Validity and Reliability of a Linear Position Transducer to Measure Barbell Velocity, Duration, and Displacement During the Bench Press.

Abstract

This investigation evaluated validity and reliability of the HUMAC360 linear position transducer (LPT) compared to the Tendo Sport Weightlifting Analyzer (TENDO) for measuring mean velocity (MV), peak velocity (PV), and displacement (D) during the bench press. Seventeen recreationally active individuals completed three visits. During visit one, participants were assessed for their one repetition maximum (1RM) bench press. During subsequent visits, participants completed two sets of three repetitions of bench press at 30, 50, 60, and 70% 1RM. The HUMAC and TENDO measured MV, PV, and D simultaneously, while the HUMAC also measured repetition duration (T). Validity of the HUMAC and inter-set and inter-day reliability for MV, PV, D, and T were assessed using Intraclass Correlation Coefficients (ICCs). The HUMAC demonstrated limited validity when compared to the TENDO as ICCs ranged from poor to good across all measurements. Significant differences were observed between devices for MV, PV, and D at all intensities (p < 0.001). Inter-set reliability was excellent for all intensities and measurements, but inter-day reliability was impaired for MV, PV, and D at higher intensities. Validity of the HUMAC for measuring MV, PV, and D is limited when compared to TENDO. As the HUMAC reliably assesses MV, PV, D, and T, both inter-set and interday (up to 60% 1RM), it may serve as an autoregulatory tool for velocity-based training.