Some people don't gain muscle with certain workout volumes, but they might grow a lot when switching to a different amount—meaning everyone might respond best to their own 'sweet spot' for lifting volume.

Lifting heavy weights and lifting lighter weights can both build muscle just as well for different people, as long as you do the same total amount of work. It suggests that how hard you push might not be the main thing that matters for muscle growth.

When you lift weights more often, your muscles get bigger at a steady pace even if you go really high volume, but your strength gains slow down much faster — meaning your body builds muscle and gets stronger in different ways.

If older adults do not gain muscle from regular weight training, doing more sets and reps might help them finally start building muscle.

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.

When you lift weights more often or heavier, your strength goes up fast at first but then slows down a lot quicker than your muscles growing — so strength gets tired of extra work sooner than muscle size does.