Study On Electromyography Variation Characteristics Of Weight-bearing Squat With Stable Support And Unsteady Support

Purpose: By analyzing the changes of EMG of squat with stable support and unstable support,this paper provides experimental data for future research on squat with unstable support and provides reference for the selection of different squat methods in training practice.Methods: Sixteen male subjects(age: 22.3±2.4(year),height: 176.4± 6.8(cm),weight: 74.3 ± 9.2(KG),1RM: 82.8 ± 8.9(KG),training years:2.3±1.2(year))Surface electromyogram signal test(s EMG)was performed for stable support and non-stable support weight-bearing squat,and Tibialis Anterior muscle was selected for the test.TA),Gastrocnemius(GM),Vastus Medialis(VM),Vastus Lateralis(VL),Rectus Femoris(Rectus Femoris)RF),Biceps Femoris(BF),Erector Spinal muscle(ES),Gluteus Maximus(GMA).Three kinds of squats with free hand,30%1rm and 60%1rm were performed under stable support and unsteady support,and the integrated electromyogram(i EMG)value of each muscle was calculated under different squat loads.The EMG signal was collected in the whole process.SPSS22.0statistical software was used to analyze the i EMG of squat muscles under different loads under the same state and the i EMG of squat muscles under the same load under different states using single-factor variance analysis.Independent sample T-test was used to analyze the i EMG of squat muscles under different loads.Results:1?Squat under unsteady support condition,muscle IEMG gradually increased with the increase of load,and the IEMG of muscle in each group showed significant difference(P<0.05);The IEMG growth rate of GM,VL,RF,ES and GMa increased gradually.The contribution rate of TA decreased gradually,the contribution rate of GMa and RF increased gradually,the contribution rate of GM remained unchanged with the increase of load,the contribution rate of VM and BF showed a trend of first increase and then decrease,and the contribution rate of VL and ES showed a trend of first decrease and then increase.2?Under the condition of stable support,the IEMG of muscle increased gradually with the increase of load,and the IEMG of muscle in each group showed significant difference(P<0.05),and the growth rate of IEMG of TA,VM,VL,RF,BF and ES increased gradually;The contribution rates of TA and VM decreased gradually,while the contribution rates of VL and GMa increased gradually.The contribution rates of ES did not change with the increase of load,while the contribution rates of GM,RF and BF remained unchanged after the increase.VM had the largest contribution rate in each group of load squat.3.The IEMG of TA was significantly different between stable support and non-stable support(P<0.05),the IEMG of VM and RF in the stable support group was higher than that in the non-stable support group.4.The IEMG of TA,VM and VL was significantly different between stable support and non-stable support 30%1RM squat(P<0.05).5.The IEMG of TA,GM,VM,VL,RF,BF,ES and GMa were significantly different between stable support and non-stable support 60%1RM squat(P<0.05).6.There was no significant difference in the IEMG of TA,GM and ES compared with the squat with stable support 30%1RM and the squat with free hand without stable support(P<0.05),and the IEMG of TA,GM and VL group was higher than that of 1RM squat group with stable support 30%.7.There was no significant difference in the IEMG of TA,GM and ES compared with the 60%1RM squat with stable support and 30%1RM squat with unsteady support(P<0.05),and the IEMG of TA and GM showed that the non-stable support 30%1RM weight squat group was higher than the stable support 60%1RM weight squat group.Research Conclusions:1.When squatting under stable support condition,VM and TA contributed the most.With the increase of load,the IEMG of muscle gradually increased,and the ability of VL and GMa to recruit muscle fiber gradually increased with the increase of load.The muscle contribution rate changed,in which the contribution rate of VL and GMa increased gradually,while the contribution rate of TA and VM decreased gradually.2.When squatting under unsteady support,TA and VL contributed the most.With the increase of load,muscle IEMG increased gradually,among which GM,RF,VL,ES and GMa showed a gradually enhanced ability to recruit muscle fibers.The muscle contribution rate changed,in which the contribution rate of RF and GMa increased gradually,while the contribution rate of TA decreased gradually.3.When squatting under unstable support,in order to maintain posture stability and promote the body to collect more muscle fibers,compared with stable support,the ability of ankle muscles to collect muscle fibers is enhanced;With the increase of load,the IEMG of muscle increases gradually,and the ability of muscle fiber recruitment at the knee joint and hip joint is gradually enhanced.In training practice,coaches can choose different support squat methods according to different training purposes.