No,there is no such subforum. While you could say there is SOME demand in such a category,I'm afraid that the inevitability of people recommending baseless "advices" would follow.
In my opinion,such a subforum will probably be chaos incarnated.And what's worse,exercise is a dangerous thing if done incorrectly.People that "have heard it from somewhere" could really do some damage.
Don't get me wrong,I would love to see that,I am pretty fit and into working out,but I have high faith that it can't work out. If you feel like sharing,I have seen a couple of posts regarding working out and regimes in "The Lounge".