Lifting light weights—less than half of what you can lift once—can still help beginners get stronger and build muscle, but not as much as lifting heavier weights.

Lifting heavier weights might help you get stronger a bit more than lifting lighter weights, but the difference is so small that we can’t be sure it’s real — it could just be luck.

Lifting heavy weights might help you build slightly more muscle than lifting light weights if you're new to training, but the difference isn't big enough to say for sure it's real.

Lifting heavy weights at least twice a week, doing full movements for a few sets each time, and doing it early in your workout can help healthy adults get stronger compared to not exercising or doing other types of training.

Lifting heavier weights for nine weeks made young men stronger in a max lift test than lifting lighter weights, even when both groups worked until they couldn't do another rep.

If you get much stronger—like more than 20% stronger—on an exercise you’ve been doing for a long time, it probably means your muscles got bigger, not just your brain getting better at telling your muscles to work harder.