Integrated portable device and method implementing an accelerometer for analyzing biomechanical parameters of a stride
An accelerometer analyzing biomechanical parameters of the stride of a runner, including: fastening a device on the torso of the runner that is electrically self-sufficient and includes a triaxial accelerometer, chronograph, digital processor and display; measuring a sequence of acceleration data in at least the vertical direction using the accelerometer, while the runner runs a certain distance along a running course; during or at the end of the course, having the processor calculate the biomechanical parameters of the stride, including the lowering of the center of gravity and/or the elevation of the center of gravity and/or the sum of the lowering and of the elevation of the center of gravity and/or the vertical mechanical work of the center of gravity of the runner, on the basis of the acceleration data, of the distance and of a period of time measured by the chronograph; and displaying the parameters on the display.
1. A device designed for analyzing the biomechanical parameters of the stride of a runner, comprising:
a self-sufficient electric power source;
a triaxial accelerometer capable of supplying at least one sequence of acceleration data in at least the vertical direction whilst the runner travels a distance on a running course;
a chronograph;
a belt;
a display;
a digital processor programmed for calculating, during or at the end of the run, biomechanical parameters of the stride of said runner on the basis of said acceleration data, of said distance and of a duration counted by said chronograph, and for displaying said parameters on said display, wherein the biomechanical parameters of the stride comprises the vertical oscillation of the center of gravity of said runner between a lowest position and a highest vertical position of the center of gravity of said runner, and include the distance the center of gravity lowers and/or the distance the center of gravity elevates in a stride, and/or sum of the lowering of the center of gravity of said runner from a first highest vertical position to a second lowest vertical position and of the elevation of the center of gravity of said runner from the second lowest vertical position to the first highest vertical position, and wherein the biomechanical parameters are calculated at each stride, and wherein the digital processor is further programmed for calculating an average, per stride, of at least some calculated biomechanical parameters of the stride, wherein said lowering of said center of gravity is obtained as a function of maximum bearing force, of contact time and of the runner's mass, wherein the maximum bearing force is multiplied by the square of the contact time and divided by the runner's mass and wherein the function includes at least a constant.
2. The device according to claim 1 , wherein said elevation of said center of gravity is obtained as a function of vertical takeoff speed.
3. The device according to claim 1 , wherein said biomechanical parameters include a stiffness, calculated as a function of said maximum bearing force and of said lowering.
4. The device according to claim 1 , wherein said biomechanical parameters include a stride regularity index, calculated on the basis of the reactivity dispersion determined by means of said acceleration data.
5. The device according to claim 4 , wherein said biomechanical parameters include a fatigue level indicator on the basis of said regularity index.
6. The device according to claim 1 , wherein said biomechanical parameters include the asymmetry between at least one parameter of the left leg and at least one corresponding parameter of the right leg.
7. The device according to claim 6 , wherein said biomechanical parameters include an injury risk indicator calculated on the basis of said asymmetry.
8. The device according to claim 1 , wherein said biomechanical parameters include a takeoff angle of the center of gravity at the moment when the foot leaves the ground, obtained from an average speed and a vertical speed at the moment of takeoff.
9. The device according to claim 8 , wherein said average speed is calculated on the basis of said travelled distance and said duration counted by said chronograph, whilst said vertical speed at the moment of takeoff is obtained by integration of said acceleration data.
10. The device according to claim 1 , wherein said biomechanical parameters include a landing angle of the leg on the ground.
11. The device according to claim 1 , wherein said biomechanical parameters include the distance travelled by the runner's center of gravity during the duration when the foot is in contact with the ground.
12. The device according to claim 1 , wherein a sequence of acceleration data in at least the anteroposterior direction is measured by said accelerometer and processed separately from said sequence of acceleration data in the vertical direction in order to calculate at least some of said parameters.
13. The device according to claim 1 , wherein a sequence of acceleration data in at least the lateral direction is measured by said accelerometer and processed separately from said sequence of acceleration data in the vertical direction in order to calculate at least some of said parameters.
14. The device according to claim 1 , wherein an anteroposterior direction is determined by determining the spatial direction in which the displacement is largest.
15. A method for analyzing the biomechanical parameters of the stride of a runner, using a device of which comprises:
a self-sufficient electric power source;
a triaxial accelerometer capable of supplying at least one sequence of acceleration data in at least the vertical direction whilst the runner travels a distance on a running course;
a chronograph;
a belt;
a display;
a digital processor;
the method comprising the steps of,
calculating, during or at the end of a run, biomechanical parameters of the stride of said runner on the basis of acceleration data, of distance and of a duration counted by said chronograph, and wherein the biomechanical parameters of the stride comprise the vertical oscillation of the center of gravity of said runner between a first lowest vertical position and a second highest vertical position, and include the distance the center of gravity lowers and/or the distance the center of gravity elevates in a stride, and/or sum of the lowering of the center of gravity of said runner from the second highest vertical position to the first lowest vertical position and of the elevation of the center of gravity of said runner from the first lowest vertical position to the second highest vertical position; and
calculating an average, per stride, of at least some calculated biomechanical parameters of the stride,
obtaining said lowering of said center of gravity as a function of maximum bearing force, of contact time and of the runner's mass, wherein the maximum bearing force is multiplied by the square of the contact time and divided by the runner's mass and wherein the function includes at least a constant.
16. A device designed for analyzing the biomechanical parameters of the stride of a runner, comprising:
a self-sufficient electric power source;
a triaxial accelerometer capable of supplying at least one sequence of acceleration data in at least the vertical direction whilst the runner travels a distance on a running course;
a chronograph;
a belt;
a display;
a digital processor programmed for calculating, during or at the end of the run, biomechanical parameters of the stride of said runner on the basis of said acceleration data, of said distance and of a duration counted by said chronograph, and for displaying said parameters on said display, wherein the biomechanical parameters of the stride comprises a stiffness parameter based on the maximum force exerted by the ground on the foot and on the lowering of the center of gravity when this maximum force is exerted, and wherein the biomechanical parameters are calculated at each stride, wherein said lowering of said center of gravity is obtained as a function of maximum bearing force, of contact time and of the runner's mass, wherein the maximum bearing force is multiplied by the square of the contact time and divided by the runner's mass and wherein the function includes at least a constant, and wherein the digital processor is further programmed for calculating an average, per stride, of at least some calculated biomechanical parameters of the stride.
17. A method for analyzing the biomechanical parameters of the stride of a runner, using a device of which comprises:
a self-sufficient electric power source;
a triaxial accelerometer capable of supplying at least one sequence of acceleration data in at least the vertical direction whilst the runner travels a distance on a running course;
a chronograph;
a belt;
a display;
a digital processor;
the method comprising the steps of,
calculating, during or at the end of a run, biomechanical parameters of the stride of said runner on the basis of acceleration data, of distance and of a duration counted by said chronograph, and wherein the biomechanical parameters of the stride comprise a stiffness parameter based on the maximum force exerted by the ground on the foot and on the lowering of the center of gravity when this maximum force is exerted; and
calculating an average, per stride, of at least some calculated biomechanical parameters of the stride,
obtaining said lowering of said center of gravity as a function of maximum bearing force, of contact time and of the runner's mass, wherein the maximum bearing force is multiplied by the square of the contact time and divided by the runner's mass and wherein the function includes at least a constant.
18. The device of claim 1 , wherein said function of maximum bearing force, of contact time and of the runner's mass is defined by the formula
A f =( F max ,T c ,M )=|−( F max *T c 2 )/( M*π 2 )+( G*T c 2 )/8|
wherein Fmax is the maximum bearing force, T c the contact time, M the runner's mass, G the gravity acceleration constant.
19. The method of claim 15 , wherein said function of maximum bearing force, of contact time and of the runner's mass is defined by the formula
A f =( F max ,T c ,M )=|−( F max *T c 2 )/( M*π 2 )+( G*T c 2 )/8|
wherein Fmax is the maximum bearing force, T c the contact time, M the runner's mass, G the gravity acceleration constant.
20. The device of claim 16 , wherein said function of maximum bearing force, of contact time and of the runner's mass is defined by the formula
A f =( F max ,T c ,M )=|−( F max *T c 2 )/( M*π 2 )+( G*T c 2 )/8|
wherein Fmax is the maximum bearing force, T c the contact time, M the runner's mass, G the gravity acceleration constant.
21. The method of claim 17 , wherein said function of maximum bearing force, of contact time and of the runner's mass is defined by the formula
A f =( F max ,T c ,M )=|−( F max *T c 2 )/( M*π 2 )+( G*T c 2 )/8|
wherein Fmax is the maximum bearing force, T c the contact time, M the runner's mass, G the gravity acceleration constant.