"Extensor action is exclusively the steady effort to straighten the bent Right Arm. This stretches but does move the Left Arm and produces a structural rigidity that is a strong deterrent to collapse under the stresses of Acceleration and Impact."
The pressure applied by pressure point number three to help keep the left arm straight. I like to feel pressure point number 1 applying pressure to the left thumb throughout the swing as well, this has the affect of straightening the left arm and eliminating slack from the arm swing. I also feel as though it helps to keep the hands at their address height in the takeaway, important for drawing a straight plane line and thus maintaining initial posture.
