“You need to lift heavy weights to build muscle.”
Light weights build about as much muscle as heavy weights, as long as each set is pushed until another rep is very hard.
You can build muscle with light dumbbells, bands or your body weight, not just heavy barbells. What matters is pushing each set until the last few reps are a real struggle. Heavy weights are the better choice for gaining strength, but they are not required for gaining muscle.
Pick a weight you can lift 15 to 25 times, and keep going each set until you can do only one or two more good reps.
Two meta-analyses of 21 and 28 studies found that light and heavy weights built about the same muscle when sets were taken to failure. Confidence is moderate because the studies were small and short, mostly in young untrained adults, and light weights only matched heavy ones when sets were pushed very hard.
Light weights build about as much muscle as heavy weights, as long as each set is pushed until another rep is very hard. In 28 studies of 747 healthy adults who took every set to failure, muscle growth did not differ between light, moderate and heavy weights. Heavy weights did build more strength.
A separate review of 21 studies, comparing loads of 60 percent or less of the most a person can lift once with heavier loads, also found similar muscle growth and greater one-lift strength with heavy loads. Effort is the catch with light weights: in an 8-week trial of 25 untrained men, light sets taken to failure grew the thigh muscle by about 8 percent, the same as heavy sets, but light sets stopped at about half the possible reps grew it by only about 3 percent, a change too small to rule out chance.
Do heavy weights build more strength?
Yes. In the 28-study review, heavy and moderate weights built more strength than light weights, so heavy lifting is worth it if getting stronger on a lift is your goal.
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