The Golfing Machine’s title comes from the idea that to better understand and perform the golf swing, you should think of your body as a machine. Mr Kelley says: “It is soon apparent that the body can duplicate a machine. Grasp the parallel and escape limiting old concepts.”(1) Mr Kelley goes on to compare various parts of the body to their mechanical counterparts: the right arm as a piston, the hands as adjustable clamps, and the left shoulder as a hinge. It’s from this last example we derive the hinge action component of the golf stroke.

Hinge action is the manipulation of the hands through the impact interval. How you move your hands through impact affects the clubface, and this in turn affects ball flight.(2) We’ve already discussed movement of the hands in the Power Accumulator chapter, namely the second and third accumulators. These accumulators relate to the secondary lever assembly, where the left wrist acts as a fulcrum. Hinge action describes how we can move the hands not from the left wrist, but from the left shoulder. It is a closer look at the fulcrum of the primary lever assembly, through impact and beyond.(3)

Your shoulder joint is a clever piece of equipment. It’s known in medical circles as the glenohumural joint.(4) This ball-in-socket is the most flexible joint in your body, allowing you to move your arms in many directions with a wide range of motion. While beneficial in most day-to-day activities, this can be a hindrance to your golf swing. The actual golfing machine described and sketched by Mr Kelley “...is simple and has few moving parts, but the human body as its counterpart has altogether too many. Every such part requires control by some pre-selected procedure.”(5)

Hinge action is a way of limiting the movement of the left arm, the left wrist and the club to a particular plane of motion. This, in turn, limits the clubface motion through impact. There are two motions the clubface may take through the impact interval. They are “closing” and “laying back”. By closing we mean the clubface is rotating anti-clockwise from the player’s perspective.(6) By laying back we mean the clubface reclines and points more to the sky.

With these two motions there are three possible combinations of clubface movement through the impact interval. They are: closing without lay-back, lay-back without closing, and closing and lay-back at the same time.(7) These three clubface motions are produced by the three basic hinge actions. Click on the link below to learn more about each one.

Not only do the three on-plane hinge actions produce different clubface motions during their use, they can also affect how far the clubhead travels between impact and the end of the follow through.(8) This is due to the orientation of the flat left wrist (or equivalent) and the angle between the left arm and clubshaft, i.e. the third power accumulator angle. With a club in your hands, make this angle 180˚ so that the left wrist is uncocked and left arm and clubshaft are in a straight line. Now stop the club after a short chip shot, where both arms are in the straight position. You can now see how rotating the left wrist to produce the angled, dual action horizontal and dual action vertical hinge actions change the orientation of the clubface, but does not alter the location of the clubhead itself.

Now cock your left wrist so the 180˚ angle between the left arm and clubshaft decreases. If you were to rotate the flat left wrist to create the different hinge actions, you’d see not only does this affect the clubface, it now also changes the location of the clubhead. dual action horizontal makes the clubhead travel the furthest and dual action vertical the least.(9)

Mr Kelley seldom mentions how the golf swing should “feel”. He states in the Golfing Machine’s introduction one should “...learn feel from mechanics rather than mechanics from feel.” An exception to this is how the different hinge actions feel to the player, because these feelings are universal. Mr Kelley describes the appearance and feel of the different hinge actions on the left wrist in the table above.(10)