不同足部姿势受试者使用外侧楔形鞋垫后股四头肌肌电和膝关节力学特征改变的研究

Effects of lateral wedged insoles on knee kinematics and quadriceps femoris EMG activity of different foot postures subjects

目的:研究不同足部姿势受试者使用外侧楔形脚垫后股四头肌的肌电和膝关节力学特征的变化。方法:利用静态足部姿势指数筛选收集5例中立足、5例旋后足、7例旋前足的健康年轻人作为受试者,试验过程:①受试者先在5m的步行道上采用自由速度行走7次,使用测力板(AMTI,Optima HPS,美国)收集受试者的力学数据,表面肌电系统(Delsys,MyomonitorⅢ,美国)收集受试者右侧股直肌、股内侧肌、股外侧肌的肌电信号,三维步态分析系统(Vicon Ltd,Oxford,英国)收集受试者的运动学数据;②受试者换上外侧楔形脚垫再进行7次自由速度的步态试验,收集肌电、力学、运动学数据。分析使用外侧楔形鞋垫前后肌肉活动、运动学、动力学数据的变化。结果:中立组在使用外侧楔形鞋垫之后股直肌肌肉活动增加、足底压力中心向外侧移动、膝关节的内收力矩第一峰值(P<0.05)和垂直轴地面反向作用力减小(P<0.05),差异具有显著性意义;旋前组在使用鞋垫之后股直肌的肌肉活动出现较小的降低,膝关节内收力矩第一峰值降低(P<0.05),垂直轴地面反向作用力增大(P<0.05);旋后组使用外侧楔形脚垫之后股直肌活动降低(P<0.05)、膝关节的内收力矩没有明显变化。结论:静态足部姿势或许可以用来预测受试者对使用外侧楔形脚垫的生物力学和肌电反应。为临床受试者使用外侧楔形鞋垫提供了不同足部姿势受试者的基础力学和肌电数据。

Objective:To study the changes of myoelectricity of quadriceps and biomechanics characteristics of knee joint in subjects with different foot posture using lateral wedged insoles.Method:Foot posture index was used to select healthy young subject 5 neutral,5 supinaton and 7 pronation.Testing process:①the subject walked 7 times at a free speed on a walking path of 5m with the force plate(AMTI,Optima HPS USA).The EMG activities of rectus femoris,vastus medialis and vastus lateralis of the right leg were recorded by surface myoelectric system(Delsys,MyomonitorⅢ,USA),kinematic data were recorded by the three-dimensional gait analysis system(Vicon Ltd,Oxford,UK)at the same time;②The subjects with the lateral wedged insoles into a pair of shoes performed 7 times at free speed gait tests.The kinematics,kinetics and surface electromyographic data were recorded and analyzed.The changes in knee adduction moment,kinematics data and integrated EMG were analyzed about before and after the use of the lateral wedged insoles.Result:In the neutral group,the use of lateral wedged insoles increased the muscle activities of rectus femoris,decreased the first peak of knee adduction moment(P<0.05)and the center of pressure shifted laterally,the vertical axis of the ground counteracting force was decreased(P<0.05).The muscle activities of rectus femoris muscle,the first peak of knee adduction moment decreased(P<0.05)and the vertical axis of the ground counteracting force increased(P<0.05)after the lateral wedged insoles were used in the pronation groups.In the supinaiton group,the rectus femoris activities decreased by lateral wedged insoles(P<0.05).Conclusion:The static foot posture may be used to predict the individual's biomechanical and electromyographic response to the use of lateral wedged insoles.It provides an important basis for the use of lateral wedged insoles clinically and orthopedic braces to provide basic biomechanical and electromyographic basis.