Nearly 50 years ago, when describing how he built his incredible physique, Arnold Schwarzenegger said that the last three or four reps are what makes a muscle grow—and that enduring the intensity and discomfort is what sets champions apart from the rest. Undoubtedly, this sentiment has since inspired quite a bit of bravado in the gym. In fact, it reflects a concept any good gym rat is plenty familiar with these days: ‘training to failure’.
But how physiologically accurate was Arnold’s assertion? Do you actually need to train to the point of pain and failure to make progress? There’s a lot to unpack here, so I’m going to lay out everything you need to know about this popular training pillar—and how to maximize your training sessions and muscle gains.
First Things First: What is Failure?
We should probably start with a brief check of the bodybuilding dictionary here because training to failure probably means something different to just about everyone. Some people might consider failure the onset of pain or ‘the burn’ (certainly not Arnold…), whereas others could describe failure as the point at which you actually keel over mid-workout.
Lucky for you, failure isn’t quite as extreme as that second scenario (good thing, right?). In scientific literature, failure is often described as the point at which you can no longer perform a repetition with the appropriate form. So what does that look like? Let’s say you’re performing squats to failure. Eventually, you’re going to get to a point when your quads have fatigued and you begin shifting the load to your hips instead. We’ve all seen this; in order to perform the full range of motion, you end up leaning forward, compromising your squat form. Though your hip extensors may still have some juice in the tank, this forward lean marks the point of failure for your quads.
Of course, failure is much easier to pinpoint in isolation exercises (like dumbbell biceps curls) or machine exercises (like seated leg extensions). In these cases, you’ve reached failure when you can no longer complete a full range of motion repetition (in a biceps curl, you might be able to curl up halfway and then crap out).
Regardless of what kind of exercise you’re doing, though, an easy way to define failure is simply as the point at which you’re no longer able to perform a sound full range of motion repetition of the exercise you’re doing. Odds are, at this point, your muscles will already be screaming at you and you’ll probably feel pretty ready for a break.
Are The Benefits Of Training To Failure Legit?
I’ll skip the boring physiology background here and get right down to business: Your muscles need to be challenged in order to grow and become stronger. Lifting light weights and never approaching failure simply isn’t enough of a challenge to force your muscles to adapt. This means that, yes, lifting to failure essentially guarantees that you’ve stressed the muscle to the point of it needing to adapt. Training to failure allows you to leave the gym with some peace of mind, knowing that you gave your workout everything you had.
Another less-discussed benefit of training to failure is that it provides some mental fortitude practice. Reaching the point of failure is uncomfortable, and every repetition you make in the march toward it is a small victory in the face of adversity. I’ll spare you the cheesy metaphors and analogies about what this means for everyday living, but I will say that a tough set to failure is a great way to improve your mindset in myriad settings.
Training to failure is also a great way to track your progress in the gym. Of course, measuring progress is extremely important during your fitness journey because it allows you to, a) see the results of your hard work and, b) determine the effectiveness of your training. For example, you can use sets to failure to determine your improvements in strength. Many people will use a one rep max (1RM) test to measure strength change, but you can just as well perform a 3RM, 5RM, or even 10RM to measure strength. That way, you still get a great workout without taking on the inherent risks of a 1RM test. As long as you can move more weight at a given rep max, you’ve probably gotten stronger!
Finally, training to failure in compound (multi-joint) exercises like the squat or bench press can highlight your technical flaws. Let’s say you’re training mostly for strength and want to improve your squat strength. Training to failure and filming your sets will show you where your form begins to break down. You can then use this information to identify your weak points and design appropriate workouts to improve upon them. In this way, failure is a great feedback mechanism, especially if you align it with a specific goal (like improving squat strength).
Are There Drawbacks To Training To Failure?
If you’ve ever trained close to failure, you know one thing for sure: It hurts. Training to failure is not only extremely uncomfortable in the moment, but the muscle soreness you experience after your workout is almost certainly more intense. For that reason, if you want to train to failure in a given workout, plan on at least one extra rest day before you hit those muscles again. They’ll thank you for the extra day off in the long run.
The reason this is important: If you train to failure too extensively or too often, you actually run the risk of losing muscle. When we perform intense training, we damage muscle tissue from mechanical aspects (tiny fiber tears) and biochemical aspects (inflammation, metabolic stress). When you increase the mechanical and metabolic stress imposed on the muscle, you also increase your recovery threshold substantially. In fact, your body might use all of the resources you provide (rest and nutrition) simply to repair the muscle, rather than actually grow it. Since repair and growth are two separate processes, you need to ensure your repair needs don’t outpace your growth goals.
Another issue with training to failure is that it immediately impacts your performance in the rest of your workout. Let’s say you hit a 10-rep max (10RM) on the bench press for your first set. It’s quite unlikely you’re going to be able to hit that again. You might get seven or eight reps on your second set, and then probably five or six on your third for a total of 22 to 24 reps. You could have also just done three sets of eight reps at that same weight and you would have performed the same overall volume and gotten the same stimulus—all without having to drag someone over to spot every set.
Plus, not only does training to failure directly fatigue your muscles, but it can also fatigue your central nervous system (CNS). This makes it harder to activate your muscles and actually lessens the effectiveness of the rest of your workout.
Lastly, training to failure is inherently riskier than regular lifting, especially if you’re performing free-weight exercises. If you actually reach failure and are unable to complete a rep, you’d better hope someone is there to spot you! Otherwise, you might be stuck under the weight for an uncomfortable period of time. Those moments might make for an excellent YouTube video, but they’re miserable and potentially dangerous.
How To Try Training to Failure
My first recommendation around training to failure is to only do so on single-joint movements or machine exercises. A training program is only as effective as it is safe, and there’s really no reason to push a multi-joint exercise to failure unless you’re tracking your technique or weak points.
Second, I’d limit to-failure training to about two sets per muscle group per workout—and even then, you should only do them during a specific block in your long-term training plan. For instance, you might throw in these sets for two to four weeks at a time but then move on to something else. If you keep training to failure for weeks and months on end, you continually open the door for undesirable outcomes (like muscle breakdown).
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When you perform your sets to failure, make sure you give yourself a little extra rest time between sets. If you normally rest for two minutes, bump that up to three or four. That’s going to give you a little extra recovery time and maybe, just maybe, give you a chance at performing the same number of reps at that same weight one more time.
Lastly, as I mentioned before, give whatever muscle group you trained to failure more recovery time before hitting it again. If you normally train legs on Monday and Thursday but trained to failure on Monday, you might want to wait until Friday or Saturday to hit legs again. Make sure you have no lasting soreness or tightness before re-training a muscle group. In the meantime, optimize your nutrition, hydration, and sleep efforts to get the most out of your recovery.
The Bottom Line
In short, training to failure is not necessary for making gains. In fact, numerous studies have shown that training to failure imparts no difference in muscle strength or size outcomes when compared to stopping a few reps short of failure. However, there are a few instances in which training to failure can be helpful, as long as you adjust the rest of your training and lifestyle to get the most out of it.
Known as ‘The Muscle Ph.D.,’ Dr. Jacob Wilson has a knack for transforming challenging, complex concepts into understandable lessons that can support your body composition and health goals. A skeletal muscle physiologist and sports nutrition expert, Wilson is a leader in muscle sports nutrition. As the CEO of The Applied Science & Performance Institute and researches supplementation, nutrition, and their impact on muscle size, strength, and power.