School of Human Movement and Nutrition Sciences , The University of Queensland, Brisbane, QLD 4072, Australia.
J Exp Biol. 2021 Jul 1;224(13). doi: 10.1242/jeb.242263. Epub 2021 Jul 12.
The human foot is known to aid propulsion by storing and returning elastic energy during steady-state locomotion. While its function during other tasks is less clear, recent evidence suggests the foot and its intrinsic muscles can also generate or dissipate energy based on the energetic requirements of the center of mass during non-steady-state locomotion. In order to examine contributions of the foot and its muscles to non-steady-state locomotion, we compared the energetics of the foot and ankle joint while jumping and landing before and after the application of a tibial nerve block. Under normal conditions, energetic contributions of the foot rose as work demands increased, while the relative contributions of the foot to center of mass work remained constant with increasing work demands. Under the nerve block, foot contributions to both jumping and landing decreased. Additionally, ankle contributions were also decreased under the influence of the block for both tasks. Our results reinforce findings that foot and ankle function mirror the energetic requirements of the center of mass and provide novel evidence that foot contributions remain relatively constant under increasing energetic demands. Also, while the intrinsic muscles can modulate the energetic capacity of the foot, their removal accounted for only a 3% decrement in total center of mass work. Therefore, the small size of intrinsic muscles appears to limit their capacity to contribute to center of mass work. However, their role in contributing to ankle work capacity is likely important for the energetics of movement.
人类足部在稳态运动中通过储存和返回弹性能量来辅助推进。虽然其在其他任务中的功能尚不明确，但最近的证据表明，足部及其内在肌肉也可以根据非稳态运动中质心的能量需求产生或消耗能量。为了研究足部及其肌肉在非稳态运动中的贡献，我们比较了在应用胫神经阻滞前后跳跃和着陆时足部和踝关节的能量学。在正常情况下，随着工作需求的增加，足部的能量贡献增加，而足部对质心做功的相对贡献随着工作需求的增加保持不变。在神经阻滞下，足部对跳跃和着陆的贡献都减少了。此外，在两种任务中，阻滞对踝关节的贡献也减少了。我们的结果强化了足部和踝关节功能反映质心能量需求的发现，并提供了新的证据，表明在增加能量需求下，足部的贡献保持相对稳定。此外，虽然内在肌肉可以调节足部的能量容量，但它们的去除仅导致总质心做功减少 3%。因此，内在肌肉的小尺寸似乎限制了它们对质心做功的贡献能力。然而，它们在贡献踝关节工作能力方面的作用对于运动的能量学可能很重要。
