Differences in contractile behaviour between the soleus and medial gastrocnemius muscles during human walking
Differences in contractile behaviour between the soleus and medial gastrocnemius muscles during human walking
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DOI：
10.1242/jeb.078196
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发表时间：
2013-03-01
影响因子：
2.8
通讯作者：
Peltonen, Jussi
中科院分区：
文献类型：
--
作者：
Cronin, Neil J.;Avela, Janne;Peltonen, Jussi
在人类行走过程中，各个下肢肌肉的功能作用可能因行走速度或持续时间而异。在这项研究中，11名志愿者在跑步机上行走了60分钟。min的速度对应于最佳和20%以上的最佳能量成本的运输，而氧消耗和内侧腓肠肌（MG）和比目鱼肌束长度进行了测量。虽然运输的能量成本在更快的速度下高出12%，但它在60以上保持不变。这表明人类可以在一系列速度下长时间行走而不影响能量效率。这两种肌肉的束表现出相当'等距'的行为在早期到中期的立场阶段的步行，这似乎是独立的步行速度或运动效率。然而，在肌肉之间观察到几种功能差异。MG表现出时间和速度依赖性的工作长度减少，缩短更快的推离阶段在更快的步行速度。相反，比目鱼肌表现出一致的收缩行为，无论步行速度或持续时间，总是缩短慢于MG在pushoff。Soleus似乎在行走过程中发挥比MG更重要的功能作用。这可能是特别真实的，当步行时间较长，或在速度以上的最有效的能量，其中力的潜力，从而功能的重要性MG似乎下降。
The functional roles of individual lower limb muscles during human walking may differ depending on walking speed or duration. In this study, 11 volunteers walked on a treadmill for 60. min at speeds corresponding to both optimal and 20% above optimal energetic cost of transport whilst oxygen consumption and medial gastrocnemius (MG) and soleus fascicle lengths were measured. Although energetic cost of transport was similar to 12% higher at the faster speed, it remained constant over 60. min at both speeds, suggesting that humans can walk for prolonged periods at a range of speeds without compromising energetic efficiency. The fascicles of both muscles exhibited rather 'isometric' behaviour during the early to mid stance phase of walking, which appears to be independent of walking speed or movement efficiency. However, several functional differences were observed between muscles. MG exhibited time- and speed-dependent decreases in operating length, and shortened faster during the pushoff phase at the faster walking speed. Conversely, soleus exhibited consistent contractile behaviour regardless of walking speed or duration, and always shortened slower than MG during pushoff. Soleus appears to play a more important functional role than MG during walking. This may be especially true when walking for prolonged periods or at speeds above the most energetically efficient, where the force potential and thus the functional importance of MG appears to decline.