Doing certain exercises not only helps your swing but gives you an understanding of who you are motion wise. Start by lying on the ground with your feet up in a chair. Just let your lower back relax into the ground. Then breath from your diaphragm. This relaxes your body and create a neutral pelvis. Then go to your hands and knees. Pike your body up. Then try to put your heels on the ground. IF this is hard for you to do. Then you need to be careful how much angle you put in your hips in your set up. Last Kneel at a chair, put one knee at the back of the other foots heel. Then stand and straighten your legs. Keep your hands on the chair. This stretches your hamstrings. A big part of being able to maintain your spine angle in a swing.