Countermovement jump performance assessment using a wearable 3D inertial measurement unit

The aim of this study was to validate a wearable inertial measurement unit (IMU), containing a 3D accelerometer andgyroscope, for the estimation of countermovement jump height. The absolute vertical acceleration of the IMU positioned onthe back of the participant at L5 level, compensated for trunk rotations, was used to obtain jump height by applying theequation of free-fall to the motion of the IMU. The methodology was tested on 28 participants performing fivecountermovement jumps each. A reference value for this quantity was obtained using stereophotogrammetry (35.4 cm,s¼4.9). Jump height scores obtained using the proposed methodology (35.9 cm, s¼5.5) presented no significant differencewith respect to stereophotogrammetry (P¼0.61). A low bias of 0.6 cm confirmed the accuracy of the estimate, which alsoshowed a high (r¼0.87) and significant (P50.0001) correlation with reference values. Furthermore, without compensatingaccelerations for trunk rotation, jump height was largely underestimated (P50.0001) (bias:712.7 cm) and poorlyassociated (r¼0.31) with stereophotogrammetry. The results of this study show that the estimation of jump height usinginertial sensors leads to accurate results when the measured accelerations are corrected for trunk rotations.