So I got this for Christmas, and thought oh this looks nice and easy. Bahh hahahaha! Easy my eye. Anyway, after I finally figured out how to get it to say on, I did the upper body work out, only a 15 minute workout. Felt good after wards and went to bed. The next morning I wake up and what hurts? My hamstrings! Okay... I'm thinking something here isn't right! :) I'll have to give it another go. I'm really going to laugh if I do the leg set and my biceps hurt!