I rock and feeling absolutely amazing. Silly I know but I didn't think in a million years I would be able to do and I did it, without to much trouble. The only problem I had was that I was holding my stupid iPhone too tight and I kept hitting the pause button. V irritating. Oh, and the tightening calf muscles. What's that all about? Does anyone know of some exercises I can do to stretch my calf muscles before I start running? Other than that no side effects, aches or pains after the event.