Why are fatigue and cramp so evident in elite sport?

Last Monday evening, while we were discussing the Kerry-Tyrone game, a large number of comments came in about cramp and fatigue. Mostly, people were asking why were Kerry players cramping so much?What is cramp? Why does it happen? A reason that was put forward is that the players weren’t used to the intensity for such a long period of time. There was over 80 minutes of normal time and an extra 20 minutes of extra time. We were joined by one of Kerry’s best marathon runners, Derek Griffin, who’s also a clinical specialist physiotherapist at the Bon Secours Hospital, Tralee.