When you take your really skinny friend to the gym, and he/she keeps insisting they belong on the treadmill/cycling machine.
So in an attempt to prove that your weight lifting makes you physically superior to him/her in every physical manner, you both get on a treadmill, trying to outlast each other, while simultaneously turning up the intensity of the machines.
Nobody wins because this game sucks.
Gym Rat 1: You should take Sarah to the gym
Gym Rat 2: NAH BRO, I already did, she just wants to play a game of Cardio Chicken
Gym Rat 1: Tough brah, did you at least beat her
Gym Rat 2: ...
Gym Rat 1: Brutal dude
Gym Rat 2: BRO I SWEAR SHE'S A TRACK STAR OR SOMETHING