You can find this exercise on page 91 of the book Synergistic Golf.
Exercise Type: STRENGTH
Exercise Category: LEGS - FEET, POWER PRODUCTION, STRENGTH
Stand tall behind bench (no higher than 20inches). Step up with right and allow left leg to follow. Pause on top of bench then return to floor with right leg then left. Focus on posture and placing all weight into heel of leading leg going up and control weight on balls of feet coming down. Repeat each leg 10-15x.