Muscle hypertrophy response across four muscles involved in the bench press exercise: Randomized 10 weeks training intervention

Abstract

Background and purpose: Resistance training exercise provides increases in muscle size and is used by coaches and health care professional as a tool to improve functional performance. The aim of the present study was to investigate the effect of 10 weeks of resistance training program performed on the bench press (BP) exercise on the hypertrophic responses of four different muscles (pectoralis major, anterior and medial deltoid, brachii, and pectoralis minor) involved in the task compared to controls.

Methods: Twenty-four healthy males were recruited, and thirteen performed a resistance training intervention while eleven were control. RT group trained for 10 weeks and the protocol consisted of a time under tension for each set of 36s (3-4 sets) with 12 repetitions with an intensity of 50-55% of the 1RM, a training frequency of 3 times a week, with a 3 min rest between sets. Muscle cross-sectional area (CSA) was measure by magnetic resonance imaging.

Results: Individuals in the RT group demonstrated higher changes in CSA of the pectoralis major, pectoralis minor, anterior deltoid, and triceps brachii (P ≤ 0.019) than in the Control group. It was identified in the RT group higher increases in CSA of all muscles compared to medial deltoid (P ≤ 0.016), while pectoralis major demonstrated larger increases in CSA than pectoralis minor and triceps brachii (P ≤ 0.030).

Conclusions: We demonstrated that 10 weeks of resistance training performed on the BP exercise led to increases in muscle size of the muscles involved in the task, but not in the same magnitude.

Keywords: Agonist muscles; Bench press exercise; Magnetic resonance imaging; Muscle cross-sectional area; Resistance training; Synergist muscles.