MEAN VELOCITY VS. MEAN PROPULSIVE VELOCITY VS. PEAK VELOCITY: WHICH VARIABLE DETERMINES BENCH PRESS RELATIVE LOAD WITH HIGHER RELIABILITY?

This study aimed to compare between 3 velocity variables (mean velocity [MV], mean propulsive velocity [MPV], and peak velocity [PV]): (a) the linearity of the load-velocity relationship, (b) the accuracy of general regression equations to predict relative load (%1RM), and (c) the between-session reliability of the velocity attained at each percentage of the 1-repetition maximum (%1RM). The full load-velocity relationship of 30 men was evaluated by means of linear regression models in the concentric-only and eccentric-concentric bench press throw (BPT) variants performed with a Smith machine. The 2 sessions of each BPT variant were performed within the same week separated by 48-72 hours. The main findings were as follows: (a) the MV showed the strongest linearity of the load-velocity relationship (median r(2) = 0.989 for concentric-only BPT and 0.993 for eccentric-concentric BPT), followed by MPV (median r(2) = 0.983 for concentric-only BPT and 0.980 for eccentric-concentric BPT), and finally PV (median r(2) = 0.974 for concentric-only BPT and 0.969 for eccentric-concentric BPT); (b) the accuracy of the general regression equations to predict relative load (%1RM) from movement velocity was higher for MV (SEE = 3.80-4.76%1 RM) than for MPV (SEE = 4.91-5.56%1RM) and PV (SEE = 5.36- 5.77%1 RM); and (c) the PV showed the lowest within-subjects coefficient of variation (3.50%-3.87%), followed by MV (4.05%- 4.93%), and finally MPV (5.11%-6.03%). Taken together, these results suggest that the MV could be the most appropriate variable for monitoring the relative load (%1RM) in the BPT exercise performed in a Smith machine.