# US 9,873,018 B2 · Integrated portable device and method implementing an accelerometer for analyzing biomechanical parameters of a stride > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 9,873,018 B2 - Document ID: US9873018B2 - Status: Granted - Kind: B2 - Application number: 15/090,254 - Filed: 2016-04-04 - Published: 2016-07-28 - Granted: 2018-01-23 - Earliest claimed: 2011-06-08 - Assignees: Myotest SA - Applicants: Myotest SA - Inventors: Patrick Flaction; Jacques Quievre; Jean-Benoit Morin - Web page: https://patentgrep.com/patent/US9873018B2 ## CPC - A63B 24/0006: {Computerised comparison for qualitative assessment of motion sequences or the course of a movement} - A61B 5/1038: {Measuring plantar pressure during gait} - A61B 5/112: {Gait analysis} - A61B 5/1122: {of movement trajectories} - A61B 5/6831: {Straps, bands or harnesses} - G01C 22/006: {Pedometers} - G01P 15/18: in two or more dimensions - G06V 40/23: {Recognition of whole body movements, e.g. for sport training} - A61B 2562/0219: Inertial sensors, e.g. accelerometers, gyroscopes, tilt switches - G06F 2218/00: Aspects of pattern recognition specially adapted for signal processing - A63B: APPARATUS FOR PHYSICAL TRAINING, GYMNASTICS, SWIMMING, CLIMBING, OR FENCING; BALL GAMES; TRAINING EQUIPMENT (apparatus for passive exercising, massage A61H) - A61B: DIAGNOSIS; SURGERY; IDENTIFICATION (usefulness limited to only animals A61D) - G01C: MEASURING DISTANCES, LEVELS OR BEARINGS; SURVEYING; NAVIGATION; GYROSCOPIC INSTRUMENTS; PHOTOGRAMMETRY OR VIDEOGRAMMETRY (measuring liquid level G01F; radio navigation, determining distance or velocity by use of propagation effects, e.g. Doppler effects, propagation time, of radio waves, analogous arrangements using other waves G01S) - G01P: MEASURING LINEAR OR ANGULAR SPEED, ACCELERATION, DECELERATION, OR SHOCK; INDICATING PRESENCE, ABSENCE, OR DIRECTION, OF MOVEMENT (measuring or recording blood flow A61B5/02, A61B8/06; monitoring speed or deceleration of electrically-propelled vehicles B60L3/00; vehicle lighting systems adapted to indicate speed B60Q1/54; determining position or course in navigation, measuring ground distance in geodesy or surveying G01C; combined measuring devices for measuring two or more variables of movement G01C23/00; measuring velocity of sound G01H; measuring velocity of light G01J7/00; measuring direction or velocity of solid objects by reception or emission of radiowaves or other waves and based on propagation effects, e.g. Doppler effect, propagation time, direction of propagation, G01S; measuring speed of nuclear radiation G01T; measuring acceleration of gravity G01V; {measuring or recording the speed of trains B61L23/00; speed indicators incorporated in motor vehicles B60K35/00; measuring frequency or phase G01R; traffic control G08G}) - G06V: IMAGE OR VIDEO RECOGNITION OR UNDERSTANDING - G06F: ELECTRIC DIGITAL DATA PROCESSING (computer systems based on specific computational models G06N) ## Abstract A method implementing an accelerometer for analyzing biomechanical parameters of a runner's stride. The method includes fastening a device (1) on the runner that has a triaxial accelerometer (17), a chronograph (16), a digital processor (19) and a display (11). The method measures a sequence of acceleration data in at least the vertical direction using the accelerometer, while the runner runs a certain distance (D) along a running course. During or at the end the running course, the processor calculates the biomechanical parameters of the stride, including lowering the center of gravity and/or the elevation (E) of the center of gravity and/or the sum of the lowering and of the elevation (E) and/or the vertical mechanical work of the center of gravity, based on the acceleration data, of the distance (D) and a period of time measured by the chronograph (16); and displays the parameters. ## Claims ### Claim 1 A device designed for analyzing biomechanical parameters of a stride of a runner, comprising: a self-sufficient electric power source; a tri-axial accelerometer capable of supplying at least one sequence of acceleration data in at least a vertical direction whilst the runner travels a distance on a running course; a GPS receiver; a chronograph; 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 a distance measured by said GPS receiver and/or by said accelerometer, and of a duration counted by said chronograph, wherein the biomechanical parameters of the stride comprises a vertical oscillation of a center of gravity of said runner, and include a distance the center of gravity lowers and a distance the center of gravity elevates in a stride, and a sum of the lowering and of the elevation of the center of gravity, and wherein the biomechanical parameters are calculated at each stride; wherein said digital processor is programmed for determining an anteroposterior direction during the run of the runner; wherein a sequence of acceleration data in said anteroposterior direction is measured by said accelerometer during the run and processed separately from said sequence of acceleration data in the vertical direction; wherein said digital processor is further programmed for calculating, during or at the end of the run, at least some of the biomechanical parameters of the stride of said runner, also on the basis of said acceleration data in said anteroposterior direction; a wireless interface for exchange of data with another data processing device. ### Claim 2 (depends on 1) The device according to claim 1, comprising a display, the digital processor programmed for displaying said parameters on said display. ### Claim 3 (depends on 1) The device according to claim 1, comprising a belt or a clip for fixing the device on the runner's torso, the center of mass being located at a place where the device and/or the accelerometer is fastened. ### Claim 4 (depends on 1) The device according to claim 1, wherein said lowering of said center of gravity is obtained as a function of a maximum bearing force, of a contact time and of a mass of the runner. ### Claim 5 (depends on 1) The device according to claim 1, wherein said elevation of said centre of gravity is obtained as a function of a vertical takeoff speed. ### Claim 6 (depends on 1) The device according to claim 1, wherein said biomechanical parameters include a stiffness, calculated as a function of a maximum bearing force and of said lowering. ### Claim 7 (depends on 1) The device according to claim 1, wherein said biomechanical parameters include a stride regularity index, calculated on a basis of the reactivity dispersion determined by means of said acceleration data. ### Claim 8 (depends on 7) The device according to claim 7, wherein said biomechanical parameters include a fatigue level indicator calculated on the basis of said regularity index. ### Claim 9 (depends on 1) The device according to claim 1, wherein said biomechanical parameters include the asymmetry between at least one parameter of a left leg and at least one corresponding parameter of a right leg. ### Claim 10 (depends on 9) The device according to claim 9, wherein said biomechanical parameters include an injury risk indicator calculated on the basis of said asymmetry. ### Claim 11 (depends on 1) The device according to claim 1, wherein said biomechanical parameters include a takeoff angle of the centre of gravity at a moment when the foot leaves the ground, obtained from an average speed and a vertical speed at a moment of takeoff. ### Claim 12 (depends on 11) The device according to claim 11, 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. ### Claim 13 (depends on 1) The device according to claim 1, wherein said biomechanical parameters include a landing angle of a leg on the ground. ### Claim 14 (depends on 1) The device according to claim 1, wherein said biomechanical parameters include a distance travelled by the runner's centre of gravity during a duration when the foot is in contact with the ground. ### Claim 15 (depends on 1) The device according to claim 1, wherein a sequence of acceleration data in at least a 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. ### Claim 16 (depends on 1) The device according to claim 1, wherein the vertical direction is determined on the basis of the acceleration data when the runner is at a standstill. ### Claim 17 (depends on 1) The device according to claim 1, wherein said anteroposterior direction is determined by determining a spatial direction in which displacement is greatest. ### Claim 18 (depends on 1) The device according to claim 1, wherein a transformation of a frame of reference is performed when the axes of said accelerometer do not coincide with a vertical respectively anteroposterior axes. ### Claim 19 (depends on 1) The device according to claim 1, wherein said biomechanical parameters include a variation of a stiffness of the leg muscles. ### Claim 20 (depends on 14) The device according to claim 14, wherein said digital processor is programmed for calculating said distance travelled by the runner's center of gravity during a duration when the foot is in contact with the ground, on the basis of the speed on said anteroposterior direction.