For young women, lifting lighter weights can be just as good as lifting heavier ones for building muscle and getting stronger, as long as you do the same total amount of work.

For young women, doing lighter weightlifting for 10 weeks can build leg muscle just as well as heavier lifting, with muscle growth between 3% and 12%.

Lifting heavier weights with proper form was better than lifting lighter weights for building both muscle strength and size in men after 3 months of training.

For young women lifting weights, how much total work you do might matter more for building muscle and strength than how heavy the weights are, because studies show similar results when the total effort is the same but intensity differs.

For young women, doing resistance training with lighter weights for 10 weeks can build leg strength just as well as training with heavier weights, with strength gains around 10-16%.

If you're an older adult who's already getting stronger from light weight training, doing even more weight training might help you build even more muscle—but not as much as it helps people who didn't respond to light training at all.