When we think of fatigue, we generally think of burning muscles, lactic acid building up, and several other descriptors that have rightly or wrongly entered the lingo of endurance athletes and coaches over the years. In essence though, fatigue is all about slowing down, or preventing that from happening.
From a coaching standpoint we often think of the physiologic items that either cause this slow down or prevent it. Traditional coaches might think of increases in VO2max, HR, or acidic conditions and think of ways to influence these physiologic changes that are going on. However, what we seldom think of or address is how fatigue manifests itself.
We have all seen athletes start to change their form when the proverbial bear has jumped on someone’s back in the final portion of the race. Or as my college kids like to call, when someone “hits bricks.” You might see the athletes back arching, the turnover slowing, and the arms swing getting increasingly. But even before that point, there are subtle changes going on mechanically.
These changes occur as the body tries to navigate the ever changing environment. Why do we start to swing our arms more forcefully? Simply because our stride is shortening under fatigue and we are trying to compensate by increasing our arm swing, hoping that it causes us to maintain stride length and/or speed. It’s all compensation for trying to keep things together.