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Fatigue Masks Fitness

Oct 20, 2019

Fatigue Masks Fitness

 Luke Tulloch

As I write this, the rugby World cup 2019 is getting towards the pointy end of the competition. While the top teams in the world have never been closer on paper, there have been some seriously one-sided results. This morning I watched a great Irish team play at half the pace of a blistering All Blacks assault; the Kiwis were so relentless that victory never looked in doubt.

There’s a common theme I’ve noticed in online discussion of professional sport. Incredibly, some simpletons believe that professional rugby players in a team ranked near the top in the world, after playing the domestic European season, after playing in the Six Nations against other top international sides, AND after enduring gruelling World Cup training camps, are somehow “not fit enough”.

Any knowledge of strength and conditioning aside, the absence of logic is stupefying.

But this little anecdote aside, I want to address the linked concepts of fatigue and fitness and how they pertain to all of us – even if you’re a pro athlete exclusively in your head. It’s not only Facebook commentary that displays a misunderstanding of these ideas. My inbox on Instagram is often filled with people frustrated at slow progress, plateaus or recurrent injury. Understanding the interplay between fatigue and fitness is at the heart of the solution for these types of questions.

Consider my rugby reference above. If you were put through a tough training camp in humid Japan after playing rugby at the highest level for 9 months straight with barely a week off, I imagine you might feel a little overdone. This is a primary tenet in exercise science: fatigue masks fitness. Players are unable to express their physical ability if fatigue prevents them from doing so.

Perhaps I should lay out the direction of this article.

First, I’ll define fitness. Then I’ll explain how we improve it with training. From there, I’ll define what contributes to fatigue and link it together with our theme: fatigue masks fitness.

Fitness Is More Than Cardio

To the layperson, fitness typically conjures up the idea of cardiovascular endurance. From a technical perspective, fitness refers to any discrete physical quality that significantly contributes to our performance. In a sport like rugby fitness can refer to endurance, speed, power and strength for example.

There are plenty of dimensions to consider: body composition, cardiorespiratory, muscular strength and endurance, flexibility.

There are also skill-related aspects to fitness: agility, coordination, reaction time, ball skills and so on.

It’s important to note that every physical activity has a different emphasis. Shotput places no importance on aerobic fitness and power is a highly desirable quality. Different positions in team sports have different fitness requirements based on their role.

Since my audience is mostly physique and strength sports oriented, I’ll refer to fitness in that context from now on.


Improving Fitness

To improve any of these physical qualities, we train them. The body is a highly adaptable system and it readily responds to environmental cues. You place tension on a muscle by lifting a load and in response proteins are synthesized, neural pathways are strengthened, bones are reinforced, and fuel depots are restocked. All it takes is to perform a task that’s specific to the adaptation you want to drive – then to do it repeatedly to invoke a response from the body.

It’s from this process we derive a training prescription like “Back squats, 5 sets of 10 reps with 100kg” if we aim to grow our glutes and quads. We use a stimulus and are rewarded with adaptation. Our legs grow, we get stronger and we can tolerate a greater stimulus in the future.

The spanner in the works comes with what happens in between the stimulus and adaptation.

The SRA Model

SRA stands for “Stimulus, Recovery, Adaptation”.

Improving fitness is easy enough – provide the appropriate stimulus and you’re on your way. The problem is that it takes time and resources to realise adaptation.

In other words, a stimulus induces fatigue. Let’s say I asked you to do a hard leg session. If I asked you to repeat that performance 3 hours later, you wouldn’t be able to do it. How about 12 hours later? Unlikely.

24 hours? It’s looking more of a possibility, but I still wouldn’t bet on it.

But at some point, you would be able to put on a repeat performance. Your system is temporarily diminished, it needs time to recover and bring you back up to baseline. If you’ve accurately gauged the dose of the stimulus, you should be recovered in a couple of days’ time and hopefully gained some fitness. In sports science, this is called physical preparedness.

In simpler terms, if your workout is hard enough (but not over the top) then you’ll recover and improve a little bit. These small improvements add up over time, making you bigger/stronger/fitter.

This process is illustrated in the SRA curve.


You’ll notice the end of the curve marked “involution”. This just means that you need to stimulate the system again to maintain your adaptations or you’ll lose them and detrain. You wouldn’t expect to maintain your strength gains if you only squatted every three weeks, so we need to have a reasonable interval between training sessions to continue to improve.


Fatigue and Fitness

So far, we’ve been looking at the concept of fatigue on a per session basis. We call this acute fatigue, and it occurs in the minutes and hours following a training session. What I want to get at is how fatigue accumulates over time to mask fitness.

Let’s go over a quick definition of fatigue. In this scenario, we’re talking about cumulative fatigue.

This is the result of accumulated stress across various systems in your body (muscles, nervous system, connective tissues and so on) that prevents sustained performance over weeks or months. It includes not only pure physical stress, but psychological factors, nutrition, sleep and so on. The result is the inability to continue to produce the muscle force, cardiovascular output, skill execution etc. that the individual is capable of.

Let’s say you recover to 95% each time you train. You can’t wait until you’re 100% fatigue free because that means you hit the end of the SRA curve – the point of involution, or detraining.

Eventually, over weeks or months, systemic fatigue accrues. It reaches a point where physical preparedness is so low that on any given day, your ability to perform is significantly diminished.

To bring it back to my story about the Rugby World Cup: by the time the players have reached the biggest tournament of their careers on the back end of an 8-month long season, they’re well and truly adapted to the demands of test match rugby. The issue is managing the interplay between maintaining their fitness (training and playing games), managing their fatigue (psychology, travel, nutrition included) and maximizing physical preparedness.

In some cases, there’s just not a lot you can do to ensure maximum preparedness. If you have a tough game in the pool stages and have to play again three days later, you must accept that the players are not going to be able to display their strength, endurance and skills to their maximum capabilities.

Managing Fatigue

The solution to the problem of cumulative fatigue is simple. Reduce the stimulus, allow recovery to occur and fatigue will dissipate given enough time.

In fact, maintenance of a physical quality takes much less stimulus than developing it in the first place. This means we can afford to reduce the training stimulus temporarily for the greater goal of dissipating fatigue.

Enter the concept of a deload. This is a commonly used term, and often you’ll find pre-planned deloads within training cycles to account for the inevitable accumulation of fatigue. It simply involves reducing either the volume or load used in training (or both) to allow recovery to “catch up”. It’s typically done over one week of training since most programs are done on a repeating weekly cycle.

Although this is the standard, it’s not the only way to do it. The broader concept of having some less stimulative training sessions every so often can be applied in a variety of ways.

An experienced trainee could learn to recognise features of cumulative fatigue and reactively take a couple of easy days, for example.

This is where many novice and intermediates get stuck. The idea of simply working harder and never missing a training session is a romantic one, but it seems to often get to the point of being unhelpful, if not downright harmful to progress.

If you’re tired, achy and not progressing you are experiencing indicators of fatigue. If you’ve never deloaded or rarely take easier sessions, you’re quite likely a bit overcooked. Since many of the factors that contribute to cumulative fatigue are variable (sleep, psychological stress) you need to be able to assess somewhat objectively and consider events in your personal life as well as your training. Fatigue is not always easily predictable ahead of time.

If this sounds familiar, take note – gaining more by doing less is a great position to be in!

Fatigue Masks Fitness

Players at the end of a season are not in peak physical condition. Repeatedly running into monstrous athletes with the express intent of hurting you for months on end is a recipe for fatigue.

So, armchair experts – please spare us this nonsense of not being fit enough. The last thing these guys need is more fatigue-inducing running. We’re no longer in the era of pointless laps around the park and pushups ‘til failure. Leave that in the 80s where it belongs.

The All Blacks looked in top shape against the Irish this weekend. There’s no doubt that their game planning is precise and their players are superlative athletes, but I also think it’s telling that the Irish have had a tough campaign whilst the Kiwis had an extra week of recovery due to typhoon-affected fixtures.

Let me leave you with some practical advice. If you’ve recognised yourself in the previous section, please try an easy week of training. Halve your training volume and make sure you get nowhere near failure.

At worst, you’ll maintain your current gains. But far more likely you’ll come out of that week feeling energised and physically prepared to make gains.

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