METHOD FOR CALCULATING A REPEATABILITY INDEX WHEN USING A TENNIS RACKET

• US 20130316855A1
• Filed: 05/22/2013
• Published: 11/28/2013
• Est. Priority Date: 05/23/2012
• Status: Active Grant

• Current Assignee: Babolat VS (Société Civile Babolat)
• Original Assignee: Babolat VS (Société Civile Babolat)
• Inventors: MACE, Pierre
• Granted Patent: US 9,358,442 B2
• Time in Patent Office: Days
• US Class Current: 473/422
• CPC Class Codes: A63B 69/38 for tennis A63B61/006, A63B69/0073 and A63B69/0097 take precedence
• CPC Class Codes: G09B 19/0038 Sports

Abstract

This method for calculating a repeatability index of gestures and shots of a player striking a tennis ball with a racket, includes:

• • a preliminary step a) in which behavioural data of the racket are generated during tests, the behavioural data indicating first playing data, related to gestures and shots as a function of parameters including at least several types of hits,
  • a playing step b) in which second playing data are measured;
  • an analysis step c) in which:
    • the second playing data are compared with the behavioural data,
    • the type of hit is deduced for each shot made in the playing step b), and
    • for each type of hit, the value of the repeatability index of the player'"'"'s gestures and shots is determined by comparing the second playing data with each other.

Claims

1. Method for calculating a repeatability index of gestures and shots of a player striking a tennis ball with a racket, wherein it comprises:

a preliminary step a) in which behavioural data of the racket are generated during tests, the behavioural data indicating first playing data related to gestures and shots, such as vibrations, linear acceleration and angular velocity of the racket, as a function of parameters including at least several types of hits,

a playing step b) in which the player strikes the balls with the racket and in which second playing data related to gestures and shots of the player, such as vibrations, linear acceleration and angular velocity of the racket, are measured,

an analysis step c) in which;

the second playing data are compared with the behavioural data,

the type of hit is deduced for each shot made in the playing step b), and

for each type of hit, the value of the repeatability index of the player'"'"'s gestures and shots is determined by comparing the second playing data with each other, the repeatability index indicating the player'"'"'s ability to repeat the hit type identically.

2. Method for calculating according to claim 1, wherein during the preliminary step a) and the playing step b), behavioural data and playing data are obtained by measuring the vibrations, the angular velocity and the linear acceleration of the racket.

3. Method for calculating according to claim 1, wherein the repeatability index is determined by comparing raw measurements output from the measurement system, namely output signals from sensors fixed to the racket and preferably related to vibrations, linear acceleration and the angular velocity of the racket, for hits of the same type made during playing step b).

4. Method for calculating according to claim 1, wherein the repeatability index is determined by comparing at least one first parameter obtained from measurements output from the measurement system, namely from output signals from sensors fixed to the racket and preferably related to vibrations, linear acceleration and the angular velocity of the racket, for each hit of the same type made during the playing step b),

wherein a head of the racket is divided into several zones,

wherein the first parameter relates to the impact zone of the ball on the head, and wherein the repeatability index is expressed as a function of a first variable related to dispersion, around a first average value, of the first parameter.

5. Method for calculating according to claim 1, wherein the repeatability index is determined by comparing at least one parameter, called second parameter, obtained from measurements output from the measurement system for each shot of the same type made during the playing step b), namely from output signals from sensors fixed to the racket and preferably related to vibrations, linear acceleration and the angular velocity of the racket,

and wherein the second parameter relates to the angle of orientation of the head,

and wherein the repeatability index is expressed as a function of a variable, called second variable, related to dispersion of the second parameter, around an average value, called second value.

6. Method for calculating according to claim 1, wherein the repeatability index is determined by comparing at least one parameter, called third parameter, obtained from measurements output from the measurement system, namely output signals from sensors fixed to the racket and preferably related to vibrations, linear acceleration and the angular velocity of the racket, for each shot of the same type made during the playing step b);

the third parameter relates to the quantity of effect transmitted to the ball

and the repeatability index is expressed as a function of a variable, called third variable, related to dispersion around a third average value, of the third parameter.

7. Method for calculating according to claim 4, wherein the repeatability index includes at least three terms added together, each term depending on one of the variables.

8. Method for calculating according to claim 4, wherein each variable is a standard deviation or a coefficient of variation.

9. Method for calculating according to claim 4, wherein each variable is corrected by an adjustment coefficient that normalises the variable to bring it to a scale for which all the balls are struck identically.

10. Method for calculating according to claim 4, wherein it also includes steps in which:

tests are done to compare shots made by highly skilled players with shots made by less skilled players,

each variable is corrected by a weighting factor that hierarchises the variables as a function of their relevance, as a function of these tests.