METHOD AND SYSTEM FOR FEEDBACK ON RUNNING STYLE FIELD AND BACKGROUND OF THE INVENTION

• US 20140195023A1
• Filed: 08/09/2012
• Published: 07/10/2014
• Est. Priority Date: 08/09/2011
• Status: Active Grant

• Current Assignee: Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno
• Original Assignee: Nederlandse Organisatie Voor Toegepast-Natuurwetenschappelijk Onderzoek Tno
• Inventors: Statham, Andrew, Hoppenbrouwers, Marcus Benedictus
• Granted Patent: US 9,687,712 B2
• Time in Patent Office: Days
• US Class Current: 700/91
• CPC Class Codes: A61B 5/1038 Measuring plantar pressure during gait
• CPC Class Codes: A63B 69/0028 for running, jogging or speed-walking movable endless bands A63B22/02

Abstract

The invention relates to a system and method for providing feedback to a user on his or her running style or running technique. The system employs a pressure sensitive surface to record a gait line of the center of pressure exerted by the user'"'"'s foot on an underlying surface during a footstep period. In case of a fore or mid-foot landing the gait line may be observed to move backwards with respect to the sagittal plane. From a backwards-going gait line two time stamps are determined. The first timestamp T1 is the time that the foot strikes the ground. The second timestamp T2 is the time that the gait line reaches the most backward position. From the time difference between these two timestamps a loading time dT is determined. The reactivity of the running style describes the viscoelastic behavior of the muscle-tendon unit and may be calculated as a function of this loading time and/or the distance moved by the centre of pressure backwards towards the heel. Correspondingly, a feedback signal may be provided to the user about his running reactivity.

Claims

1. System for generating feedback on a subject'"'"'s running style, the system comprising

a pressure sensitive surface (A) with a plurality of pressure sensors for generating an electronic signal (Sp) as a function of a pressure (P) exerted on said pressure sensitive surface (A);

a clock (502) arranged for providing timestamp information;

a memory (503) arranged for storage and retrieval of data;

a readout device (501) arranged for reading out the plurality of pressure sensors and the clock and storing data in the memory comprising a time-dependent (T) measurement of a moving center of pressure (C) exerted by a subject'"'"'s foot on the pressure sensitive surface (A), the moving center of pressure (C) forming a pressure gait line (211,212) at least distinguished along a forward axis (Xf) of a running direction;

a feedback device (505) arranged for generating one or more of a visual, audio, or haptic feedback signal (Sf) and controlled by a processor (504), said processor (504) arranged for

reading the data from the memory (503);

determining from the data a first timestamp (T1) at a first registered moment that the subject'"'"'s foot starts touching the ground;

determining from the data a second timestamp (T2) at a moment that the center of pressure (C) reaches the most backwards registered position along the gait line with respect to the forward axis (Xf);

calculating a time difference between the first (T1) and second timestamps (T2) as a defined loading time (dT); and

controlling the feedback device (605) to generate a feedback signal (SD as a function of the loading time (dT).

2. System according to claim 1, wherein the processor is further arranged for

calculating a distance between the measured center of pressure (201) at the moment that the first timestamp (T1) was recorded and the measured center of pressure (202) at the moment that the second timestamp (T2) was recorded as a defined loading distance (d);

and

controlling the feedback device to generate the feedback signal (Sf) as a function of the calculated loading distance (d).

3. System according to claim 1, wherein

the memory (503) comprises a conversion table for converting the moving center of pressure (C) to a moving heel position (U);

and

the processor (504) is further arranged for converting the moving center of pressure (C) to a moving heel position (U) and controlling the feedback device (605) to generate the feedback signal as a function of the moving heel position (U).

4. System according to claim 3, wherein the pressure sensitive surface comprises a heel sensor (303) and the processor is arranged for converting the moving center of pressure (C) to a moving heel position (U) if a heel pressure measured by the heel sensor is below a threshold heel pressure.

5. System according to claim 1, wherein the pressure sensitive surface (A) is shaped as an insole for placement inside a shoe wherein the insole defines a front and back area of the subject'"'"'s foot and the pressure sensitive surface comprises front sensors at the front area and/or a heel sensor at the back area.

6. System according to claim 1, wherein the processor is further arranged for calculating an inverse of the loading time (dT) as a defined running reactivity (R) and controlling the feedback device to generate a reactivity feedback signal (Sf) as a function of the calculated running reactivity (R).

7. System according to claim 1, wherein the processor is further arranged for

calculating during a mass measurement interval the subject'"'"'s mass (M) from a summation of a total measured pressure (P) and multiplying this sum by a calibration constant (Kc);

and

controlling the feedback device to generate the feedback signal (Sf) as a function of the subject'"'"'s mass (M).

8. System according to claim 1, wherein the processor is further arranged for

determining a time of flight (TOF) between a last registered moment that the subject'"'"'s foot stops touching the ground (T3) and a first registered moment (T1) that the subject'"'"'s next foot starts touching the ground;

and

normalizing the feedback signal as a function of the time of flight.

9. System according to claim 1, wherein the feedback device comprises a loudspeaker and an audio controller arranged for producing an audio feedback signal via the loudspeaker according to a loudness, pitch, or pulse frequency of the audio signal as a function of the calculated running reactivity.

10. Method for generating feedback on a subject'"'"'s running style, the method comprising the steps of:

receiving data (D) comprising a time-dependent (T) measurement of a moving center of pressure (C) exerted by the subject'"'"'s foot on a pressure sensitive surface (A), the moving center of pressure (C) forming a pressure gait line (211,212) at least distinguished along a forward axis (Xf) of a running direction;

determining from the data a first timestamp (T1) at a first registered moment that the subject'"'"'s foot starts touching the ground;

determining from the data a second timestamp (T2) at a moment that the center of pressure (C) reaches the most backwards registered position along the gait line with respect to the forward axis (Xf); and

calculating a time difference between the first (T1) and second timestamps (T2) as a defined loading time (dT); and

controlling the feedback device (605) to generate a feedback signal (Sf) as a function of the loading time (dT).

11. Method according to claim 10, wherein the feedback signal (Sf) is generated as a function of a calculated loading distance (d) between locations of a measured center of pressure (201) at the moment that the first timestamp (T1) was recorded and a location of the measured center of pressure (202) at the moment that the second timestamp (T2) was recorded.

12. Method according to claim 10, further comprising the step of calculating an inverse of the loading time (dT) as a defined running reactivity (R) and controlling the feedback device to generate a reactivity feedback signal (Sf) as a function of the calculated reactivity (R).

13. Method according to claim 10, wherein the calculated running reactivity is multiplied by the subject'"'"'s mass (M) prior to generating the feedback signal.

14. Method according to claim 13 wherein the subject'"'"'s mass (M) is calculated by adding the total measured pressure exerted by the subject'"'"'s foot on the pressure sensitive surface (A) and multiplying this total measured pressure by a calibration constant (Kc).

15. Human interface device (550) wearable on a subject'"'"'s wrist or arm for providing a user with feedback (SO on a running style, the device (550) comprising

a wireless transceiver (503) arranged for receiving a signal (Sw) indicative of the subject'"'"'s running reactivity (R), the running reactivity defined as a parameter (R) inversely proportional to a measured time period (dT) between a first moment (T1) that a foot of the subject hits the ground and a second moment (T) that a center of pressure (C), exerted by the subject'"'"'s foot reaches a most backward position (202) with respect to the subject'"'"'s running direction (F);

a display (504) arranged for displaying an image as a function of the received signal (Sw) of the subject'"'"'s running reactivity (R);

attachment means (512) arranged for attaching the display (504) to the subject'"'"'s wrist or arm