Maybe networks need a little more cross-training: more "spartan" racing thinking. Obstacle course racing, in general, is on the rise. Why? Because runners and other athletes can get bored. Some 3 million people participated last year -- up from 50,000 in 2010. If only networks and programs could get the same results. NBCSN, the NBC Sports Network, will show six races of the Reebok Spartan Race series starting July 22. Dirt, grime, sweat, warrior-paint -- and thinking out of the box -- is optional.