The cast of Hawaii Five-0 is getting down and dirty as they film for season 6.

'Hawaii Five-0' Season 6: Michael Maize To Recur, McGarrett Underestimates The Highly Connected Criminal?

The CBS drama is in the midst of filming its fourth episode of the summer (airing order unknown), and McGarrett (Alex O'Loughlin), Kono (Grace Park), Danny (Scott Caan), and Chin (Daniel Dae Kim) spent the last few days getting in touch with their competitive side. It appears Oahu's heroes will take on a Tough Mudder-esque challenge in the near future.

Executive producer Peter Lenkov even posted a photo of the gang's race day gear - blue and black wet suits that boast the words "Five-0hana" (see photos below).

'Hawaii Five-0' Season 6: Why Isn't Danny In Every Episode? Scott Caan Explains

"Cue the Rocky theme!" actor Masi Oka teased on twitter, posting a photo of McGarrett and Co. working out.

Between mud pits and sprinting, the actors certainly have their work cut out for them. Their characters, however, must balance out their training with solving the case of the week. It's currently unknown why robbery/homicide/kidnapping/terrorist activity will need Five-0's attention, but what ever it is, it will require Chin to pull out his brand new electric motorcycle.

Find out more when Hawaii Five-0 returns to CBS on Sept. 25 at 9 p.m. ET.