[stilltrying]

If you are saying that you tried to prevent your left wrist from cocking or uncocking at any time during a full swing, that isn't what you're supposed to be doing. The left wrist should start out level at Address. It then cocks and/or uncocks as the right arm bends/straigtens and is level again at Impact. Post Impact, the left wrist continues to uncock to full extension.

If you saw improvement, my guess would be that your efforts resulted in a better Extensor Action (and your left wrist probably cocked anyway). The Left Wrist cocking and uncocking is a source of power.

I wasn't trying to prevent my left wrist from cocking, it felt like it wasn't cocking as much. Most likely I had been letting my right wrist cock as well. Better extensor action seemed a result as well.