Acute Effects Of Different Intensity Of Flywheel Half Squat Based On Velocity On Vertical Jump

Purpose:This study aimed to evaluate the postactivation potentiation(PAP)effects of flywheel half squat by different movement velocity.In order to better understand the potential mechanism of the flywheel squat at different movement velocity for acute adaptation,and to further investigate the potential benefits of velocity measurement as a method of intensity prescription in inertial flywheel squat training,data of kinematics and ground reaction force during drop jump was collected.Methods:To set up three range of movement velocity,the average velocity of flywheel squat during concentric phase was monitored,respectively,the fast range(0.95-1.05 m/s),medium range(0.65-0.75 m/s)and slow range(0.35-0.45 m/s).Fourteen national second rank athletes who Specialize in running and jumping were selected to participate in PAP induction in three movement velocity ranges,and the changes of ground reaction force and mechanical power output and other indexes were examined under different movement velocity and time points.Eight high-speed infrared cameras and 2 three-dimensional force plates were used to simultaneously acquire kinematics and ground reaction force during drop jump.A two-way repeat measurement ANOVA was used to evaluate the effects.Results:1,movement velocity significantly influence impact force and vertical ground reaction force(F=21.984,P=0.000),keen eccentric powers(F=14.495,P=0.001)and concentric power(F=9.070,P=0.001),keen extension moment(F=38.131,P=0.000),average power output(F=34.125,P=0.000),reaction strength index and jump height(F=19.574,P=0.000 and F=129.385,P=0.000).2,as for vertical ground reaction force,average power output and jump height,at 4,8,12 minute of enhancement effect of fast range is better than that of medium range(P<0.05)and slow range(P<0.01),medium range is superior to the slow range(P<0.05).There was no significant enhancement effect in the slow range(P>0.05).at 4,8 and 12 minute,the enhancement effect of reaction strength index is better in fast range than in slow range(P<0.01),and at 4 and 8 minute,fast range is better than in medium range(P<0.05),and medium range is better than in slow range(P<0.05).There was no enhancement effect in the slow range at any time point(P>0.05).3,The enhancement effect of keen eccentric powers and keen extension moment at 4,8 and 12 minute point showed that the medium range was better than the fast range(P<0.05)and the slow range(P<0.01),and the fast range was better than the slow range(P<0.05).There was no significant enhancement effect in the slow range(P<00.05).Conclusions:1,fast and medium range can induce PAP to improve the ability of drop jump,Whereas slow range can no.2,fast range program to induce PAP is better for those elements that is based on SSC,whereas medium range program is better for muscle strength.