| Purpose: The purpose of this investigation was to compare the electromyography(EMG)characteristics of the front squat,high-bar back squat,low-bar back squat,and their influences on lower limb movement function;then provide the science basis for choosing the appropriate type of squat in practical training.Methods: Eight subjects(height=176.63±4.69cm;body mass=80.25±7.07kg;age=25.00±0.87yr;training age=6.25±1.64yr)were tested at a 10 RM front squat,high-bar back squat and low-bar back squat separately,with every type of squat repeated four times.The results of the 10 RM test were then used to do the EMG test.The eight muscles chosen for the EMG test were the erector spine,gluteus maximus,biceps femoris,semitendinosus,vastus lateralis,rectus femoris,vastus medialis and gastrocnemius(inside).32 subjects(height=177.69±4.92cm;body mass=76.69±9.59kg;age=24.53±1.84yr;training age=6.25±2.24yr)were divided into four groups(front squat group,high-bar back squat group,low-bar back squat group and control group)randomly.The subjects then completed six-weeks of continuous squat training,including two training classes every week,with every class consisting of four sets of squats,with eight repetitions in each set.The initial training weight was 10 RM,then the Two-By-Two principle was used to add weight progressively.During both pre and post-training,subjects would do a jump test,knee joint isokinetic test,Y Balance Test and a 10 RM squat test.Results: The test concluded that the erector spine,gluteus maximus,biceps femoris and semitendinosus muscle RMS in low-bar back squats were significantly higher than in high-bar back squats(p<0.05);and the erector spine,gluteus maximus,biceps femoris and semitendinosus muscle RMS in high-bar back squats were significantly higher than in front squats(p<0.05).The vastus lateralis,rectus femoris and vastus medialis muscle RMS in front squats were higher than high-bar back squats;and the vastus lateralis,rectus femoris and vastus medialis muscle RMS in high-bar back squats were higher than low-bar back squats;but all results had no statistical differences between groups except rectus femoris(p<0.05).There were no statistical(p<0.05)differences between the front squat,high-bar back squat,and low-bar back squat in the gastrocnemius muscle(inside).The experiment concluded that front squat,high-bar back squat and low-bar back squat training can significantly improve jump test,knee joint isokinetic test and Y Balance test performance(p<0.05).After the training,the front squat group's countermovement jump(CMJ)and squat jump(SJ)height were significantly higher than the control group(p<0.05);while the high-bar back squat group and low-bar back squat group had no statistical differences from the control group.After the training,the subjects of the trained groups of knee extension strength were significantly higher than control group(p<0.05);while there were no statistical differences between trained groups and the control group in knee flex strength.After the training,the posteromedial direction scores of the Y Balance test for the lower quarter of trained groups were significantly higher than the control group(p<0.05);while there were no statistical differences between trained groups and the control group in the anterior and posterolateral directions scores of the Y Balance test for the lower quarter.Conclusion: If the training purpose is to develop trunk extension and hip extension muscles,then low-bar back squat would be the best choice.If the training purpose is to develop knee extension muscles,then front squat would be the best choice.If the training purpose is to develop trunk extension,hip extension and knee extension muscles simultaneously,then high-bar back squat would be the best choice.If the training purpose is to develop vertical jump performance,front squat would be the best choice.Squats cannot improve the strength of knee flex significantly.Squats can improve the posteromedial direction scores of the Y Balance test significantly. |
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