The math used in this study shows it’s almost certain that more lifting leads to more muscle and strength, and more frequent workouts lead to more strength—but not necessarily more muscle.

When counting how much you lift, giving partial credit to exercises that work multiple muscles at once (like squats) gives the most accurate picture of your training load.

Muscle size and strength don’t respond the same way to more training—strength peaks faster, so adding more sets helps muscle growth longer than it helps strength.

When people lift weights without pushing to their absolute limit, they actually get stronger faster than if they push to failure, as long as the total amount of lifting isn't the same. This comes from a big review of studies on adults.

Doing more weightlifting gets you stronger, but after a certain point, extra sets don’t help much—way more than when you’re trying to build muscle size, where more work still gives you decent gains.

Lifting more weights each week makes you stronger, but the extra strength you gain from each additional set gets smaller faster than the muscle gains do.