Editor & Fact Checker
Strength training is a crucial exercise for muscle strength and balance. It helps you build and maintain muscle, which is especially important to do as we age.
Whether you’ve just started training, or have been training for a while, you’ve probably came across the term “training to failure” at some point.
Is training to absolute failure really beneficial for your muscles, or are you doing more harm than good? Could it be that something your trainer recommends is compromising your results?
What makes it difficult to determine whether training to failure is worthwhile is the fact that very few reports have actually addressed the question, however, we’ve dug up a few interesting studies to present to you the possible pros and cons of this method of resistance training.
Firstly, What Is Training To Failure?
Let’s start by looking at the scientific explanation of training to failure. 
Training to failure refers to muscular failure, which, in resistance training, is the point during performing an exercise when the neuromuscular system isn't able to produce any more adequate force to continue to move the weight or overcome any specific workload. In other words, you can’t complete another rep – because your muscles physically just aren’t able to.
Here's an example: your training program requires you to do three sets of ten repetitions of an exercise (let's say, barbell curls). Training to failure, in this case, means you'll be choosing a weight that's heavy enough so that your last repetition tires you out to the point that you struggle to complete it.
When you can no longer complete another rep, the exercise typically ends, and a brief rest period begins. During this rest period, certain metabolic by-products (such as ions, hydrogen, lactate, inorganic phosphates, potassium, and creatine) are removed and restored inside and outside of muscle fiber tissues.
The muscles, even though they can no longer produce enough force to complete the exercise, aren't entirely fatigued at this point. If you or your personal trainer lightened the resistance, you would be able to overcome the lighter exercise.
Many bodybuilders and weightlifters believe that, if you want to get more done in less time, training to failure is the only way.
The Pros Of Training To Failure
Anyone who knows a little about weight training will probably think that training to failure is one of the most powerful tools in a bodybuilder’s training regime. Many personal trainers swear by it – and probably wouldn’t advise you to do it any other way.
So, what are the pros of training to failure? Even though there’s little research comparing training to failure with sub-maximal training out there, several studies show there are some pros worth mentioning.
For example, according to a review of several studies, training to failure uses more motor units (MU) – and recruiting more motor units could mean an increase in muscle and strength gains over time. 
What this means is that training to failure might be beneficial for advanced lifters – for breaking through training plateaus. It should only be incorporated into short-term micro-cycles periodically – and should only be something they do occasionally. Because of this greater activation of motor units (as well as secretion of growth-promoting hormones), training to failure could be something advanced bodybuilders may want to try.
Some research also suggests that training to failure could boost muscle strength. One study showed that advanced lifters experienced greater increases in muscle strength and mass when lifting to failure – compared to the group who exercised without failure. 
To sum up, here are the pros of training to failure:
- It promotes muscular hypertrophy
- It could help advanced lifters break through training plateaus
- Could boost muscle strength and mass
The Cons of Training to Failure
Regardless of how popular in the fitness world it is, there are plenty of drawbacks to failure training.
One of the most problematic things about training to failure is the fact that it’s based on very little scientific research, despite being considered the cornerstone of resistance training.
In fact, over the years, research hasn’t supported training to failure as an effective way to gain extra muscle – and has even shown that it may have a detrimental effect on your overall fitness achievements.
A recent study (2018) into performance outcomes following resistance training using relative intensity or repetition maximums actually shows that training to failure not only doesn’t produce positive results – but also may reduce the effectiveness of the rest of the workout! 
The participants in the study weren't newbies in the fitness world, but rather well-trained lifters. They were divided into two groups – one group trained using repetition maximums (trained to failure), while the other group only trained to relative intensity (65%-93%). Otherwise, the programs were identical.
The results were quite significant. The RM group achieved worse results overall – while the RI group performed significantly better across the board (the only exclusion being strength performance). The RM group didn’t outperform their relatively intensely-training counterparts – and it was apparent that relative intensity training yielded greater success.
To sum up, here are the cons of training to failure:
- Lack of research supporting its effectiveness compared to sum-maximal training
- Could lead to damaged muscles – especially when no professional trainer is present
- Could lead to central system fatigue
How Often Should You Train to Failure?
So, now that you’re aware of the pros and cons of training to failure, you may be asking yourself how often should I do it.
Well, there's no straightforward answer, I'm afraid. Opinions differ. Training too often could be harmful to your body because it could lead to muscle damage, and nervous system fatigue – so it’s important to avoid that. 
Now, fitness professionals recommend doing training to failure for a week – that’s three to four workouts in total – then doing a very light recovery week before going back to your usual for the remaining two weeks of the month.
Remember that this applies to those who have been doing strength training consistently for a while (and we mean years, rather than weeks!). If you’re a newbie in the bodybuilding and weight-lifting world, training to failure isn’t something you should be doing yet.
Training to failure has always been something that’s widely discussed in the fitness world. There have always been plenty of proponents, critics, and those who are undecided. And that’s not surprising, really.
If we look at scientific data that backs training to failure as an effective training method, the amount of data is a little disappointing. Training to failure hasn’t been studied in-depth to determine whether resistance exercises should be performed to failure as a rule – which is quite interesting considering the fact it is so popular among the bodybuilding and weightlifting community.
However, some studies suggest that more advanced bodybuilders could benefit from training to failure occasionally to help them break through training plateaus. But if you’re new to strength training, your best bet would be to choose relative intensity training instead.