Running gags call for Donald (Hal Sparks) to be called "out-of-shape" and Chase (Billy Unger) to be called a weakling nerd; however, these are arguably the two most in-shape athletic people in the show (only approached by Kelli Berglund's accomplishments as a multi-style dancer). Hal Sparks practices kung fu and has earned several martial art black-belts while Billy studies and participates in extreme martial arts, advanced stunting, motocross, surfing and skateboarding. These two provide most of Lab Rats' physical comedy, with their physical agility making it look easy.