| Objective: Studies showed that static stretching before competition and training reduces athletic speed,strength,and energy output,thereby reducing athletic performance and adversely affecting performance in sports that rely primarily on maximum strength and power output.In recent years,post activation potentiation,as a new type of warm-up that leads to the improvement of muscle performance and the acute increase of muscle strength and explosive power,has been highly valued by the academic community.It can be speculated that the static stretching combined with PAP in warm-up exercises may be beneficial for taekwondo athletes,not only improving the athletes’ flexibility level,but also possibly maintaining or improving explosive power.The current study mainly explored the effects of static stretching(SS)and static stretching combined with PAP(longitudinal jump with knee bend,SS+PAP)on lower limb explosive power(height of run-up,number and force of front and back transverse kicks in 10s)and hip joint flexibility of male college taekwondo athletes in North University of China and provide a practical evidence for the beneficial effects of SS+PAP on hip joint flexibility and athletic performance of taekwondo athletes.Methods: 18 male college taekwondo athletes from North University of China were chosen and randomly divided into static stretching group(SS group,n=9)and static stretching +PAP group(SS+PAP group,n=9).Subsequently,the SS group received static stretching(5 movements,30s/ each movement)and the SS+PAP group received static stretching(5 movements,30s/ each movement)combined with PAP(longitudinal jump with knee bend,3 sets,5/sets).In order to assess the hip flexibility and lower limb explosive power,the angles of hip flexion,extension,adduction and abduction,the number and force of front and back transverse kicks in 10 s and the height of run-up of subjects in both groups were measured before,immediately,4min,8min and 12 min after intervention.Results:1)Compared with before intervention,the angles of the hip flexion and abduction of male college Taekwondo athletes in SS group and SS+PAP group significantly increased immediately,4min,8min and 12 min after intervention(P<0.01,P<0.05);the angles of hip extension and adduction of male college Taekwondo athletes in SS group and SS+PAP group significantly increased(P<0.01,P<0.05)immediately and 4min after intervention;in addition,there were no significant difference of the angles of the hip flexion,extension,adduction and abduction immediately,4min,8min and 12 min after intervention between the two groups.As time went by,hip flexibility of Taekwondo athletes in the two groups gradually decreased.2)Compared with before intervention,the force of front and back transverse kicks in 10 s of male taekwondo athletes in SS group decreased significantly immediately after SS intervention(P<0.01,P<0.05),but the number and force of front and back transverse kicks in 10 s at other time points had no significant changes(P>0.05 respectively);the force of front and back transverse kicks in 10 s at 4min after intervention and the number and force of front and back transverse kicks in 10 s at 8min after intervention significantly increased(P<0.01,P<0.05),while the number and force of front and back transverse kicks in 10 s at other time points were not significantly changed in SS group and SS+PAP group(P>0.05 respectively).Compared with SS group,the force of front transverse kicks in 10 s significantly increased at 4min and 8min after intervention in SS+PAP group,and the force of back transverse kicks in 10 s significantly decreased immediately after intervention(P<0.01,P<0.05)in SS+PAP group.There were no significant differences in the number and force of front and back transverse kicks in 10 s at other time points between the two groups(P >0.05 respectively).3)There were no significant differences in the vertical jump height of single leg in place at other time points and the vertical jump height of both legs in place at all time points in SS group compared with before intervention except that the vertical jump height of single leg in place immediately after intervention decreased(P<0.05).Compared with before intervention,the vertical jump height of single leg and double leg in place immediately after intervention in SS+PAP group decreased significantly(P<0.05,P<0.01),and the vertical jump height of single leg and double leg in place increased significantly 8 minutes after intervention(P<0.05).There were no significant differences between the above indexes and those before intervention at other time points(P >0.05 respectively).Conclusions:(1)Static stretching(30 seconds per movement)can improve the hip joint flexibility of male college Taekwondo athletes,and the increase in hip joint flexibility(Hip flexion and abduction)can be maintained for up to 12 minutes after static stretching.(2)Static stretching(30 seconds for each movement)has little effect on lower limb explosive power of male college students Taekwondo athletes,but the lower limb explosive power gradually recovered with the delay of time after stretching,and the recovery is obvious in 12 min after stretching.(3)Static stretching combined with kneeling longitudinal jump can not only enhance the hip flexibility but also enhance the lower extremity explosive power of male college Taekwondo athletes. |
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