Training to the point where you’re unable to perform more repetitions, despite attempting to do so, is often presented as a non-negotiable variable in training for muscle growth. But is it necessary, or will you get the same growth by stopping shy of failure?

Overview

What did they test? The authors examined the current literature to see if training to failure is superior to non-failure training.
What did they find? There were no meaningful differences between the failure and non-failure conditions for muscle growth.
What does it mean for you? Training to failure on every set is not necessary for maximizing muscle growth. However, training close to failure is still needed to ensure your training effectively promotes hypertrophy.

What's the Problem?

Training to failure is a topic that has received a lot of attention in and out of the scientific community in the past years. From studies exploring the effects of training to failure on muscle growth and strength to studies that define muscular failure, there’s quite a bit of literature on the topic. Outside the scientific literature, training to failure is often discussed or preached among gym goers, sometimes even portrayed as necessary for achieving maximum muscular gains. New lifters often hear about “effective reps” and “giving 100% on each set” when learning about maximizing muscle growth. Legendary bodybuilders like Tom Platz and Dorian Yates, just to name a few, are remembered for their ability to take sets to their absolute limit, often heard preaching about the importance of not leaving any reps in the tank. 

Failure is the point where one reaches momentary failure, where one cannot perform another concentric repetition with a full range of motion 1. In the literature, we often see the term “volitional failure,” a term used to describe the point where an individual thought they had no more repetitions left in the tank but did not attempt an additional repetition and failed to complete it. Additionally, there are also instances where a clear definition of failure is not provided in a given study and the term “failure” is used as an umbrella term, which further hinders our ability to understand the actual proximity to momentary failure needed to maximize muscle growth.

We know that training close to failure is essential when trying to maximize muscle growth as muscle fiber recruitment increases as you approach momentary failure, thus leading to more muscle growth. However, training to actual momentary failure, as you may have already experienced, also comes with quite a bit of fatigue, especially when failure is reached repeatedly over multiple sets throughout a session. Given that training volume is important for muscle growth, being very fatigued after a few sets taken to failure may lead to less overall volume performed in a given session, leading to suboptimal muscle growth. 

Previous research has shown that training to momentary failure is not superior to training to non-failure when training volume is the same 2. However, as mentioned above, the definition of failure in the literature is not always the same, limiting the conclusions and practical recommendations we can draw from the literature.

This is why the authors of this systematic review and meta-analysis performed a scoping review where they grouped the current literature into 3 different themes. Theme A included studies that specifically defined failure as ‘momentary failure’ and compared failure to non-failure conditions, Theme B included studies that used any definition of failure, which was called ‘set failure’, and also compared failure to non-failure conditions and lastly, Theme C included studies that compared different proximities to failure using velocity loss thresholds. Velocity loss is expected as one approaches momentary failure, ie: the last reps of a set will always be the slowest, and previous research has found that training performed to a higher velocity loss (>25%) were better for muscle hypertrophy than sets terminated at a lower velocity loss (<25%) 3. Their scoping review revealed that training to failure is not superior to non-failure training for muscle growth 4. Still, the authors mentioned that it was unclear whether meta-analyzing the data from the studies included in each theme category would alter their conclusions.