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, 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.

Most of the research on how much to lift and how often was done on young men who already train—so we don’t know if the same rules apply to women, older people, or beginners.

People grow muscle at very different rates — but each person tends to grow their arms and legs similarly, no matter what weight they use. This means your genes and biology matter more than how heavy your weights are.

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%.

If you lift weights until you can't do another rep, you might build more muscle than if you stop before reaching that point—but we’re not totally sure yet.