The Effct Of 6-week Hypobaric Resistance Training On Muscle Recruitment And PAP In Sprint Athletes

Obejective:The purpose of this study is to investigate the effect of 6-week hypobaric and normoxia resistance training on the sprinter's post-activation potentiation(PAP)and muscle recruitment.Methods:In this research,fourteen plain-sprint sprinters were randomly divided into normoxic(N)and hypoxic(H)groups.The two groups of subjects underwent a six-week squat training,which was twice a week,in a normoxic and a hypoxic environment separately.Each training set consisted of 5 sets of 10 reps of barbell squat exercises which the strength was 70%of 1RM in each group with 1 minute's rest between sets.Before and after the experiment,the subject was subjected to a barbell squat 1RM test and a hypoxic PAP test.Results:In the PAP test,the PAP effect basically on isometric muscle strength and CMJ were observed separately after high intensity(3 sets of 3 reps,90%of 1RM)and low intensity(3 sets of 6 reps,45%of 1RM)squat activation exercises under hypoxia environment.The test time-points for isometric muscle strength were 4,Band 12 minutes after the exercises finishing,recording the integrated electromyography(iEMG).While the test time-points of CMJ were the moment immediately after the activation as well as 4,8,and 12 minutes after the activation.The results of the study were as following:Firstly,either high-intensity(time:4min;CMJ:55.4±2.9;P<0.05)or low-intensity(4min,8min;56.5 ± 4.11 55.6 ± 4.4;P<0.05)activation exercises under a low hypoxic environrment before the training can cause the PAP effect of CMJ.After 6 weeks of training,either high-intensity(4 min;59.9±5.8;P<0.05)activation exercises or low-intensity(immediate moment,4 min;59±5,5,59.4±5.4;P<0.05)activation exercises in the H group produced the PAP effect of CM,J.While the PAP effect of CMJ happened only after low-intensity(4min;58.8±3.3;P<0.05)activation exercises in the N group.More than that,after 6 weeks of training,the PAP effect level of CMJ in H group after high-intensity activation exercise and low-intensity activation exercise was significantly higher than before the training(high-intensity:immediate moment,4min;58 ± 5.7,59.9±5.8;P<0.05,low-intensity:immediate moment;59 ± 5.5;P<0.05).Secondly,the PAP effect did not happen in isometric torque of the quadriceps femoris before or after the training.Thirdly,before the training,the iEMG reduced significantly after the high and low intensity activation exercises(Ex.the left rectus femoris muscle:high-intensity:4 min;3196.4±1786.7;P<0.05,low intensity:8 min;3300.1±1296.0;P<0.05).In the H group,the integrated electromyography after the low-intensity activation exercises was significantly lower than that before the trainingConclusions:Hypobaric low-intensity activation exercises can effectively cause PAP effect and promote the outpaces recruitment.long-term hypoxia resistance training can effectively improve the efficiency of muscle recruitment,hypoxia resistance training can be used as a new training method,to improve the sports ability of explosive athletes.