对股四头肌肌电图单谱指标与功率输出的研究

目的]探讨30s内全力蹬踏自行车运动过程中,股四头肌SEMG指标与输出功率的变化特征.方法]测试30s全力蹬踏加有7.5%自身体重负荷的功率自行车过程中的功率输出和MegaWin肌电测试系统记录股四头肌外侧肌在整个过程中的肌电变化,进行运动中的开始5s和最后5s的肌电参数MF(Median Frequency中值频率)、MPF(MeanPowerFrequency平均功率频率)、ZCR(ZeroCrossingRate零点通过率)、AE MG(AveragedEMG平均肌电图)和SPA(SpectrumArea频谱区)分析比较.结果]①除相对峰值,实验组学生的峰值、最小功率、相对最小功率、平均功率、相对平均功率都极显著大于对照组(P<0.01);②对照组后5s疲劳时MF和MPF极显著增加,ZCR显著增加,AEMG和SPA则极显著下降(P<0.01);实验组则只有AEMG和SPA极显著下降(P<0.01).③实验组与对照组比,前5s肌电图参数MF、MPF和ZCR显著增加(P<0.05),而AEMG和SPA有所下降,但未达显著水平,后5sMF、MPF、AEMG和SPA与对照组无显著差异,仅有ZCR显著增加.结论]训练和疲劳都使单谱肌电图指标MF、MPF、ZCR增加,使AEMG、SPA下降.提示前5s的单谱肌电图指标MF、MPF、ZCR、AEMG、SPA可反映训练水平,后5s可反映疲劳程度.

Analysis of EMG indices and power output of quadriceps femoris muscle-vastus lateralis

Objective]To explore correlation between EMG indices and power output of Quadriceps femoris muscle-vastus literalist in 30 seconds braked ergo meter bike.Methods]Testing the power output of pedaling the bicycle with 7.5% body heavy load with all strength in 30seconds and analyzing the changeable of the femoris muscle-vastus with the Mega Win system and comparing the parameter of the MF,MPF,ZCR,AEMG and SPA in the initial and final 5 second exercises.Results]①The peak power,minimum power,relative minimum power/kg,average power,relative average power/kg of the training students’are much more than the normal students’(P<0.01),except relative peak power.②The normal students MF and MPF who have been tired have increased significantly,as well as the ZCR,but AEMG and SPA has decreased significantly (P<0.01) in the final 5 second period;the change of the AEMG and SPA of training students is the same to the normal students.③The students of the training major’s EMG index:MF,MPF and ZCR have increased apparently,but AEMG and SPA have dropped a little in the first 5 seconds,while the final 5 seconds’MF,MPF,AEMG and SPA have no apparent difference comparing with the normal students,only the ZCR increased significantly (P<0.05).Conclusion]Both training and fatigue make MF,MPF,and ZCR increase and AEMG and SPA decrease.The first 5 seconds indices of EMG reflect degree of training and the final 5 seconds indices reflect degree of fatigue.