Bertholy is clear that the 'retaining' action of the trail hand would ideally increase wrist cock but at a minimum retain what was there.
While I understand what you're saying in my case it's possible to get an additional 20-30 deg of wrist cock with positive pressure while maintaining a flat lead wrist and not letting my grip slip. The excercises advised by Bertholy (hold in position 2 with pressure to maximize wrist cock) is instructive. This is where I found out what my maximum was and it was more than I thought. It should not be a suprise that to the extent a ROM limitation is due to flexibility, positive pressure will increase it (I think this was the case with Nicklaus) and with proper excercises the limit can be extended. This is Bertholy's point in the excercises as summed up in:
Now once our student Golfer has reached this plateau where he has actually developed the capability of superior stretched muscles and tendons, he has overcome the physical aspect of his problem. This by no means indicates that he is now prepared to step up to the ball and hit it without a Hit Impulse, while cocking his wrists even more during the downswing. He has merely developed the capability but not the faculty, of doing it in actual ball hitting. This requires still more counter-hit-impulse and progressive conditioning. The next step in this progressive conditioning is called the Golden Excercise and is Program Number Three in the Bertholy Method.
