This is known as the "muscle power accumulator"(1) and is quite simply the bending and straightening of the right arm (for right handed golfers - and for these chapters I’ll assume you are).

The first accumulator forms one side of the Triangle Assembly.(2) This is, appropriately enough, a triangle formed by three straight lines. There are: from right to left shoulder, from left shoulder to left hand, and from right shoulder to right hand.

Of the three straight lines forming the triangle assembly, only one may change in length from address to follow-through, that being the distance between the hands and right shoulder. When the right arm bends, the right elbow then hangs below the triangle assembly.

The left arm must not bend until after follow-through,(3) ensuring a constant distance between the hands and left shoulder. The distance between the shoulders remains consistent also.

The straight left arm, although inert, is very important to the first accumulator as it acts as a checkrein, preventing the right arm from bending too much when accumulating and also to help guide the hands into impact when releasing the accumulator’s stored power. If you haven’t done so already, try swinging the club with your right arm only to better appreciate the left arm’s importance in regulating the right arm’s action.

If you recall, the second imperative of the golf swing is a “clubhead lag pressure point”.(4) This pressure point Mr Kelley refers to can be one, or a combination of power accumulator pressure points.(5) Each power accumulator has a separate corresponding pressure point. That's to say, an area on your body where you can feel pressure when releasing a power accumulator’s stored power.

The first accumulator’s pressure point is located “in the heel of the right hand where it touches the left hand thumb or the clubshaft” depending on your grip.(6) Referring back to the primary lever assembly, you’ll note this pressure point is the force pushing the weight of the golf club around the fulcrum of your left shoulder.

The pressure points are a result of accelerating one of the lever assemblies using a particular power accumulator. When accelerating a lever assembly, the weight will resist the change in velocity, creating pressure at the source of the force.(7) So in order to feel pressure at a pressure point, one must be accelerating a lever assembly. It’s this acceleration that aides us in “sustaining the line of compression”, the secret of golf.(8)