I can see by the way this coach is presenting the drills that he is heavily influenced by Loren Seagrave’s Speed Dynamics. This is not the way A’s and B’s were designed to be done by Gerard Mach. I know this first hand. (Gerard worked with my training group in '91 or '92. A’s and B’s were a major portion of our training)
I had a long discussion with Charlie about this at Vancouver 2002. (I was experimenting with a Seagrave style stepover technique on drills with my athletes at the time) I was surprised to learn that Charlie’s focus for the drills are relaxation and rhythm. Charlie explained that there is “no time” to step over during these drills and still have proper ground contact times.