The soccer-players turned runners thread got me thinking, why is soccer such good prep for a successful running career? Because you're running so much, yet rest enough to not overdo it? What other activities are good?
Related, why is cross-training seen as a sub-par activity, only for injured athletes and losers? At least that's my experience. I'm currently training for a triathlon and it's the first time in three years that I've been able to train consistently without IT-band problems. It's great.