School of Kinesiology and Health Studies, Queen's University, 28 Division Street, Kingston, Ontario, Canada.
Gait Posture. 2011 Oct;34(4):561-3. doi: 10.1016/j.gaitpost.2011.06.022. Epub 2011 Jul 30.
While a stable trunk and centre of mass (CoM) trajectory are required during lifting, it is unclear how stability is controlled. Thirty healthy participants (15M, 15F) performed repetitive, symmetric lifting at 10 cycles per minute for 3 min with a load-in-hands equivalent to 10% of their maximum back strength. Short- and long-term maximum finite-time Lyapunov exponents (λ(max-s) and λ(max-l)), describing responses to small (local) perturbations, estimated the local dynamic stability of the foot, shank, thigh, pelvis, lower back, and upper back segments. Instability (λ(max-s)) significantly increased when moving up the kinematic chain (p<0.001). Therefore, to maintain trunk equilibrium and accurately regulate CoM trajectory during lifting, stability of the distal (fixed) lower limb segments is prioritized. This is contrary to previous results observed during gait, indicating that trunk control via kinematic chain stability is accomplished differently for walking and lifting.
虽然在举升过程中需要稳定的躯干和质心 (CoM) 轨迹，但目前尚不清楚如何控制稳定性。30 名健康参与者（15M，15F）以 10 次/分钟的频率进行重复、对称的举升，持续 3 分钟，手中的负荷相当于他们最大背部力量的 10%。描述对小（局部）扰动响应的短期和长期最大有限时间李雅普诺夫指数 (λ(max-s) 和 λ(max-l))，估计了足部、小腿、大腿、骨盆、下背部和上背部的局部动态稳定性。当沿着运动链向上移动时，不稳定性（λ(max-s)）显着增加（p<0.001）。因此，为了在举升过程中保持躯干平衡并准确调节 CoM 轨迹，需要优先考虑远端（固定）下肢节段的稳定性。这与在步态中观察到的先前结果相反，表明通过运动链稳定性对躯干的控制在行走和举升时的方式不同。
