Some people have good flexibility naturally. For those of us who don’t, flexibility is needed and can be developed, but you have to work at it everyday. Stretching allows the development and maintenance of optimal joint range of motion, so that the golfer can move through the necessary planes of motion. If you are inflexible in your lower back or lumbar spine, you will tend to overuse other muscles such as your shoulders leading to injury and swing compensations.

Lie on the floor facedown.
Place both hands on about shoulder height.
Slowly arch your back lifting your head and chest off the floor as high as you can. Hold position for 8 to 10 counts and return to start position.
Do 8 to 10 repetitions.
This stretch will help you complete your follow-through in the golf swing.