In 12-3 you'll see that Homer listed extensor action in almost every part of the page. As a hitter, I skip adjusted address by starting at impact fix. Extensor action is what places pressure against the #1 pressure point. The only time that I don't keep pressure against the penny is in the finish. The flying wedges are still assembled, but the pressure isn't the same.
Yoda told me that in 12-3, extensor action could have been added in the adjusted address position, which would support ALWAYS keeping pressure on the penny.(until finish)
[Bold by Yoda.]
Luke is right.
Extensor Action -- stretching the Left Arm via the Heel of the Right Hand against the Left Hand thumb -- is indeed present in Adjusted Address (8-3). However, the reason the Mechanical Checklist (12-3) does not stress Extensor Action in that Section (of the Stroke) is that such Action ultimately will Flatten the Swinger's Bent Left Wrist. In which case, with the Left Wrist no longer Bent, Adjusted Address (10-9-A) will have become an Impact Address (10-9-B).
And you cannot be in both at the same time.
So, there you go:
Easy on the Extensor Action in Adjusted Address, boys. But 'let'er rip' in Start Up, because that Bent Left Wrist has got to get Flat...