One of the areas I look at is forearm control with the trail arm. Observing a players forearm pattern which, evolves from the way you settle your hands on to the club. gives me a key indication of the sort of ball control a player is able to achieve.
At the top level numerous styles of hold can be seen, so the hold isn't an exact science. Impact positions to control the club face and club path are required which inevitable comes back to forearm position and stabilisation.
The following exercise demostrates how a stable forearm allows the wrists to move freely while restricting destructive pronation.
Try this :- Hold your right hand out ready to shake hands. place your left thumb on your right wrist so you can feel the radial bone (top one). Clamp your left fingers under the right ulna bone (bottom one), now try and rotate your right palm down (pronate), add pressure to your left hand grip to resist rotation. Your wrist can rotate and move freely. but the palm is restricted in palm down movement creating a more stable base for wrist release and therefore a more stable clubface.
As players we do want some clubface rotation especially when applying power but equally we want counter rotation with the shorter more high spinning shots.
Understanding the multiplication of vectors from the club shaft and club face is a crucial element for ball control. While this may sound complex if we look at other ball sports such as tennis and table tennis we can easily see the influence of bat positioning reletive to bat direction to create different spinning shots. A sliced back hand, by its nature, produces a slower ball speed with a high bat speed and this action links to golf with a slicing golf shot that may have lots of shaft speed but lower distance.
These two examples of clients are demonstrate how a fast clubhead spped isn't the holy grail for power and distance.
One player had a club head speed of over 90mph with a 7 iron. This is fast and potentially very powerful movement, however he hit the ball 150yds at best, often his numbers were mid 140's. We dropped the clubhead speed to below 90mph, created a more effective path, allowed the club face motion to move in time the ball speed increased and the spin dropped producing consistent 180yds shots.
A second player was hitting drivers with 104mph clubhead speed, pretty quick for a casual player however the ball didnt go any further than 240yds.
This time a I emphasised the importance of the path and helped him with an address position change. The right forarm position needed stabilising which allowed the wrist release to be more agrressive. The result was an instant gain to 290yds and a far more consistent shot
Ultimately the sensitve relationship between clubface position and club path at impact are keys to consistent play. The controllers are the forearms, especially the trail arm, and then wrist release patterns, based on your setup and hand formaton can express a powerful controlled shot.