You can find this exercise on page 214 of the book Synergistic Golf.
Exercise Type: HEAVY BALL
Exercise Category: ARMS - HANDS, CHEST, POWER PRODUCTION, SHOULDERS, STRENGTH
Place both hands on ball: thumbs facing forward and fingertips aiming downward. Lift into plank position with legs straight and feet together. Chest remains directly over ball. Inhale and bend arms lowering chest toward ball. Exhale and push back up to straight arms keeping body straight and abdominals tight. Goal: 10 repetitions.