A tight trail arm forces the body to turn
The speaker explains that keeping the trail arm tight forces the body to turn to get the arms to the top and quits all the extra runoff at the top. His checkpoint: when the body is done turning, the arms are then done swinging.
Channel: PorzakGolf
Watch official source at 8:04Why this context matters
He reassures that the tight feeling in the trail arm is supposed to be there.