I just completed my first marathon two weeks ago. I was very happy to complete the race but at mile 14 my calf muscles started to cramp. I was able to stretch it out and even ran backwards some to get thru it. They got worse and more often as I went. This was a fairly flat course with one hill in the middle. I am getting ready for a ultra marathon thru the mountains of Pa. in Oct. Talked in to it by my 30 year old nephew. What was I thinking. Does anyone have thoughts on what I may have done wrong or what I could do to prevent this from happening again. I'd appreciate any help.