Step‐to‐step kinematic validation between an inertial measurement unit (Imu) 3d system, a combined laser+imu system and force plates during a 50 m sprint in a cohort of sprinters

Abstract

The purpose was to compare step‐by‐step kinematics measured using force plates (crite-rion), an IMU only and a combined laser IMU system in well‐trained sprinters. Fourteen male experienced sprinters performed a 50‐m sprint. Step‐by‐step kinematics were measured by 50 force plates and compared with an IMU‐3D motion capture system and a combined laser+IMU system attached to each foot. Results showed that step kinematics (step velocity, length, contact and flight times) were different when measured with the IMU‐3D system, compared with force plates, while the laser+IMU system, showed in general the same kinematics as measured with force plates with-out a systematic bias. Based upon the findings it can be concluded that the laser+IMU system is as accurate in measuring step‐by‐step kinematics as the force plate system. At the moment, the IMU‐ 3D system is only accurate in measuring stride patterns (temporal parameters); it is not accurate enough to measure step lengths (spatial) and velocities due to the inaccuracies in step length, especially at high velocities. It is suggested that this laser+IMU system is valid and accurate, which can be used easily in training and competition to obtain step‐by step kinematics and give direct feedback of this information during training and competition.