运动性疲劳对跑运动学与下肢肌电的影响

The Effect of Exercise Fatigue on Body Kinematics and Leg Electromyography during Running

目的:通过对人体跑至疲劳过程中的运动学与下肢表面肌电图变化特征进行分析,为更好地认识疲劳对人体运动动作的影响提供参考。方法:选取8名男性受试者在跑台上进行12km/h恒速度跑至疲劳,对3个阶段运动学参数及表面肌电时频指标进行单因素方差分析。结果:跑至疲劳的3个阶段,1)单步步长和步频均存在显著性差异(P<0.05),右脚至左脚步长减小(均值为1.68m、1.65m、1.65m),步频增加(均值为2.77步/s、2.84步/s、2.87步/s),而左脚至右脚步长增加(均值为1.61m、1.64m、1.64m),步频减小(均值为2.88步/s、2.84步/s、2.78步/s);2)躯干倾斜、扭转幅度显著增加(P<0.05),髋、膝关节角度出现规律性变化(P<0.05),踝关节角度变化无统计学意义(P>0.05);3)下肢肌积分肌电总体呈上升趋势,不同肌肉平均功率频率指标变化趋势并不一致。结论:中等强度恒速跑至疲劳过程中,随着疲劳的产生与发展:1)从左脚至右脚单步步长增加、步频减慢,而从右脚至左脚出现相反的变化规律,躯干扭转幅度变大,后仰增加,"坐姿"跑成为必然趋势;2)除腓肠肌外,下肢肌肉的积分肌电逐渐增加,平均功率频率呈下降趋势,但左右侧变化的时间段和幅度不完全一致。

Objective：The purpose of present study was to evaluate the effect of fatigue on kinematics and electromyography data during exhaustive running. Methods： 8 healthy male volunteers participated in this study by running to fatigue on the treadmill at 12Km/h. Body Kine- matics was recorded and analyzed along with surface electromyography of lower Extremities muscles. Results ： During the process of running to fatigue, 1 ） the stride length and frequency changed significantly （P〈0.05） ;right-left step decreased（1.68m to 1.65m）, left-right step increased（ 1. 6 l m to 1. 64m）, on the contrary, the stride frequency increased （2. 77steps/s, 2.84 steps/s,2.87 steps/s） and decreased（2.88 steps/s, 2.84 steps/s, 2. 78 steps/s）. 2） Torso tilt and rotation angle varied （P〈0.05） ,joint angle of hip and knee differed at the end of running（P〈0.05）, no difference was found pre and after fatigue in ankle ioint angle; 3） IEMG of lower limb muscles trend to increase during running to fatigue, no consistency was found between MSF of bilateral muscles. Conclusion; During the process of running to fatigue 1） the step length of left to right foot increased and the step frequency decreased, meanwhile the step length of right to left foot shortened with step frequeney raised. Exhaustive running intensified the whirl of the torso and led to a less torso tilt strategy. 2 ） the muscles IEMG increased while the MSF tend to decreased except gastrocnemius, however the phase and amplitude of changes between two legs were not the same.