Abstract:

Abstract:Objective To understand the characteristics of surface electromyography（sEMG）of vastus medialis muscle fatigue induced by isokinetic flexion and extension movement,and to further provide references for the application of sEMG on dynamical movements.Methods Arial isokinetic equipment and ME6000 equipment were combined to analyze the time domain indices including root mean square (RMS) integrated electromyography (iEMG) and spectrum indices including median frequency (MF) and mean power frequency (MPF) for vastus medialis from ten students from Shenyang Sport University during isokinetic fatigue.Results During the isokinetic muscle fatigue the RMS and iEMG were significantly increased (P<0.05),accompanying with higher effect sizes for  iEMG than for  RMS. As for the spectrum indices,MF and MPF were significantly decreased (P<0.05) with larger effect sizes for MPF than for MF.The increase rate of iEMG was significantly higher in iEMG than RMS (P<0.05), and the decline rate of MPF was larger than MF (P<0.05).Conclusion The iEMG as a time domain index and MPF as a spectrum index can be sensitive indexes to assess the dynamic muscle fatigue.

Key words: surface electromyography, fatigue, isokinetic flexion and extension