The foot race isn't new. Cave men probably invented it. But suddenly it's gushing wealth for entrepreneurs, big companies and private-equity firms.

The weekend-warrior market is a gold mine, and tapping into it doesn't require Silicon Valley-style geek credentials or venture capital. Nor must a sports-business career begin anymore in the mail room of a sports network or big-league franchise.

Hard to tell from this article what the size of the running market is.