You can find this exercise on page 200 of the book Synergistic Golf.
Exercise Type: STRENGTH
Exercise Category: LEGS - FEET, POWER PRODUCTION, STRENGTH
Stand tall with hands on hips. Lean slightly forward from hips as you reach back with right leg and dip right knee toward floor. Keep feet in alignment and put only right toes on floor...never heel. Shift weight slightly more toward back foot and bring upperbody back to upright position. Return back to start position by pushing through left heel...not toe...and buttocks muscles. Slow and controlled movements. Repeat other side.