My main problem since March 2003. Left training for a marathon too late, tried to do too much too quickly, and ended up with ITB problems. Didn't really know what was wrong, so after it occured again a week later I stopped training (still did the marathon a month later with knee support). Has come back every time i've pushed myself since - probably because I never build up my training and just seem to think I can run 20k whenever I want. So i'm now working on my training to build up my strength, esp in my knees / core.