Exercise to Failure: Is it worth it?
- AF Health & Fitness
- Jun 19, 2020
- 2 min read
Often you hear fitness coaches emphasise to perform a particular exercise until you can’t do another rep, but is this ‘training to failure’ the best approach? I am going to discuss this concept of ‘training to failure’ versus a concept called ‘reps in reserve’.Reps in reserve is simply where you stop 1-3 reps before hitting muscular failure when performing an exercise.
What do the Studies say?
What research has shown is that as we do additional reps and get closer to failure during a set, the more motor unit recruitment and overall muscle activation our muscle experiences. Meaning that in theory, going to failure would lead to maximal motor unit recruitment and mechanical tension resulting in more muscle growth (1).
Secondly, similar to motor unit recruitment, muscle protein synthesis is lower when you don’t train hard enough in your sets as opposed to when you go to failure. Which again would theoretically mean more growth when you train to failure (2).
However training to failure is mentally and physically very demanding and results in high levels of fatigue in the muscles. In fact, research has shown that training to failure causes excessive muscle damage which extends your recovery time considerably. Subjects generally required roughly 24-48 hours longer for their performance to fully recover when training to failure as compared to stopping short of failure during each set (3).
Worryingly, research has shown that when this is done over long periods, it eventually can lead to a state of “over-training.” This state results in a reduction in your muscle building hormones. which hinders muscle development and can even increase the risk of injury (4).
A number of studies showed that muscle activation and muscle protein synthesis in the deltoids and trapezius muscles peaked 3-5 reps shy of failure. This suggests that there is no additional benefit of going to failure in these cases. An additional study showed the effects of training to failure on one leg versus the reps in reserve concept on the other leg observed that after 14 weeks, the reps in reserve leg actually ended up seeing slightly better muscle growth and strength when compared to the failure leg. That’s despite both legs performing the same amount of volume (2). And although you may think that training to failure each set leads to increased workout volume (more reps done in a session) this is not necessarily the case.
For example:
The two concepts both end with the same workout volume, however it is the reduced time needed for recovery after training which indicates that using the reps in reserve concept is the smarter approach.
Conclusion:
Based on these findings, it seems that not training to failure by leaving roughly 1-3 reps in reserve is your best bet. Since this enables you to maximise your motor unit recruitment and workout volume. But with less effort and without compromising your recovery. However, don’t go too far to the other end of the spectrum. Research has shown that stopping well short of failure, so for example, stopping at 5 reps in a set when you could have done 10 reps to failure, is inferior for muscle growth.
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