Here are some exercises. :-
Stand tall with feet apart and breathe deeply to relax your shoulders and neck.
Feel your feet comfortably on the floor beneath you.
Put hands on hips and take in a breath, then as you breathe out use you stomach muscles to gently pull in your tummy.
Repeat 4 times.
Now, knowing that your stomach muscles are gently engaged and supporting your spine, bring your right hand off your hip and reach over your head and gently bend to the left. Keep the left hand on your hip to help support your spine and feel a little side stretch of the right side. Repeat 4 times then do the left side in an identical way.
This is side flexion of the lumbar spine and not something we do in ordinary life very often, but, combined with other movements it is done in GARDENING.