I have a sky box and I've noticed in thier planner they have a series of Fit in 5. I've downloaded a few to my skybox and I think I might try a few of the core and leg ones. I'm sure I could find a five min slot in the morning to give them a go. They seem to be in easy medium and hard. I like the fact they give you alternative moves if you need it. It's by a trainer called Marvin Ambrosuis.