Abstract

Females have been reported to utilize a feedforward control strategy during landing in which they compensate for decreased rate of torque development (RTD) of the hip extensors through earlier pre-activation of the knee extensors. The purpose of this study was to determine the influence of a 4-week hip-focused training program on hip extensor RTD and feedforward control of the hip and knee extensors. Twenty-one females underwent hip extensor RTD evaluation and electromyographic assessment of the hip and knee extensors during a drop-jump task. Post-training, there was a significant improvement in hip extensor RTD (21.68 ± 5.44 to 23.33 ± 5.45 Nm/kg s, p = 0.009), and pre-activation of the hip extensors (87.1 ± 63.6 to 56.2 ± 60.9 ms, p < 0.001) and knee extensors (272.3 ± 113.8 to 124.0 ± 67.7 ms, p < 0.001) occurred closer to ground contact. A negative association was found between the change in hip extensor RTD and the change in knee extensor onset (r = −0.48, p = 0.03). We propose that the observed change in feedforward control is reflective of the decreased need for preparatory muscle activity owing to the improved capacity of the hip extensors to rapidly generate force.

摘要

据报道，女性在着陆期间利用前馈控制策略，通过早期预激活膝伸肌来补偿髋伸肌扭矩发展 (RTD) 降低的速度。本研究的目的是确定为期 4 周的以髋部为重点的训练计划对髋部伸肌 RTD 和髋部和膝部伸肌的前馈控制的影响。21 名女性在跳伞任务期间接受了髋伸肌 RTD 评估和髋关节和膝关节伸肌的肌电图评估。训练后，伸髋肌 RTD 有显着改善（21.68 ± 5.44 至 23.33 ± 5.45 Nm/kg s，p  = 0.009）和预激活髋伸肌（87.1 ± 63.6 至 56.2 ± 60.9 ms，p < 0.001) 和膝伸肌 (272.3 ± 113.8 到 124.0 ± 67.7 ms, p  < 0.001) 发生在更接近地面接触的地方。髋伸肌 RTD 的变化与膝伸肌起始的变化之间存在负相关（r = -0.48，p  = 0.03）。我们认为，观察到的前馈控制的变化反映了由于髋伸肌快速产生力量的能力提高，对准备肌肉活动的需求减少。