Doing light weight exercises until you can't do any more for 8 weeks won't make your arms stronger or more powerful if you're new to lifting — you probably need to lift heavier or move faster to see real gains.

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.

You can get stronger and bigger muscles by lifting light weights until you're exhausted — even if you never lift heavy, which challenges the old idea that heavy weights are required.

For people who already lift weights, it doesn’t matter much if you rest 30 seconds or 2.5 minutes between sets of light weights — you get the same muscle growth and strength gains either way.

If you're already someone who lifts weights, doing light weights twice a week until you can't do more reps can make your muscles bigger and stronger in just 8 weeks.

If you lift weights until you can’t do another rep—whether you use heavy weights or light ones—you’ll end up with about the same muscle growth after nine weeks, as long as you’re putting in the same effort and number of reps.