As a kid growing up playing golf, we were taught that we should have a CUPPED Left Wrist at the top of our swings. ( I didn’t have to work at that because it came to me naturally).
Then in the 1970’s, we were told that the Left Wrist should be FLAT at the top (This was greatly publicized by the SQUARE TO SQUARE GOLF SWING which advocated a FLAT Left Wrist).
Now days, we’re seeing more and more BOWED (or Convex Wrists) as evidenced by great young players like Dusting Johnson, Jon Rahm, Daniel Berger and others.
SO, which way is right? And the obvious fact is that THERE’S NO ONE RIGHT WAY FOR EVERYBODY.
The major factors that determine wrist positions are
1). What type of Grip do you have; Strong, Neutral or Weak? A Strong grip ‘Generally Speaking’ promotes more of a Cupped Wrist, as where a very Neutral or Weak Grip promotes a Flat Wrist Etc. (Having said that – there are exceptions as seen in the case of Dustin Johnson, Daniel Berger, and Lee Trevino who had Strong Grips but BOWED their wrists.
2). Factor #2 is: What type of Musculature do you have? If you’re thick chested – thick armed, etc., you’ll tend to have less flexion and have more of a flat wrist.
So unless your wrist position is causing major difficulties, my advice is Don’t worry about it, and if it is; then look at the factors I mentioned to see How they’re affecting your wrists.