The goal of this is to centralize and reduce the pain in your lower back, or move the pain from the leg into the low back. This exercise is called a Prone Press-Up, Mackenzie Extension, or a "Cobra" in Yoga.
From my clinical experience using repeated extensions, they seem to work best with patients that have referred pain into the hip or down the leg, they may or may not have neurological signs (pins & needles and/or numbness), get pain with sitting or flexion, and their pain is eased with standing and walking.
Do these at home with 3 sessions of 10 extensions, 5 times per day. As you keep going with the extensions, your pain should become more centralised (less far down their leg).
If your pain is unchanged, or goes further down the leg, definitely discontinue this exercise.