Department of Sport Biomechanics, Faculty of Physical Education and Sport Sciences, University of Mazandaran, Babolsar, Iran; BSNlab Co., Rasht, Iran.
Department of Health and Sports Rehabilitation, Faculty of Sports Sciences and Health, Shahid Beheshti University, Tehran, Iran.
J Biomech. 2024 Nov;176:112338. doi: 10.1016/j.jbiomech.2024.112338. Epub 2024 Sep 21.
The aim of the current study was to compare the reliability and validity of jump variables determined from torso- and waist-worn inertial measurement units (IMU) in comparison to force platform measures. Twenty-seven students-athletes completed eight countermovement (CMJ) and squat jumps (SJ) on a force platform with IMUs mounted on the pelvis and torso. Variables including jump height and phase-specific duration, impulse and power were calculated from force platform and both IMUs independently. Considering both IMU locations, the coefficients of variation (CV) observed for all CMJ variables were ≤ 2.5 % larger than the force platform with the exception of concentric impulse with the torso-worn worn IMU (6.9 %). Differences in CVs observed between IMU and force platform variables appeared greater in the SJ. For velocity-derived jump height and concentric impulse from both IMU placements, and torso-worn IMU mean power, CVs were > 2.5 % larger than the force platform. Both IMU placements overestimated jump height determined by flight time (+22 to +35 %) and underestimated jump height determined by take-off velocity (-10 to -18 %). In conclusion, the reliability of IMU metrics was largely comparable to the force platform. However, systematic bias was observed for most metrics. Practitioners should exercise caution if seeking to model jump performance with IMUs.
本研究的目的是比较躯干和腰部佩戴惯性测量单元（IMU）的跳跃变量与力量平台测量值的可靠性和有效性。27 名学生运动员在力量平台上完成了 8 次反向跳跃（CMJ）和深蹲跳跃（SJ），同时在骨盆和躯干上安装了 IMU。从力量平台和两个 IMU 独立计算了跳跃高度和特定相位持续时间、冲量和功率等变量。考虑到两个 IMU 位置，除了躯干佩戴的 IMU 的向心冲量（6.9%）外，所有 CMJ 变量的变异系数（CV）观察值都比力量平台大 2.5%。SJ 中观察到的 IMU 和力量平台变量之间的 CV 差异更大。对于来自两个 IMU 位置的速度衍生跳跃高度和向心冲量，以及躯干佩戴的 IMU 的平均功率，CV 比力量平台大 2.5%。两个 IMU 位置都高估了通过飞行时间确定的跳跃高度（+22%至+35%），低估了通过起飞速度确定的跳跃高度（-10%至-18%）。总之，IMU 指标的可靠性在很大程度上可与力量平台相媲美。然而，大多数指标都存在系统偏差。如果从业者希望使用 IMU 来模拟跳跃性能，应谨慎行事。
