Lifting lighter weights with very short breaks between sets makes your muscles swell up more right after working out than lifting heavy weights with long breaks—so if you want that pumped feeling fast, go light and quick.

If young men lift light weights with very short breaks between sets for 8 weeks, their upper arms grow more than if they lift heavy weights with long breaks—even if they do the same total amount of lifting—because the short breaks create more muscle-burning stress that helps muscles grow bigger.

If you lift lighter weights with only 30 seconds of rest between sets, your body might spike growth hormone and make your muscles look bigger right after the workout—more than if you lift heavier weights and rest for 3 minutes between sets, as long as the total amount of lifting is the same.

You can make your workout feel harder and your muscles burn more by resting less between sets—but you can still lift the same total weight without getting weaker.

If you lift light weights with short breaks between sets for eight weeks, your upper arms might grow bigger than if you lift heavy weights with long breaks—even if you do the same total amount of work. Light weights + quick rest = more muscle growth in this study.

Whether you use light or heavy weights, your muscles can grow about the same amount if you train hard enough—both methods work for building muscle size.