Valid and Reliable Barbell Velocity Estimation Using an Inertial Measurement Unit

The accurate assessment of the mean concentric barbell velocity (MCV) and its displacement are crucial aspects of resistance training. Therefore, the validity and reliability indicators of an easy-to-use inertial measurement unit (VmaxPro®) were examined. Nineteen trained males (23.1 ± 3.2 years, 1.78 ± 0.08 m, 75.8 ± 9.8 kg; Squat 1-Repetition maximum (1RM): 114.8 ± 24.5 kg) performed squats and hip thrusts (3–5 sets, 30 repetitions total, 75% 1RM) on two separate days. The MCV and displacement were simultaneously measured using VmaxPro® and a linear position transducer (Speed4Lift®). Good to excellent intraclass correlation coefficients (0.91 p p2 −1) and hip thrusts (0.01 ± 0.05 m·s−1) and a low limit of agreement (LoA −1) indicated an acceptable validity. The within- and between-day reliability of the MCV revealed good ICCs (0.55 −1). Although the displacement revealed a systematic bias during squats (p p2 p = 0.784; ηp2 ® is considered to be a valid and reliable tool for the MCV assessment