arnold achwarzenegger bicep curl training to failure

Research: Resistance Training to Failure Leads to Less Muscle Hypertrophy Than Sub-Maximal Training

Training to failure is a common characteristic of many strength-training programs. So much so that we often see it as essential to optimize muscle growth and strengthening.

And although we think of training to failure as "training hard" there's mounting evidence to suggest we may not have to in order to achieve optimal gains.

So it's interesting to see recent research from a group in Tennessee, USA that challenges this long-held belief.

Let's have a look at what they found and what it means for us and our resistance-based training regimes.


The Idea Behind Training to Failure

Before we get into the specifics of the study, it's important to provide some context.

Training to failure refers to exhausting skeletal muscle with resistance until you can no longer perform another repetition of the exercise.

This concept was originally popularized by Arthur Jones - developer of Nautilus exercise equipment and pioneer of the gym machine revolution.

The theory behind this approach involves optimizing local muscle and nerve recruitment. Training the muscle to failure may more specifically target fast-twitch fibers responsible for improved strength and power. Similarly, maximum fatigue is thought to facilitate maximum muscle activation, adaptation, and potential for growth.

And when you're in the gym working hard for those gains, training to failure does make sense. As mentioned in the introduction, "failing" is seen as a badge of honor for those who push themselves to the limit. These trainers are often the most dedicated with strong results to show for it.

On a personal note, training to failure has been the foundation of my weights program since my late teens.

But as it turns out there's mixed evidence to suggest training to failure is superior to other forms of resistance training. In many cases research fails to account for changes in training volume - a metric seemingly more robust in its ability to influence muscle adaptation.

Related: Read why you should no longer use ice to treat your injuries (and what to do instead).


Risks of Training to Failure

Whether training to failure is the best approach for muscle growth or not, pushing your body to its limits does have its risks.

Obvious risks include:

  • Heightened risk of injury
  • The challenge to maintain correct form when failing
  • Overtraining
  • Potential for diminishing returns if training stimulus not varied
  • Longer, more intense periods of post-exercise soreness (DOMS)
  • Longer recovery times

Details of the Study

Published on July 11th, 2019 the study looked at the effects of resistance training on skeletal muscle. They wanted to know whether training to failure or at a relative intensity would account for greater changes in muscle hypertrophy.

Fifteen well-trained males (between the ages of 23 and 31) were included in the study. Each performed 3 weight training sessions a week for 10 weeks. Eight trained each exercise to failure while the remaining seven did not. Each performed the same dynamic warm-up.

Exercises included back squats, bench press, deadlifts, dips, and other typical movements.

Training volume was normalized by having all participants perform the same number of sets and repetitions for each exercise. The group not training to failure just performed their exercises at a lower intensity. This was 65-90% of their maximum depending on the day, week and exercise.

A Quadriceps (Vastus Lateralis) muscle biopsy was taken to measure progress, with samples acquired at least 72 hours before and after the study. They also used Ultrasound to gauge muscle cross-sectional area and thickness before and after the program.

What the Study Found About Training to Failure

Interestingly, the study found training to failure resulted in less muscle growth than those who trained sub-maximally. This included both the size of the whole muscle as well as individual muscle fibers.


Why Training to Failure May Be Less Advantageous

As a Physiotherapist, I can appreciate why training to failure is still so popular in gyms around the world.

It's logical to expect more muscle fatigue to lead to greater outcomes in strength and muscle hypertrophy. After all the body is one robust adaptive machine.

So it's intriguing to think about why training to failure may be less productive than a lower intensity.

In my opinion, we may find the answer to this question just by re-considering what we already know about training and muscle growth.

Muscle fatigue is necessary, however, sleep and recovery are where the real growth occurs.

And this is where the distinction may be.

Training to failure requires a longer recovery process which training routinely more than 3 times a week may not facilitate. All things being equal, this may lead to a more incomplete recovery process compared to training at lower percentages.

This idea is supported by another study that found training to failure added an extra 24-48 hours to recovery with bench press and back squats.

Perhaps the need for a more complete recovery outweighs the need to recruit the most fibers and experience the most fatigue?


Limitations of the Study

As with every piece of research, it's important to consider it limitations. These may compromise our ability to generalize any findings to the wider population.

The following are things to consider:

  • A relatively small study (15 participants)
  • No female participants
  • Did not account for sleep quality and duration
  • Did not account for nutrition
  • All participants were well-trained, not everyone is
  • Participants not representative of an older population

It's interesting to note the study did not account for both sleep or nutrition despite their crucial role in muscle building.

I'd imagine the results would be similar regardless but it's an interesting little asterisk nonetheless.

Clearly more research is needed to explore to support this study, but it does present a strong case to consider.

Related: Here's why I'm at odds with evidence-based practice.



So with all this in mind perhaps re-consider training to failure if your goal is to maximize muscle growth. You are still highly likely to see change but any potential delay in recovery may subdue long-term results.

Instead, the essence of this study suggests training at sub-maximal intensities may lead to better muscle hypertrophy - particularly if you are a well-trained male in your late 20s.

This study has certainly given me pause for thought. Hopefully I'm not alone!

Do you train to failure? How do you find your recovery compared to training at sub-maximal intensities? Let me know in the comments below.


Skeletal Muscle Fiber Adaptations Following Resistance Training Using Repetition Maximums or Relative Intensity: Sports2019, 7 (7), 169;


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