Predictive control of ankle stiffness at heel contact is a key element of locomotor adaptation during split-belt treadmill walking in humans
Predictive control of ankle stiffness at heel contact is a key element of locomotor adaptation during split-belt treadmill walking in humans
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DOI：
10.1152/jn.00497.2012
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发表时间：
2014-02-01
影响因子：
2.5
通讯作者：
Nakazawa, Kimitaka
中科院分区：
文献类型：
--
作者：
Ogawa, Tetsuya;Kawashima, Noritaka;Nakazawa, Kimitaka
分带式跑台步行是研究人类双足运动适应性的一种有效模型。虽然以前的研究已经清楚地确定了不同类型的运动适应，如反应性和预测性调整，但步态模式如何调整的细节尚未完全了解。为了进一步了解裂带式跑步机适应的策略，我们研究了22名健康受试者在裂带式跑步机行走期间和之后的三维地面反作用力（GRF）和下肢肌肉活动。结果表明，前组成部分的GRF（制动力）表现出明确的模式的适应和随后的后效。制动力的变化与胫骨前肌在站立早期的肌电活动有关。与此相反，GRF（推进力）的后部组件显示出一致的增加/减少，在适应期的快/慢腿，并没有随后的后遗症。腓肠肌在站立期的肌肉活动在适应期逐渐减弱，在洗脱期出现代偿反应。结果表明，预测前馈控制是必要的，以设置最佳的踝关节刚度准备在脚跟接触的影响和被动反馈控制用于生产的反射诱导的推进力在分裂带跑步机适应的立场阶段结束。本研究提供了有关裂带适应的详细机制的信息，应该是有用的建设具体的康复方案。
Split-belt treadmill walking has been extensively utilized as a useful model to reveal the adaptability of human bipedal locomotion. While previous studies have clearly identified different types of locomotor adaptation, such as reactive and predictive adjustments, details of how the gait pattern would be adjusted are not fully understood. To gain further knowledge of the strategies underlying split-belt treadmill adaptation, we examined the three-dimensional ground reaction forces (GRF) and lower limb muscle activities during and after split-belt treadmill walking in 22 healthy subjects. The results demonstrated that the anterior component of the GRF (braking force) showed a clear pattern of adaptation and subsequent aftereffects. The muscle activity in the tibialis anterior muscle during the early stance phase was associated with the change of braking force. In contrast, the posterior component of GRF (propulsive force) showed a consistent increase/decrease in the fast/slow leg during the adaptation period and was not followed by subsequent aftereffects. The muscle activity in the gastrocnemius muscle during the stance phase gradually decreased during the adaptation phase and then showed a compensatory reaction during the washout phase. The results indicate that predictive feedforward control is required to set the optimal ankle stiffness in preparation for the impact at the heel contact and passive feedback control is used for the production of reflexively induced propulsive force at the end of the stance phase during split-belt treadmill adaptation. The present study provides information about the detailed mechanisms underlying split-belt adaptation and should be useful for the construction of specific rehabilitation protocols.