SEMG Signal Changes And Its Physiological Significance On Musculus Quadriceps Femoris During Incremental Exercise

Purpose:The author analyzes the data obtained by the surface electromyogram technology analysis to investigate the relative changes of surface electromyogram signal and its physiological significances on musculus quadriceps femoris during incremental exercise,deepen the research on physiological function assessments,and widen its measuring means.Furthermore,the author attempts to bring in a new physiological index of sports training monitoring and effectiveness evaluation.Method:By applying the surface electromyogram technology,the author carries on a real time and thorough monitoring record through an incremental exercise on seven subjects,measuring their gaseous metabolism changes and the concentration of blood lactate at the end of every stage load synchronously and the plasma electrolyte concentration before and after exercise.Result:â‘ sEMG shows that its amplitude,iEMG and RMS are increased along with the progressive increase of sports load,iEMG threshold occurs and MF decreases with the progressive increase of sports load.â‘¡The trend of blood lactate is similar with iEMG and VE;furthermore,VE,VO₂ and the concentration of blood lactate are thickening with the increase of sports load.â‘¢Compared with that before exercise,the blood plasma concentration of Na⁺,K⁺ and Ca²⁺is increased after exercise.Conclusion:â‘ The iEMG and RMS of vastus medialis(VM),rectus femoris(RF) and vastus lateralis(VL)are increased with the progressive increase of sports load,and meanwhile MF is decreased.â‘¡The recruitment quantity,rhythmical excitation,synchronization level and nerve impulse incitogram of musculus quadriceps femoris fibre are increased markedly simultaneously during incremental exercises;in addition,the muscle fibre recruitment form shifts from FT contraction primarily in initial period to higher ST recruitment proportion in anaphase period.â‘¢The trend of VE and VO₂ increase corresponds to the increase of iEMG along with the progressive increase of sports load and its run duration.â‘£The higher concentration of K⁺ after incremental exercise may be one of the facters which lead to the decline of MF.⑤Correlation is found between EMG_FTand VT;EMG_FTcan be used to measure LT scatheless,and evaluate the aerobic athletic ability of organism.