I think I'm going to commit to Cross Fit.
The more I read about running and cycling, the more convinced I am that my biggest limiter is not my aerobic endurance but in neuro-muscular adaptation and in muscular strength. I'm one of those athletes who has built aerobic endurance over years and years. I could develop it further, and I will, of course. My running economy has improved over the years just by virtue of the fact that I have built that aerobic endurance. My running and biking economy could be improved further, though. My lungs are ready to go, but my tendons, joints and muscles need work in order for me to get better/faster/stronger.
Functional routines and plyometrics have become increasingly in vogue over the last few years because exercise scientists have realized that running economy can be improved by doing neuro-muscular work--or work that cues the brain to ask the body to move in a certain, more economical way. The fastest runners are the most efficient runners. They are able to run fast without wasting energy with movements that don't help to propel them forward at a quick pace.
The easiest way to incorporate neuromuscular work into your training diet is to do things like short hill sprints (on the bike or run), running/biking drills, strides or short sprints on the bike and lots of jumps. Just today Jen had me doing all sorts of quad jumps with weights in my hands.I anticipate that I will curse her tomorrow when I can barely walk as a result of this little jumping frenzy.
The Cross Fit folk are pretty hard core. They advocate a palieo-diet, which, I will add, I have tried and failed at several times. I like nuts, seeds, fruit, veggies and meats just as much as the next girl, but not eating anything at all processed, not even bread, is just a little too psycho for moi. As I often say, life is too short to deny one cake. or beer. or pizza. Of course one shouldn't eat that stuff ALL the time--but permanent denial is just, well, too permanent.
For training, the Cross Fits don't use weight machines of any kind. They use barbells and discs and one's own body weight to build strength. This means things like pull-ups, push-ups, hand-stands, lots of jumps. I actually don't know what else it entails, which I why I'd like to try it.
I know a few of you have tried Cross Fit. Tell me your experience with it if you have.