School of Electrical and Electronic Engineering, University College Dublin, Dublin, Ireland.
School of Mechanical and Materials Engineering, University College Dublin, Dublin, Ireland.
Scand J Med Sci Sports. 2018 Dec;28(12):2536-2546. doi: 10.1111/sms.13288. Epub 2018 Sep 26.
Hamstring injuries are common in field sport athletes. Eccentric strength training of the hamstring muscles is an integral component of rehabilitation programs. The Askling L-Protocol comprises three exercises [extender; diver; glider] that load the hamstrings during eccentric activity. When compared to a conventional exercise-based rehabilitation program, the Askling L-Protocol has been shown to reduce the time to return to sport following hamstring injury and prevalence of injury recurrence. Nevertheless, the mechanisms behind its efficacy have yet to be studied. In this work, we conducted a kinematic and electromyographic analysis of the exercises of the Askling L-Protocol. Eleven healthy individuals performed each of the exercises while electromyographic data from four muscles (including two hamstring muscles) were recorded. Hip and knee angular displacements and velocities were also synchronously recorded using a motion capture system. We found that the L-Protocol elicits a maximal contraction (up to 60% of the MVC in the glider exercise) in the hamstring muscles at a work point similar to the swing phase of running (around 62 degrees hip flexion and 23 degrees knee flexion). No difference in the levels of activation of the hamstrings was observed between the diver and glider, regardless of the different functional role they had in the two exercises. During the extender, the hamstring muscles are stretched and minimally engaged. Finally, co-activation analysis highlighted that through the combination of passive stretch and active eccentric contraction, the hamstrings are trained to co-activate using similar structural modules employed differentially to drive the movement or stabilize it.
腘绳肌损伤在球类运动员中很常见。腘绳肌的离心力量训练是康复计划的一个组成部分。Askling L-Protocol 包括三个练习[伸展器；潜水器；滑翔机]，在进行离心活动时对腘绳肌施加负荷。与传统的基于运动的康复计划相比，Askling L-Protocol 已被证明可以减少腘绳肌损伤后重返运动的时间和损伤复发的发生率。然而，其疗效的机制尚未得到研究。在这项工作中，我们对 Askling L-Protocol 的练习进行了运动学和肌电图分析。11 名健康个体在进行每项练习时，同时记录来自 4 块肌肉（包括 2 块腘绳肌）的肌电图数据。还使用运动捕捉系统同步记录髋关节和膝关节的角位移和速度。我们发现，L-Protocol 在与跑步的摆动阶段（髋关节屈曲约 62 度和膝关节屈曲 23 度）相似的工作点，使腘绳肌产生最大收缩（在滑翔练习中可达 MVC 的 60%）。在潜水器和滑翔机之间，无论它们在两个练习中具有不同的功能作用，都没有观察到腘绳肌的激活水平有差异。在伸展器中，腘绳肌被拉伸且很少参与活动。最后，共激活分析强调，通过被动拉伸和主动离心收缩的结合，腘绳肌被训练为以相似的结构模块共同激活，这些结构模块以不同的方式用于驱动运动或稳定运动。
