The Experimental Research Of Different Range And Load Squat On The Post-activation Enhancement Effect Of CMJ

Purpose:Through the intervention activities of different squat amplitudes and different loads on college athletes with the same strength level at 87 % 1RM load intensity,the effects of activation enhancement effect induced by different intervention schemes on the improvement of CMJ height were explored,and the optimal load of activation enhancement effect to improve CMJ height after induction of two squat amplitudes was determined.Methods:This study adopts the methods of literature,logical analysis,experiment and mathematical statistics.A total of 12 male college student volunteers(half squat relative strength level of 1.9 ± 0.1,deep squat relative strength level of 1.7 ± 0.1)from Shandong Sport University were selected to participate in this study.After the warm-up,the subjects underwent CMJ test as the baseline value,and then performed squats with different squat ranges,groups and times under 87 % 1RM load.A total of eight programs,including ’deep squat single group non-exhaustion ’,’ deep squat multi-group non-exhaustion ’,’ deep squat single group exhaustion ’,’ deep squat multi-group exhaustion ’,’ half squat single group non-exhaustion ’,’ half squat multi-group non-exhaustion ’,’ half squat single group exhaustion ’,’ half squat multi-group exhaustion ’.Jump tests were performed immediately after the intervention and every four minutes until twelve minutes after the intervention.The CMJ height at each time point was analyzed by paired sample T test and one-way analysis of variance.All sample T test,variance test,normal distribution test and homogeneity of variance test were completed by SPSS 26.0,and P < 0.05 was significant.Cohen ’s d value was used to represent the effect size for statistical and qualitative analysis,and η2p was used to evaluate the relative size of the differences between groups.Results:(1)There was no significant difference between the warm-up squat speed during the formal intervention of each program and the squat speed during the 1RM test(P >0.05).There was no significant difference in the warm-up squat speed between the corresponding squat ranges during the formal intervention(P > 0.05).(2)During the intervention,there was no significant difference in the starting speed,ending speed,speed loss threshold and repetition times between the corresponding squatting range schemes(P >0.05).(3)The CMJ height was significantly lower than that before the intervention(P < 0.05).Except that the CMJ height of the half squat multi-group exhaustion program was lower than the pre-test level at each time point after the intervention,the CMJ height of the other programs was improved to varying degrees at 4 min after the intervention.Among them,the half squat single group non-exhaustion program had the best effect(+ 3.15 %),which had a greater impact on the improvement of CMJ height.At 8 min after intervention,the deep squat single-group exhaustion program reached its peak height and was superior to other programs(+ 3.04 %),which had a moderate effect on the improvement of CMJ height.At 12 minutes after the intervention,the CMJ height of most of the schemes was lower than that of the pretest.Although no significant difference was observed in the non-exhaustive program of the half-squat single group,there was still a large improvement(+ 2.73 %),which had a moderate effect on the improvement of CMJ height and was superior to other schemes.Conclusions:(1)The post-activation enhancement effect induced by different load interventions has different effects on CMJ height improvement,more groups are not conducive to the post-induction activation enhancement effect to improve the CMJ height.(2)The time of CMJ peak jump height after different load intervention was also different,the peak jump height time after intervention with fewer groups and fewer repetitions was earlier than that of more groups or more repetitions.(3)The intervention of single group nonexhaustion or speed loss threshold within 5-10 % is more suitable for college athletes with relative squat strength level between 1.5-2 times body weight to increase CMJ height by post-induction activation enhancement effect.