Abstract: Objective:To quantify the high field strength MRI inertia barbell training on lumbar muscle cross-sectional(CSA)and volume(V)whether the changes of the lumbar muscles have a larger growth and to explore the mechanism of this change.Methods:A total of 30 healthy male college students were recruited,subjects were randomly divided into two groups:the experimental group-inertia barbell training group and the control group-regular barbell training group;1hour/time,3times/week,a total of eight weeks of the lumbar flexion and extension muscle strength training.Respectively before and after the experiment were asked to sit at MRI,the use of 3.0T superconducting magnetic resonance imaging system(Siemens Magnetom Trio,Tim System,MRI)scan lumbar.ImageJ software application manual processing muscle cross-sectional area of the CSA(cross-sectional area,CSA),applied several tests of muscle CSA averaging muscle volume V(Volume,V).Cronbach's test application ICC(intra(inter)-class correlation coefficient)indicators;Paired samples T-test was applied within group and independent samples T-test was applied between different groups.Results:We got independently reliability(ICC)of the test data of the same or different testers,observed the same person(B)reliability tests mean(intra-class correlation coefficient-ICC)was 0.99,95% confidence interval(Confidence interval,CI)(0.99,1),P=0.000;different testers(A and B)(Inter-class correlation coeficient)ICC mean was 0.99(95% CI)(0.99,1),P=0.000.There was no significant difference in value of fourth lumbar CSA between experimental and control groups before and after the test(pre-test P=0.27,post-test P=0.19);The fourth lumbar CSA data of with in the experimental group and control group has a very significant difference before and after the test(P=0.000);The △ CSA%,△ V% of lumbar muscles between the experiment group and control group have a very significant difference(P =0.000).Conclusion:As one of new training equipment,inertial barbell lumbar has certain advantages for the training and rehabilitation of trunk muscles and provide one of the new alternative methods for trunk muscles training and rehabilitation.