Effects Of Different Stretching Technique On Hamstring Functions

Objective:(1)to explore the immediate effect of three different stretching methods on the maximum peak moment of hamstring;(2)to explore the immediate effect of three different stretching methods on hamstring response time;(3)which stretching method is more suitable for pre match warm-up.Methods: This study is an intervention experimental study.20 healthy adults were recruited to participate in the study voluntarily.Each subject is required to participate in these three different stretching interventions.The interval between each stretching intervention is at least 48 hours.The isokinetic muscle force test system and sEMG are used to record the maximum peak moment and reaction time(pre reaction time,electro mechanical delay)before and after stretching.Results: 1)There was no significant difference among the three groups(P > 0.05);there was no significant difference among the three groups(62.7 ± 22.26,69.0 ± 25.03,70.2 ± 26.01 N·m);there was no significant difference among the three groups(0.195 ± 0.054,0.187 ± 0.035,0.160 ± 0.036 s);there was no significant difference among the three groups(P > 0.05);there was no significant difference between the three groups(0.183 ± 0.049,0.181 ± 0.039 s),There was no significant difference between the three groups(P > 0.05);the mean value of emg-m delay of biceps femoris after three kinds of stretching intervention(0.175 ± 0.049,0.178 ± 0.036,0.158 ± 0.025 s),there was no significant difference among the three groups(P > 0.05);the mean value of emg-m delay of semitendinosus after three kinds of stretching intervention(0.196 ± 0.051,0.161 ± 0.028 s),There was no significant difference among the three groups(P > 0.05);(2)There was no significant difference between the two groups(P > 0.05).After static stretching,the torque decreased(69.0 ± 25.03,71.8 ± 26.42 N·m),the difference was statistically significant(P < 0.05).After dynamic stretching,the torque increased(70.2 ± 26.01,65.2 ± 26.82 N·m),the difference was statistically significant(P < 0.05);(3)Before and after the experiment,there was no significant difference in the pre reaction time of biceps femoris in PNF stretching group(0.198 ± 0.071,0.195 ± 0.054 s)(P > 0.05);before and after the experiment,there was no significant difference in the pre reaction time of biceps femoris in dynamic stretching group(0.195 ± 0.05,0.160 ± 0.036 s)(P > 0.05);before and after the experiment,there was no significant difference in the pre reaction time of biceps femoris in static stretching group(0.181 ± 0.052 s),Before and after the experiment,there was no significant difference in response time of semitendinosus in PNF stretching group(0.199 ± 0.058,0.183 ± 0.049 s)(P > 0.05);before and after the experiment,there was no significant difference in response time of semitendinosus in dynamic stretching group(0.185 ± 0.046,0.146 ± 0.033 s)(P > 0.05);before and after the experiment,there was no significant difference in response time of semitendinosus in static stretching group(0.184 ± 0.059),0.181±0.039 s)(P>0.05);(4)In PNF group,the time of emg-m delay was longer than that before stretching intervention(0.175 ± 0.049,0.169 ± 0.043 s),the difference was statistically significant(P < 0.05);in dynamic stretching group,the time of emg-m delay was shorter than that before stretching intervention(0.158 ± 0.025 s),The difference was statistically significant(P<0.05)(0.171 ± 0.027 s),and the EMG mechanical delay of two ends of thigh in static stretching group was longer than that before stretching intervention(0.178 ± 0.036 s),The difference was statistically significant(P < 0.05);(5)the electrical mechanical delay of semitendinosus in PNF group was longer than that before stretching intervention(0.196 ± 0.051,0.178 ± 0.045 s),the difference was statistically significant(P < 0.05);the electrical mechanical delay of semitendinosus in dynamic stretching group was not statistically significant(0.178 ± 0.018 s),There was no significant difference in electromechanical delay of semitendinosus in static stretching group before and after the experiment(0.162 ± 0.026,0.161 ± 0.028 s)(P > 0.05).Conclusion:(1)static stretching can reduce the maximum peak moment of hamstring,dynamic stretching can increase the maximum peak moment of hamstring,but PNF stretching can not have a significant impact on the maximum peak force of hamstring.(2)Static stretching,PNF stretching and dynamic stretching have no significant effect on the pre reaction time of hamstring,but static stretching and PNF stretching have significant increase on the electro-mechanical delay of hamstring immediately,while dynamic stretching has significant decrease on the electromechanical delay of hamstring immediately.(3)Therefore,dynamic stretching is used to improve the performance level before training and competition,and static stretching or PNF stretching is used to relax muscles and relieve fatigue after training and competition.