If you're lifting heavy weights, you don't need to push to absolute exhaustion to grow your muscles—stopping just before failure works just as well, as long as you're lifting heavy enough.

If you're new to lifting and using light weights, you need to push your muscles until they can't do another rep to grow them bigger—otherwise, even doing more reps won't help.

If you lift light weights but push them until you can't do another rep, you can grow your muscles just as much as someone lifting heavy weights—so long as you're putting in the same total effort.

When guys who’ve never lifted weights before start training their legs for 15 weeks, the more their thigh muscles grow, the stronger they get—so muscle growth is probably why they’re getting stronger, not just better at lifting.

To get stronger, it matters more how heavy the weight is than whether you push to your absolute limit—lifting heavier weights makes you stronger, no matter if you stop short of failure.

When people train just one leg with heavy weights, their thigh muscles get bigger and stronger—and this method works well for studying how different rest times affect muscle growth.