Stop the glancing driver blow
Before adding speed, the instructor wants the driver strike going straight into the back of the ball. He explains that a leftward swing direction with an open face sends energy across the ball as a glancing blow, so the same clubhead speed can go farther if the strike is centered into the back.
Channel: Danny Maude
Watch official source at 0:44Why this context matters
This is taught before any attempt to increase swing speed.