     The elements shown may take many different forms and include multiple and/or alternate components and facilities. The example components illustrated are not intended to be limiting. Indeed, additional or alternative components and/or implementations may be used. Further, the elements shown are not necessarily drawn to scale unless explicitly stated as such. 
     As shown in  FIG. 1 , an exercise tracker  100  may be mounted to exercise equipment  105  by fastening it directly to a cable  110  used to elevate or otherwise move a stack of weights  115  when performing a “repetition” or “rep.” The exercise equipment  105  is shown as a leg extension machine but could alternatively be any exercise device that has a cable  110  that is pulled taut or otherwise tensioned with each repetition. Thus, the exercise equipment  105  shown is one example of many possible configurations of exercise equipment  105  that use the elevation of a stack of variable weights  115  to specify the resistance for an exercise routine. Further, instead of a weight-based exercise machine, the exercise tracker  100  may be used with, e.g., a rowing machine, a machine with bendable rods or other form of resistance caused by moving a cable, resistance bands, or the like. 
     In one possible approach, the exercise tracker  100  may be disposed on the cable  110  near the stack of weights  115 . In other implementations, the exercise tracker  100  may be mounted elsewhere on the cable  110 . The exercise tracker  100  may be mounted on a cable  110  travelling horizontally, vertically, or in any other orientation. Moreover, the exercise tracker  100  may be fixed relative to the cable  110  so that it moves in accordance with the movement of the cable  110 . Alternatively, the exercise tracker  100  may be fixed relative to the exercise equipment  105  so that the cable  110  moves independently of the exercise tracker  100 . 
     The cable  110  may have a generally circular cross section. Alternatively, the cable  110  may have a generally flat (i.e., a belt) or another cross-sectional shape. Sometimes, exercise equipment  105  with cables  110  will incorporate pulleys  120  that, e.g., allow the weight to move in a single direction regardless of the way the cable  110  is pulled. For instance, a pulley may allow the weight to move vertically upward during a repetition even though the cable  110  is pulled vertically downward, horizontally, or at another angle relative to the movement of the weight. Accordingly, the exercise tracker  100  may be positioned on the cable  110  at a location that will not conflict with the pulley. For instance, the exercise tracker  100  may be located on the cable  110  at a location far enough away from the pulley that it will not contact the pulley during a repetition. In implementations where a pulley cannot be avoided, such as implementations where the exercise tracker  100  must travel through a pulley to accurately count the repetition, the exercise tracker  100  may have a configuration that allows the exercise tracker  100  to travel through or otherwise avoid interfering with the pulley. If an end of the cable  110  is fixed, the exercise tracker  100  could also be mounted near this terminal such that it does not move even as the weights are raised and lowered. 
     Further, using pulleys  120  saves space by reducing the footprint of the exercise equipment  105  and may sometimes allow for a single piece of exercise equipment  105  to be used for different types of exercises using the same stack of weights  115 . The different types of exercises may require the engagement of different cables  110  or moving the cables  110  in different directions. In these instances, for example, multiple exercise trackers  100  may be installed on one or more cables  110  specific to individual exercise motions to differentiate which activities are being performed and logged. Thus, although only one exercise tracker  100  is shown, the exercise equipment  105  or the cable  110  may support multiple exercise trackers  100 . 
     Referring now to  FIG. 2 , the exercise tracker  100  may include one or more protrusions  125  and a force sensor  130  disposed on a base  135 . Other components of the exercise tracker  100  are illustrated in, and discussed below with reference to,  FIG. 5 . In one possible implementation, the base  135  and protrusions  125  may be formed from a unitary construction. Alternatively, the protrusions  125  may be disposed on the base  135  via, e.g., an adhesive, a fastener, or the like. Further, the base  135  and protrusions  125  may be formed from a relatively rigid material such as plastic or metal. In some possible approaches, the base  135  may include clips for receiving the power source, the force sensor  130 , or both. 
     The protrusions (collectively  125 ), as shown in  FIG. 2 , may be implemented as a first pin  125 A, a second pin  125 B, and a middle pin  125 C. As discussed in greater detail below, the protrusions  125  may take different forms. For instance, the protrusions  125  may have circular or non-circular cross-sections, and the shape of one protrusion  125  may be different from the shape of one or more other protrusions  125 . One or more of the protrusions  125  may be connected to another protrusion to promote structural rigidity. The protrusions  125  may be arranged on the base  135  in a way that allows the cable  110  to contact each of the protrusions  125 . For instance, the cable  110  may be in contact with each protrusion  125 , including the middle pin  125 C that may house or otherwise support the force sensor  130 , although all or any combination of protrusions  125  could support a force sensor  130  to provide the utility described herein. As illustrated in  FIG. 2 , the cable  110  may be routed such that it passes by, and contacts, each of the protrusions  125 . When the exercise tracker  100  is mounted on the cable  110 , the protrusions  125  may therefore deflect the cable  110  by a known magnitude or angle. When tension is applied to the cable  110  (i.e. the stack of weights  115  is lifted during a repetition), a force proportional to that tension may be applied to one or more protrusions  125 , such as the middle pin  125 C. 
     One or more of the protrusions  125  may be fixed relative to the base  135 . Alternatively, one or more protrusions  125  may rotate in order to provide less friction when the cable  110  is moving. The locations of the three protrusions  125  relative to one another allows the tension on the cable  110  to be measured, after calibration, for a suitable range of cable  110  diameters. In some implementations, certain protrusion  125  locations may be adjustable. For instance, the location of the middle pin  125 C may be adjusted via a positioning screw. In another approach, calibration clips, or shims, can be added to effectively alter the size of the protrusion  125  to accommodate a wider variety of cable diameters. Furthermore, the geometry of the protrusions  125  can be configured such that they can accommodate cables  110  with circular, rectangular, or any geometry of cross-section equally well. The terms “protrusion” and “pin” is used here to describe an element used to shape the cable  110  into the desired position and does not limit the shape of the structure to a circular cylinder, as a variety of shapes may be used to provide the same purpose. 
     The force sensor  130  (which may also be referred to as a load sensor or tension meter) may include any device configured to output signals (see  FIG. 3 ) representing the amount of force applied by the cable  110  when the cable  110  is, e.g., tensioned. Tensioning the cable  110  (i.e., pulling the cable  110  taut) removes slack from the cable  110  and may apply a force to one of the protrusions, e.g., the middle pin  125 C. The magnitude and profile of the force applied may be associated with the amount the middle pin  125 C deflects. The force sensor  130  may measure the deflection of the middle pin  125 C and output a force signal that represents the magnitude of the force. For instance, fluctuations of the force sensor  130  signal corresponding to acceleration of the weights as they are raised and lowered can be counted to indicate the number of repetitions. In another approach, the force sensor  130  may output the force signal each time the magnitude crosses a predetermined threshold. The predetermined threshold may be based on the magnitude of the force applied that is consistent with performing a repetition. 
       FIG. 3  illustrates example real-time data  230  that may be collected by the force sensor  130 . The data  230  may represent how the output of the force sensor  130  changes during a repetition and with a different amount of weight  115  attached to the cable  110 . For instance, the line  203 A may represent repetitions of an exercise performed at a weight of 200 lbs. The line  230 B may represent repetitions of an exercise performed at a weight of 160 lbs. The line  230 C may represent repetitions of an exercise performed at a weight of 120 lbs. The line  230 D may represent repetitions of an exercise performed at a weight of 80 lbs. The line  230 E may represent repetitions of an exercise performed at a weight of 40 lbs. The various “peaks,” “valleys,” and “plateaus” in the data  230  may indicate when a repetition has been performed. For instance, a repetition may be performed after the data  230  indicates a certain number of “peaks,” “valleys,” and “plateaus” have been observed. The data profile for a repetition may be based on the amount of weight  115  lifted. For instance, the “peaks,” “valleys,” and “plateaus” for line  230 A may be different from those for line  230 E since the weights are different. 
       FIG. 4A  is an example free body diagram illustrating one example relationship between the tension Tin the cable  110  and the force F observed by the middle pin  125 C. As discussed above, the force sensor  130  attached to the middle pin  125 C may detect the force F to measure the amount of weight being lifted. In one possible implementation, the force sensor  130  may include a strain gauge (e.g., a metal foil gauge) fixed directly to one of the protrusions  125  or an optical sensor such as an infrared (IR) emitter receiver pair. Since the middle pin  125 C may be a cantilevered body designed to deflect an amount proportional to the force applied, the force may be measured by the strain gauge, which may include a metallic foil with an electrical resistance that changes based on the amount of deflection, or the optical sensor. The change in resistance may be amplified via, e.g., a Wheatstone bridge circuit or other type of amplification circuit. In a different approach, the lateral force exerted on one or more of the protrusions  125  may be measured via a piezoresistive force sensor, a hydraulic pressure sensor, etc. 
     In an alternative approach, a sensor other than a strain gauge may be used. For example, a pressure transducer, a thin film pressure sensor, or any other force-measuring sensor could be employed. Additionally or in the alternative, the one or more protrusions  125  supporting the load sensor  130  may be replaced by a sliding element that slides in a direction perpendicular to the cable  110  when tension is applied. In another possible approach, the one or more protrusions  125  supporting the load sensor  130  may be movable via a pivoting arm rather than sliding within a track. 
     The preceding disclosure has assumed that the exercise tracker  100  attaches to a continuous cable segment. In implementations where the cable  110  is separated into multiple segments  140  (e.g., the cable  110  is cut to accommodate the exercise tracker  100  or the exercise tracker  100  is used to attach two ends of different cables  110  together), the tension can be measured directly via any number of other approaches. For instance, a spring  145  (see  FIG. 4B ) resisting the movement can allow the applied force to be determined based on a measurement of the amount of deflection in response to the tension applied to one or both segments  140  of the cable  110 . 
       FIG. 5  illustrates another view of the exercise tracker  100  mounted to a cable  110  with additional example elements mounted to the base  135 . The additional example elements shown in  FIG. 5  include a circuit board  150 , a wireless communication device  155 , an accelerometer  160 , a battery  165 , buttons  170 , and a display screen  175 . These components may be mounted, directly or indirectly, to the base  135 . 
     The circuit board  150  may include a printed circuit board  150  having conductive leads forming various electrical connections between or among different components of the exercise tracker  100 . The leads may be etched from a conductive sheet laminated onto a non-conductive substrate. The circuit board  150  may be disposed on the base  135 . The circuit board  150  may include a CPU or other form of processing device  180  and onboard memory (e.g., a data storage medium  185 ) to record and temporarily store data collected by the force sensor  130 , accelerometer  160 , or both (i.e. tension cycles, accelerometer movement). 
     The wireless communication device  155  may include any electronic component configured or programmed to facilitate wireless communication. For instance, the wireless communication device  155  may be programmed to transmit the data collected by the force sensor  130 , accelerometer  160 , or both via a telecommunication protocol such as Bluetooth®, Bluetooth Low Energy®, etc., to a remote device  190  (see  FIG. 1 ) such as a mobile phone, smartwatch, or wearable activity tracker, or to a remote server  195  (see  FIG. 1 ), such as a cloud-based server or a server associated with a particular facility (e.g., a gym). The term “remote” when used in the context of the remote device  190  and remote server  195  may refer to the spatial relationship of the remote device  190 , the remote server  195 , or both, relative to the exercise tracker  100 . Therefore, although referred to as “remote,” the remote device  190  and remote server  195  may be physically near the exercise tracker  100  (i.e., the remote server  195  may be in communication with the exercise tracker  100 , the remote device  190 , or both, via a local network connection). Alternatively, the remote device  190  or remote server  195 , or both, may be physically “remote” but still in signal communication with the exercise tracker  100  (e.g., the remote server  195  may be cloud-based). Accordingly, in some implementations, the data may be transmitted from the exercise tracker  100  to the remote device  190  or the remote server  195  (see  FIG. 1 ) via a Wi-Fi network connection. The wireless communication device  155  may be programmed to periodically transmit the collected data to the remote device  190  or remote server  195 , or transmit the data as it is collected. Alternatively, the wireless communication device  155  may be programmed to transmit the data to the remote device  190  or the remote server  195  at specific times, such as when all repetitions have been performed on a particular piece of exercise equipment  105  or when a workout is complete. The wireless communication device  155  may determine that all repetitions have been performed based on the force sensor  130  signal or that the workout is complete in response to a user input provided to the exercise tracker  100  or remote device  190 . 
     Pairing with the remote device  190  may include the wireless communication device  155  transmitting certain information to, and receiving certain information from, the remote device  190 . In some possible scenarios, the wireless communication device  155  may transmit a unique identifier to the remote device  190 . Likewise, the wireless communication device  155  may receive a unique identifier transmitted from the remote device  190 . Instead of identifying the paired remote device  190  through the unique identifier, the wireless communication device  155  may be programmed to pair with the remote device  190  that has the strongest signal over a predetermined threshold, indicating that the remote device  190  is nearby and that the user of the remote device  190  is using the piece of exercise equipment  105  associated with the exercise tracker  100 . Scanning for the unique identifiers by the wireless communication device  155  may be initiated by depression of a button  170  by the user at the beginning of a set of repetitions on the piece of exercise equipment, such as after the amount of weight resistance has been selected. 
     Instead of or in addition to signal strength, the wireless communication device  155  may pair with remote devices  190  based on signals received from the remote server  195 . For instance, the remote server  195  may triangulate the locations of one or more remote devices  190 , by signal strengths detected via the remote server  195  or other exercise trackers  100 , and command each exercise tracker  100  to pair with the closest (or otherwise most appropriate) remote device  190 . Instead of, or in addition to, triangulating based on signal strength, the remote server  195  may use an image processing technique to determine which remote devices  190  are near which exercise trackers  100 . For instance, cameras or other image sensors can be used to detect the locations of particular remote devices  190 , and the remote server  195  may generate the commands for the exercise trackers  100  to pair with particular remote devices  190  according to the images captured by the cameras. The wireless communication device  155  may receive the command from the remote server  195  and pair with the commanded remote device  190 . Global Positioning Systems (GPS) or other geo-location functionality on the remote device  190  could also be used to identify the piece of exercise equipment being operated by the user. 
     The accelerometer  160  may include any electronic device programmed to detect motion of the exercise tracker  100  in one or more directions, including the direction of the cable  110 . The motion of the exercise tracker  100  that can be detected by the accelerator may occur during exercise as, e.g., the stack of weights  115  is lifted from a starting position, cycled between positions during the exercise, and returned to the starting position. The accelerometer  160  may be programmed to generate and output signals representing such movement. The data representing the motion of the exercise tracker  100  collected by the accelerometer  160  may be processed by, e.g., the CPU, the remote device  190 , or the remote server  195  to count the number of repetitions that were performed at the measured weight setting. The data can also be used to measure other characteristics such as the length of the stroke, the tempo of the repetitions, the speed of the motion, or the aggressiveness of the action. In one possible implementation, the accelerometer  160  may include one or more gyroscopes, such as a three-axis MEMS-based gyroscope, although a single axis of movement may be sufficient to provide all of the functionality described herein. The accelerometer  160  may be disposed on the circuit board  150  and may be configured to output the signals representing the detected movement via the leads incorporated into the circuit board  150 . 
     The battery  165  may include any device configured to provide electrical energy to certain components of the exercise tracker  100 . For instance, the battery  165  may be electrically connected to the force sensor  130 , the circuit board  150  including the CPU, the wireless communication device  155 , the accelerometer  160 , the buttons  170 , and the display screen  175  as well as any other peripheral devices mounted to the base  135 . The battery  165  may be replaceable and, therefore, removably mounted to the base  135  via clips. Further, the base  135  may include leads that electrically connect the battery  165  to one or more other components when the battery  165  is mounted. In some possible approaches, the battery  165  may be charged by the movement of the cable  110 . That is, the exercise tracker  100  may include a kinetic charging feature that harvests energy from the exercise motions exerted upon the cable  110  and stores the harvested energy in the battery  165 . Energy can be harvested either from the linear oscillating motion of the device or through the force exerted onto the device via the tension exerted onto the cable  110 . 
     The buttons  170  and display screen  175  may form a user interface device that allow a user to directly provide inputs to, and receive information from, the exercise tracker  100 . For instance, the buttons  170  and display screen  175  may be used to provide user inputs associated with calibrating the exercise tracker  100  to work with a particular piece of exercise equipment  105 , accessing data collected by the exercise tracker  100 , identifying the person using the exercise equipment  105 , displaying historical exercise data to the user, synchronizing the exercise tracker  100  with a remote device  190  or remote server  195 , clearing the memory of the exercise tracker  100 , etc. The exercise tracker  100  need not have any user interface device, however, since user inputs and outputs may be presented via, e.g., a paired remote device  190  such as a mobile phone, smartwatch, or wearable activity tracker. In another approach, the unique identifier associated with the mobile device  190  may be recorded by the exercise tracker  100  and transmitted directly to the remote server  195 , via a local or wide area network connection, along with the details recorded about the exercise routine. User inputs may therefore be received at the paired remote device  190  and communicated from the paired remote device  190  to the exercise tracker  100 . Outputs may be transmitted from the exercise tracker  100  to the paired remote device  190  where they may be displayed to the user. Thus, the remote device  190  may receive user inputs and present outputs to the user regardless of whether the exercise tracker  100  includes the buttons  170 , display screen  175 , or both. 
     The ability of the exercise tracker  100  to wirelessly communicate with external devices allows for a streamlined calibration protocol. Different manufacturers of exercise equipment  105  may use cables of varying diameter and/or varying cable coating types/thicknesses to reduce wear on the cables. The effect of varying these parameters is similar to varying the angle, θ, shown in  FIG. 4A  and, therefore, proper calibration can correct for such inconsistencies. The calibration process may include prompting the user to perform a specified number of repetitions at various weight settings and fitting the collected data to a curve to predict the force detected across the full range of possible weights. If the initial calibration detects that some weights might fall outside the bounds detectable by the force sensor  130 , the calibration process may include prompting the user to add a shim to one or more of the protrusions  125  and/or alter its position using, e.g., an adjustment screw. In another approach, a component engaging the force sensor sensor could be replaced with one of a different size to achieve the desired amount of cable deflection. In an alternative approach, proper calibration may be achieved by prompting the user to follow a sequence of instructions through the display screen  175  incorporated into the exercise tracker  100  or the user&#39;s mobile device and fitting the collected data to a curve for the full range of weights. Alternatively, the calibration process may include prompting the user to elevate a known amount of weight and adjust the position of one of the protrusions  125  until the target force measurement is observed. In another approach, calibration may include prompting the user to elevate a known amount of weight and adjust a variable resistor to change the gain of an amplification circuit until the force sensor signal achieves a predetermined value. 
     In one possible scenario, the exercise tracker  100  may be “permanently” installed onto a piece of equipment. That is, the exercise tracker  100  may be attached to the cable  110  and left there for anyone using that piece of exercise equipment  105 . Alternatively, the exercise tracker  100  may be easily removed so that a single user can carry around and attach the exercise tracker  100  to each piece of compatible exercise equipment  105  that the user uses during his or her exercise routine. 
       FIG. 6  shows example exercise data  200  that may be collected by one or more exercise trackers  100 . In some instances, the data may be used only for purposes of counting repetitions. In other instances, the data may also be presented to the user via, e.g., a graphical user interface (see  FIG. 7 ). When presented to the user, the data may provide a historical record of the user&#39;s exercise routine, or at least the portion of the exercise routine that uses exercise equipment  105  with the exercise tracker  100 . Thus, the data may include the aggregate of the data collected from multiple exercise trackers  100 , each associated with different pieces of exercise equipment  105 . Further, different weights may be used, and different numbers of repetitions performed, at each piece of equipment. The data, therefore, may represent the amount of weight used, the number of repetitions performed, the number of sets performed, etc., during a workout. 
     The exercise data  200  may be generated by the processing device  180  incorporated into the exercise tracker  100 . The processing device  180  may receive the force signal output by the force sensor  130 , signals output by the accelerometer  160 , or both, to generate the exercise data  200 . Examples of exercise data  200  may include the magnitude of the weight lifted, the number of repetitions performed, the number of sets completed, etc. For instance, in the example of  FIG. 6 , the height of the bars  205  may represent the amount of weight lifted and the number of bars  205  may indicate the number of repetitions performed at that weight. Bars  205  representing repetitions performed on different pieces of exercise equipment  105  may be visually distinguishable. For instance, data collected from different pieces of exercise equipment  105  may be presented in different colors, line weights, and line types, etc. Thus, in instances where the same exercise tracker  100  is used on multiple pieces of exercise equipment  105 , the exercise tracker  100  may relate the collected data to the particular piece of exercise equipment  105 , and that relationship may be used to visually distinguish the data when viewed on a remote device  190  or computer monitor. In instances where the exercise tracker  100  is “permanently” attached to a piece of exercise equipment  105  (e.g., a situation where the exercise tracker  100  stays with the exercise equipment  105  instead of being carried around by a particular user), the exercise tracker  100  may attach an identifier to the data. The identifier may indicate on which piece of equipment the exercise was performed. Therefore, the data can be aggregated by the user&#39;s remote device  190  or the remote server  195 , and the weight used, the number of repetitions, the number of sets, etc., for each piece of exercise equipment  105  can be maintained when the data is ultimately processed or presented to the user. 
     During the calibration sequence outlined previously, the user may be prompted to identify the piece of equipment, so there is a link between each individually-installed exercise tracker  100  and the exercise routine it is being used to track. In some instances, the calibration may be performed initially when the exercise tracker  100  is installed onto the exercise equipment  105 . For pieces of exercise equipment  105  that have multiple uses, the user may be prompted to identify the exercise being performed. For instance, with reference to the example data shown in  FIG. 6 , the user may be prompted to confirm or otherwise identify that the exercise equipment  105  is being used to perform a triceps extension. When the user moves to a different piece of exercise equipment  105  or uses the same piece of equipment for a different exercise, the user may be prompted to confirm or otherwise identify that the exercise equipment  105  is now being used to perform a different exercise. For instance, still referring to the example data of  FIG. 6 , the user may be prompted to confirm or otherwise indicate that the user is performing a leg press or biceps curls when using the exercise equipment  105  associated with those exercises. 
     With continued reference to  FIG. 6 , the line  210  may represent the cumulative amount of calories burned in that day&#39;s sequence of exercise routines. The calories burned from each individual repetition can be determined by multiplying the weight being lifted by the total distance it travelled, both of which may be calculated by the exercise tracker  100  via the force sensor  130  and the accelerometer  160 , respectively. Alternatively, the total cumulative amount of weight lifted could produce a single metric to summarize the productivity of a workout. 
       FIG. 7  illustrates an example graphical user interface that may be used to present the data collected by one or more exercise trackers  100  during a workout session to a user. The graphical user interface may be presented via a remote device  190 , such as a smartphone, a wearable activity tracker, a smartwatch, or a computer which may include a desktop, a laptop, or tablet computer. As shown, the graphical user interface may present historical exercise data  215 , which may correspond to the data discussed above with reference to  FIG. 6 . Further, the graphical user interface may track and illustrate behavior and performance trends in a trend area  220 . Further, the graphical user interface may include a motivation field  225  that can be used for providing data that may motivate the user to continue to use the exercise tracker  100 . For instance, as shown, the motivation field  225  may include a user&#39;s rank relative to other people who have used exercise trackers  100  at the same or different location as the user. Besides rank, other forms of gamification may be used to provide motivation to the user to continue to exercise. If the data shown in the motivation field  225  relies upon data collected from the user or other people, for purposes of privacy, the graphical user interface may allow the user to limit who, if anybody, can see the user&#39;s data or subsets of the user&#39;s data. For instance, the motivation field  225  may only represent data collected from a small subset of people explicitly approved by the user. The interface may also allow the user to set specific goals and receive targeted motivational instructions to help the user achieve those goals. Feedback can be given to the user during their exercise routine in the form of messages on the device display screen  175 . Notifications may also be issued on the remote device  190  as a way to motivating the user toward achievement of goals, and vibration of the remote device can be used to indicate achievement of these goals without the need for visual monitoring by the user. 
     The exercise tracker  100  may compile and shares the data through a dedicated portal implemented via a remote server  195 . That is, any exercise tracker  100  used by the user may transmit the user&#39;s data to the remote server  195  where it may be aggregated and processed. The remote server  195  may present the graphical user interface with the data in response to a server request made by the user&#39;s mobile device, computer, etc. The data may be synchronized with the remote server  195  periodically, before a new user uses the exercise tracker  100 , in response to a user input, in response to a query from the remote server  195 , etc. In some implementations, the remote server  195  may act as a “master” to one or more “slave” exercise trackers  100 . 
     In some possible scenarios, the data may be shared with other fitness-tracking or health-related websites that aggregate data from multiple devices/sources. For instance, the data collected by the exercise tracker  100  may be shared with a user&#39;s physician via a website. Communication with various devices or sources may be facilitated via a third party aggregation site, an application programming interface (API) associated with the exercise tracker  100 , or the like. 
     As discussed above, the exercise tracker  100  may have many different configurations. One alternative configuration is illustrated in  FIGS. 8A-8B . In the exercise tracker  100  of  FIGS. 8A-8B , presented in an isometric view ( FIG. 8A ) and an exploded view ( FIG. 8B ), the exercise tracker  100  includes a housing  235  (serving as the base  135 , discussed above) and a cover  240  configured to house the various components including the force sensor  130  (shown as a load cell), the circuit board  150 , the batteries  165 , etc. For purposes of simplicity, other components such as the wireless communication device  155 , accelerometer  160 , processing device  180 , and data storage medium  185  are not explicitly labeled in  FIGS. 8A-8B  but may be housed in the housing  235  on, e.g., the circuit board  150 . 
     The protrusions  125  in  FIGS. 8A-8B  are illustrated as lever arms that can attach to the cable  110 , which as discussed above may have any number of cross-sectional shapes. The cover  240  may attach to the housing via a fastener  245 , and the housing  235  may further include a battery door  250  to allow the batteries  165  to be easily and quickly removed. Further, one or more screws  255  may be used to adjust the tightness of the protrusions  125  (e.g., the lever arm) relative to the cable and to connect the protrusion  125  to the force sensor  130 . 
     In general, the computing systems and/or devices described may employ any of a number of computer operating systems, including, but by no means limited to, versions and/or varieties of the Microsoft Windows® operating system, the Unix operating system (e.g., the Solaris® operating system distributed by Oracle Corporation of Redwood Shores, Calif.), the AIX UNIX operating system distributed by International Business Machines of Armonk, N.Y., the Linux operating system, the Mac OSX and iOS operating systems distributed by Apple Inc. of Cupertino, Calif., the BlackBerry OS distributed by Blackberry, Ltd. of Waterloo, Canada, and the Android operating system developed by Google, Inc. and the Open Handset Alliance. Examples of computing devices include, without limitation, a computer workstation, a server, a desktop, notebook, laptop, or handheld computer, or some other computing system and/or device. 
     Computing devices generally include computer-executable instructions, where the instructions may be executable by one or more computing devices such as those listed above. Computer-executable instructions may be compiled or interpreted from computer programs created using a variety of programming languages and/or technologies, including, without limitation, and either alone or in combination, Java™, C, C++, Visual Basic, Java Script, Perl, etc. Some of these applications may be compiled and executed on a virtual machine, such as the Java Virtual Machine, the Dalvik virtual machine, or the like. In general, a processor (e.g., a microprocessor) receives instructions, e.g., from a memory, a computer-readable medium, etc., and executes these instructions, thereby performing one or more processes, including one or more of the processes described herein. Such instructions and other data may be stored and transmitted using a variety of computer-readable media. 
     A computer-readable medium (also referred to as a processor-readable medium) includes any non-transitory (e.g., tangible) medium that participates in providing data (e.g., instructions) that may be read by a computer (e.g., by a processor of a computer). Such a medium may take many forms, including, but not limited to, non-volatile media and volatile media. Non-volatile media may include, for example, optical or magnetic disks and other persistent memory. Volatile media may include, for example, dynamic random access memory (DRAM), which typically constitutes a main memory. Such instructions may be transmitted by one or more transmission media, including coaxial cables, copper wire and fiber optics, including the wires that comprise a system bus coupled to a processor of a computer. Common forms of computer-readable media include, for example, a floppy disk, a flexible disk, hard disk, magnetic tape, any other magnetic medium, a CD-ROM, DVD, any other optical medium, punch cards, paper tape, any other physical medium with patterns of holes, a RAM, a PROM, an EPROM, a FLASH-EEPROM, any other memory chip or cartridge, or any other medium from which a computer can read. 
     Databases, data repositories or other data stores described herein may include various kinds of mechanisms for storing, accessing, and retrieving various kinds of data, including a hierarchical database, a set of files in a file system, an application database in a proprietary format, a relational database management system (RDBMS), etc. Each such data store is generally included within a computing device employing a computer operating system such as one of those mentioned above, and are accessed via a network in any one or more of a variety of manners. A file system may be accessible from a computer operating system, and may include files stored in various formats. An RDBMS generally employs the Structured Query Language (SQL) in addition to a language for creating, storing, editing, and executing stored procedures, such as the PL/SQL language mentioned above. 
     In some examples, system elements may be implemented as computer-readable instructions (e.g., software) on one or more computing devices (e.g., servers, personal computers, etc.), stored on computer readable media associated therewith (e.g., disks, memories, etc.). A computer program product may comprise such instructions stored on computer readable media for carrying out the functions described herein. 
     With regard to the processes, systems, methods, heuristics, etc. described herein, it should be understood that, although the steps of such processes, etc. have been described as occurring according to a certain ordered sequence, such processes could be practiced with the described steps performed in an order other than the order described herein. It further should be understood that certain steps could be performed simultaneously, that other steps could be added, or that certain steps described herein could be omitted. In other words, the descriptions of processes herein are provided for the purpose of illustrating certain embodiments, and should in no way be construed so as to limit the claims. 
     Accordingly, it is to be understood that the above description is intended to be illustrative and not restrictive. Many embodiments and applications other than the examples provided would be apparent upon reading the above description. The scope should be determined, not with reference to the above description, but should instead be determined with reference to the appended claims, along with the full scope of equivalents to which such claims are entitled. It is anticipated and intended that future developments will occur in the technologies discussed herein, and that the disclosed systems and methods will be incorporated into such future embodiments. In sum, it should be understood that the application is capable of modification and variation. 
     All terms used in the claims are intended to be given their ordinary meanings as understood by those knowledgeable in the technologies described herein unless an explicit indication to the contrary is made herein. In particular, use of the singular articles such as “a,” “the,” “said,” etc. should be read to recite one or more of the indicated elements unless a claim recites an explicit limitation to the contrary. 
     The Abstract is provided to allow the reader to quickly ascertain the nature of the technical disclosure. It is submitted with the understanding that it will not be used to interpret or limit the scope or meaning of the claims. In addition, in the foregoing Detailed Description, it can be seen that various features are grouped together in various embodiments for the purpose of streamlining the disclosure. This method of disclosure is not to be interpreted as reflecting an intention that the claimed embodiments require more features than are expressly recited in each claim. Rather, as the following claims reflect, inventive subject matter lies in less than all features of a single disclosed embodiment. Thus the following claims are hereby incorporated into the Detailed Description, with each claim standing on its own as a separately claimed subject matter.