Research On The Suitable Weight For Countermovement Jump With Accentuated Eccentric Loading

Research purpose:This study uses the accentuated eccentric loading(AEL)strategy in the countermovement jump(CMJ)exercise to study the acute effect of the vertical jump performance,and through the application of different AEL weights,to explore the best AEL weight and its relationship with the subject’s lower limbs Strength,reactive strength index(RSI)and other self-quality relationships,and try to predict the best practice AEL weight,so as to provide a reference for the weight selection when adopting the AEL strategy in the CMJ.Research method:This article recruited 23 male college students from Beijing Sport University and conducted a two-stage experiment.In the preparation phase,the height,weight,1RM squat weight and reaction strength index data of the subjects were measured.In the formal phase,the wireless jump test system EZEJUMP(SWIFT)and the Tendo Unit explosive force and speed feedback system were used to test the CMJ of 7 different AELs.Statistical methods such as single factor repeated measures analysis of variance,correlation analysis,and multiple linear stepwise regression analysis were used to process the experimental data.Research results:The single factor repeated measurement analysis of variance showed the jump height(JH),average power(AP),and centripetal peak velocity(CPV)in the weights range of 20kg-40kg AELs were significantly different from other weights(P<0.05).There was no significant difference in the centripetal average velocity(CAV)between the AEL weights(P>0.05).Correlation analysis showed that RSI,1RM squat weight,lower limb strength level were significantly correlated with the best AEL weight(P<0.01),and the correlation coefficients were 0.673,0.667,0.739.Multiple linear stepwise regression analysis showed that RSI,1RM squat weight and the best AEL weight have a significant linear relationship(P<0.05).Through the RSI and the 1RM squat weight two indicators,it can be concluded that the male college students can use the best AEL weight prediction equation model in the CMJ:Best Weight of AEL-CMJ=0.355 × 1RM Squat Weight+9.871 X Reaction Strength Index-39.163(R2=0.666).Research conclusions:1.The CMJ with dumbbell AEL weights in the range of 20kg-40kg has good CMJ performance;2.Athlete’s own lower limb RSI,lower limb relative and absolute strength indexes are positively correlated with the best weight of AEL-CMJ(P<0.01,r=0.673,0.739,0.667),which are important factors in choosing the optimal weight for this exercise;3.There is a linear relationship between the subject’s RSI,1RM squat weight and the best AEL weight.RSI and 1RM squat weights have a certain predictive ability for the best AEL weights used in CMJ.The prediction equation is:Best Weight of AEL-CMJ=0.355 × 1RM Squat Weight+9.871 ×Reaction Strength Index-39.163(R2=0.666).