Knee rolls
Stretches and mobilises the spine

Start position: Lie on your back. Place a small flat cushion or book under your head. Keep your knees bent and together. Keep your upper body relaxed and your chin gently tucked in.
Action: Roll your knees to one side, followed by your pelvis, keeping both shoulders on the floor. Hold the stretch for one deep breath and return to the starting position.
Repeat 8 to 10 times, alternating sides.
Tips:
- Only move as far as feels comfortable.
- Place a pillow between your knees for comfort.
Copied from http://www.nhs.uk/