Gyms are loaded with trainers who either you should keep 3-4 reps in the tank, or who believe you should train the target muscle to the point of “failure”…

… but who is right?

If your goal is to build muscle, research suggests the latter.

Studies show that if you’re trying to build a ripped, muscular physique then you should be taking many (but not all) of your sets to the point of failure.

Today I’m going to show you how to do it, because when applied correctly, training to failure is an incredibly powerful tool which can greatly improve your results in the gym and have your pals wondering what the heck you’re doing – or using! – to see such progress.

But when applied incorrectly, it’s a complete waste of time!

Let’s break it down.

“The further you can take a set beyond failure, the higher you can increase levels of these natural muscle building hormones and the further you can push muscle growth.”

– Jim Stoppani


“Failure” is defined as taking the muscle to the stage of being unable to perform another rep with good form, and it can be applied to low, mid-range or high rep sets.

A 2010 study from McMaster University, Canada, was the first to really delve into the finer details of the potential hypertrophy benefits on the table.

Using the leg extension, the researchers worked with 15 male participants who were broken into the following groups:

  • 4 sets of 4-5 reps with a weight that caused muscle failure
  • 4 sets 20-30 reps with a weight that caused muscle failure
  • 4 sets of 20-30 reps with a comfortable weight (no failure was reached)

The results were nuts. As you can see below, both of the groups who achieved muscle failure reported a significantly higher rate (40-60%) of muscle protein synthesis. (1)

training to failure muscle growth

Twelve months later, researchers from the same university conducted a follow-up study to test the muscle building properties of whey protein in the 24 hours after a workout, and it gave them a second opportunity to simultaneously test the benefits of training to failure.

This time the researchers had three groups of trained men supplementing with whey protein after performing unilateral leg extensions like this:

  • 4 sets of 4-5 reps with a weight that caused muscle failure
  • 4 sets of 20-30 reps with a weight that caused muscle failure
  • 4 sets of 20-30 reps with a comfortable weight (no failure was reached)

The researchers found that the protein shake spiked muscle protein synthesis significantly higher for the trainees who achieved failure. (2)

is training to failure better for muscle growth

One thing I hope you’ve noticed so far is that training in the higher rep ranges appears to be pretty damn good for stimulating muscle growth (more on this here), but there are also some things to consider.

The first is that the researchers in both of these studies measured muscle protein synthesis and not actual hypertrophy. Sure, MPS is a great indication that our muscles are in a state of heightened growth, but if we want to look at the bigger picture we need a study which is longer and which takes muscle measurements.

The second issue is that the two studies above did not use the rep range which is most linked with hypertrophy. Both trials had participants working with 4-5 reps and 20-30 reps, and it would be very interesting to see how the 8-12 rep range fits into the story.

We got our answer in 2012.

A study published in Journal of Physiology compared the hypertrophy results of two groups of trainees performing 3 sets of 12 repetitions on the leg extension. The participants used a relatively light weight (30% of their max) but one group slowed down the tempo to ensure they reached full muscle failure by the final rep.

The results confirmed what you’re likely already suspecting – training to failure produced greater muscle growth! (3)


Now if you’re wondering how the hypertrophy benefits of training to failure in the 8-12 rep range compare to training in higher rep ranges (to see where you could build more muscle), we can answer this question by looking at a 2012 study published in the Journal of Applied Physiology.

This time around the team weren’t interested in comparing training to failure versus NOT training to failure, because the benefits were well established at this point. Instead, they wanted to see if we can stimulate more muscle growth by taking multiple sets to failure versus just one set, and whether training to failure in the mid-range can yield a better response than using high reps.

The researchers worked with a group of eighteen trained males as they performed the following bouts of leg extensions over a 10 week program:

  • 1 set of 8-12 reps with a weight that caused muscle failure
  • 3 sets of 8-12 reps with a weight that caused muscle failure
  • 3 sets of 20-30 reps with a weight that caused muscle failure

What they discovered changed everything.

As you can see in the graph below, the study showed that the groups who achieved muscle failure across three sets improved muscle growth by around 7%, which was almost double the one-time group. This indicates that we will achieve greater hypertrophy results not just by reaching failure, but by doing so on a regular basis. (4)

high reps vs low reps

The reason this study got so much attention, though, is because it was the first study to conclusively prove that you can build just as much muscle with high reps as you can with low reps. It appeared that the low rep training brought with it more strength improvements, and the high rep training produced improvements in muscular endurance, but in terms of hypertrophy there were no great differences!

This is HUGE NEWS, because it gives you multiple ways to unlock even better results!

training to muscle failure


By now you should be starting to see the benefits of training to failure and how it can help you improve your muscle building results.

Let’s put the above research into action!

Now that we know high rep training can be just as useful as low rep training for hypertrophy, this means you can exploit two different muscle building pathways.

Progressive overload is probably the most popular muscle building pathway. This is the process of trying to lift heavier weights over time to gradually become bigger, stronger, and more muscular. It’s a highly effective strategy which works well low reps and heavy weights, but it’s not the only thing we should focus on if we want incredible results. Think about it; if we kept trying to lift heavier, eventually we would reach a plateau or get injured. (5, 6)

The good news is it’s not the only screwdriver in your toolbox!

Training with higher reps means we can stimulate muscle growth via metabolic stress. This sees the focus shift from sheer weight to time under tension. (7, 8)

It’s all about muscle fibers.

When we lift in a lower rep range with a heavy weight our body places emphasis on developing fast-twitch muscle fibers. These are explosive muscle fibers which respond well to heavier loads.

When we train with lighter weights and higher reps our body uses slow-twitch muscle fibers. These are significantly weaker but have a far greater capacity for endurance training.

But here’s the thing…

When done correctly, high rep training can actually train both types of muscle fibers.

The key to unlocking the hypertrophy benefits appears to be taking high rep sets (or at least many of them) to failure.

(In fact, all of the studies above which showed high reps to be as effective as low reps for hypertrophy had participants taking their high rep sets to muscle failure.)

This is known as the size principle, and the reason it works so well is because it allows us to fully exhaust the muscle.

You see, it appears that the body recruits muscle fibers from smallest to biggest, as if it’s trying to perform the given task with as little effort as possibe. When we pick up a very heavy weight it tries to use slow-twitch muscle fibers at first, but quickly realizes they are no match for the load and switches to explosive fast-twitch fibers. When we lift a lighter weight and take the set to failure we start off using slow-twitch fibers and then when we near failure we start recruiting fast-twitch fibers. By the end of the set you have trained both sets of muscle fibers and stimulating maximum hypertrophy with a lighter weight!


  1. Burd N. A., et al. Low-Load High Volume Resistance Exercise Stimulates Muscle Protein Synthesis More Than High-Load Low Volume Resistance Exercise In Young Men. PLoS ONE. (2010)
  2. Burd N. A., et al. Enhanced Amino Acid Sensitivity Of Myofibrillar Protein Synthesis Persists For Up To 24 Hours After Resistance Exercise In Young Men. J Nutr. (2011)
  3. Burd N. A., et al. Muscle Time Under Tension During Resistance Exercise Stimulates Differential Muscle Protein Sub-Fractional Synthetic Responses In Men. J Physiol. (2012)
  4. Mitchell C. J., et al. Resistance exercise load does not determine training-mediated hypertrophic gains in young men. J Appl Physiol (2012).
  5. Wackerhage H., et al. Stimuli and sensors that initiate skeletal muscle hypertrophy following resistance exercise. J Appl Physiol (1985).
  6. Peterson M. D., et al. Progression of volume load and muscular adaptation during resistance exercise. Eur J Appl Physiol (2014).
  7. Tee J. C., et al. Metabolic consequences of exercise-induced muscle damage. Sports Med (2007).
  8. Schoenfeld B. J., et al. The mechanisms of muscle hypertrophy and their application to resistance training. J Strength Cond Res (2010).

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