An elite bodybuilder said he uses an exercise technique called slow negatives to build more muscle. Also called eccentric reps, negatives can help optimize gains by putting more tension on the muscle.

A bigger muscle usually has the potential to produce more force, but muscle size does not decide who lifts the most weight.

A common myth in fitness is that large muscles make a person stiff or “muscle-bound.” In reality, muscle mass does not limit movement—poor training habits do. A new generation of elite bodybuilders ...