The role of series ankle elasticity in bipedal walking.
The role of series ankle elasticity in bipedal walking.
复制标题
DOI：
10.1016/j.jtbi.2013.12.014
复制
发表时间：
2014-04-07
影响因子：
2
通讯作者：
Kuo, Arthur D.
中科院分区：
文献类型：
--
作者：
Zelik, Karl E.;Huang, Tzu-Wei P.;Adamczyk, Peter G.;Kuo, Arthur D.
步行过程中跟腱的弹性伸缩循环可以减少串联的足屈肌的主动工作需求。然而，这并不能解释为什么或何时需要在步态中进行这种脚踝工作，无论是肌肉还是肌腱。因此，我们使用一个简单的两足步行模型来研究踝关节工作和系列弹性如何影响经济运动。我们的模型表明，踝关节弹性可以使用被动动力学来帮助单人支撑后期的推离，将身体的重心(COM)运动重新定向到向上。适时、有弹性的推出有助于减少对侧后跟撞击时的耗散碰撞损失，从而减少抵消这些损失和推动稳定行走所需的正功。因此，该模型展示了弹性踝关节工作如何减少步行的总能量需求，包括更近端的膝盖和臀部肌肉所需的工作。我们发现，使用踝关节弹性来实现经济步态的关键要求是脚踝僵硬与足长的适当比例。这些参数的最佳组合确保了在对侧后跟撞击之前适当的弹性能量释放时间，以及足够的能量存储来重定向COM速度。事实上，存在理论上产生无碰撞行走的参数组合，因此需要零主动功，尽管具有相对较高的脚踝扭矩。脚踝的弹性也允许髋关节通过间接的推开来推动经济的步行。无论步行是由脚踝还是臀部提供动力，脚踝的弹性都可能通过减少碰撞损失来帮助步行经济。
The elastic stretch-shortening cycle of the Achilles tendon during walking can reduce the active work demands on the plantarflexor muscles in series. However, this does not explain why or when this ankle work, whether by muscle or tendon, needs to be performed during gait. We therefore employ a simple bipedal walking model to investigate how ankle work and series elasticity impact economical locomotion. Our model shows that ankle elasticity can use passive dynamics to aid push-off late in single support, redirecting the body's center-of-mass (COM) motion upward. An appropriately timed, elastic push-off helps to reduce dissipative collision losses at contralateral heelstrike, and therefore the positive work needed to offset those losses and power steady walking. Thus, the model demonstrates how elastic ankle work can reduce the total energetic demands of walking, including work required from more proximal knee and hip muscles. We found that the key requirement for using ankle elasticity to achieve economical gait is the proper ratio of ankle stiffness to foot length. Optimal combination of these parameters ensures proper timing of elastic energy release prior to contralateral heelstrike, and sufficient energy storage to redirect the COM velocity. In fact, there exist parameter combinations that theoretically yield collision-free walking, thus requiring zero active work, albeit with relatively high ankle torques. Ankle elasticity also allows the hip to power economical walking by contributing indirectly to push-off. Whether walking is powered by the ankle or hip, ankle elasticity may aid walking economy by reducing collision losses.
登录
查看更多内容
影响因子：
9.2
作者：
Kuo, AD
通讯作者：
Kuo, AD
DOI：
10.1115/1.2798313
发表时间：
1998-04-01
影响因子：
1.7
作者：
Garcia, M;Chatterjee, A;Coleman, M
通讯作者：
Coleman, M
DOI：
10.1098/rspb.2011.1194
发表时间：
2012-02-07
影响因子：
4.7
作者：
Herr, Hugh M.;Grabowski, Alena M.
通讯作者：
Grabowski, Alena M.
影响因子：
2.8
作者：
Doke, J;Donelan, JM;Kuo, AD
通讯作者：
Kuo, AD
DOI：
10.1097/00002060-199106000-00006
发表时间：
1991-06-01
影响因子：
3
作者：
GITTER, A;CZERNIECKI, JM;DEGROOT, DM
通讯作者：
DEGROOT, DM