Definition: Muscle failure refers to lifting weights to the point where a muscle can no longer contract concentrically. If you're a bodybuilder, powerlifter or involved in competitive strength training, lifting to momentary muscular failure may be part of your training. For the average exerciser, you don't necessarily have to lift to complete failure to increase strength and see results. Make sure that you lift a heavy enough weight that you can ONLY complete your desired number of reps - the last rep should be difficult, but not impossible and you should be able to finish the set with good form.
Learn more about choosing how much weight to lift during your workouts.
