The answer is friction. When Bruce does his 1-inch punch, there's a frictional force between the floor and his feet pushing to the right. This frictional force pushes the center of mass to the right.

The One Inch Punch perk also has a fascinating history. One Inch Punch is a term that describes a real-life combat technique popularized by martial arts legend Bruce Lee, though it was not ...

Posting on Reddit, a user by the name of Jazzlike-Fee-3493 has shown off an Advanced Va’ruun Inflictor with the One-Inch Punch mod built into it.