The relationships between muscle, external, internal and joint mechanical work during normal walking
The relationships between muscle, external, internal and joint mechanical work during normal walking
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DOI：
10.1242/jeb.023267
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发表时间：
2009-03-01
影响因子：
2.8
通讯作者：
Kautz, Steven A.
中科院分区：
文献类型：
--
作者：
Sasaki, Kotaro;Neptune, Richard R.;Kautz, Steven A.
肌肉的机械功是人体运动分析中的一个重要生物力学量，目前常用的力学量有外功、内功和关节功。本研究的目的是调查这些传统上使用的估计在人类行走的机械工作之间的关系，并评估它们是否可以被用来作为准确的估计musculotendon和/或肌纤维的工作。肌肉驱动的向前动态步行模拟生成量化的机械工作措施。总关节工作（即在一个完整的步态周期的绝对关节功率的时间积分）被发现低估总肌肉肌腱工作，由于激动剂-拮抗剂共同收缩，尽管双关节肌肉工作和被动关节工作的影响，这起到了减少低估。我们确实发现，当步态周期内的净被动关节功可以忽略不计时，净关节功（即净关节功率的时间积分）与净肌肉肌腱功（以及净肌纤维功，因为净肌腱功在整个步态周期内为零）相当。因此，在步行条件下，当被动关节功可以忽略不计时，净关节功可以用作净肌肉功的估计。无论是外部总功还是内部总功（或它们的总和）都不能合理估计肌肉肌腱总功。我们的结论是，联合工作是有限的，在其能力来估计肌肉肌腱的工作，外部和内部的工作不应该被用来作为估计肌肉肌腱的工作。
Muscle mechanical work is an important biomechanical quantity in human movement analyses and has been estimated using different quantities including external, internal and joint work. The goal of this study was to investigate the relationships between these traditionally used estimates of mechanical work in human walking and to assess whether they can be used as accurate estimates of musculotendon and/or muscle fiber work. A muscle-actuated forward dynamics walking simulation was generated to quantify each of the mechanical work measures. Total joint work (i.e. the time integral of absolute joint power over a full gait cycle) was found to underestimate total musculotendon work due to agonist-antagonist co-contractions, despite the effect of biarticular muscle work and passive joint work, which acted to decrease the underestimation. We did find that when the net passive joint work over the gait cycle is negligible, net joint work (i.e. the time integral of net joint power) was comparable to the net musculotendon work (and net muscle fiber work because net tendon work is zero over a complete gait cycle). Thus, during walking conditions when passive joint work is negligible, net joint work may be used as an estimate of net muscle work. Neither total external nor total internal work (nor their sum) provided a reasonable estimate of total musculotendon work. We conclude that joint work is limited in its ability to estimate musculotendon work, and that external and internal work should not be used as an estimation of musculotendon work.