LOS ANGELES — With macho-sounding names like Tough Mudder, Warrior Dash and the Spartan Race, obstacle course races have turned mud, sweat and tears into a flood of revenue. Over the past year, ...

And what do you know? I fell in love. I found races on Groupon and signed up for every event I came across. I brought my children to some of the races so they could do the kids competitions-they loved ...