Müller Roy, Häufle Daniel Florian Benedict, Blickhan Reinhard
Motionscience, Institute of Sport Sciences, Friedrich Schiller University Jena, Seidelstraße 20, 07749 Jena, Germany
Department of Sport and Exercise Science, University of Stuttgart, Allmandring 28, 70569 Stuttgart, Germany.
J Exp Biol. 2015 Feb 1;218(Pt 3):451-7. doi: 10.1242/jeb.113688. Epub 2014 Dec 18.
While running on uneven ground, humans are able to negotiate visible but also camouflaged changes in ground level. Previous studies have shown that the leg kinematics before touch down change with ground level. The present study experimentally investigated the contributions of visual perception (visual feedback), proprioceptive feedback and feed-forward patterns to the muscle activity responsible for these adaptations. The activity of three bilateral lower limb muscles (m. gastrocnemius medialis, m. tibialis anterior and m. vastus medialis) of nine healthy subjects was recorded during running across visible (drop of 0, -5 and -10 cm) and camouflaged changes in ground level (drop of 0 and -10 cm). The results reveal that at touchdown with longer flight time, m. tibialis anterior activation decreases and m. vastus medialis activation increases purely by feed-forward driven (flight time-dependent) muscle activation patterns, while m. gastrocnemius medialis activation increase is additionally influenced by visual feedback. Thus, feed-forward driven muscle activation patterns are sufficient to explain the experimentally observed adjustments of the leg at touchdown.
在不平整地面上跑步时，人类不仅能够应对可见的地面高度变化，还能应对伪装的地面高度变化。先前的研究表明，着地前的腿部运动学随地面高度而变化。本研究通过实验调查了视觉感知（视觉反馈）、本体感受反馈和前馈模式对负责这些适应性变化的肌肉活动的贡献。在九名健康受试者跨越可见的（下降0、-5和-10厘米）和伪装的地面高度变化（下降0和-10厘米）跑步过程中，记录了双侧下肢三块肌肉（腓肠肌内侧头、胫骨前肌和股内侧肌）的活动。结果显示，在着地且飞行时间较长时，胫骨前肌的激活纯粹通过前馈驱动（与飞行时间相关）的肌肉激活模式而降低，股内侧肌的激活增加，而腓肠肌内侧头的激活增加还受到视觉反馈的影响。因此，前馈驱动的肌肉激活模式足以解释实验中观察到的着地时腿部的调整情况。
