In elite male weightlifters with at least 8 years of competitive experience, 8 weeks of low-load, high-repetition resistance training (30–60% of 1-RM, 15–30 repetitions per set) produces similar increases in skeletal muscle mass (approximately 3%) and maximal muscle strength (1-repetition maximum in back squat and snatch) as high-load, low-repetition training (60–90% of 1-RM, 3–8 repetitions per set), despite differences in training volume and intensity.

When muscles are worked with light weights and many repetitions, the stress triggers a specific molecular signal that turns on protein building without using the usual growth pathway. This signal boosts the machinery that assembles muscle proteins, repairs damaged fibers quickly, and makes the muscle fibers thicker. Thicker fibers produce more force, which increases maximum strength. The same outcome happens with heavy weights, but the body uses a different molecular route to get there.