You can find this exercise on page 115 of the book Synergistic Golf.
Exercise Type: BIG BALL
Exercise Category: ABDOMINALS, POWER PRODUCTION, SHOULDERS
Lie face down on ball with hands in fists and elbows tucked under chest. With control and maintaining straight spine, lift upper body off ball by pushing forearms into ball and engaging entire shoulder girdle and abdominals. Exhale on the lift. Lift and lower 10x.