Foot-strength test device and methods for use

The present disclosure provides a device for testing the strength of a human foot. The device includes a substantially planar member having a top surface and a bottom surface. The device also includes a foot-engaging member moveable along the top surface substantially planar member from a first position to a second position. In addition, the device includes a force sensor fixed with respect to the substantially planar member, where the force sensor resists movement between the first position and the second position. Further, the device includes a tension bearing element connecting the foot-engaging member to the force sensor.

BACKGROUND

Intrinsic foot muscles contribute to the support of the medial longitudinal arch and work in conjunction with the plantar aponeurosis, plantar ligaments and extrinsic foot muscles to control the stresses on the foot during gait. As such, the strength of intrinsic foot muscles is important in normal functional activities. Weakness of these muscles has been implicated in foot pathology, impaired balance, and addressed in rehabilitation clinical guidelines. Intrinsic foot muscle weakness has also been implicated in the development of pes cavus in Charcot-Marie-Tooth disease (CMT), heel pain, claw toe deformity, hammer toe deformity, and hallux valgus. The level of intrinsic muscle weakness necessary for the development of these deformities and disorders is unknown. To assess the degree of weakness and to determine the effect of strengthening intrinsic muscles, a valid and reliable measure of intrinsic muscle strength is needed. There are diverse methods available for measuring intrinsic muscle properties, but there is lack of agreement regarding the most appropriate measure of strength. Therefore, an improved device and method for measuring intrinsic foot muscle strength may be desired.

SUMMARY

Example devices and methods described herein describe various devices and methods for measuring intrinsic foot muscle strength. Such devices and methods will provide a quantitative measure of foot strength that may be used for screening for prevention, evaluation of patients with lower extremity pathology, and as a variable in lower extremity research studies. While various exercises have been provided to patients to strengthen these muscles, there are no practical devices and methods to quantify the strength of these muscles.

Thus, in one aspect, a device is provided for testing the strength of a human foot. The device includes a substantially planar member having a top surface and a bottom surface. The device also includes a foot-engaging member moveable along the top surface substantially planar member from a first position to a second position. In addition, the device includes a force sensor fixed with respect to the substantially planar member, where the force sensor resists movement between the first position and the second position. Further, the device includes a tension bearing element connecting the foot-engaging member to the force sensor.

In a second aspect, a method is provided for testing the strength of a human foot. The method may include (a) positioning the human foot on a top surface of a substantially planar member, (b) engaging one or more toes of the human foot with a foot-engaging member, wherein the foot-engaging member is moveable along the top surface substantially planar member from a first position to a second position, and wherein a tension bearing element connects the foot-engaging member to a force sensor, (c) while a heel of the human foot is stationary on the top surface of the substantially planar member, moving the one or more toes of the human foot from the first position to the second position, and (d) recording a peak force detected by the force sensor.

DETAILED DESCRIPTION

Example methods and systems are described herein. It should be understood that the words “example,” “exemplary,” and “illustrative” are used herein to mean “serving as an example, instance, or illustration.” Any embodiment or feature described herein as being an “example,” being “exemplary,” or being “illustrative” is not necessarily to be construed as preferred or advantageous over other embodiments or features. The example embodiments described herein are not meant to be limiting. It will be readily understood that the aspects of the present disclosure, as generally described herein, and illustrated in the figures, can be arranged, substituted, combined, separated, and designed in a wide variety of different configurations, all of which are explicitly contemplated herein.

As used herein, with respect to measurements, “about” means +/−5%.

As used herein, the term “coefficient of static friction” means the ratio of the force of friction between an object and a surface to the frictional force resisting the motion of the object when the object is at rest.

As used herein, the term “coefficient of kinetic friction” means the ratio of the force of friction between an object and a surface to the frictional force resisting the motion of the object when the object is moving.

As used herein, the term “peak force” means the highest value of recorded by a force sensor during a particular trial.

As used herein, the term “average force” means a magnitude of force over a given time period (t0-t1) during a particular trial.

The present disclosure provides devices and methods for testing the strength of a human foot. As discussed above, such devices and methods may provide insight into the intrinsic foot muscle function in patients with foot and ankle disorders. As such, the device may be used to record baseline strength of the intrinsic muscles of the foot. As the patient performs various therapy and treatment to increase strength, the baseline measurements can be used as a point of comparison for future measurements using the device.

With reference to the Figures,FIG. 1Aillustrates an example foot-strength testing device100. The device100may include a substantially planar member102having a top surface104and a bottom surface106. The device100may also include a foot-engaging member108, a force sensor110fixed with respect to the substantially planar member102, and a tension bearing element112connecting the foot-engaging member108to the force sensor110. The foot-engaging member108is moveable along the top surface104from a first position to a second position, where the foot-engaging member108is closer to the force sensor110in the first position than in the second position. As such, a force applied to the force sensor110increases as the distance between the foot-engaging member108and the force sensor100increases. In addition, as shown in FIG.1B, the device100may include an adjustable seat105positioned over the substantially planar member102. The seat may be adjustable in height to accommodate a variety of patient heights.

The substantially planar member102may have a length in the range of about 18 inches to 48 inches, and a width in the range of about 4 inches to about 12 inches. In one example, the substantially planar member102may be foldable. For example, the substantially planar member102may include a hinge on the bottom surface106, such that the substantially planar member102is configured to fold in half for storage. In another example, the substantially planar member102may include a cutout for a hand grip for easy portability. In addition, the top surface104of the substantially planar member102has a low coefficient of kinetic friction. For example, the top surface104may include a melamine resin, Polytetrafluoroethylene (PTFE), plastic, metal, tempered glass, and/or composite material. As such, the top surface104has a coefficient of kinetic friction (μk) less than about 0.5. In contrast, the bottom surface106of the substantially planar member102may have a high coefficient of static friction. For example, the bottom surface106may include rubber, silicone gel, wood, metal, and/or composite material. As such, the bottom surface106has a coefficient of static friction (μs) greater than about 0.5. In another example, the bottom surface106may be the same material as the top surface104, but the bottom surface106may include one or more gripping elements positioned on the bottom surface106. In one specific example, there may be four gripping elements positioned at four corners of the bottom surface106. Such gripping elements may be materials that have a high coefficient of static friction, such as rubber, silicone gel, wood, metal, and/or composite material. Such gripping elements may have a coefficient of static friction (μs) greater than about 0.5. In addition, the top surface104of the substantially planar member102may include one or more markings to indicate a location for heel and or toe placement of a foot being tested.

In another example, the device100may further include a second substantially planar member103positioned adjacent to the substantially planar member102. In such an example, the second substantially planar member103has a thickness equal to the thickness of the substantially planar member102, such that both feet of a user are level when using the device100. The second substantially planar member103may be coupled to the substantially planar member102via a hinge, for example. In another example, the second substantially planar member103may not be attached to the substantially planar member102.

The foot-engaging member108enables a user of the device100to apply a tension force, via the tension bearing element112, to the force sensor110using the user's toes and intrinsic muscles of the feet. As such, the foot-engaging member108may take various forms. In one example, the foot-engaging member108comprises a cloth114, as shown inFIG. 2. In such an example, the cloth114may include a grommet for attaching to the tension bearing element112. The cloth114is dimensioned to underlie a portion of a user's forefoot. As such, the cloth114may be generally rectangular, with a width in the range of about 3 inches to about 6 inches, and a length in the range of about 4 inches to about 8 inches. A top surface116of the cloth114may include a gripping surface, for example including a rubber or other material with a high coefficient of static friction. In contrast, the bottom surface118of the cloth114may include a material with a low coefficient of kinetic friction such that the cloth114slides easily along the top surface104of the substantially planar member102. In operation, the first metatarsal head of a user's foot may be aligned with the end of the cloth114furthest away from the force sensor110. In this position, the tension bearing element112may be pulled so that there is no slack. The user may then pull on the cloth114with their toes and forefoot from the first position to the second position while keeping their heel in a stationary position on the substantially planar member102. The force applied to the cloth114is transferred, via the tension bearing element112, to the force sensor110and the peak force detected by the force sensor110may be recorded. In addition, the force sensor110may further determine a time to reach the peak force, an average force, the peak force over time, the work exerted on the cloth114, and power, among other measurements.

In another example, the foot-engaging member108comprises a dowel rod120, as shown inFIG. 3. The dowel rod120may include a hole122,124at each end of the dowel rod for connecting to the tension bearing element112. The dowel rod120may be dimensioned such that a user can position their foot between the two holes122,124and grab the dowel rod120using their toes. As such, the dowel rod120may have a length in the range of about 4 inches to about 8 inches, and a diameter in the range of about 0.25 inches to about 2 inches. In operation, the user may position their toes around the dowel rod120. In this position, the tension bearing element112may be pulled so that there is no slack. The user may then pull on the dowel rod120with their toes from the first position to the second position while keeping their heel in a stationary position on the substantially planar member102. The force applied to the dowel rod120is transferred, via the tension bearing element112, to the force sensor110and the peak force detected by the force sensor110may be recorded. In addition, as discussed above, the force sensor110may further determine a time to reach the peak force, an average force, the peak force over time, the work exerted on the dowel rod120, and power, among other measurements.

In another example, the foot-engaging member108comprises a molded plastic component126, as shown inFIG. 4. The molded plastic component126may include one or more indentations128to receive the toes of the foot being tested. In one particular example, the molded plastic component126may include two indentations, one for the big toe and one for the remaining toes. In another example, the molded plastic component126may include a single indentation extending the width of the molded plastic component126for all of the toes of the user. At least a portion of the top surface130of the molded plastic component126may include a gripping surface, for example including a rubber or other material with a high coefficient of static friction. In contrast, the bottom surface132of the molded plastic component126may include a material with a low coefficient of kinetic friction such that the molded plastic component126easily along the top surface104of the substantially planar member102. In operation, the user's toes may be positioned in the one or more indentations128of the molded plastic component126. In this position, the tension bearing element112may be pulled so that there is no slack. The user may then pull on the molded plastic component126with their toes from the first position to the second position while keeping their heel in a stationary position on the substantially planar member102. The force applied to the molded plastic component126is transferred, via the tension bearing element112, to the force sensor110and the peak force detected by the force sensor110may be recorded. In addition, as discussed above, the force sensor110may further determine a time to reach the peak force, an average force, the peak force over time, the work exerted on the molded plastic component126, and power, among other measurements.

In yet another example, the foot-engaging member108comprises a shape including a cutout in the center of the shape. The shape including the cutout may take various forms. In one example, as shown inFIG. 5A, the shape may be a triangular foot-engaging member134. In another example, as shown inFIG. 5B, the shape may be a rectangular foot-engaging member136. In yet another example, as shown inFIG. 5C, the shape may be an elliptical foot-engaging member138. Other shapes are possible as well. Each of the foot-engaging members may be metal, plastic, metal with a plastic coating, wood, and/or composite material. Further, as illustrated inFIGS. 5A-5C, each of the foot-engaging members may include an eyelet140used to couple the foot-engaging member to the tension bearing element112. In another example, the tension bearing element112is coupled directly to the foot-engaging member.

The force sensor110is fixed with respect to the substantially planar member102. In one example, as shown inFIG. 1A, the force sensor110is fixed to the top surface104of the substantially planar member102. In another example, the force sensor110is fixed to the ground adjacent to the substantially planar member102. Other examples are possible as well.

The force sensor110may be configured to apply tension to the foot-engaging member108, such that the tension increases with the distance displaced from the force sensor110. The force sensor110may use a spring, a moveable weight, a piston, or another mechanism to generate force in a direction toward the force sensor110. In one example, the force sensor110may be a mechanical force gauge, such as a spring scale. The spring scale may include a moveable indicator that moves as the spring is displaced from its relaxed position. Once a peak force is reached, the indicator remains in the position corresponding to the peak force, and a user can determine the peak force by comparing the position of the indicator and scale markings positioned on the spring scale. In another example, the force sensor110may be a digital force gauge. Such a digital scale may include a load cell, electrical components, software and a display. The load cell is an electronic device that is used to convert a force into an electrical signal. Through a mechanical arrangement, the force being sensed deforms a strain gauge. The strain gauge converts the deformation (strain) to electrical signals. The software and electronics of the digital force gauge convert the voltage of the load cell into a force value. In one example, the force sensor110includes a display113to provide a visual display of the force applied to the foot-engaging member108. In addition, as discussed above, the display113may further provide a visual display of a time to reach the peak force, an average force, the peak force over time, the work exerted on the tension bearing element112, and power, among other measurements made by the force sensor110.

As discussed above, the force sensor110is coupled to the foot-engaging member via a tension bearing element112. As such, as the foot-engaging member moves from the first position to the second position, the tension bearing element transfers the force applied to the foot-engaging member108to the force sensor110. The tension bearing element112may include a cable, a chord, a belt or a band, as examples. In one example, the tension bearing element112includes a coupling mechanism between the force sensor110and the foot-engaging member108, such that the foot-engaging member108may be detachable from the tension bearing element112. As such, a physician may be able to easily switch between various foot-engaging members108, such as between the cloth114and the dowel rod120, as an example. The coupling mechanism may take various forms. In one example, the tension bearing element112may include an eyelet at the end closest to the foot-engaging member108, and a second tension bearing element connected to the foot-engaging member108may include a complementary hook or clasp to connect the tension bearing element112to the second tension bearing element. In another example, the tension bearing element112may include a threaded rod at the end closest to the foot-engaging member108, and the second tension bearing element connected to the foot-engaging member108may include a complementary female threaded port to receive the threaded rod. Other example coupling mechanisms are possible as well.

In another example, as shown inFIG. 1C, the device100may further include a recessed track107on the top surface104of the substantially planar member102, and a complementary flange109on a bottom surface of the foot-engaging member108. The complementary flange109may be positioned within the recessed track107such that the foot-engaging member108moves along the recessed track107from the first position to the second position. The recessed track107may prevent the foot-engaging member108from moving in a lateral (e.g., side-to-side) direction as a user moves the foot-engaging member108from the first position to the second position.

FIG. 6illustrates an example schematic drawing of a computer network infrastructure. In one system600, a computing device602communicates with the force sensor110using a communication link604, such as a wired or wireless connection. The computing device602may be any type of device that can receive data and display information corresponding to or associated with the data. For example, the computing device602may be a mobile phone, a tablet, or a personal computer as examples.

Thus, the computing device602may include a display system606comprising a processor608and a display610. The display610may be, for example, an optical see-through display, an optical see-around display, or a video see-through display. The processor608may receive data from the force sensor110, and configure the data for display on the display610. Depending on the desired configuration, processor608can be any type of processor including, but not limited to, a microprocessor, a microcontroller, a digital signal processor, or any combination thereof.

The computing device602may further include on-board data storage, such as memory612coupled to the processor608. The memory612may store software that can be accessed and executed by the processor608, for example. The memory612can include any type of memory now known or later developed including but not limited to volatile memory (such as RAM), non-volatile memory (such as ROM, flash memory, etc.) or any combination thereof.

According to an example embodiment, the computing device602may include program instructions that are stored in the memory612(and/or possibly in another data-storage medium) and executable by the processor608to facilitate the various functions described herein. Although various components of the system600are shown as distributed components, it should be understood that any of such components may be physically integrated and/or distributed according to the desired configuration of the computing system.

The force sensor110and the computing device600may contain hardware to enable the communication link604, such as processors, transmitters, receivers, antennas, etc.

InFIG. 6, the communication link604is illustrated as a wireless connection; however, wired connections may also be used. For example, the communication link604may be a wired link via a serial bus such as a universal serial bus or a parallel bus. A wired connection may be a proprietary connection as well. The communication link604may also be a wireless connection using, e.g., Bluetooth® radio technology, communication protocols described in IEEE 802.11 (including any IEEE 802.11 revisions), Cellular technology (such as GSM, CDMA, UMTS, EV-DO, WiMAX, or LTE), or Zigbee® technology, among other possibilities.

FIG. 7is a block diagram of an example method for adjusting a fluid flow rate through a fluidic control device. Method700shown inFIG. 7presents an embodiment of a method that could be used by the device100ofFIGS. 1-6, as an example. Method700may include one or more operations, functions, or actions as illustrated by one or more of blocks702-708. Although the blocks are illustrated in a sequential order, these blocks may also be performed in parallel, and/or in a different order than those described herein. Also, the various blocks may be combined into fewer blocks, divided into additional blocks, and/or removed based upon the desired implementation.

Initially, at block702, the method700includes positioning the human foot on a top surface of a substantially planar member. As discussed above, the top surface of the substantially planar member may include one or more markings to indicate a location for heel placement of the foot being tested. At block704, the method700includes engaging one or more toes of the human foot with a foot-engaging member, wherein the foot-engaging member is moveable along the top surface substantially planar member from a first position to a second position, and wherein a tension bearing element connects the foot-engaging member to a force sensor. The foot-engaging member may take various forms, as discussed above in relation toFIGS. 2-5C. At block706, the method700includes moving the one or more toes of the human foot from the first position to the second position while a heel of the human foot is stationary on the top surface of the substantially planar member. At block708, the method700includes recording a peak force detected by the force sensor. As discussed above, the peak force detected by the force sensor may be recorded manually, or the force sensor may transmit the detected peak force to a computing device. In addition, as discussed above, the force sensor may further determine a time to reach the peak force, an average force, the peak force over time, the work exerted on the tension bearing element, and power, among other measurements. In such an example, the method700may further include recording one or more of these measurements. Such measurements may be useful in determining patient fatigue, for example.

In one example, the method may further include repeating steps702-708two additional times to record three values of peak force. The three values may then be averaged to determine a mean value for peak force. These steps may be repeated for each foot of the user. Further, the user may perform steps702-708in a seated position, and may then repeat steps702-708in a standing position. In addition, steps702-708of method700may be performed when a user is in a position of maximum foot pronation. In another example, steps702-708of method700may be performed when a user is in a position of maximum foot supination. Other examples are possible as well.

Since many modifications, variations, and changes in detail can be made to the described example, it is intended that all matters in the preceding description and shown in the accompanying figures be interpreted as illustrative and not in a limiting sense. Further, it is intended to be understood that the following clauses (and any combination of the clauses) further describe aspects of the present description.