[towlejunior]

If the claim is that muscles don't fatigue, then I am skeptical.

In college, I took a weightlifting class with a bunch of athletes in it. One day, we did lunges (no weight) around and around, in a line like ants. Nearing the end, my brain thought I was totally fine. I cannot stress that enough. Bam, like a light switch, my legs went from 60% strength to 2% three quarters of the way through the last lap. Had the instructor not caught me, I would have fallen right over.

[lj3]

Why do you suppose your legs went from 60% to 2% so rapidly? Do you think your muscle really depleted in function that quickly, or did your brain cut off the electrical signals to the leg in order to protect it from permanent damage?

But you're correct in that there is more to it. Adrenaline masks fatigue. It allows you to temporarily exceed what your brain would normally allow you to do in order to save your life. You pay for it later, though.

[ndonnellan]

I would recommend reading the article, it is fairly interesting and suggests based on the body of research that the brain (subconsciously) creates the emotion of fatigue prior to muscle "exhaustion" to prevent injury.

"These sensations of fatigue are unique to each individual and are illusionary since their generation is largely independent of the real biological state of the athlete at the time they develop."

[fernly]

No, I think you are anecdotally supporting the posted article: you worked your muscles to physical exhaustion but you did not feel "fatigue", ergo, the conventional theory that "fatigue" is caused by lactic acid or other muscle chemistry is disproved.

[jcoffland]

What result would disprove the article?

[cpncrunch]

> If the claim is that muscles don't fatigue, then I am skeptical.

No, the article isn't claiming that at all. It is saying there is an extra system in the brain which generates the sensation of fatigue. This usually happens before the muscles reach their limit (and this has been demonstrated).

As others have noted, it may not have been your muscles. Why would your muscles suddenly go from 60% strength to 2%? I suspect either it was central fatigue (which can also manifest as muscle weakness), or perhaps your form was wrong on the last lap.