just real quick.. I don't think jumping jacks should go for five minutes. I always use that as a warm up to shake up the muscles.. as part of the stretching portion..
I might be wrong.. but maybe if you havent yet, consult a guide for a fitness regiment so that you include warm up portions.. also different regiments maybe for those who want to work on a specific thing on a particular day, cardiovascular, upper body.. etc..
I like the layout tho.. this is a great use of Stencyl and I'd definitely try an app like this. I hope you can finish it.