The present invention is a golf swing training device which guides the golfer's leading leg in an arc around the trailing heel, maintaining a minimum distance between the leading leg and trailing heel. This device guides the golfer's leg action in a 3-dimensional manner to produce a coiling motion on the backswing, which maintains a consistent spine angle as recommended by modern golf instructors. This device comprises a leg brace with flexible cuff which attaches to a golfer's leading leg above the knee, an adjustable strut, and a heel base for the golfer's trailing foot which tilts slightly in the leading direction. For left-handed golfers, this device substitutes a heel base with opposite swivel placement and tilt. This invention resets automatically to the correct position during practice sessions. The benefit for a golfer of using this invention is increased consistency, accuracy, and power.