Valid and Reliable Barbell Velocity Estimation Using an Inertial Measurement Unit

Abstract

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 < ICC < 0.96) with a small systematic bias (p < 0.001; ηp2 < 0.50) for squats (0.01 ± 0.04 m·s−1) and hip thrusts (0.01 ± 0.05 m·s−1) and a low limit of agreement (LoA < 0.12 m·s−1) indicated an acceptable validity. The within- and between-day reliability of the MCV revealed good ICCs (0.55 < ICC < 0.91) and a low LoA (<0.16 m·s−1). Although the displacement revealed a systematic bias during squats (p < 0.001; ηp2 < 0.10; 3.4 ± 3.4 cm), no bias was detectable during hip thrusts (p = 0.784; ηp2 < 0.001; 0.3 ± 3.3 cm). The displacement showed moderate to good ICCs (0.43 to 0.95) but a high LoA (7.8 to 10.7 cm) for the validity and (within- and between-day) reliability of squats and hip thrusts. The VmaxPro® is considered to be a valid and reliable tool for the MCV assessment.

The effectiveness of traditional vs. velocity-based strength training on explosive and maximal strength performance: A network meta-analysis

“…Within the last decades, velocity-based resistance training (VBT) as an alternative strength training approach has gained increasing attention ( González-Badillo and Sánchez-Medina, 2010 ). During VBT the training intensity is controlled by monitoring the mean concentric velocity (MCV) of each repetition ( González-Badillo and Sánchez-Medina, 2010 ) using inertial sensors ( Held et al, 2021b ) or linear position transducers ( Held et al, 2021a ). In general, the level of fatigue increases gradually as a function of increasing effort during a training set ( Sánchez-Medina and González-Badillo, 2011 ).…”

Velocity-based approach to resistance training: the reproducibility and sensitivity of commercially available velocity monitoring technologies

“…However, it should be noted that the validity of these devices was not evaluated in the current study due to the absence of a gold standard (i.e., the MOCAP system). In addition, the validity of GymAware, PUSH2 and Vmaxpro devices has been examined in previous studies using different approaches with con icting ndings reported, especially for PUSH2 and Vmaxpro devices 16,17 . Therefore, future research is required to comprehensively examine the validity of these devices.…”

“…More recently, two wearable, wireless, IMU-based velocity monitoring devices PUSH2 (PUSH Inc., Toronto, ON, Canada) and Vmaxpro (alias EnodePro; Blaumann & Meyer-Sports Technology UG, Magdeburg, Germany) have grown in popularity among athletes and recreational trainees due to their versatility and relatively affordable price. Several studies [15][16][17] have examined the test-retest reliability of PUSH2 and Vmaxpro devices with free-weight exercises. However, it is important to highlight that the test-retest reliability assessment inevitably contains errors due to biological variation.…”

Test–Retest and Between–Device Reliability of Vmaxpro IMU at Hip and Ankle for Vertical Jump Measurement

“…The Vmaxpro (Blaumann & Meyer-Sports Technology UG, Magdeburg, Germany) consists of a triaxial accelerometer, a gyroscope, and a magnetometer, weighing 16 g and measuring 4.5 × 2.7 × 1.2 cm. It has a sampling rate of 1000 Hz [ 31 ] and can be attached to metal surfaces by magnets or placed elsewhere using an elastic strap. This IMU is primarily designed for velocity-based resistance training [ 32 ], obtaining data from acceleration integration, so it can provide values for related variables such as peak velocity, average velocity, peak eccentric velocity, average eccentric velocity, percentage of force development, percentage of eccentric force development, average propulsive velocity, distance, and duration.…”