How Training to Failure Can Make You Fitter

Regardless of your fitness goals, the surest way to success is, ironically, failure.

That’s what research in recent years has revealed about the relationship between reps and results, which progress in sync with one another.

What Is “Training to Failure?”

Momentary muscular fatigue — also known as training to volitional failure or “maxing out” — simply demands performing movements until you can no longer do them without compromising form. Rather than setting an arbitrary ceiling for yourself and hoping to, again arbitrarily, increase that ceiling over time, maxing out uses your body’s current capabilities to decide the variables (weight, reps, etc.), whether it’s high-intensity cardio, weight training, or any combination of the two.

Once that ceiling is reached, you achieve failure, with the gains coming in the form of your body’s ability to go just a bit further the next time. “If you never fail at a set, you aren’t pushing hard enough,” says Steve Edwards, former Vice President of Fitness and Nutrition at Beachbody.

But beyond a red-blooded sense of accomplishment, why is is training to volitional failure important? Edwards says, “Pushing towards failure is the only way to derive all of the benefits of a workout as it’s designed.” Most workouts, Edwards says, target energy systems, which, to be simplistic, are the physiological processes that facilitate the conversion of fuel into fitness. To make these systems more efficient — which is the very definition of fitness — Edwards says you’ve gotta fail.

“It’s the founding principle of all athletic training, or really, all physiological processes in the human body.”

How Training to Volitional Failure Works

Anaerobic activity (including interval and weight training) is designed around the body’s failure point in one of the aforementioned energy systems. In resistance training, this is represented by the amount of weight needed to fail at a given number of reps. In the case of cardiovascular workouts — most often interval training — this is represented by the use of body weight, speed, jumping, and stopping to achieve failure.

“Training, philosophically, is about putting your body in environments that it’s not entirely adapted to,” says Dr. Marcus Elliott, Founder and Director of P3, a facility that applies scientific research to athletic performance. “Training to failure suggests taking your body as far as it can go. That is what your body responds to: being challenged.”

Resistance training has long been known to stimulate muscle growth, but recent research finds that there are diminishing returns to simply adding weight. A 2010 study commissioned by Canada’s Natural Sciences and Engineering Research Council found that low-load, high-volume resistance exercise (i.e., less weight, more repetitions) is more effective at building muscle than high-weight, low-rep resistance training. The researchers determined that muscle growth is dependent not only on weight, but also the number of reps performed.

The results are greater strength, muscle endurance, and, of course, mass. But the benefits aren’t limited solely to muscle development. “In addition to muscle adaptation,” says Elliott, “you also increase adaptive response to lactic acid,” the chemical that builds up in overworked muscles, creating that burning feeling. “When you take a workout to failure, you can become more efficient at utilizing lactate (lactic acid) as energy.”

Adapting to lactate means that, instead of gasping and vomiting during intense exercise, you breathe more easily. You also develop blood buffers, which help maintain a healthy blood pH and prevent nausea. “How that shows up in terms of fitness is if you’re climbing or on a run, and the guy next to you is suffering and you’re not,” explains Elliott.

While not all of the particulars explaining the effects of training to failure are clear, Dr. Francis Stephens at the U.K.’s University of Nottingham, says, “It likely has to do with metabolic and mechanical stress associated with fatigue within the muscle signaling for the adaptation.” Translation: burn it down.

Don’t Forget Recovery

A vital component here is rest (also known as recovery). The harder the workout, the more muscle fiber and neuron groupings — known as motor units — are recruited. Outside of long-distance running, most workouts target the moderate and high motor units. The more those units are recruited, the more recovery is required.

“This is why almost all training is broken into microcycles (weekly training schedule) and macrocycles (longer schedules) so that your recovery is properly balanced between your training,” says Edwards. That explains why weight training is often staggered by muscle group, and why very intensive training (plyometrics, et al) is done only once per week.

Edwards says there was a time when professionals were afraid to use programs like high-intensity interval training (HIIT) with out-of-shape subjects. “This started changing in the early ’90s as studies began on highly de-conditioned people and saw them respond much quicker to HIIT than traditional low-level aerobic work.” That means the only people to whom training to failure doesn’t apply are those with an injury or physical limitation that might prohibit it.

Still, Edwards advises that maxing out should constitute the bulk of training for most people. As he says trainers always say, “Failure is not an option.”