Training to Failure

jamie in focus march 2016

Training to failure

by Matt Lloyd


From climbing to CrossFit, training to failure is an extremely powerful tool to improve performance and strength.  As such, understanding its basics, as well as a few nuances (including its pitfalls) can improve the efficacy and efficiency of any athlete’s training program.

Disclaimer: there is a lot of contradictory research on this subject, this is rough summary of what I’ve learned in research and personal experience.


What exactly is “training to failure?”

For our purposes we define training to failure as the achievement of complete, momentary muscle failure through intentional repetition of any particular movement.  An example would be moderate weight bench press (50-80% 1RM) for as many reps as possible until you cannot push the bar up any more, or for climbers it could be running laps to failure on a route well below your redpoint max.  This failure is not due to skill or technique but rather the muscles inability to continue moving a load.


Benefits of training to failure:

brittany after a wod may 2016Reaching complete muscle failure stimulates the nervous system to create real physical changes that ultimately lead to enhanced muscle activation (improved strength and endurance).  Training to failure causes stimulation of the central nervous system (just like heavy weightlifting but without as much risk of injury) which results in a beneficial condition described as “central fatigue.”  You can conceptualize central fatigue as the brain’s (the central nervous system’s) response to a significant physical stimulus that indicates the our current strength is inadequate.  It’s logical; we can literally change our brain and the way it interacts with our muscles by providing enough stimulus.  Central fatigue is the key to how failure training improves strength and endurance.  You’re not just growing the muscle (also called hypertrophy, although that also happens), you’re changing your brain’s ability to trigger that muscle.


A quick understanding of muscle fibers is needed to understand why failure training can be so productive…

“Muscle fibers are recruited sequentially based on need.  That is, the lower the demand, the fewer fibers required and the greater the demand, the more fibers required.  Low-demand efforts recruit the smaller, lower threshold, slower-to-fatigue motor units.  When more effort is required, the larger, higher threshold, faster-to-fatigue motor units are called upon.”


When we train to failure we recruit a larger percentage of both because as the low threshold fibers fatigue and we approach failure, we start recruiting the high threshold fibers to fill in and move the load.  This is also true not just for the individual muscle fibers as we just discussed but for the muscles as a whole.  As our primary muscles tire and lack the sufficient energy to move the given load, our central nervous system starts recruiting other secondary muscles to help accomplish the given task.  This process happens primarily as we approach muscle failure and allows us to train a larger cross-section of individual muscle fibers and full muscles.  This will deliver a very potent stimulus to the muscle.

The result of this training has a specific benefit to us as athletes.  In recent studies, failure training has been shown to improve localized muscle endurance.  In the Journal of Applied Physiology (, they said this:

“This investigation demonstrated a potential beneficial stimulus of NRF (non-failure training) for improving strength and power…whereas performing sets to failure resulted in greater gains in local muscular endurance.”  

“NRF (non-failure training) resulted in larger gains in muscle power output…whereas after RF (failure training) resulted in larger gains in the maximal number of repetitions performed during the bench press.”


How training to failure is often misused:

While training to failure can be an extremely effective tool, it should not be overused.  For climbers it is often incorrectly employed as their primary training protocol (e.g. running laps to failure on a given route or climbing as many routes as possible before complete failure and reaching the point they are no longer able to recover and continue their climbing session).  One of the most common mistakes made in regard to failure training is believing that any workout in which you achieve total muscle failure is optimal.  This is a standard pitfall of climbers, who historically focus heavily on this type of training.


Why you should be concerned:

niko-10min-airdyne-sept-2016Training to failure can drastically increase the presence of the catabolic hormone cortisol (and if you read my last post on the endocrine system you already know why this is a bad thing).  Because all bodily mechanisms are governed by our exquisitely balanced physiologies, it is quite easy to overtrain a particular movement and throw the body into a stress response that turns off its ability to grow and recover adequately.  A recent Spanish study found that training to failure can lead to a dramatic increase of a chemical called nucleotide adenosine monophosphate (AMP).  The build up of too much  AMP is a signal that cells have been overly depleted of energy.  In response, the body suppresses anabolic growth factor, which in turn leads to decreased protein synthesis (a.k.a. brain and muscle growth).  It’s easy to see how this can drastically limit long term progress.


Why and how should training to failure be used:

suzu hanging in kraft april 2016Training to failure can often be anabolic, which leads to muscle growth and improved strength when done sparingly and with adequate recovery.  If you don’t give your body enough recovery time or train to failure too often you can throw yourself into the stress response and activate the above described catabolic conditions (not good).  This will end up contributing to performance plateaus.  It is advisable to incorporate failure training infrequently and only at the end of a workout (this is standard practice in CrossFit, where we often do strength training before our metcon).  Studies have shown failure training is most effective as a final set.  Any additional exertion after the muscle reaches momentary failure will be mitigated by the muscles fatigue eliminating any potential progress of the subsequent work.  In other words if you train to failure early in a workout, any strength training that will take place after will be considerably less effective.


Tips On Training to Failure:

  • Training to failure is best suited for endurance not strength.
  • Train to failure at the end of your workout or by itself, try to avoid it before strength training.  For climbers that means train hard boulders followed by climbing laps on routes…not the other way around.
  • Provide the body additional rest when complete muscle failure has occurred.  Muscle failure may only take 24 hours to recover from but central fatigue often takes days.  Trust your body and how it feels.
  • Don’t do more than two sets to failure in a specific day, even if they are in different parts of the body or muscle groups.  The catabolic hormones released by one muscle can and do affect other muscles.
  • Periodize your training.  Plan no more than 4 weeks of training to failure in a row without a period of recovery.  



P1200853Matt Lloyd is an owner of a climbing training and CrossFit gym, Mountain Strong Denver.  He has been climbing nearly two decades, has climbed 5.14, and prides himself on always being ready to rock and doing whatever it takes to succeed.


photos: Joshua Edric Photography (@joshuaedric) (

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