BengeBoy 

The article was about cross-training -- was making the point that if you want to perform at your ultimate in any given sport, you shouldn't engage in cross-training because then your muscles would be suboptimized for the sport you want to excel out. Most of the article was about triathletes, and how if they they want to excel at a marathon (for example) they cut out biking and swimming so they can improve their running.

I am not a good enough swimmer to ever consider a triathlon. I'd like to see a biking triathlon:

1. One leg time trial.
2. One leg mountain bike off-road
3. One leg touring bike with 60 pounds of gear in panniers, over the North Cascades highway.