Optimizing Strength and Hypertrophy: The Combined Effect of Intensity and Velocity Loss Thresholds in Bench Press Training.

Abstract

To analyze the effects of 1) different relative intensities (percentage of one-repetition maximum [%1RM]) when matching velocity loss (VL); 2) different VL thresholds when matching %1RM; and 3) the interaction between %1RM and VL on strength gains and hypertrophy during the bench press exercise. We hypothesized that high-intensity (70%-85% 1RM) with a moderate VL (25%) would maximize strength gains, while a high VL (50%) would optimize hypertrophy. One hundred and fifty-eight resistance-trained men were randomly assigned to 12 groups after an 8-wk bench press training program. Each group was categorized into one of three intensity ranges (40%-55% 1RM, 55%-70% 1RM, and 70%-85% 1RM) and distinguished by the VL allowed per set (0%, 15%, 25%, and 50%). Assessments performed before and after the training program included: 1) cross-sectional area (CSA) of the pectoralis major, 2) maximal isometric strength, 3) progressive loading test, and 4) maximum number of repetitions (MNR), in bench press. Significant "intensity × time" interactions were observed for CSA, 1RM, velocity attained against submaximal loads, and MNR, with 70%-85% 1RM producing the greatest gains. Significant "VL × time" interactions were found for CSA, 1RM, and MNR, with VL50 yielding the highest increases in CSA and MNR, while VL25 resulted in the greatest improvements in 1RM. Bench press training adaptations depend on intensity and VL. High intensities (70%-85% 1RM) consistently optimized strength and hypertrophy, while VL modulates outcomes: greater VL (50%) maximized muscle growth and endurance, while moderate VL (25%) produced superior maximal strength gains.