[Closed] Cramp in Calf Muscle - Only on turbo trainer..

I've been using a turbo trainer to try and get fit again as unfortunately I do not have the time to get out of the house on the bike as much as I would like.

Anyhow. I have been when out in the real world and never get near to having cramp. I tend to do about 1 hr long sessions on the turbo using 2 or 3 different plans, one being the Sufferest Angels. On every plan I use I am ok, however the last 3 times I have done the Angels plans I have nearly got cramp in my right calf. Last night though I got a really bad cramp to the extent today my leg feels bruised and is actually quite painful.

The weird thing is, I only get the cramp after the end of the last work session of the DVD, about 2 mins in to the cool down. Is it just my body cathching up and saying its knackered and I have pushed myself too hard? I just dont understand why I dont feel the cramp coming on when Im working hard but when I ease off I feel it coming on ?!!?