The independent effect of added mass on the stability of the sagittal plane leg kinematics during steady-state human walking
The independent effect of added mass on the stability of the sagittal plane leg kinematics during steady-state human walking
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DOI：
10.1242/jeb.026153
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发表时间：
2009-06-15
影响因子：
2.8
通讯作者：
Kurz, Max J.
中科院分区：
文献类型：
--
作者：
Arellano, Christopher J.;O'Connor, Daniel P.;Kurz, Max J.
研究了人体行走过程中附加质量对腿部运动学稳定性的独立影响。我们推断，增加质量会影响身体的惯性状态，从而挑战腿部在行走时改变和加速身体总质量的能力。我们假设，走路时增加质量会降低腿部运动学的稳定性。记录了23名受试者在跑步机上以自己喜欢的速度在有无附加质量的情况下行走时的下肢矢状面关节运动学。每个受试者的总质量是通过模拟减重和增加负荷的组合来操纵的。腿部运动学的稳定性是通过计算Poincare映射的特征值(即Floket分析)来评估的，该映射定义了右髋关节、膝盖和脚踝在脚后跟接触和挥杆中期的位置和速度。在不同的附加质量条件下(P=0.040)和在步态周期的瞬间(P=0.001)，稳定性有显著差异。术后分析显示，与不增加质量的步行相比，增加30%质量的步行会降低腿部运动学的稳定性(P=0.031)。此外，与摆动中相比，脚跟接触时的不稳定性更大(P=0.001)。我们的结果表明，增加质量的步行会引起腿部运动学上更大的扰动，这可能与整个步态周期中身体的重定向和加速有关。增加质量的步行会降低腿部运动学的稳定性，可能还会降低行走模式的整体平衡。
This study investigated the independent effect of added mass on the stability of the leg kinematics during human walking. We reasoned that adding mass would influence the body's inertial state and thus challenge the ability of the leg to redirect and accelerate the total mass of the body while walking. We hypothesized that walking with added mass would reduce the stability of the leg kinematics. Lower extremity sagittal plane joint kinematics were recorded for 23 subjects as they walked on a treadmill at their preferred speed with and without added mass. The total mass of each subject was manipulated with combinations of simulated reduced gravity and added load. The stability of the leg kinematics was evaluated by computing the eigenvalues of the Poincare map (i.e. Floquet analysis) that defined the position and velocity of the right hip, knee and ankle at heel-contact and mid-swing. Significant differences in stability were found between the various added mass conditions (P=0.040) and instant in the gait cycle (P=0.001). Post-hoc analysis revealed that walking with 30% added mass compromised the stability of the leg kinematics compared with walking without additional mass (P=0.031). In addition, greater instability was detected at the instance of heel-contact compared with mid-swing (P=0.001). Our results reveal that walking with added mass gives rise to greater disturbances in the leg kinematics, and may be related to the redirection and acceleration of the body throughout the gait cycle. Walking with added mass reduces the stability of the leg kinematics and possibly the overall balance of the walking pattern.