Validity And Reliability Of Devices To Measure Barbell Velocity During Resistance Training

Objective:Velocity-Based training(VBT)has been widely used in resistance training practice,and monitoring the accuracy and reliability of barbell velocity is the primary premise of VBT.Therefore,the purpose of this study was to evaluate the test-retest reliability and criterion validity of 5 commonly used devices for monitoring resistance training using mean velocity and peak velocity.Methods:Nineteen male subjects with more than 1 year of resistance training experience were first tested with one repetition maximum(1RM)test of the three resistance training exercises of High Pull,Back Squat and Bench Press.And then the free weight and smith machine High Pull,Back Squat and Bench Press tests were completed with 45%,55%,65%,75%and 85%1RM,respectively.The test took the three-dimensional motion capture system Qualisys as the "gold standard"and barbell mean velocity and peak velocity were simultaneously monitored with 5 commonly used VBT devices(GymAware,Push Band 2.0,Flex,Vmaxpro and Output).The test-retest reliability of the above VBT devices was evaluated by the Intraclass Correlation Coefficient(ICC)and Coefficient of Variation(CV),and the criterion validity of the above VBT devices was assessed by Pearson correlation coefficient and the paired sample t-test.Results:(1)Test-retest reliability:GymAware had a high test-retest reliability(ICC=0.732～0.944,CV=5.67～9.83%)when monitoring all measured resistance training exercises,and the remaining 4 devices showed high reliability only when monitoring specific resistance training exercises(ICC=0.348～0.940,CV=5.84～17.10%).GymAware,Push Band 2.0,Flex,Vmaxpro,and Output showed the proportion of exercises that could accept test-retest reliability was 100%,42%,75%,67%,and 67%,respectively in all measured resistance training exercises.(2)Criterion validity:In addition to monitoring High Pull using mean velocity had high errors,GymAware revealed very large to almost perfect correlation and small errors when monitoring other resistance training exercises(r=0.788-0.998,MD=-0.05～0.05m/s).In addition to monitoring smith machine High Pull using mean velocity and monitoring free weight and smith machine High Pull using peak velocity,Push Band 2.0 showed very large to almost perfect correlation and small errors when monitoring other resistance training exercises(r=0.731-0.966,MD=0.06～0.05m/s).Flex showed very large to almost perfect correlation and small errors(r=0.895-0.987,MD=-0.04～0.04m/s)when monitoring resistance training exercises using mean velocity except free weight High Pull(r=0.895-0.987,MD=-0.04～0.04m/s).In addition to High Pull,Vmaxpro showed almost perfect correlation and small errors when monitoring both Back Squat and Bench Press(r=0.960-0.986,MD=0.02～0.04m/s).Output showed very large to almost perfect correlation and small errors(r=0.860-0.956,MD=0.00-0.05m/s)only when monitoring free weight and smith machine Back Squat and Bench Press using mean velocity and smith machine Bench Press using peak velocity.Conclusion:GymAware has high test-retest reliability and criterion validity when monitoring other measured resistance training exercises in addition to measuring High Pull using mean velocity.Push Band 2.0 only has high test-retest reliability and criterion validity when monitoring free weight High Pull and Back Squat using mean velocity and free weight Back Squat and Bench Press using peak velocity.Flex has high test-retest reliability and criterion validity when monitoring free weight High Pull,Back Squat,Bench Press and smith machine Back Squat and Bench Press using mean velocity.Vmaxpro has high testretest reliability and criterion validity when monitoring Back Squat and Bench Press.Output has high test-retest reliability and criterion validity only when monitoring Back Squat using mean velocity.