Stopping a few reps short lets you do about the same total amount of work over weeks as going all the way to failure — because you can recover faster and do more sets without burning out.

You don’t need to push to absolute failure to grow your thigh muscles — stopping just before failure works just as well and leaves you less tired, making it easier to train consistently.

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.

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, or stop just before failure, your thigh muscles grow about the same amount after eight weeks — but stopping short feels less exhausting each time.

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.