Inertial Measurement Units (IMUs) are promising alternatives to laboratory-based motion capture methods in biomechanical assessment of athletic movements. The aim of this study was to investigate the validity of an IMU system for determining knee and trunk kinematics during landing and cutting tasks for clinical and research applications in sporting populations. Twenty-seven participants performed five cutting and landing tasks while being recorded using a gold-standard optoelectronic motion capture system and an IMU system. Intra-class coefficients, Pearson’s r, root-mean-square error (RMSE), bias, and Bland-Altman limits of agreements between the motion capture and IMU systems were quantified for knee and trunk sagittal- and frontal-plane range-of-motion (ROM) and peak angles. Our results indicate that IMU validity was task-, joint-, and plane-dependent. Based on good-to-excellent (ICC) correlation, reasonable accuracy (RMSE < 5°), bias within 2°, and limits of agreements within 10°, we recommend the use of this IMU system for knee sagittal-plane ROM estimations during cutting, trunk sagittal-plane peak angle estimation during the double-leg landing task, trunk sagittal-plane ROM estimation for almost all tasks, and trunk frontal-plane peak angle estimation for the right single-leg landing task. Due to poor comparisons with the optoelectronic system, we do not recommend this IMU system for knee frontal-plane kinematic estimations.

惯性测量单元 (IMU) 是运动运动生物力学评估中基于实验室的运动捕捉方法的有前途的替代方案。本研究的目的是调查 IMU 系统在着陆和切割任务期间确定膝关节和躯干运动学的有效性，用于运动人群的临床和研究应用。27 名参与者在使用黄金标准光电运动捕捉系统和 IMU 系统进行记录的同时执行了五项切割和着陆任务。类内系数，Pearson's r运动捕捉和 IMU 系统之间的均方根误差 (RMSE)、偏差和 Bland-Altman 限制被量化为膝盖和躯干矢状面和额状面运动范围 (ROM) 和峰值角度. 我们的结果表明 IMU 有效性是任务、关节和平面相关的。基于良好到优秀 (ICC) 的相关性、合理的准确度 (RMSE < 5°)、2° 以内的偏差和 10° 以内的一致性限制，我们建议使用此 IMU 系统进行膝关节矢状面 ROM 估计切割，双腿着陆任务期间躯干矢状面峰值角度估计，几乎所有任务的躯干矢状面 ROM 估计，以及右侧单腿着陆任务的躯干额状面峰值角度估计。由于与光电系统比较差，