The American College of Sports Medicine (ACSM) published an overview of reviews updating its 2009 Position Stand on resistance training (RT) for healthy adults. Synthesizing 137 systematic reviews covering over 30,000 participants, the study evaluated RT prescription variables (RTx) on muscle function, hypertrophy, and physical performance. Compared to no exercise, RT significantly improved strength, size, power, endurance, gait speed, balance, and physical function.

Few RTx variables consistently affected primary adaptations. However, voluntary strength was enhanced by heavier loads (≥80% one-repetition maximum), full range of motion, 2–3 sets, training at session start, and ≥2 sessions/week. Hypertrophy benefited from higher volumes (≥10 sets/week) and eccentric overload.

Power improved with moderate loads (30%–70% 1RM), low-to-moderate volume, Olympic weightlifting, and fast concentric phases. Power RT enhanced physical function. Training to fatigue, equipment type, complexity, set structure, time under tension, blood flow restriction, and periodization did not consistently impact outcomes.

The ACSM concludes healthy adults should perform progressive RT with variable prescription aligned to these findings to optimize muscle function, size, and performance.