Most of my golfers need this exercise regardless of their ability level. The “Unresisted Wall Reach” is an exercise example to help golfers who struggle with maintaining their spine angle in their backswing.
Spine angle is the angle between the thighs and the back (generally about 110-130°). It is a key factor in enabling you to turn efficiently, and to swing powerfully and consistently, while protecting your back and avoiding back pain and injury.
Remember, as with all postural behavior exercises, it is important that this exercise is performed under the direction of a trained clinician.