Here is a link that was shared by Elliott Hulse today and I thought I would pass it along. It's a beneficial abdominal exercise for those people that suffer from lower back pain or injury.
If you are someone who has experienced an injury or low back discomfort, you should consult with a physician or qualified physiotherapist before attempting this or any other exercise that is new to you or that you're unfamiliar with.
Here is the link to the exercise
Safe Abdominal Crunch
Have a great day!