Sit up tall in a chair, cross your arms over your chest, feet flat. Without letting your hips or knees turn, turn your shoulders to look behind you on each side. A good result is turning about halfway around, your shoulders close to facing the side wall (about 45 degrees). This checks how well your upper back, the part between your shoulder blades, can rotate. That is where a golfer should turn for the backswing. If it is stiff here, your body turns from your lower back instead or you stand up out of your stance, which means a short or flat backswing and a swing that loses power and bugs your back.

Sit up tall in a chair, feet flat and about shoulder-width apart. Keep your lead-side knee pointing straight ahead and do not let it move, then slide that foot out to the side, away from your other foot, as far as it comfortably goes. Do the same on the other side and compare. Sliding the foot out turns the hip inward, which is exactly the turn your lead hip makes as you rotate through the ball. If that hip is tight and one side does not go as far, your lower back ends up doing the turning, you stand up early and lose your posture, and your back takes the stress.

Stand with your feet together, knees soft, and bend forward from your hips to reach toward your toes, keeping your back long and flat, not rounded over. A good result is touching the top of your shoes or lower while your back stays straight. This checks your hamstrings and your ability to bend from the hips, which is how you get into golf posture without straining your back. If this is tight, you set up rounded over or stand up out of your stance during the swing, and your lower back picks up the load.

Stand on your lead leg with your eyes open and hold steady for 20 seconds, with no hopping, big wobbles, or grabbing anything. Want a tougher test? Try it with your eyes closed for 10 seconds. Your lead leg has to plant and hold strong to take your weight as you swing through. If it cannot stay steady, your lead side cannot anchor the swing, so you slide toward the target, lose speed, and hit the ball less solid.

Stand up tall and reach your lead arm straight across your chest toward your other shoulder, keeping your chest tall and your shoulder from rolling forward. A good result is your upper arm crossing past the middle of your chest without shrugging or twisting your body to cheat it. This checks the shoulder and upper-back range you need to make a full backswing turn. If it is tight, you cannot finish your turn with your arms, so your backswing gets short or your lead arm folds and breaks down through the ball.