Markinsons disease is a disorder of the brain that leads to shaking/tremors while trying to record your friends killing it on a skateboard.
Ace: Damn Mitch that's the last time we're taking you filming!
Mitch: WTF, Why, What did I do?
Ace: You can't keep the camera steady to save your life.
Mitch: My bad dude, I was just diagnosed with Markinsons disease :(