GB2607469A

GB2607469A - Force platform and method of operating

Info

Publication number: GB2607469A
Application number: GB2211024.1A
Authority: GB
Inventors: Cohen Daniel
Original assignee: Vald Operations Ltd
Current assignee: Vald Operations Ltd
Priority date: 2017-02-26
Filing date: 2017-02-26
Publication date: 2022-12-07
Anticipated expiration: 2037-02-26
Also published as: GB2607469B; GB2606668A; GB201703092D0; GB202211024D0; GB2606668B; GB2561335B; WO2018154323A1; GB2561335A; GB202211023D0

Abstract

A method of operating a force platform system comprising a plurality of force platforms with force measuring and recording means, the method comprising the steps of: a) connecting the plurality of force platforms directly or indirectly to an external device for result display and analysis; b) performing an exercise or test with a first subject on a first force platform which produces a first set of force-time data from measured force measurements; c) performing an exercise or test with at least one further subject on at least one further force platform which produces at least one further set of force-time data from measured force measurements; d) communicating both the first set of force-time data and the at least one further set of force-time data to the external device; and e) performing real-time comparison of force-time data received at the external device to facilitate at least one of competition and analysis between different subjects. Another aspect is a force platform system. The external device may be a tablet, mobile phone, television or computer. The external device may automatically determine a type of exercise performed by each subject. Each set of force-time data may be raw force-time data.

Description

FORCE PLATFORM AND METHOD OF OPERATING

The present invention relates to a force platform and a method of operating thereof.

Force platforms typically comprise a flat plate instrumented with sensors allowing measurements of forces applied by a body interacting with it. Some may measure forces in all 3 orthogonal axes fx, fy and fz, others measure only vertical fz forces. They typically sample forces at a rate of between 500 and 1,000 Hz and occasionally more.

Previously proposed methods involving application of fundamental physical equations using measured force-time data can estimate a number of common variables related to the measured motion such as velocity, power, impulse and displacement. In addition, a wide range of other parameters can be derived which are of potential interest in sports performance and sports medicine, such as peak forces, rates of force development, mean forces during and durations of specific phases of activities performed on the platforms.

Use of force platforms has previously been proposed in connection with biomechanical applications for the measurement of various aspects of human performance, including gait analysis, balance, neuromuscular fatigue, injury risk and recovery. Typically, a test will comprise of a subject performing an exercise or activity of a standardised form conducted wholly or in part on such a force platform. Readings from the force platform allow assessment of this performance against either -2 -that individual's previous results in similar tests or against normative data. More recently there has been interest in use of pairs of force platforms whereby subjects perform tests with one limb on each force platform, allowing additional assessment of bilateral asymmetry -most typically in the lower body.

In the context of sports practitioners, such as sports scientists, strength and conditioning specialists and physiotherapists will often have subjects perform movements or activities on a force platform. So for example a commonly used test across a wide range of sports is the countermovement jump (CMJ). To perform this test, the subject stands either on a single force platform or with one foot on each of a pair of force platforms. They then bend their knees and rapidly descend into a flexed position of self-selected depth followed by a rapid extension at ankles, knees and hips to jump vertically as high as possible. The subject then lands back on the force platform or platforms.

Such a test involves a variety of different sections or phases. So a CMJ may typically be separated into three stages. The first phase is eccentric movement where the subject is bending their legs and descending into a crouch; the second stage is the concentric phase of movement where the subject is straightening their legs and passing back through the vertical leading up to the take-off and jump; and the third stage is the landing stage. It is often of interest to practitioners to be able to assess the subject's performance during -3 -these individual phases. So for example, a practitioner may wish to assess a subject's bilateral (left + right) power or inter-limb (left v right) asymmetry solely during the eccentric, concentric, or landing phases.

There are established techniques in the art for separating out the individual components of such tests in order to allow such separate assessment of parameters. This involves first identifying the type of activity or test undertaken. Traditionally this involved exporting the raw force-time data provided by the force platform into a suitable spreadsheet or database to facilitate such processing. The disadvantage is that this means a significant time lag between test and availability of results, undermining the usefulness of the data in informing any sort of immediate decisions about an athlete's ongoing activities or workload. In addition, not providing feedback to the subject at the time of testing tends to reduce the athlete's interest in performing these tests. At elite levels of athletics motivation to participate is critical to the sustainability of testing and therefore to the effectiveness of monitoring processes.

More recently, an exercise identification and assessment module has been embedded in software that is directly connected to the data feed provided by the force platforms. Once subjects have undertaken a prescribed activity or test, the practitioner can activate an analysis process which identifies the type of activity or test undertaken from the characteristic force-time profile presented and derives the -4 -various physical parameters of potential interest to give resultant bilateral, left, right and inter-limb asymmetry 'output variables" of interest. Selected output variables can then be automatically presented to the practitioner and athlete within seconds.

This process nonetheless still suffers from a number of disadvantages. All current techniques provide post-hoc analysis of a number of repetitions of the same test. The subject will be required to stop at the end of each set of repetitions of a test to allow the computer to perform the necessary analysis. The results of a series of tests are therefore buffered with analysis implemented after the test is completed. This approach has several disadvantages: -it does not lend itself to the conduct of a large number of different tests that are often part of an athlete evaluation protocol as this approach only allows one type of test to be performed within a recording window; -athlete feedback is only generated at the end of the set of tests, such that there is no means of providing objective assessment of how well they are performing the test. This means that neither motivational feedback nor objective information on technique can be provided between repetitions during the test. The operator may wish to take into account not output variables (such as e.g. jump height), but the manner in which the subject has performed a test (i.e. the length of time they had spent in each phase of the movement, the levels of asymmetry, etc.) in order to instruct the subject to adjust their technique for subsequent tests. -5 -

-furthermore, this approach means that even if a repetition at the start of a test would have indicated that a subject had a significant deficit, which could be indicative of risk or fatigue -this would not be revealed until the athlete had completed the full series of repetitions. This means that athletes may perform unnecessary testing which takes up valuable time and increases overall workload something which both they and sports science/medicine practitioners aim to avoid.

This unnecessary loading combined with the time cost of conducting force platform testing and extracting data remain the principal barriers to the adoption and integration of this technology into sports settings despite more than three decades of evidence demonstrating the value of their use in these settings. Although the latest versions of force platform software have streamlined the process it remains time intensive -particularly with respect to the data extraction and feedback process. Certain sports have very large squads of players who ideally would all be subjected to testing on a regular basis. Further, the practitioners administering force platform testing have needed to have significant expertise and experience in order to operate the software and conduct the testing, and such individuals are in relatively short supply, and command relatively high wages. Accordingly, it would be desirable to reduce the time taken to conduct tests, and/or allow multiple tests to be conducted simultaneously by the same practitioner. This would enable adoption of this technology in sports where currently there is very -6 -limited use due to the numbers of athletes in their squads and resulting time cost of testing and analysis -American Football and Baseball -as well as in the military.

There are also limits to how much time elite athletes can be persuaded or compelled to spend undertaking activities which they see as not specific to their sport, or which doesn't generate immediate feedback on performance. Having the subject's "buy-in" is vital to many of the tests, which require the athlete to expend maximum effort to allow proper assessment of their capabilities and to expose deficits and asymmetries.

It is an aim of the present invention to overcome these disadvantages, or at least provide a useful and/or commercial alternative.

According to aspects of the invention there may be provided a method of operating a force platform system and a force platform system as set out in the appended claims.

According to another aspect the present invention is directed to a method of operating a force platform system which comprised one or more force platforms with force measuring and recording means, the force platform contains an analysis and result storage device, the force platform is in communication with one or more external devices for result display and analysis, which are equipped with results _ 7 _ storage means, which can be pre-programmed with historical data comprising the steps of: a) performing an exercise or test on a force platform which records the results; b) conducting initial analysis in the force platform to produce limited results and storing full data set in the recording means; c) communicating initial results to external devices for near real time display of limited results; d) contextualising performance by visualisation against the athlete's prior (historical) data and or athlete performing the same test in parallel within the dashboard; and e) using results displayed to provide inter repetition feedback to athlete on technique, current and prior performance in order to motivate, alter execution or type of exercise being performed or to terminate the exercise.

Preferably the data from more force platforms can be displayed on the same external device, advantageously a tablet, mobile phone, 20 television or computer.

The present invention may have an exercise identification and assessment module in a system that runs continuously so that exercises can be constantly identified as soon as they are -8 -performed, and associated parameters, derived and presented to the operator and/or subject instantaneously.

Furthermore the present invention may allow the subject's "live" 5 results to be compared in real time with historical results, allowing immediate identification of the subject's progress or decline. The comparison between current and historical results can be displayed to the subject during testing to introduce a competitive element that encourages the subject's committed 10 engagement with the testing.

An advantage of the present invention is to enable the operator to make immediate decisions about whether or not subsequent tests are to be performed, and to provide corrective and motivational instructions on technique and output of activities being performed.

A further benefit of this approach is that it allows a single operator to control multiple systems and subjects at the same time, reducing the time it takes to test large groups of subjects and maximising the utilisation of the limited number of skilled operators. This also allows multiple subjects to view each other's results simultaneously while they are undertaking the tests, introducing a further competitive element to additionally encourage committed participation in the tests. -9 -

Embodiments of the disclosure are now described by way of example with reference to the accompanying drawings in which: Figure 1 shows a diagrammatic representation of a traditional force platform analysis; Figure 2 shows a diagrammatic representation of a more recent force platform analysis; Figure 3 shows a diagrammatic representation of a ForceDecksT, system; Figure 4 shows a diagrammatic representation of a force platform system; Figure 5 shows a diagrammatic representation of another force platform system; and Figure 6 shows a diagrammatic representation of yet another force platform system.

Figure 1 shows the traditional force platform analysis. A force platform 10 which measures the exercise performed by the subject or athlete. The force platform 10 can comprise a pair of force platforms with one for each limb being tested.

The force platform 10 is directly connected to a break-out box 12, generally an oscilloscope, by a real time link operating for example at 1000Hz. During the exercise of the subject, measuring means 11 on the force platform 10 provide data to the break-out box 12 in real-time. This data is then manually exported from the break-out box 12 to a computer 14. The data is then inputted in a laborious post-hoc analysis in a spreadsheet 16 on the -10 -computer 14 of raw-force time data to determine the type of exercise performed from characteristic F-T profile and derive relevant variables e.g. power; rate of force development; nominal jump height; etc. Figure 2 shows a newer style force platform analysis. A force platform 10 is directly connected to a computer 18, by a real time link operating for example at 1000Hz. The raw force-time data is now directly recorded on the computer 18. This data is then operationally manually exported into a separate PC application on that computer or on another computer 14. The data still requires a laborious post-hoc analysis in a spreadsheet 16 of raw-force time data to determine the type of exercise performed from characteristic F-T profile and derive relevant variables e.g. power; rate of force development; nominal jump height; etc. Figure 3 shows the ForceDecks"J system used by the applicant. A force platform 10 is directly connected to a computer 18, by a real time link operating for example at 1000Hz.The raw data is displayed on the computer in an application. A skilled operator initiates a relevant analysis inside the application by "pushing" a button 20 within the same application providing near instantaneous analysis of the raw force-time data to determine the type of exercise performed and derive relevant variables with results displayed in readily comprehensible fashion. All this takes place with the same application, but still requires manual input.

Figure 4 shows stage 1 of a method according to the present invention. A force platform 10 is directly connected to a computer 18, by a real time link operating for example at 1000Hz. The raw force time data is automatically displayed. The automatic analysis of the raw force-time data to determine the type of exercise performed, derive relevant variables and display results occurs and is displayed potentially alongside the raw force time data. The analysed data can be compared with stored data from previous exercises carried out by the subject enabling conclusions with regard to the subject's progress to be made.

Figure 5 shows stage 2 of a method according to the present invention. The force platform 10 is directly or indirectly connected to one or more external devices; such as a computer 18, a phone 22 or a tablet 24. The force platform 10 is interrogable by clients contained on the connected devices by wired or wireless connections. The logic embedded into the force platform 10 undertakes immediate analysis of the raw force time data to determine types of exercise performed and derive relevant variables. An onboard memory storage is provided to buffer and cache results, allowing initial results uploaded to clients including summary data with full data to follow.

-12 -Figure 6 shows a continuation of stage 2 of a method according to the present invention. Multiple force platforms 10, in this Figure four, are directly connected to a central computer 18. The semi processed data of each force platform 10 is fed into the central computer 18 to facilitate real time competition or analysis between different subjects.

Claims

-13 -CLAIMS: 1. A method of operating a force platform system comprising a plurality of force platforms with force measuring and recording 5 means, the method comprising the steps of: a) connecting the plurality of force platforms directly or indirectly to an external device for result display and analysis; b) performing an exercise or test with a first subject on a first force platform which produces a first set of force-time 10 data from measured force measurements; c) performing an exercise or test with at least one further subject on at least one further force platform which produces at least one further set of force-time data from measured force measurements; d) communicating both the first set of force-time data and the at least one further set of force-time data to the external device; and e) performing real-time comparison of force-time data received at the external device to facilitate at least one of 20 competition and analysis between different subjects.
2. The method of claim 1, wherein the external device comprises one of a tablet, mobile phone, television or computer.
-14 - 3. The method of claim 1 or 2, wherein each force platform processes the measured force measurements to produce its respective set of force-time data.
4. The method of any one of claims 1 to 3, further comprising the step of automatically determining a type of exercise performed by each subject.
5. The method of claim 4, wherein the external device derives 10 and displays relevant variables of a determined type of exercise performed by each subject.
6. The method of any one of claims 1 to 5, wherein each force platform comprises onboard memory storage configured to buffer and cache data.
7. The method of any one of claims 1 to 6, wherein each set of force-time data comprises raw force-time data.
8. The method of claim 7, wherein the raw force-time data from each set is automatically displayed on the external device.
9. The method of any one of claims 1 to 8, wherein the plurality of force platforms are wirelessly connected to the external device.
-15 - 10. The method of any one of claims 1 to 9, further comprising the step of comparing the force-time data of each subject with historical results.
11. A force platform system comprising: a plurality of force platforms with force measuring and recording means; and an external device connected to the plurality of force platforms for result display and analysis; wherein each of the plurality of force platforms are configured to communicate measured force data of a subject to the external device, and wherein the external device is configured to perform real-time comparison of force-time data received at the external device to facilitate at least one of competition and analysis between different subjects.
12. The force platform system of claim 11, wherein the external device comprises one of a tablet, mobile phone, television or computer.
13. The force platform system of claim 11 or 12, wherein each force platform processes the measured force measurements to produce its respective set of force-time data.
-16 - 14. The force platform system of any one of claims 11 to 13, wherein the external device is configured to automatically determine a type of exercise performed by each subject.
15. The force platform system of claim 14, wherein the external device derives and displays relevant variables of a determined type of exercise performed by each subject.
16. The force platform system of any one of claims 11 to 15, wherein each force platform comprises onboard memory storage configured to buffer and cache data.
17. The force platform system of any one of claims 11 to 16, wherein each set of force-time data comprises raw force-time data.
18. The force platform system of claim 17, wherein the raw force-time data from each set is automatically displayed on the external device.
19. The force platform system of any one of claims 11 to 18, wherein the plurality of force platforms are wirelessly connected to the external device.
20. The force platform system of any one of claims 11 to 19, 25 wherein the external device is configured to compare the force-time data of each subject with historical results.