[jeremytliles]

I can save him the trouble of writing the book with one (compound) word: Crossfit.

[_pius]

Crossfit is awesome, but impossible unless you've already got some baseline level of physical fitness.

[aarongough]

I can't agree with that... Yes, it hurts, but if you start off with shorter than usual sessions you will keep up eventually. Talk to whoever is running the classes and don't be afraid to leaave half-way through a class!