If you’ve never lifted weights before, you can get stronger by doing either light or heavy weights — as long as you push each set until you can’t do another rep.

For young women new to weight training, lifting weights until you can't do more reps (either 5-7 reps per set or 10-14 reps per set) three times a week for two months gives about the same muscle growth and strength gains, no matter which rep range you use.

When young women lift weights until they can't anymore, using lighter weights (30% of max) gives about the same strength gains as heavier weights (80% of max) over 6 weeks, with arms and legs getting stronger by similar amounts.

Women who had never lifted weights before got stronger in their arms and legs after doing 12 weeks of lifting light or heavy weights to exhaustion — and both ways made them just as strong.

When young women do strength exercises until they can't do any more, their arm and leg muscles get stronger by about 15-27% after 6 weeks. It doesn't matter if they lift heavy or light weights—both ways work just as well for building strength.

Even though your body releases similar growth hormones after light workouts whether you rest a little or a lot, you still get stronger and bigger muscles either way.