According to a representative from the show, the 2PM members filmed the episode on June 3rd after returning from Kumamoto, Japan for the K-Pop Festival 2013.
The representative commented, "In this filming, two members of 2PM along with martial arts director Jung Doo Hong and fellow martial arts athletes [are] featured as guests. As you can already anticipate from this lineup of guests, the concept of the episode is a strength challenge and will be an exciting battle."
Can't wait to see them on "Running Man"!!