Wang Ruoli, Gutierrez-Farewik Elena M
KTH Mechanics, Royal Institute of Technology, Stockholm, Sweden.
KTH Mechanics, Royal Institute of Technology, Stockholm, Sweden; Department of Women's and Children's Health, Karolinska Institute, Stockholm, Sweden.
Gait Posture. 2014 Mar;39(3):926-32. doi: 10.1016/j.gaitpost.2013.12.002. Epub 2013 Dec 10.
Excessive co-contraction causes inefficient or abnormal movement in several neuromuscular pathologies. How synergistic muscles spanning the ankle, knee and hip adapt to co-contraction of ankle muscles is not well understood. This study aimed to identify the compensation strategies required to retain normal walking with excessive antagonistic ankle muscle co-contraction. Muscle-actuated simulations of normal walking were performed to quantify compensatory mechanisms of ankle and knee muscles during stance in the presence of normal, medium and high levels of co-contraction of antagonistic pairs gastrocnemius+tibialis anterior and soleus+tibialis anterior. The study showed that if co-contraction increases, the synergistic ankle muscles can compensate; with gastrocmemius+tibialis anterior co-contraction, the soleus will increase its contribution to ankle plantarflexion acceleration. At the knee, however, almost all muscles spanning the knee and hip are involved in compensation. We also found that ankle and knee muscles alone can provide sufficient compensation at the ankle joint, but hip muscles must be involved to generate sufficient knee moment. Our findings imply that subjects with a rather high level of dorsiflexor+plantarflexor co-contraction can still perform normal walking. This also suggests that capacity of other lower limb muscles to compensate is important to retain normal walking in co-contracted persons. The compensatory mechanisms can be useful in clinical interpretation of motion analyses, when secondary muscle co-contraction or other deficits may present simultaneously in subjects with motion disorders.
在多种神经肌肉疾病中，过度的共同收缩会导致低效或异常运动。跨越踝关节、膝关节和髋关节的协同肌如何适应踝关节肌肉的共同收缩，目前尚不清楚。本研究旨在确定在拮抗踝关节肌肉过度共同收缩的情况下维持正常行走所需的补偿策略。进行了正常行走的肌肉驱动模拟，以量化在腓肠肌+胫骨前肌和比目鱼肌+胫骨前肌这两对拮抗肌正常、中等和高水平共同收缩时，踝关节和膝关节肌肉在站立期的补偿机制。研究表明，如果共同收缩增加，协同踝关节肌肉可以进行补偿；在腓肠肌+胫骨前肌共同收缩时，比目鱼肌将增加其对踝关节跖屈加速度的贡献。然而，在膝关节处，几乎所有跨越膝关节和髋关节的肌肉都参与了补偿。我们还发现，仅踝关节和膝关节肌肉就能在踝关节提供足够的补偿，但髋关节肌肉必须参与才能产生足够的膝关节力矩。我们的研究结果表明，背屈肌+跖屈肌共同收缩水平较高的受试者仍能正常行走。这也表明，其他下肢肌肉的补偿能力对于共同收缩人群维持正常行走很重要。当运动障碍患者可能同时出现继发性肌肉共同收缩或其他缺陷时，这些补偿机制在运动分析的临床解释中可能会有用。
