Fitness enthusiasts want your patients to reach muscle failure. Is this safe?

By Claire Wolters | Fact-checked by Davi Sherman
Published December 8, 2023

Key Takeaways

  • Muscle failure, in relation to exercise, is when your muscles are incredibly fatigued and can no longer properly complete a ‘rep’ of a workout.

  • Research shows this can lead to muscle growth but is not essential.

  • While many people can safely perform muscle failure workouts, those who overstrain may be prone to injury.

In pilates-inspired solidcore, failure is just another word for success. The workout combines high-intensity strength work with pilates-like machines on which clients perform crunches, weighted lunges, and more. Coaches encourage students to hold—and pulse through—poses until their body starts to shake, and then hold them a little longer. The goal: to work their muscles hard enough that they can’t work anymore, thereby entering muscle failure.

While coaches rave about the technique, a ‘failing’ body part isn’t always a good sign. What is muscle failure in exercise, and is it safe and effective?

What is muscle failure?

Daniel Diaz, DO, FAAFP, CAQSM, Medical Director of Sports Medicine at AltaMed Health Services in Los Angeles, CA, describes muscle failure as “the point at which a muscle or a group of muscles can no longer produce enough force to perform a specific movement without compromising your form.”

The technique isn’t unique to solidcore and is used in other types of strength-building workouts. Perhaps most commonly, aspiring to reach muscle failure is used as a “measurement of progress in resistance training,” Dr. Diaz says.

“For example, when a person does bicep curls and they can no longer lift the weight to perform another repetition, the muscle has reached its absolute limit,” he adds.

Solidore defines muscle failure as three stages: perceived, controlled, and total muscle failure. According to documents from solidcore, the three stages progress into one other and can be described as:

  1. Perceived muscle failure: Mental and physical discomfort during exercise can be normal. Some people may perceive muscle failure as a burning sensation in their muscles.

  2. Controlled muscle failure: Challenge is added to the discomfort. Not only are the muscles burning, but also struggling to complete the exercise in good form. Some people may notice that their muscles begin to shake during controlled muscle failure.

  3. Total muscle failure: The muscles are so fatigued that they can no longer perform the exercise—and the student probably needs a break.

Is muscle failure safe?

The term ‘muscle failure’ may sound scary, but it doesn’t have to be—so long as it is kept in context with fitness and working out. As a fitness term, ‘muscle failure’ does not imply true muscular death or that a person is losing long-term muscle function.

“With muscle failure, your muscles can function normally; you’re just pushing them to the point of fatigue,” Dr. Diaz says.

In contrast, “When a person’s muscles completely fail, their muscles don’t work; therefore, the person is unable to contract their muscles normally,” he adds. “Muscle function loss, even if partial or temporary, can have serious health consequences and should always be treated as a medical emergency.”

Perhaps less jarringly, muscle failure could be described as muscular fatigue. While muscle failure exercises can be performed safely,  Dr. Diaz adds that they are “not suitable for all.”

He adds that overstraining in order to reach muscle failure can lead to injury. They could also feel uncomfortable, decreasing their motivation to workout in general, he says.

“If a person is interested in doing muscle failure exercises, I recommend doing them with a trained professional,” Dr. Diaz says.

Risks of overstraining

In rare cases, overstraining during exercise can lead to rhabdomyolysis, a condition that causes the muscles to break down rapidly, leading to muscle death.[]

Someone can develop rhabdomyolysis from intense exercise if their muscles do not have the time and ability to heal, particularly if they are not accustomed to exercising. For people with this condition, components of the muscles can leak into the blood, putting pressure on the kidneys to properly filter them out (while also posing risks to the kidneys). As mentioned above, this condition is rare and is not implied by the term ‘muscle failure.’ However, if someone is experiencing rhabdomyolysis, they should stop exercising and instead seek medical attention. 

Is muscle failure effective for building muscle?

Studies show that training to muscle failure can be effective for building muscle size and strength in some people but that it probably isn’t necessary for everyone. Researchers also note that the practice may have different implications for people who are already practicing strength training workouts than it does for those who are just starting out. When guiding your patients to choose safe and effective workouts, encourage them to choose something that works for their body and to talk to a coach or doctor if they are worried that they are overdoing an exercise and feel unsafe.[]

What this means for you

Training to muscle failure is a resistance training technique through which athletes perform the same motion until their muscles become greatly fatigued and they cannot continue. Physicians should know that he technique can lead to muscle growth but can pose injury risks to those who overstrain their muscles.

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