The deal gives the athletic clothing maker exclusivity in the footwear and apparel categories at Tough Mudder events.

FORBES: Under Armour Signs Groundbreaking Deal With Tough Mudder

The partnership with Tough Mudder, which holds endurance races over obstacle courses, represents the first endurance event sponsorship for Under Armour.

FORBES: Under Armour Signs Groundbreaking Deal With Tough Mudder

Tough Mudder, founded in 2010, plans to run 35 events world-wide in 2012 and projects 500, 000 participants, up from 140, 000 in 2011.

WSJ: Office Workers Run Extreme Obstacle Courses