It’s all in the hips
It’s an old cliche in a lot of sports but it does have some grounding. Like in most sports, the glutes are a massive source of power. To utilise these muscles in a rotational sport you need to internally and externally rotate as well as extend your hip joint. If you are limited in any of these movements then you will not be able to utilise the full power of your glutes and all the strength and power work you have done is ineffective because you didn’t do sufficient mobility work in your warm-up.
During the swing of a right-handed golfer, the right hip socket at address starts neutral and moves gradually into internal rotation as the hips close to target and the foot remains planted. In good golfers, the right hip changes direction and starts moving towards neutral before the backswing is complete. Then it will go into external rotation before the right foot comes off the ground which will require hip extension in order to have a successful weight shift and a good finish position. The left hip follows the opposite pattern through the backswing, neutral to externally rotation back to neutral then into internal rotation. The left hip requires a greater range than the right as your left foot doesn’t come off the ground. There are some exceptions to this who are very good golfers such as Jordan Spieth. He lifts his left foot in his follow through because he doesn’t have the range required to keep it planted. You also need good hip extension in the left hip for good impact and follow through positions. Having poor mobility doesn’t make golf impossible but having good mobility will make it easier, improve performance and reduce overloading and injuring other joints.
There is a need to both mobilise the joint and increase the range of the muscles acting on the joint. There are plenty of variations of these exercises, some that are more effective and isolate the joint more than others and some that work on the mobility of the general area. Find the ones that are most effective for you and make them part of your everyday routine.
Personally, I like to use a number of exercises for the hip socket in a warm-up. I use a modified version of James DeFranco’s Agile 8 that has been adapted to suit my needs a little more as I do with all my athletes. I would suggest doing a warm-up of this style before all your training sessions and before leaving the house/hotel for your golf. A further warm up whilst at golf will be needed but it would be difficult to get sufficient mobility work done at the course without rolling around on the floor.