Biomechanical changes at the knee after lower limb fatigue in healthy young women
Biomechanical changes at the knee after lower limb fatigue in healthy young women
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DOI：
10.1016/j.clinbiomech.2013.02.010
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发表时间：
2013-04-01
影响因子：
1.8
通讯作者：
Maly, Monica R.
中科院分区：
文献类型：
--
作者：
Longpre, Heather S.;Potvin, Jim R.;Maly, Monica R.
背景：本研究的目的是确定由于下肢神经肌肉疲劳而在步态过程中发生的膝关节运动学、动力学和僵硬的变化。方法：收集健康年轻女性(n=20)在两次疲劳前后的步态运动学、运动学和肌电测量。在基线步态分析后，完成了两次疲劳性收缩。在最大自主等长收缩过程中，使用50组等张伸膝和屈膝，以峰值扭矩的50%来诱导疲劳。疲劳的定义是膝关节伸展或屈曲的最大自愿等长力矩比基线至少下降25%。在每一轮疲劳之后完成步态分析。动态膝关节僵硬的计算方法为膝关节屈曲力矩的变化除以膝关节屈曲角度的变化，范围为步态周期的3%到15%。计算出股二头肌和股直肌的联合激活分别为步态的3%到15%和40%到52%。重复测量的方差分析评估了基线和每次疲劳后的离散步态测量、膝关节扭矩和肌电幅度的差异。结果：疲劳降低了峰值等长扭矩。疲劳不会改变膝关节内收力矩、膝关节屈曲角度、膝关节动态僵硬或肌肉协同激活。疲劳降低了膝关节的最大伸展力矩解释：虽然膝关节肌肉的神经肌肉疲劳改变了健康年轻女性在步行过程中的矢状面膝关节力矩，但高强度疲劳与已知的与膝关节病理或损伤有关的机械环境不一致。皇冠版权所有(C)2013由爱思唯尔有限公司出版。保留所有权利。
Background: The purpose of this study was to identify changes in knee kinematics, kinetics and stiffness that occur during gait due to lower limb neuromuscular fatigue.Methods: Kinematic, kinetic and electromyographic measures of gait were collected on healthy, young women (n = 20) before and after two bouts of fatigue. After baseline gait analysis, two bouts of fatiguing contractions were completed. Fatigue was induced using sets of 50 isotonic knee extensions and flexions at 50% of the peak torque during a maximum voluntary isometric contraction. Fatigue was defined as a drop in knee extension or flexion maximum voluntary isometric torques of at least 25% from baseline. Gait analyses were completed after each bout of fatigue. Dynamic knee stiffness was calculated as the change in knee flexion moment divided by the change in knee flexion angle from 3 to 15% of the gait cycle. Co-activations of the biceps femoris and rectus femoris muscles were calculated from 3 to 15% and 40 to 52% of gait. Repeated measures analyses of variance assessed differences in discrete gait measures, knee torques, and electromyography amplitudes between baseline and after each bout of fatigue.Findings: Fatigue decreased peak isometric torque. Fatigue did not alter knee adduction moments, knee flexion angles, dynamic knee stiffness, or muscle co-activation. Fatigue reduced the peak knee extension momentInterpretation: While neuromuscular fatigue of the knee musculature alters the sagittal plane knee moment in healthy, young women during walking, high intensity fatigue is not consistent with known mechanical environments implicated in knee pathologies or injuries. Crown Copyright (C) 2013 Published by Elsevier Ltd. All rights reserved.