At no point do his hands leave his wrists.
This is a cool video of the author of “The Speed Bag Bible” himself Alan H. Kahn, showing us his skills at the bag. He has the ability to hit the bag with hands, forearms and elbows in any direction. It is a real treat to watch him work the bag as casually as he is dressed. This must be how he got the nick name “The Godfather of the Speed Bag”.