Extension exercises can be a very useful home treatment tool for managing the pain of flexion intolerant low backs, disc bulges and herniations, particularly when there is leg pain associated.
On doing these exercises, its important to look for centralization of pain- ie. your pain moves out of the leg and towards the back. It really gives the control back to patients by enabling them to manage their own pain. However, before trying any exercises for pain control, please make sure you have consulted with your practitioner for a thorough functional evaluation and diagnosis to confirm which exercises are appropriate and how to progress.