One of the best things that came out this week is an article by Chris Beardsley on fatigue. If you’re an exercise science nerd like me, I would highly recommend the read, but if you prefer to drop the science nerd from that, I’m happy to provide you with just the good stuff.
For a bit of context, fatigue is one of the most curious topics for the exercise physiologist, partly because it’s a fascinating mystery of physiology but mostly because hacking fatigue means performance gains.
Chris’ article identifies four performance inhibitors when you get worn out:
decrease in coordination
inhibition of the agonist muscle group (the ones you need to work the hardest)
a drop in maximum muscle fiber force production
a drop in muscle shortening (speed it can contract)
Although, if you’ve ever hit a hard workout, you’re likely saying, “Well, duh.” Your muscles don’t work quite right for that last interval or hard set.
I would love to dive into the changes happening, but there is way too much to discuss for a weekend newsletter. There’re many altered chemical reactions, depletion of energy substrates, and then a worried brain, who’s trying to keep the body safe.
Instead, I want to hit on the most critical point, and that’s the belief that a higher degree of fatigue means more significant performance gains—but that’s not always the case.
“I would argue that fatigue during exercise most commonly impairs most of the adaptations that we want to create during strength training for athletes and even strength athletes, and that accumulated fatigue is similarly not very helpful.”
The moral of the story is that you shouldn’t leave every workout trashed, but instead, you should feel like a superhero ready to save the world as you wrap the majority of your training sessions. That’s because building high strength, speed, and better coordination doesn’t happen too well when you’re pooped.
Training Sweet Spot
We got to the very end but never actually defined fatigue. As the article explains it,
“It’s the reduction in our ability to produce force, exert force at a specific speed, or exert force for a specific period of time. It is not a perception or a feeling.”
That’s right, folks. Despite your gym bro’s testimony of some crazy hard workout they just crushed, fatigue is objective. To know how fatiguing something is, you need a score.