The Minimal Difference Needed to Be Considered Real and the Standard Error of Measurement for Examining Barbell Velocity During the Bench Press

Although 1 repetition maximum (1 RM) testing is critical for the measurement of low-speed muscular strength, the ability to accurately examine changes in velocity during dynamic constant external resistance (DCER) muscle actions may also be an important consideration for strength and conditioning professionals, particularly when testing athletes that participate in power-oriented sports. PURPOSE: The purpose of this study was to determine the minimal difference (MD) needed to be considered a real change, as well as the standard error of measurement (SEM), during barbell velocity testing for the bench press using the reliability procedures described by Weir (2005). METHODS: Twenty-one healthy, resistance-trained men (mean ± SD age = 23.5 ± 2.7 yr; 1 RM bench press = 1 25.4 ± 1 8.4 kg) volunteered to perform 9 separate submaximal bench press repetitions as explosively as possible from 1 0% to 90% of the pre-determined 1 RM on two occasions separated by at least 48 hours. These repetitions were performed in sequential order (i.e., 1 0% 1 RM, followed by 20% 1 RM, etc.) and separated by three minutes of rest. Peak barbell velocity was determined for each repetition using a TENDO FiTROdyne (TENDO Sports Machines; Trencin, Slovak Republic). RESULTS: The MD needed to be considered a real change and the corresponding SEM (expressed as a percentage of the mean barbell velocity value) was 0.35 m/s (4.2%), 0.33 m/s (5.0%), 0.1 7 m/s (aio/o), 0.21 m/s (4.7%), 0.17 m/s (4.6%), 0.15 m/s (4.8%), 0.1 4 m/s (5.8%), 0.1 9 m/s (1 0.3%), and 0.1 8 m/s (1 2.6/o) for the loads examined at 1 0, 20, 30, 40, 50, 60, 70, 80, and 90% 1 RM, respectively. RESULTS from a two-way repeated measures analysis of variance (ANOVA) indicated no significant trial ? % 1 RM interaction, and no main effect for trial, but there was a significant main effect for % 1 RM. Marginal mean pairwise comparisons (collapsed across trials) demonstrated that the highest barbell velocity occurred at 1 0% 1 RM and significantly decreased with each of the higher intensities examined. CONCLUSION: The results from this study demonstrated that when barbell velocity was examined across a range of relative intensities for the bench press, the MD and SEM values remained relatively constant from 1 0-70% 1 RM. At 80 and 90% 1 RM, however, greater MD and SEM values were observed relative to the mean barbell velocity values. PRACTICAL APPLICATIONS: Examining barbell velocity at higher percentages of the 1RM may be associa