University of Groningen, University Medical Center Groningen, Center for Human Movement Sciences, Groningen 9713 AV, The Netherlands
University of Groningen, University Medical Center Groningen, Center for Human Movement Sciences, Groningen 9713 AV, The Netherlands.
J Exp Biol. 2018 Jul 6;221(Pt 13):jeb174896. doi: 10.1242/jeb.174896.
Human bipedal gait is inherently unstable, and staying upright requires adaptive control of dynamic balance. Little is known about adaptive control of dynamic balance in reaction to long-term, continuous perturbations. We examined how dynamic balance control adapts to a continuous perturbation in gait, by letting people walk faster with one leg than the other on a treadmill with two belts (i.e. split-belt walking). In addition, we assessed whether changes in mediolateral dynamic balance control coincide with changes in energy use during split-belt adaptation. In 9 min of split-belt gait, mediolateral margins of stability and mediolateral foot roll-off changed during adaptation to the imposed gait asymmetry, especially on the fast side, and returned to baseline during washout. Interestingly, no changes in mediolateral foot placement (i.e. step width) were found during split-belt adaptation. Furthermore, the initial margin of stability and subsequent mediolateral foot roll-off were strongly coupled to maintain mediolateral dynamic balance throughout the gait cycle. Consistent with previous results, net metabolic power was reduced during split-belt adaptation, but changes in mediolateral dynamic balance control were not correlated with the reduction of net metabolic power during split-belt adaptation. Overall, this study has shown that a complementary mechanism of relative foot positioning and mediolateral foot roll-off adapts to continuously imposed gait asymmetry to maintain dynamic balance in human bipedal gait.
人类的双足步态本质上是不稳定的，要保持直立需要对动态平衡进行自适应控制。对于长期连续的扰动对动态平衡的自适应控制，我们知之甚少。我们通过让人们在两条带（即分体带行走）的跑步机上用一条腿比另一条腿更快地行走，来研究动态平衡控制如何适应步态的连续扰动。此外，我们还评估了在分体带适应过程中，中侧向动态平衡控制的变化是否与能量使用的变化相吻合。在 9 分钟的分体带行走中，中侧向稳定性和中侧向足滚动在适应强制的步态不对称时发生了变化，尤其是在快速侧，在冲洗过程中恢复到基线。有趣的是，在分体带适应过程中没有发现中侧向足放置（即步宽）的变化。此外，初始稳定性和随后的中侧向足滚动与维持整个步态周期的中侧向动态平衡密切相关。与之前的结果一致，净代谢功率在分体带适应期间降低，但中侧向动态平衡控制的变化与分体带适应期间净代谢功率的降低无关。总的来说，这项研究表明，相对足部定位和中侧向足滚动的互补机制适应连续施加的步态不对称，以维持人类双足步态的动态平衡。
