What are the most important muscles for golf? I suppose today's experts would say the core muscles and the legs--though I can't say for certain, not being an expert in such things. I would argue, with support from some of the best golfers to ever play the game, that the most important muscles are in the hands, wrists, and forearms--especially the hands.
There are golfers who have lost the use of their legs, but can still play decent golf out of a chair using their hands and arms. I had a friend who played decent golf despite having lost one leg up to the knee and several toes on his remaining foot. I had another friend when I played at Pine Ridge who played a respectable game despite having only one hand. One famous old English teacher, Ernest Jones, lost a leg during the war and developed his teaching system called "swing the clubhead" based upon what he learned in terms of using his hands and arms to still play good golf despite his handicap.
The fact is you don't have to be rooted to the ground to effectively strike a golf ball. Look at some of these trick shot artists if you have any doubts. Bobby Jones felt, quite rightly, that anyone with a good set of hands can play respectable golf. He may not hit it as far as the young and physically fit players, but he can play golf well enough to thoroughly enjoy the game if he learns to use his hands properly.
In fact, one of the attributes that we often give to great players is that they possess a great set of hands. Often this refers to their touch, but it also involves their ability to deliver a real wallop to the ball using their hands. Arnold Palmer had enormously powerful hands and forearms, and he used them to great effect. Sam Snead did as well. Jackie Burke, when talking about Snead's advice to grip the club like a baby bird, apparently suggested that, in Snead's case, the baby bird was definitely an eagle. Snead may have gripped the club softly for him, but you can bet that when he delivered the strike that club head wasn't about to twist in those powerful hands for anything.
Now we will likely never be endowed with the kind of strength in our hands and forearms that Palmer or Snead possessed, but we can certainly get stronger. One of England's finest players and teachers, Henry Cotton, discovered the value of a simple car tire to not only build strong hands, wrists, and forearms, but also to learn to deliver a solid, square strike. He had his students out there striking a tire with the left hand only, the right hand only, and both hands; getting the feel of how both hands work to deliver the club head to the ball and make a solid strike. They also discovered the importance of the top hand (the left hand for right-handed golfers) in delivering the club square to the ball.
The results he saw were almost instantaneous with many students who, caught up in swing mechanics, had forgotten that golf, in the final analysis, was about striking the ball with the head of the club; not making a pretty swing. I have my tire in the back garden and, now that the weather's good, intend to regularly go out and whack the daylights out of it. It might just accomplish two things--strengthen my golf muscles and eliminate any stress I might be feeling. Actually, it might accomplish three things. It might also annoy my neighbours, who will have to listen to their crazy neighbour whacking a car tire. I better make certain I don't decide to do it at midnight.
As for Jeff; he's going to start beating a tire as well.