This exercise is great if you have sciatica problems and also for stretching your legs and back.
Go on all fours and place your hands in front of you.
Slowly rise and straighten your legs. Put your head between your arms.
If you can, try to push your heels down on the ground and you will feel a stretch in your hamstrings.
Hold in this position for 10 seconds and then slowly return to starting position.
Slowly repeat several times.