Talk about F.A.T.S
Great clip, and very good self analysis by Johnson. He creates a very dynamic action through impact and unreal force across the shaft with that move.
His magic dynamic achieved by bending the plane line twice, first left then right and stressing the shaft in the same general direction both times.
At the top his extremely bowed left wrist bends the plane line way left, down at the bottom his pitch right elbow jams his right forearm in front of his right hip and he bends the plane line back out to the right...left then right equals somewhere near middle. All this is done torquing the heck out of the shaft. WOW!