When young women lift weights until they can't anymore, they do more total work with lighter weights than heavier ones, but this extra work doesn't make their muscles grow any more, showing that just doing more reps isn't what makes lifting effective.

This study shows that when young women lift weights until they can't anymore, it doesn't matter if they use light or heavy weights—both ways build muscle about the same.

When young women push themselves as hard as they can during weight training, it seems that how much weight they lift doesn't matter for building muscle size or strength—both light and heavy weights give similar results after 6 weeks.

Whether you lift lighter weights or heavier weights until you can't do any more reps, both ways give you the same muscle growth and strength gains if you're already used to training.

When young women lift weights until they can't anymore, they build similar muscle size and strength whether using light or heavy weights. This suggests that pushing to muscle failure fully activates muscles no matter the weight.

Lifting heavy weights for fewer reps and lighter weights for more reps both build muscle about the same in young men when you push yourself to the max, showing that the total work done matters more than how heavy you lift.