If you're lifting weights at about 85% of your max for 12 weeks, going until your muscles can't do another rep doesn't make you stronger or bigger than stopping just before exhaustion — you'll still get great results without hitting failure.

If you lift weights until you literally can't do another rep, you'll feel more tired right after than if you stop a couple reps before failure — even if you're someone who regularly lifts weights.

Lifting weights until you can't do another rep leaves you much more tired during and after the workout than stopping a few reps short — even if both methods build muscle equally.

Lifting heavy weights until you can't lift anymore makes young male athletes much stronger than lifting lighter weights over 8 weeks, showing that heavier loads train muscles and nerves better.

If you lift weights until you can't do another rep, or stop just before failure, your thigh muscles grow about the same amount after eight weeks — but stopping short feels less exhausting each time.

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.