The Effect Of Different Intensity Squat Training On The Running Economy Of Middle-aged Male Marathon Runners

Purpose:The purpose of this study is to improve the maximum strength of lower limbs to explore the effect of different intensity squat training on the running economy of middle-aged male marathon runners.Methods:22 subjects were randomly divided into 3 groups,9 in the G90 group,7in the G60 group and 6 in the control group.The G90 and G60 groups were required to do squats three times a week for six weeks in addition to completing their own running training.The training load of G90 group was 90%of 1RM,and 5 sets were performed 4 times each session.The training load of G60 group was 60%1RM,and 5sets were performed 6 times each.The volume of each training group was 18RM.Before and after the training,all subjects test 1RM,jump height,VO_2max,V-VO_2max,running economy,knee isokinetic strength,body composition and 3km performance respectively.ANOVA and paired t test were used to process the data before and after the experiment.Results:After six weeks of squats,there were no significant changes in body weight,body composition,VO_{2 max}and V-VO_{2 max}Results of 1RM squats in G90group and G60 group were significantly improved（P<0.01）,while there was no significant change in 1RM squat before and after the control group.The mean value of RMS of rectus femoris in G90 group was significantly decreased（P<0.05）,but no significant change was observed in the other two groups.The countermovement jump of the G90 group was significantly increased after the experiment（P<0.01）,and that of the G60 group was significantly increased after the experiment（P<0.05）.There was no significant change in the control group,and there was no significant difference in the longitudinal jump height between the groups after the experiment.The 3km of G90 group and G60 group were significantly improved（p<0.01）,while the 3km of the control group were not significantly changed before and after the experiment.At 60°/s velocity,the peak extension torque of the left and right knee joints in the G90 group increased significantly（p<0.05）,while there was no significant change before and after the experiment in the other two groups.The peak torque of right knee flexion in the G90 group increased significantly at 180°/s（p<0.05）,while there was no significant change before and after the experiment in the other two groups.The absolute value of change amplitude of RE10 was moderate correlated with the absolute value of change amplitude of 1RM squats（r²=0.521）.Conclusions:60%and 90%1RM squat training can significantly improve the middle-aged male marathon runners 3km performance,running economy at 10km/h,countermovement jump height,and 1RM squat weight.There is no significant difference between the two training intensities on the above indicators.But the overall effect of squat training at 90%1RM intensity is better.