Should You Train To Failure? The Science Of Training To Failure

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Training to failure is not a particularly popular approach to training simply because it is downright exhausting both physically and mentally, making it unappealing for most people.

However, some of the most dedicated and focused weightlifters carry the belief that you have to train as hard as possible in order to achieve the results that you are looking for. 

But should you train to failure? What does it mean to train to muscle failure? Is training to failure an effective way to build muscle, or do the risks outweigh the benefits?

In this article, we will discuss what it means to train to failure, the pros and cons of training to failure, and how to train to failure.

We will cover the following: 

  • What Does Training to Failure Mean?
  • Is It Good to Train to Failure? Potential Benefits of Training to Failure
  • Is Training to Failure Bad? Downsides of Training Sets to Failure

Let’s dive in! 

A person weight training to failure.

What Does Training to Failure Mean?

So, are you wondering how to train to failure?

Training to failure, or training to muscle failure, refers to performing as many reps as possible with the weight that you have selected for the exercise until you can no longer perform another rep without compromising your form.

Essentially, you are fully exhausting your muscle and reaching muscle failure, which is the point at which your muscles can no longer contract forcefully enough or stabilize your body enough throughout the range of motion of the exercise to eke out another rep.

Is It Good to Train to Failure? Potential Benefits of Training to Failure

In theory, it may seem that there are many benefits of training to failure, namely the fact that if you are truly pushing your body to your limits, you will reap the most significant improvements in strength and mass, leaving nothing on the table and accelerating your gains.

A person doing a bicep curl.

But is training to failure the best approach to building muscle and maximizing strength?

Most strength and conditioning professionals suggest that it is better to train smarter rather than harder, which typically precludes the need to actually train to muscle failure in your workout sets.

Typically, training to failure is a weightlifting technique used by bodybuilders or those looking to optimize muscle growth. It is much less common among strength athletes, powerlifters, and Olympic lifters.

The primary reason for this distinction in the use of training to failure as a technique for hypertrophy vs. strength is that resistance training recommendations for hypertrophy generally involve higher volume training in which getting a couple of extra reps in a set may help accelerate muscle growth via triggering raider muscle protein synthesis.

Essentially, the more mechanical tension you can achieve in a workout set, the greater your potential for muscle growth.

In order to maximize your mechanical tension, you need more time under tension, which can correlate to a higher number of reps without a break in between repetitions (as in, more reps in a set before taking a rest before the next set).

The reason that increasing the mechanical tension or time under tension in an exercise set best facilitates muscle growth is that the longer your muscles are leading to contract or sustain an effort against a load, the more motor units are recruited.

A person doing a deadlift.

To better understand how this potentially increases muscle growth, let’s briefly cover what a motor unit is and how motor units work.

A motor unit consists of a motor neuron, which comes from the brain, and then travels to the muscle, where it innervates anywhere from just a few muscle fibers to over 1000 fibers, depending on the size and type of the muscle.

When the motor neuron fires, all of the innervated muscle fibers in that motor unit contract as long as the neuromuscular signal (known as an action potential) surpasses a certain threshold of intensity. 

With consistent exercise training, neuromuscular function improves, and motor units are able to contract more efficiently and rapidly without fatiguing. 

This leads to more coordinated, forceful, and rapid muscle contractions, enabling you to produce more power and strength. 

There is an order in which motor units are recruited in a muscle when you are performing an exercise or contracting that muscle.

A person lifting a weight plate.

The reason that training to failure is thought to help stimulate muscle growth is that the greater the mechanical tension on your muscles, and the longer they are required to contract to produce force without rest, the more motor units, and thus muscle fibers, are activated.

Essentially, even though an individual motor unit operates on an all-or-nothing outcome, most major muscles involved in strength training exercises have hundreds or even thousands of motor units in them.

The body likes to conserve energy, which means that as few motor units as possible are activated to initiate and continue producing force for an exercise or to support your body during an everyday movement activity.

Furthermore, when you first begin a muscle contraction, the slow-twitch muscle fibers are the first ones to be recruited. Slow-twitch muscle fibers (type I fibers) are endurance muscle fibers that can utilize oxygen to generate energy.

As the slow-twitch muscle fibers fatigue, according to Henneman’s size principle of muscle fiber activation, fast-twitch muscle fibers (type II muscle fibers) start to contract to allow you to continue generating force to sustain the contraction.

As time goes on and you continue to perform reps, more and more muscle fibers are recruited as others fatigue, such that you can really activate all or nearly all of the muscle fibers in the muscle.

A person doing a heavy back squat.

Ultimately, by the time you have reached muscle failure when you are training to failure, all of the motor units, and thus all of the muscle fibers, have been activated and used to their maximal abilities.

Gains in muscle size are primarily achieved through the growth of the type II muscle fibers, so training to failure is a great way to truly recruit all of the muscle fibers, especially the most crucial ones you need to be training when trying to achieve muscle hypertrophy.

Similarly, another benefit of training to failure for muscle growth is that when you do not train with enough intensity, potential muscle protein synthesis is compromised.

By default, when you train to failure in a workout set, you are maxing out on the intensity you can sustain, which in turn, can induce a much more significant muscle protein synthesis response than training with fewer reps and leaving a lot “in the tank.”

Finally, as mentioned, muscle growth, or hypertrophy training, is thought to be best supported by increasing your training volume.

Therefore, theoretically, it would seem that training to failure, which is ultimately maxing out on the volume you can handle, would optimize muscle-building results.

A person doing a dead lift.

Is Training to Failure Bad? Downsides of Training Sets to Failure

Despite the seeming potential benefits of training to failure, there are also plenty of risks if you decide to train to failure. Even the research has been mixed on whether or not training to failure is actually advantageous.

First of all, training to failure is extremely uncomfortable and unenjoyable.

As such, it may decrease motivation and increase psychological stress or dread heading into a workout. This, in turn, may reduce adherence to your strength training program or cause you to get less out of yourself during the workout.

In other words, you may find that your physical and mental energy to give it your all during your strength training sessions wanes when you know that you cannot stop the set until you have reached muscle failure. 

You may even find that you are reaching muscle failure earlier or in fewer reps simply because your central governor (or brain) is telling your body that failure has been achieved so that you can rest and move on. 

A person doing a barbell exercise.

The impact of the mental component of intense strength training for muscle growth should not be understated. 

Enjoying your workouts, having a positive mindset, and feeling motivated and energized can translate to better performance in the gym, which ultimately can lead to better gains.

From a physiological standpoint, studies have found that training to failure can lead to excessive muscle damage.

This, in turn, will increase your recovery time and may mean that you cannot hit your next workout as soon, reducing your frequency of training and, therefore, your overall training volume.

Research indicates that training to failure may extend recovery time by as much as 24 to 48 hours relative to stopping before muscle failure is reached.

Furthermore, according to research, fatigue can accumulate over time when you are training to failure, which can increase the risk of overtraining.

A person doing a deadlift.

Research even indicates that within a given workout, when you perform a set to muscle failure, your performance in subsequent sets may be compromised.

This, again, will impede your potential progress in the gym and your muscle growth.

So, if training to failure isn’t the best strategy for building muscle, what is?

Most strength coaches and outcomes of research recommend training about 3 to 5 reps short of failure as ideal.

From a practical standpoint, this means that if you can potentially perform 14 reps with the weight that you are using, you should perform 9-11 reps to maximize the benefits and minimize the risks of hypertrophy training at a high volume.

For more information about strength training programming, check out our complete guide to deloading here.

A person doing an overhead press.
Photo of author
Amber Sayer is a Fitness, Nutrition, and Wellness Writer and Editor, as well as a NASM-Certified Nutrition Coach and UESCA-certified running, endurance nutrition, and triathlon coach. She holds two Masters Degrees—one in Exercise Science and one in Prosthetics and Orthotics. As a Certified Personal Trainer and running coach for 12 years, Amber enjoys staying active and helping others do so as well. In her free time, she likes running, cycling, cooking, and tackling any type of puzzle.

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