You’ve read all of your free items this month. To register, get added benefits and unlimited access to articles, Become a Member. Already a Member? Sign in. Advertising Age Article Abstract Brands Stake Out a Place on Courses of Jaw-Dropping Endurance Competitions Tough Mudder, Spartan Race and CrossFit Games Are Growing Year Over Year By Cotton Delo, Published on January 17, 2014 1 Want more Access, Content & Connections? Upgrade to Membership. We are glad you are enjoying Advertising Age. To get uninterrupted access and additional benefits, become a member today. Become a Member Already a member? Log in.