McCaw S T, DeVita P
Department of Health, Physical Education, Recreation and Dance, Illinois State University, Normal 61790-5120, USA.
J Biomech. 1995 Aug;28(8):985-8. doi: 10.1016/0021-9290(94)00151-s.
The purpose of the study was to quantify the effect of errors in spatial alignment between the center of pressure recorded from a force platform and the coordinates of the foot recorded from film on resultant joint torques in the lower extremity during the stance phase of gait. Two-dimensional kinematic and kinetic data from eight subjects performing walking and running were analyzed using inverse dynamics with the obtained center of pressure values and with +/- 0.5 and +/- 1.0 cm shifts in the anteroposterior location of the center of pressure under the support foot. Shifting the center of pressure posteriorly increased the flexor (dorsiflexor) torques at the hip and ankle and decreased the extensor (plantarflexor) torques at these joints. This shift also caused an increase in the extensor and a decrease in the flexor torques at the knee. Shifting the center of pressure anteriorly caused the opposite effects at each joint. The +/- 0.5 and +/- 1.0 cm shifts in the location of the center of pressure caused, on average, 7 and 14% changes, respectively, in maximum joint torque and angular impulse values. Relative transition times between flexor and extensor torques were either increased or decreased, on average, by 7 and 13%, respectively for the two conditions over all trials. Based on these results, it is concluded that due to potential errors in the spatial alignment of kinetic and kinematic data, joint torques in the literature on gait should be considered as approximations of the true values.
本研究的目的是量化在步态站立期，力平台记录的压力中心与胶片记录的足部坐标之间空间对齐误差对下肢合成关节扭矩的影响。使用逆动力学分析了八名受试者行走和跑步时的二维运动学和动力学数据，分析时采用了获得的压力中心值以及支撑脚下压力中心前后位置分别有±0.5厘米和±1.0厘米偏移的情况。将压力中心向后移动会增加髋部和踝部的屈肌（背屈肌）扭矩，并降低这些关节的伸肌（跖屈肌）扭矩。这种移动还会导致膝部伸肌扭矩增加，屈肌扭矩减少。将压力中心向前移动会在每个关节产生相反的效果。压力中心位置±0.5厘米和±1.0厘米的偏移分别平均导致最大关节扭矩和角冲量值发生7%和14%的变化。在所有试验中，两种情况下屈肌和伸肌扭矩之间的相对过渡时间平均分别增加或减少了7%和13%。基于这些结果，可以得出结论，由于动力学和运动学数据空间对齐中存在潜在误差，步态文献中的关节扭矩应被视为真实值的近似值。
