If you are around my age, you might remember having to pass the Presidential Fitness Test in P.E. Part of that test was flexibility demonstrated by sitting on the ground with the legs extended and the knees straight. Then, you would reach forward as far as you could. Not to brag, but I could reach well beyond my feet. I was, in fact, the most flexible boy in my whole middle school. I remained pretty flexible until I was in college when I hurt my low back. Since then, I can barely touch my toes on a good day.
With any injury, the body has protective measures. When you hurt your low back, the hamstrings will shorten to protect against bending forward and causing further damage. Like most of these reactions though, the body doesn’t always know when to stop guarding which can prolong the healing process or lead to more problems down the line. My recommendation is to first start improving the function of the low back through chiropractic adjustments, and then to start regularly stretching the hamstrings.
I created the following video to help you do this stretch properly. Remember that in order to actually lengthen a muscle, you must sustain the stretch for at least 30 seconds. It can take time before you see results. If after several weeks of stretching you are not improving, it most likely means that there is still a significant amount of dysfunction in your low back that you need to address.