Did you ever wonder why you were feeling more tired in certain conditions than others, knowing that you had the same amount of rest, or sometimes more, than usual ?
Let’s have a look at The Central Governor Model of Exercise, proposed by Tim Noakes, who shows, after having studying a large amount of world-level champions, few interesting characteristics .
The fatigue would come from the brain, who send signals to the muscles, according to some (psychologic & environmental) factors. The muscles then process the information and send a feedback to the brain. Depending of external factors, you might feel a different level of fatigue, who is not correlated to the actual physical fatigue of your muscles.