If there is little to no pain during spine/back flexion, the type of exercises you should be doing are those that are flexion bias and examples of these is the William's flexion exercises.
Before doing the unlock your hip flexor program, I suggest you identify first if you are extension or flexion bias. Next, perform only the exercises that extend the back (if you're extension bias) and or the exercises that flex the spine (if you're flexion bias). Kindly monitor your symptoms and stop right away when an exercise does not feel right or it is aggravating.
You may want to try these:
- Abdominal drawing-in maneuver (Core strengthening important in stabilizing the spine)
-Lie on your back with knees bent or extended; Sitting (Choose whichever is the most comfortable for you)
-Place 1 fingers on your front pelvic bone, and then slide an inch inward and downard, to feel or palpate for the muscle.
-Next, draw in or pull the lower abdomen towards the spine. You're supposed to feel a mild contraction under your fingers.
-Hold for 7-10 seconds, without holding your breath. You may try counting slowly to breathe naturally. Repeat for 10 times.
-You may incorporate this into your daily activities such as when standing, sitting or walking, to help stabilize the spine.
- Maintaining a neutral pelvis
-This is the ideal pelvic position. This is the midway between an anterior pelvic tilt (buttocks sticking out) and a posterior pelvic tilt (buttocks pushed forward).
-Try to incorporate this in all your daily activities to lessen stress on your back.