You can find this exercise on page 287 of the book Synergistic Golf.
Exercise Type: STRENGTH
Exercise Category: BALANCE, LEGS - FEET, STRENGTH
Start with arms out to the sides parallel with floor to aid in balance. Place feet in wide staggered stance: left foot firmly in front with most of the weight on heel, while right foot is behind body with only ball and toes of foot on floor. Weight and body should be centered between both feet. Inhale as you lower right knee down about two inches from floor, then on exhale lift back up. Repeat same leg position 10-15x. Then repeat other side. Keep eye line lifted and chin up looking forward.