Progressive Overload and Muscle Hypertrophy: Its Relation to Muscle Use in Training Session

ABSTRACT: Kassiano, W, Manske, I, Miguel, A, Dias, RNdS, Siqueira, JP, Dantas, L, Prado, A, Costa, B, and Cyrino, ES. Progressive overload and muscle hypertrophy: Its relation to muscle use in training session. J Strength Cond Res XX(X): 000-000, 2026-To investigate the effects of progressive overload on skeletal muscle hypertrophy and its relationship with muscle use during training. The study comprised 2 components: a training intervention (part 1) and 2 acute resistance exercise bouts (part 2). Forty-one untrained young women had each arm randomized to progressive overload (n = 29), no-progressive overload (N-PO, n = 23), or a time-matched nonexercise control (Ctrl, n = 30). In part 1, subjects performed unilateral elbow flexion (3 sets of 8-12 repetitions, 3 d·wk-1) for 8 weeks. Progressive overload (PO) increased load when the upper repetition limit was reached, whereas N-PO maintained constant load and repetitions. Elbow flexor muscle thickness was measured pre- and post-training at 60 and 70% of arm length and summed (∑EF). In part 2, subjects performed an acute exercise bout at pre- and post-testing. Muscle thickness was measured before and immediately after exercise as a proxy for muscle use. Both training conditions increased muscle thickness vs. Ctrl, with greater increases in PO than N-PO. Acute thickness increases were similar between conditions at pretesting, but at post-testing were greater in the Ctrl and N-PO than PO, with no differences between Ctrl and N-PO. Progressive overload augments muscle hypertrophy, likely by maintaining higher muscle use during exercise.