Acute Effects Of Static Stretching And Ballistic Stretching On Velocity During Acceleration Phase In Male Athletes

Objective: to study the effect of different stretching modes on men's accelerated running speed.Methods: more than 30 healthy and physically active college students were selected without any history of lower limb injury.They were able to perform static stretching of the posterior femoral muscle group without any discomfort.Three experiments were conducted.Experiment 1.Prepare for non-stretching activities and then do the accelerated run test.First,participants were asked to jog for 8 minutes at a pace of 7 '30' /km,lift their legs in place for 15 seconds + speed up,and their preparation time was consistent with that of the stretching group.Then the acceleration test is carried out to collect valid data.Experiment 2: Warm up protocol was same with Experiment 1.And then Stretching protocol was performed and that was followed Nelson's stretching protocol:the subjects lie on their back on the mat and one leg straight on the mat,and the other leg was lift with knee joint keep straight.The straight leg flexed the hips beyond the vertical position.Repeat 3 times for each leg,30 seconds at a time,and change another leg 20 seconds later.Then run the acceleration test.Experiment 3: Warm up protocol was same with Experiment 1.And then ballistic stretch was performed : standing kick 3× 30 times(1HZ)for both legs.Then run the acceleration test.The time of practice of each subject remained the same.The test equipment is Optojump Next optical system.Test indicators were speed,stride length,flight time,touchdown time.Research results: 10 steps average velocity after ballistic stretching was significantly faster than condition without stretching(p=0.003)and the condition with static stretching(p=0.026).The flight time was reduced after ballistic stretching,but the step length is not decreased.After static stretching,the step length is shortened and the step duration time is not changed.Conclusion:Ballistic stretching of hamstring would increase velocity during acceleration phase.Static stretching would not decrease velocity during acceleration phase.Static stretching of hamstring could be performed during warm up and Ballistic stretching of hamstring should be given priority to perform during warm up from performance prospective.