This is because Machamp punches 500 times a second

Okay this one is short. We have to keep dividing till we hit 1. By dividing 500 by 60, we get 8.3333333 (etc) hertz. Well I don't know how much lower we can get for it to work, so unless someone has another way to get the answer, I am going to say he punches once every 8.3333333 (etc) hertz