Ya, I kind of figured that one out when my leg started cramping yesterday Normally, I would not do any lifting during season, but upon a session with a personal trainer, I took their advice and added it to my routine. It was developed as an on season circuit training routine by a competitive cyclist to help with core strength and losing some weight. I think I will get together with them this week and modify it so I eliminate or lessen the leg portions and keep the upper body and core workout.