Everything You Need to Know About Muscle Failure

Muscle failure refers to lifting weights to the point where a muscle can no longer contract concentrically. That's a fancy way of saying that the muscle is simply unable to perform another repetition.

The way the body builds muscle is by lifting more weight than it can handle. We overload the muscle so that it will adapt by growing more and bigger muscle fibers (to help handle that added weight). The ultimate form of overload is to train to momentary muscle failure, which recruits the maximum number of motor units and muscle fibers. That is why many bodybuilders use this kind of training. But there's no consensus that this is always the best way to build muscle.

The idea is that you do as many repetitions as you can, with good form, until you're tired. Then you keep going until you can barely get through the last rep—a push that will feel uncomfortable. You don't want to drop a weight on your head, for example, but recognize when your form is slipping and stop at that point.

Most regular exercisers don't train to complete failure. Those who do are usually bodybuilders, powerlifters, people involved in competitive strength training, or people with the specific goal of building larger muscles.

While it's important to lift heavy weights, whether you're a man or woman, a bodybuilder or just an average joe or jane, training to failure isn't always the way to go. It has its drawbacks:

• Training to failure hurts. It's really hard to reach muscle failure every single time you do an exercise. It taxes your body and your mind, and it's very hard to push yourself like that unless you're motivated by a competition.
• It can lead to overuse injuries. Doing this over and over can put your body at risk for injury and overtraining.
• It requires more rest time. The harder you work, the more rest you need and the less exercise you can do in general. That means you're not working out as much—a hindrance, since volume is an important part of any strength program.
• It may not be necessary. The jury is still out as to whether going to complete failure is really the best way to build bigger muscles. 

Instead of training to muscle failure all the time, consider doing it on some exercises or during some workouts. This can be a way to periodize your workouts and focus on cycles where you work on training intensity and lifting to failure and then cycles where you focus more on volume and avoid working to complete failure.

You can also weave failure training into regular workouts by picking a muscle group or an exercise (such as push-ups, biceps curls, or triceps dips) and seeing how far you can go. But remember that even if you don't lift to failure, you're still doing something good for your body when you lift weights.