The Tough Mudder adventure race is a 12 mile run with around 20 physical obstacles and objectives in the middle. I participated in the 2012 and 2014 events in Seattle Washington.
The first Tough Mudder occurred during my training for the Seattle half-marathon. That involved running twice a week and going to the gym once a week for three months before the event. I felt very prepared and easily completed the event at what felt like a relaxed pace.