Training to failure for double the muscle growth?
Getting DOUBLE the muscle growth by training to failure. Does that sound too good to be true?
Read time: 5-7 minutes
Take-aways
Training closer to failure non-linearly increased muscle growth. This relationship was attenuated, but remained present, when higher volumes (sets/week) were performed.
For hypertrophy, most training should take place between 2-0 repetitions from failure. Start around 2, and go to failure on your last set for an exercise.
There was no meaningful relationship between proximity to failure and strength gains when the load (%1RM) lifted was equated.
Mostly train heavy and sub-maximally for strength, going a bit closer to failure to practice grinding a heavy lift when you near a competition/max-out.
This study represents the first study to view proximity to failure as a continuous variable and included many studies that previous meta-analyses hadn’t included. The addition of new data is both a strength and limitation of this study and explains why the results of this analysis differ from previous meta-analyses.
Training to failure is controversial. Some will insist that you need to train to failure; that only those last few reps before failure are effective. However, previous studies had shown no difference in hypertrophy when training to failure vs training shy of failure (1, 2).
This is where this latest meta-analysis comes in, pre-printed in May 2023. I know the authors personally and asked for their input on these results, too.
Muscle Growth
Training closer to failure resulted in more growth, all the way to true failure, where you actually fail a rep. As you can see below, the relationship between proximity to failure and muscle growth was not linear; in fact, the closer you went to failure, the more growth was seen, non-linearly. In other words, going from 1 repetition in reserve (RIR) to 0 RIR increased growth more than going from 5RIR to 4RIR. The closer you go to failure, the more additional growth you get. As a result, most of your training for hypertrophy should probably take place within 2-0 repetitions from failure.
Relationship between repetitions in reserve and muscle growth on a given set.
Why?
As you go closer to failure, more muscle fibers are recruited and activated. This is Henneman’s Size principle.Once you get to those last few reps before failure, all muscle fibers are experiencing tension, which initiates muscle growth. This likely explains the potent stimulus of training to failure for muscle growth.
Strength
To briefly touch on strength, there was no substantial relationship between proximity to failure and strength gains when load (%1RM) was equated.
Relationship between repetitions in reserve and strength changes.
So, while you may wish to train closer to failure before a powerlifting competition or max-out to practice the skill of grinding out a nearly-maximal lift, for the most part, submaximal, heavy training is best (e.g. sets of 1-3 repetitions with 3-6 reps in the tank).
Why?
Strength improvements (1RM, for example) are generally greater with loads and force production similar to the outcome (for a 1RM, that would be heavy loads and high force production). As you go closer to failure, your ability to produces force drops, making the training less specific to the outcome.
If you’d like to chat about this study, feel free to comment below.
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