How can swinging a golf club upside-down increase your clubhead speed? By improving your timing and release.
Professionals and better amateur golfers achieve acceleration on the downswing, so that the clubhead reaches its maximum speed in the space just before impact and through the other side. Less-skilled players often release the club early, meaning their wrists unhinge well before reaching the ball, or too late, meaning they haven’t full uncocked the hands and rotated the forearms at impact.
Both moves are major power killers.
The following drill will teach you to accelerate the club into the ball without adding effort:
Go a step further by pairing this drill with the two-club drill. First, make 10 swings with two clubs, then 10 with an upside-down club. The two-club drill will boost your strength and control, while the upside-down club drill improves your timing and release.