Knockout Punch is a min-game found in the Whirligig Way alley. It requires you to throw a series of punches and duck punches according to a pattern displayed on the robots mid rift. You score points for successfully completing the required move set and the mini game lasts 60 seconds.
Be aware of your hands as you squat down to duck. The Sensor picks up hand movements as punches when you are moving and counts these as an incorrect move. After several attempts, my highest score was 18 rounds and that was pushing it! This seems to be pretty much the most physical achievement in the game in my opinion but it is not impossible.
If you get a 'duck' instruction, you can punch on the way up and this will count as an action. This can save you valuable seconds!