Reliability and Validity of Using the Push Band v2.0 to Measure Repetition Velocity in Free-Weight and Smith Machine Exercises.

Abstract

Hughes, LJ, Peiffer, JJ, and Scott, BR. Reliability and validity of using the Push Band v2.0 to measure repetition velocity in free-weight and Smith machine exercises. J Strength Cond Res XX(X): 000-000, 2019-The purpose of this study was to investigate the test-retest reliability and concurrent validity of using the Push Band device 2.0 (PUSH) to quantify repetition velocity across 4 common resistance training exercises performed using free-weight and Smith machine training modalities. Twenty well-trained men (age: 25.1 ± 2.9 years, height: 182.4 ± 6.0 cm, body mass: 77.9 ± 12.0 kg, training age: 5.2 ± 1.4 years) visited the laboratory on 6 occasions (3 free-weight and 3 Smith machine sessions). Baseline strength assessments were conducted in the first session with each modality for squat, bench press, overhead press, and prone row exercises. The subsequent sessions featured repetitions performed with 30, 60, and 90% 1-repetition maximum. During these sessions, velocity was measured simultaneously using a validated linear position transducer (LPT; considered the criterion for this study) and 2 PUSH devices, one in body mode (PUSHBODY) and the other bar mode (PUSHBAR). Test-retest reliability was examined using the intraclass correlation coefficient (ICC) and coefficient of variation (CV). The LPT demonstrated slightly greater reliability (ICC = 0.80-0.98, CV = 0.4-5.1%) than the PUSHBODY (ICC = 0.65-0.95, CV = 0.8-6.9%) and PUSHBAR (ICC = 0.50-0.93, CV = 0.7-7.1%) devices. Near-perfect correlations existed between velocity measured using LPT and PUSH devices (r = 0.96-0.99). No significant differences existed between mean velocity measures obtained using LPT and either PUSH device. The PUSH device can be used in either bar or body mode to obtain reliable and valid repetition velocity measures across a range of loads and exercises performed using either free weights or a Smith machine.