Effects of different velocity loss thresholds on strength, neuromuscular adaptations, and muscle hypertrophy during bench press training in women.

This study aimed to compare the effect of three velocity loss (VL) thresholds - 0% (VL0: one repetition per set), 25% (VL25), and 50% (VL50) - on strength gains, neuromuscular adaptations, and muscle hypertrophy during the bench press (BP) exercise. Forty-nine resistance-trained women were randomly assigned to three groups that followed an 8-week (16 sessions) BP training program using intensities ranging from 70% to 85% of 1-repetition maximum (1RM). Training groups differed in the VL achieved in each set (VL0, VL25, and VL50). Assessments performed before and after the training program included: 1) muscle thickness of the triceps brachii (TB); 2) maximal isometric test; 3) progressive loading test; and 4) fatigue test, all in the BP exercise. Electromyography signal was recorded from TB during these tests. Although all groups obtained significant gains in all strength variables, VL50 showed greater gains in 1RM strength and velocity against heavy loads than VL0 (group × time interaction: P < 0.001 and P = 0.04, respectively). Significant improvements in the force-time variables and electromyography amplitude (P = 0.01, with light loads) were observed exclusively in the VL25 group. Additionally, only VL50 exhibited significant increases in TB muscle thickness (P = 0.01). The greater the VL threshold, the more positive the effects on performance against heavy loads and muscle hypertrophy. Moderate VL thresholds improved the ability to produce force at high velocity and led to positive neuromuscular adaptations. Performing only one repetition per set was enough to improve strength in intermediate-trained women but was insufficient to maximize strength gains.