Fatigue sucks. Let’s face it, it can make you feel dreadful. Try to squat when you’re fatigued and you’ll wonder if you even lift, want to call your session quits and just go home and crawl into bed. Imagine if you could train and not feel fatigued? I would love to be able to tell you how to do this, but I can’t.
What I can do, however, is tell you how fatigue is actually important to your gains, as both a training variable and a metric by which to judge your workout.
What is Fatigue?
Before I can do that, we need to understand just what fatigue is. Fatigue is by definition
The consequence of physical work, which, as a result, reduces the capacity of the neuromuscular and metabolic systems to continue physical activity. 
In layman’s terms, this means that the more training you do, the less energy you can produce to do it. Sounds pretty obstructive to your training, right? We know that generally with enough rest, be that in between sets or sessions, we can recover our energy stores and get back to it.
The idea of intra-session fatigue dispersing is generally correct. However, this is only in relation to acute fatigue – i.e. fatigue built up over a short period of time and work. The other, nastier, type of fatigue is chronic fatigue, this builds up and lasts over a period of days, weeks, and sometimes even, months.
Acute fatigue will not always dissipate in between sessions, particularly if you train with a good amount of frequency. A failure to manage fatigue will result in a drop in performance and adaptation and will also likely increase your risk of injury. Luckily, my aim is to show you how to deal with, and manage fatigue in such a way that you can understand it, factor it into your training and even use it as a training variable.
Why do we need fatigue?
The human body is naturally quite lazy; it yearns for homeostasis. We could just plod along without growing in strength or size quite easily. However, if you’re reading this, I doubt that’s what you want to do. We need to push our bodies away from this easy platform and push on, and the way to do this is with overload and more specifically, progressive overload.
Overload is when the training stimulus (weight, reps or sets) is within the maximal threshold of the adaptive system, and the stimulus is on average greater than any in recent history. So progressive overload, put simply, is the slow increase of the work done during a workout. This increase can be done via the weight lifted, the repetitions per set or the sets themselves. By training within this threshold, your body is forced to recover to a point wherein it is stronger than it was previously. Training in this area taxes us, depletes our energy and recovery ability, that is, it causes fatigue.
Fatigue’s effect on the Nervous System
The nervous system is made up of the Central Nervous System(CNS) and the Peripheral Nervous System (PNS), its job is to activate and coordinate the function of the cells in the human body.
Lifting heavy is a strenuous affair to the nervous system as it disrupts the homeostasis of the cells which in turn leads to our accumulated fatigue, taking it from a matter of acute fatigue to chronic.
A fatigued nervous system can be quite a troublesome thing to experience. It can lead to
- Reduced neural output to muscles – leading to lower strength and force output
- Poorly coordinated firing patterns – shows up as technique and movement breakdowns
- Reduces the efficiency of the CNS, meaning that it will find it harder to acquire new skills or skill patterns.
When it comes to reducing nervous system fatigue the main player is the volume of your workouts. Lowering volume will help reduce the tension on the nerves dramatically. However, intensity also plays a role here so lowering this won’t be a bad idea either.
As you’ve seen so far, fatigue itself sucks, but it is a necessary by-product of hard work in our training. So now that we know this, how do we make it suck less?
Firstly, we need a good understanding of our own limits. What I mean by this is that we could definitely become more fatigued by doing sets of 100% of our 1 Rep Max, but this does not mean we would grow as a result. With a good understanding, we know what kind of weights, and what kind of volume should be causing us to struggle, and what kinds should be easy for us. This just takes some experience, but you can ask yourself a few questions while training if you need to. These can include
- Does the weight feel heavier than usual?
- Do you feel slower than usual?
- Do you have less desire to train than usual?
If you replied “yes,” to any of these than you are likely too fatigued to train optimally and should reduce your volume. This idea links in to Mike Israetel’s work on Maximum ;Recoverable Volume (MRV), which is the “maximum volume of training a lifter can perform, recover from and benefit from.” The MRV will vary from lifter to lifter and what phase of training you are in.
Having a good idea of how much volume you can take will put you in good stead for the rest of your training.
If you do deem yourself to be fatigued after asking these questions than there are ways to mix things up to help ease your fatigue, beyond just lowering the volume. Such as:
Change the type of lifts
Machine exercises, followed closely by isolation exercises, are by far the least fatiguing and this is due to the limited muscle and joint movements produced to do them. At the opposite end of the spectrum is the compound lifts, which is fantastic news for us powerlifters here. In terms of the big three, the bench press is the least fatiguing; followed by the squat and, unsurprisingly; the deadlift. This means that if you are struggling with fatigue, and can afford to, it might be an idea to switch out the occasional compound movement for a machine or isolation exercise.
Having a better technique means for a more efficient movement and therefore less energy leakage throughout the movement. This also allows for more control against such pesky forces as gravity.
Planning ahead is always the best way to go with this. Factoring in rest days, light training sessions, recovery sessions and de-loads will give you both a physiological rest as well as a psychological one. Your nervous system will thank you for it.
Making Fatigue work for you
Various programs will utilise fatigue in order to push you further into that adaptive overload threshold mentioned above. While pretty much any kind of increase in volume will lead to further fatigue and technically more overload, it needs to be approached smarter than this. The amount of fatigue, and therefore stress needs to managed and manipulated via careful tracking and planning. This can be done via such methods as determining your MRV for yourself and the phase you’re in or by tracking and manipulating the volume with specific fatigue work.
Manipulating fatigue is important as once we have adjusted to a particular training volume we begin to adapt to that volume. If some of this volume is removed for a short time, your body will still recover as efficiently from the same volume as before.
This means that if your body is used to being fatigued down to 70% and then recovering up to 100%, you could potentially train so that you are only fatiguing to 75% and your body will still recover by the previous 30%, putting you, for a short time, at roughly 105%.
This is why ‘over reaching’ is used in sports such as powerlifting. The athlete will be worked to a point close to over training in order to take advantage of the compensation effect. Meaning that, if planned correctly, a powerlifter could turn up on meet day at something like 105%. (This is where the planning ahead mentioned in the last section comes in handy).
Fatigue feels like it sucks, but it’s actually a pretty terrific metric for measuring performance, volume and stress. While it would be easy to just lower volume whenever we feel it, it would not be beneficial to our gains. Accept fatigue, use it wisely, and reap the benefits of it and its manipulation.
 Bompa, Tudor, O. – Periodisation – Theory and Methodology of Training – p.108
The Scientific Principles of Strength Training – Mike Israetel, Chad Wesley Smith, James Hoffman
 The Scientific Principles of Strength Training – Mike Israetel, Chad Wesley Smith, James Hoffman
 This is in reference to the work of Mike Tuch scherer in ‘The Reactive Training Manual.’
About The Author
Danny Lee is a strength coach and owner of Danny Lee Fitness based in Taylor’s Strength Training in Liverpool. He has been coaching since 2013 and has competed in Powerlifting since 2014.