Our gym coaches/owners have gotten on this new kick that our 8 - 10 athletes need to endurance run. They feel this will lean them out and give them the endurance for floor. They are making our athletes run, at a full sprint most of the time, for 15 - 20 minutes. I have always believed that endurance running will decrease the fast twitch of an athlete and therfore they lose strength and power. Am I totally off base? For the coaches, how much do you make your atheltes run? My dd seems to be losing skills and not progressing since this routine has started. Is it just coincidence? BTW the owner is a marathon runner and does not have any experience with gymnastics.