Department of Bioengineering, Imperial College London, London, UK.
Fortius Clinic, London, UK.
Scand J Med Sci Sports. 2021 Aug;31(8):1674-1682. doi: 10.1111/sms.13974. Epub 2021 May 6.
Rehabilitation is an important treatment for non-insertional Achilles tendinopathy. To date, eccentric loading exercises (ECC) have been the predominant choice; however, mechanical evidence underlying their use remains unclear. Other protocols, such as heavy slow resistance loading (HSR), have shown comparable outcomes, but with less training time. This study aims to identify the effect of external loading and other variables that influence Achilles tendon (AT) force in ECC and HSR. Ground reaction force and kinematic data during ECC and HSR were collected from 18 healthy participants for four loading conditions. The moment arms of the AT were estimated from MRIs of each participant. AT force then was calculated using the ankle torque obtained from inverse dynamics. In the eccentric phase, the AT force was not larger than in the concentric phase in both ECC and HSR. Under the same external load, the force through the AT was larger in ECC with the knee bent than in HSR with the knee straight due to increased dorsiflexion angle of the ankle. Multivariate regression analysis showed that external load and maximum dorsiflexion angle were significant predictors of peak AT force in both standing and seated positions. Therefore, to increase the effectiveness of loading the AT, exercises should apply adequate external load and reach maximum dorsiflexion during the movement. Peak dorsiflexion angle affected the AT force in a standing position at twice the rate of a seated position, suggesting standing could prove more effective for the same external loading and peak dorsiflexion angle.
康复是治疗非插入性跟腱病的重要手段。迄今为止，离心加载运动（ECC）一直是主要选择；然而，其使用的力学依据仍不清楚。其他方案，如重阻力慢加载（HSR），已显示出可比的结果，但训练时间更少。本研究旨在确定外部加载和其他影响 ECC 和 HSR 中跟腱（AT）力的变量的效果。从 18 名健康参与者中收集了 ECC 和 HSR 期间的地面反作用力和运动学数据，用于四种加载条件。从每位参与者的 MRI 中估计了 AT 的力臂。然后使用逆动力学获得的踝关节扭矩计算 AT 力。在离心阶段，在 ECC 和 HSR 中，AT 力都不比向心阶段大。在相同的外部负载下，由于踝关节背屈角度增加，在 ECC 中膝盖弯曲时通过 AT 的力大于 HSR 中膝盖伸直时通过 AT 的力。多元回归分析表明，在站立和坐姿两种姿势下，外部负载和最大背屈角度是 AT 峰值力的重要预测因子。因此，为了增加加载 AT 的效果，运动应施加足够的外部负载并在运动过程中达到最大背屈。在站立位置，峰值背屈角度对 AT 力的影响是坐姿的两倍，这表明在相同的外部负载和峰值背屈角度下，站立可能更有效。
