'Murph' is a classic Functional Fitness workout known as a Hero WOD. Hero WOD's are made by CrossFit & other Functional Fitness Organizations to honor the men and women that have fallen in the line of duty. This one is specifically to honor Navy Lieutenant Michael Murphy, who was killed in action in Afghanistan on June 28th, 2005.

This workout itself was Michael's favorite workout to do, which at the time referred to it as 'Body Armor', hence the 20-lb vest or body armor as part of the workout prescription. So, every year, CrossFitters synonymously around the world pay special tribute to Lieutenant Murphy by joining together and suffering through this workout.