If your rotator cuff is bringing your golf game down, you should learn how to increase your shoulder strength to the point where a round of golf won't affect it. Here are some great golf-related exercises to build up your rotator cuff using your clubs and a resistance band.
Consider the type of resistance band you're going to want for your exercises. Resistance bands come in several categories. It's a good idea to have a couple—at least a light one and a heavier resistance one. Having more than one band will give you the luxury of adjusting your workout as you build strength in your shoulder.
Tie a resistance band around either a heavy chair leg or some other fixed piece of furniture. You need it down close to ground level. Take the other end of the resistance band and tie it to your club (preferably an iron). Now you're set for two really good resistance exercises that will work your shoulder. Stand so that you are gripping the club as if you were going to hit the ball. Your club head should be facing away from the tie down point. Now push the club head forward. Do three sets of 10, holding for two seconds at the farthest point of resistance. Now turn so that your club head is facing the tie down point. Now pull the club head back. Do three sets of 10, holding for two seconds at the farthest point.
The second set of exercises is quite similar to the ground resistance exercises, only it works a different area of your swing. This time you'll want to tie off on a door knob and, once again, on the shaft close to the club head. Stand so that your club is in the air, emulating the posture of your downswing. Now push down on the club head as far as you can, hold it for two seconds and then bring it back. Do three sets of 10. Next turn around so that you are emulating your upswing. Pull the club up as far through your follow through as you can, hold it for two seconds and then let it back down. Do three sets of 10.