【摘要】 目的:研究递增静力性收缩中,反映局部肌肉氧供平衡被打破的肌氧拐点(阈)的存在性及肌氧变化与肌电活动变化、心率变化之间的联系。方法:对递增等长伸膝运动中股外侧肌处近红外肌氧、表面肌电变化及心率变化过程进行监测和分析。结果:递增等长伸膝运动中肌氧氧指标(OI)变化过程存在拐点现象,并且OI、肌电均方根值(sEMGrms)、心率(HR)3种生理参数之间呈现显著相关性(r2>0.951,P<0.001)。另外,sEMGrms及HR的上升变化过程也存在拐点现象,而且肌氧拐点(OIBp,46.4±2.1(SE)%MVC)、肌电拐点(EMGBp,50.8±1.9%MVC)和心率拐点(HRBp)三者之间没有显著差别(P>0.05)。结论:递增静力性收缩运动中也存在肌氧拐点现象,而且肌氧拐点的出现与肌电幅值及心率的急剧增加密切相关。更多还原

【Abstract】 Objective: To study(1) the existence of breakpoints(Bp) in muscle oxygenation(an indicator of the breaking up of the balance between muscle oxygen supply and consumption);(2) the relationship between muscle oxygenation and muscular neuro-electrical activity,heart rate during incremental isometric knee extensions.Methods: The muscle oxygenation by near infrared spectroscopy(NIRS) and neuro-electrical activity by surface electromyography(sEMG) in vastus lateralis,and the heart rate(HR) were monitored and analyzed comprehensively.Results: There were significant correlations among muscle oxygenation index(OI),root mean square of sEMG signal(sEMGrms),and heart rate(r2>0.951,P<0.001);There were Bp in the trends of muscle oxygenation index,sEMGrms,HR changes,and no significant difference among the Bp of muscle OI(OIBp,46.4±2.1(SE) %MVC),Bp of sEMGrms(EMGBp,50.8±1.9 %MVC) and Bp of HR(HRBp)(P>0.05).Conclusion: There are Bp of muscle oxygenation changes during incremental isometric contractions,and the OIBp is associated with the significant increase in sEMGrms and HR.更多还原