Comment by 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.