The University of Queensland, School of Human Movement and Nutrition Sciences, Centre for Sensorimotor Neuroscience, Brisbane, QLD 4072, Australia
The University of Queensland, School of Human Movement and Nutrition Sciences, Centre for Sensorimotor Neuroscience, Brisbane, QLD 4072, Australia.
J Exp Biol. 2019 Jun 4;222(Pt 11):jeb191247. doi: 10.1242/jeb.191247.
The elastic tendinous tissues of distal lower limb muscles can improve the economy of walking and running, amplify the power generated by a muscle and absorb energy. This paper explores the behaviour of the tibialis anterior (TA) muscle and its tendinous tissue during gait, as it absorbs energy during contact and controls foot position during swing. Simultaneous measurements of ultrasound, surface electromyography and 3D motion capture with musculoskeletal modelling from 12 healthy participants were recorded as they walked at preferred and fast walking speeds. We quantified the length changes and velocities of the TA muscle-tendon unit (MTU) and its fascicles across the stride at each speed. Fascicle length changes and velocities were relatively consistent across speeds, although the magnitude of fascicle length change differed between the deep and superficial regions. At contact, when the TA is actively generating force, the fascicles remained relatively isometric as the MTU actively lengthened, presumably stretching the TA tendinous tissue and absorbing energy. This potentially protects the muscle fibres from damage during weight acceptance and allows energy to be returned to the system later in the stride. During early swing, the fascicles and MTU both actively shortened to dorsiflex the foot, clearing the toes from the ground; however, at the fast walking velocity, the majority of shortening occurred through tendinous tissue recoil, highlighting its role in accelerating ankle dorsiflexion to power rapid foot clearance in swing.
下肢远端肌肉的弹性腱组织可以提高步行和跑步的经济性，放大肌肉产生的力量并吸收能量。本文探讨了胫骨前肌（TA）及其腱组织在步态中的行为，因为它在接触时吸收能量并在摆动时控制脚的位置。从 12 名健康参与者中同时记录了超声、表面肌电图和 3D 运动捕捉以及肌肉骨骼建模的测量数据，他们以舒适和快速的步行速度行走。我们在每个速度下量化了 TA 肌肌腱单元（MTU）及其肌束在整个步幅中的长度变化和速度。尽管在深区和浅区之间，肌束长度变化的幅度不同，但肌束长度变化和速度在速度上相对一致。在接触时，当 TA 主动产生力时，肌束保持相对等长，因为 MTU 主动延长，可能会拉伸 TA 腱组织并吸收能量。这可能会保护肌肉纤维免受承重时的损伤，并允许能量在步幅的后期返回系统。在早期摆动时，肌束和 MTU 都主动缩短以背屈脚，使脚趾离开地面；然而，在快速步行速度下，大部分缩短是通过腱组织的回弹发生的，这突出了它在加速踝关节背屈以快速清除摆动中的脚的作用。
