The Effects Of Low-intensity Resistance KAATSU Training On Lower Extremity Muscle Activation Of Swimmers

Objective:To explore the effect of low-intensity resistance KAATSU training on lower extremity muscle fiber recruitment and post-activation potentiation of swimmers.Methods:The 12 members(age:18.3±3.28,height:180.75±5.38cm,weight:73.41±8.70kg)of the Beijing swimming team were selected as the subjects.The experiment was designed by random interaction,the results of the experiment were self-control.Each subject needed to carry out three tests at the same time of one day,each test interval was 72 hours.The intervention plan of weight-bearing squat for three times:HRT group:90%1RM(5 times in total,60s interval each time);LRT group:30%1RM(30+20 times,60s interval between groups);BFR-LRT group:blood flow restriction combined with 30%1RM(40mmHg,200mmHg,30+20 times,60s interval between groups).Before and after each half squat intervention,measured counter movement jump(CMJ)height at the 8th minute after the intervention,max voluntary contraction(MVC)strength of back support leg when starting's knee joint flexion and extension at the 10th minute after the intervention.And collected the RMS of surface electromyography of two bilateral medial femoris,two rectus femoris and biceps femoris of back support leg when starting during the process of MVC and half squat.Results:After the intervention of the three schemes:(1)Only the CMJ height of the BFR-LRT group increased significantly(P<0.05),while the CMJ height of the other two groups increased not significantly(P>0.05);(2)MVC strength of knee flexion was increased significantly only in the BFR-LRT group(P<0.05);(3)The RMS of the rectus femoris muscle was increased significantly in the BFR-LRT group only when the leg was stretched with MVC(P<0.05),and the RMS of each muscle in the other two groups was not improved significantly(P>0.05);(4)During HRT training,the RMS of biceps femoris increased significantly with the training site(P<0.05);during LRT training,the RMS of the left medial femoral muscle was increased significantly with the training site(P<0.05);during the BFR-LRT training,the RMS of the left medial femoral muscle,the right leg femoral muscle and the back support leg biceps femoris increased significantly as the training progressed(P<0.05);(5)During the training,there was no significant difference in the activation of each muscle in the LRT and BFR-LRT groups(P>0.05).The left rectus femoris,right medial femoris and right rectus femoris were significantly lower in the BFR-LRT group than in the HRT group(P<0.05).Conclusion:Low-intensity resistance KAATSU training has a positive effect on lower extremity muscle activation of swimmers.The 90%1RM weight-bearing half-squat is not suitable for inducing swimmers to produce post-activation potentiation in the lower extremity.