Simpson Jeffrey D, Stewart Ethan M, Turner Alana J, Macias David M, Wilson Samuel J, Chander Harish, Knight Adam C
Sports Medicine and Neuromechanics Laboratory, Department of Movement Sciences and Health, University of West Florida, 11000 University Parkway, Pensacola, FL, USA.
Neuromechanics Laboratory, Department of Kinesiology, Mississippi State University, PO Box 6186, Mississippi State, MS, USA.
Hum Mov Sci. 2019 Apr;64:133-141. doi: 10.1016/j.humov.2019.01.013. Epub 2019 Feb 2.
While neuromuscular control deficits during inversion perturbations in chronic ankle instability (CAI) cohorts are well documented in the literature, anticipatory motor control strategies to inversion perturbations in CAI are largely unknown. The purpose of this study was to examine neuromuscular control and ankle kinematics in individuals with CAI (n = 15) and matched controls (n = 15) during unexpected and expected single leg drop-landings onto a tilted surface rotated 20° in the frontal plane. Muscle activity from 200 ms pre- to post-landing was recorded from the tibialis anterior (TA), medial gastrocnemius (MG), peroneus longus (PL) and peroneus brevis (PB). Mean muscle activity, co-contraction index (CCI), and peroneal latency was analyzed. Ankle inversion angle at initial contact, time to maximum inversion angle, maximum inversion angle and velocity were also assessed. Significantly longer PL latency, less time to maximum inversion and greater maximum inversion angle was found in CAI compared to controls. Regarding landing condition, significantly greater maximum inversion angle, less inversion at initial contact, longer PB latency, less TA activity and frontal plane CCI during the post-landing phase was found during the unexpected perturbation. Prolonged PL latency and altered ankle kinematics suggests reduced frontal plane ankle stabilization in CAI. However, similar motor control strategies were utilized in both groups during the ankle inversion perturbations.
虽然文献中已充分记录了慢性踝关节不稳（CAI）人群在足内翻扰动期间的神经肌肉控制缺陷，但CAI人群针对足内翻扰动的预期运动控制策略在很大程度上尚不清楚。本研究的目的是在意外和预期的单腿下落至在额状面旋转20°的倾斜表面上着陆期间，检查CAI个体（n = 15）和匹配对照组（n = 15）的神经肌肉控制和踝关节运动学。记录着陆前200毫秒至着陆后胫骨前肌（TA）、腓肠肌内侧头（MG）、腓骨长肌（PL）和腓骨短肌（PB）的肌肉活动。分析平均肌肉活动、共同收缩指数（CCI）和腓骨肌潜伏期。还评估了初始接触时的踝关节内翻角度、达到最大内翻角度的时间、最大内翻角度和速度。与对照组相比，发现CAI组的PL潜伏期明显更长、达到最大内翻的时间更短且最大内翻角度更大。关于着陆情况，在意外扰动期间，在后着陆阶段发现最大内翻角度明显更大、初始接触时的内翻更小、PB潜伏期更长、TA活动更少以及额状面CCI更小。PL潜伏期延长和踝关节运动学改变表明CAI中额状面踝关节稳定性降低。然而，在踝关节内翻扰动期间，两组采用了相似的运动控制策略。
