Analysis Of EMG Signal Characteristics Of Teenager Badminton Players Before And After Isokinetic Contraction Of Lower Extremity Muscles

Objective: Through the analysis and research on the surface electromyography index of the lower limbs of teenager badminton players,explore the physiological mechanism of muscle fatigue induced by isocentric centripetal and isokinetic centrifugation,to study the characteristics of surface emg signals of badminton players before and after fatigue induced by isokinetic contraction of lower extremity muscles,and provide reference for scientific training of teenager badminton players.Methods: 10 female teenager badminton players were asked to perform isokinetic and isokinetic centrifugal contraction of the knee and ankle respectively on the isokinetic muscle strength tester.The test speed was selected as 60°/s with 30 repetitions.At the same time,surface electromyography was used to record the surface electromyography of flexor and extensor muscles of the knee and ankle joints.Results: after isokinetic exercise fatigue,IEMG and RMS of flexor and extensor muscles of knee and ankle joints were higher than before exercise fatigue,while MF and MPF of flexor and extensor muscles of knee and ankle joints were lower than before exercise fatigue,with statistical significance(P<0.05).After the centripetal contraction fatigue of the rectus femoris,the variation amplitudes of IEMG,RMS,MF and MPF of emg were all higher than the variation amplitudes of emg indexes after isokinetic centrifugal contraction fatigue(P<0.05).After flexural fatigue of biceps femoris,the variation amplitude of IEMG and MPF of emg was higher than that of each index after isokinetic centrifugal fatigue(P<0.05).After the centripetal contraction fatigue of the anterior tibial muscle,the variation amplitude of IEMG and MPF of emg was higher than that of each index after the isokinetic centrifugal contraction fatigue(P<0.01).After centripetal contraction fatigue of gastrocnemius muscle,the variation amplitude of IEMG,RMS,MF and emg were all higher than that of each index after isokinetic centrifugal contraction fatigue(P<0.05).Conclusion: after isokinetic muscle fatigue,surface emg time domain index showed an overall upward trend,while frequency domain index showed a general downward trend.After fatigue,the variation amplitude of myoelectric index of centrifugal contraction muscle is smaller than that of centripetal contraction,indicating that centrifugal contraction muscle is more resistant to fatigue than centripetal contraction.