Analysis On Activation Of Thigh Muscles And Lumbar Multifidus Muscle During Squat Exercises At Different Knee Flexion Angles With And Without Leaning Against The Wall

OBJECTIVES:This work aimed to observe changes in surface electromyography(sEMG)of thigh muscles and lumbar multifidus muscles(LMM)during different states of squat training.METHODS:A total of 46 healthy volunteers were selected and divided into two groups,namely,with and without leaning against the wall.sEMG was used to record vastus lateralis muscle(VLM),vastus medialis muscle(VMM),biceps femoris muscle(BFM),and LMM at different knee flexion angles(30°,45°,60°,and 75°).The design is repeated measurement.Average EMG(AEMG),median frequency(MF),and mean power frequency(MPF)were analyzed by repeated-measures analysis of variance.RESULTS:1.The results of tested muscles’AEMG in different states of squatting:knee flexion angle exerted significant effects on all tested muscles(P<0.001).Whether leaning against the wall to squat has a significant impact on AEMG of BFM(P=0.041),It’s bigger when not against the wall.But there’s no significant effects on VLM,VMM,and LMM.2.The results of tested muscles’MF in different states of squatting:knee flexion angle exerted significant effects on VLM,VMM,VBF and LMM(The P value are P<0.001、P = 0.001、P<0.001、P<0.001).Whether leaning against the wall to squat has a significant impact on VLM and LMM(The P value are P= 0.014、P<0.001).It’s bigger when not against the wall.3.The results of tested muscles’ MPF in different states of squatting:knee flexion angle exerted significant effects on all tested muscles(P<0.001).Whether leaning against the wall to squat has a significant impact on VLM and LMM(The P value are P = 0.008、P<0.001).It’s bigger when not against the wall.CONCLUSION:For young healthy,the influence of knee flexion angle on the squatting:With increasing in knee flexion angle,muscle activation and fatigue increased for all muscles tested.The influence of whether leaning against the wall on the squatting:Squatting without leaning against the wall exerted a more marked influence on activation of BFM while increasing fatigue of VLM and LMM.Therefore,we suggest that the healthy adopt a squatting training of without leaning against the wall and in a large knee angle.