It is about bringing yourself to the game with the best physical condition. If you study the lessons on this site, injuries won't stop you, but wind and rain may affect your performance. Check here for the advance forecast. Successful golf is about being limber and relaxed. While it does not seem that way on the surface, your aerobic conditioning can affect the way you play and focus on the back nine.
Successful golf is also about technique.
Here are some quick video pointers. Click Here for some of the physical problems you may be grappling with and which could adversely impact your game. So you're perfect. I can't get full range of motion. I can't stand up too long and I can't sit down too long.