Start in a standing position with your feet shoulder-width apart.
Reach up with your right arm and bend it so your hand drops behind your upper back.
Move your left hand behind your back. slide it up the spine and try to link your hands together.
If you can't comfortably grip your hands together then use a strap or towel.
You may be able to link hands on one side, but not the other.
Repeat on the other side.