Another nod for swimming, I find it excellent training as it also (depending on how hard you swim of course) gives the back/shoulders a good workout. So a nice alternative to running/cycling that also complements and conditions many of the muscle groups you'll need for the bodyweight exercises.
I am following the swimming pattern in the '6 week POC' regime stickied at the top of the Training section and the one thing that took me by surprise was just how hard the lengths of front crawl & breast stroke legs and arms only were. Found it very good for really focussing on the specific muscles and felt like good core training as well. When doing the legs only parts, nothing was keeping the upper body floating/my head above water so I had to keep my stomach/lower back tensed to stop from drowning. Then on the arms only parts, the legs just pivot and sink meaning you have to work hard to keep yourself going.
Thought it was going to be nothing special, but having done it I can see why those lengths are included in the middle, works for me.
