hey Gett, yeah crossfit is pretty big, I live in a tiny town but they still have their own specialized gym just for crossfit. I have heard there are a lot of injuries in the sport, I guess its because sometimes there just trying to get reps in a short time so technique goes out the window. They are very fit though, and in great shape. Seems a lot of women have really taken to it also.
Speaking of Rugby and NFL comparisons (and I love both sports), a decent line backer season is to make 100 tackles in a season. I remember a rugby world cup game (semi Final) where a French dude made about 45 tackles in one game!! So that's the level of cardio fitness you need to have.
How are your workouts going gett? Any new programs?