Limb Kinematics, Kinetics and Muscle Dynamics During the Sit-to-Stand Transition in Greyhounds.
Limb Kinematics, Kinetics and Muscle Dynamics During the Sit-to-Stand Transition in Greyhounds.
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DOI：
10.3389/fbioe.2018.00162
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发表时间：
2018
影响因子：
5.7
通讯作者：
Hutchinson JR
中科院分区：
文献类型：
--
作者：
Ellis RG;Rankin JW;Hutchinson JR
从俯卧位置站起来是动物的一项重要日常活动：如果不能有效地做到这一点，可能会导致受伤的跌倒或增加捕食的敏感性。这种从坐到站的行为（StS）在生物力学上是有趣的，因为它需要从蹲伏（即，差的机械优势）到更直立的姿势。如此大的关节偏移需要肌肉-肌腱单位的大的长度变化。在这里，我们整合实验和肌肉骨骼模拟方法，以量化的关节运动，肢体力量，和肌纤维的力量，激活和长度的变化，在StS在一个极端的运动员-灰狗-它有大的后肢肌肉轴承短-reverred远端肌肉和长肌腱。研究结果表明，后肢反重力肌纤维在StS期间的长度变化接近其~50%的极限;主要是从高度延长的位置开始。StS还需要高肌肉激活（>50%），部分原因是非矢状运动。最后，StS运动需要被动的非肌肉的支持，在远侧后肢，短肢肌肉不能维持StS本身。像StS这样的非运动行为可能会在肌纤维力容量和长度变化以及主动和被动支持机制之间进行重要的权衡，而这些在运动生物力学研究中被忽视。
Standing up from a prone position is a critical daily activity for animals: failing to do so effectively may cause an injurious fall or increase predation susceptibility. This sit-to-stand behaviour (StS) is biomechanically interesting because it necessitates transitioning through near-maximal joint motion ranges from a crouched (i.e., poor mechanical advantage) to a more upright posture. Such large joint excursions should require large length changes of muscle-tendon units. Here we integrate experimental and musculoskeletal simulation methods to quantify the joint motions, limb forces, and muscle fibre forces, activations and length changes during StS in an extreme athlete—the greyhound—which has large hindlimb muscles bearing short-fibred distal muscles and long tendons. Study results indicate that hindlimb anti-gravity muscle fibres operate near their ~50% limits of length change during StS; mostly by starting at highly lengthened positions. StS also requires high muscle activations (>50%), in part due to non-sagittal motions. Finally, StS movements require passive non-muscular support in the distal hindlimb where short-fibred muscles are incapable of sustaining StS themselves. Non-locomotor behaviours like StS likely impose important trade-offs between muscle fibre force capacity and length changes, as well as active and passive mechanisms of support, that have been neglected in locomotor biomechanics studies.