There are two types of one inch punch, one is when the fist is only one inch away from the force-receiving point, and the other is when the fist is exerting force and is only one-inch away from the force-receiving point.
The child in the video used the second type of one inch punch. After punching straight, he used force to break the paper within an inch.
![](https://i.ytimg.com/vi/D9bdak_d354/maxresdefault.jpg)