Painful extension can be a common finding in LBP patients, and localized extension related pain can come from a myriad of innervated tissue, though for non radicular pains facet sensitivity and possible disc annular sensitivity could be factors.
Case report: Female, 30's, 1 year of unilateral back pain 2/10 constant and 8/10 after sports. She had ceased all exercise, though continued soccer 2x per week with consistent pain following each game. Her onset of pain was unknown, though she had episodes of same sided back pain during pregnancy.
She had had an MRI indicating HNP at L5/S1 disc, though showed no sign of nerve damage (no sensation deficit, intact reflexes, no myotomal strength loss).
Exam findings: AROM mild pain end range flexion with limited curve reversal, pain with any extension (unable to lie on stomach for more than 30 seconds), hypertonic and painful QL muscle on affected side, mild neural tension on affected side (slump test on affected yields mild increase in tension felt in back), poor lumbo-pelvic control and endurance during supine core exercise.
Treatment: QL soft tissue work followed by isometrics (starting in side-lying, progressing to angled planks then on to regular side planks), neural tension progressions, core progressions, MWM (when prone laying became tolerant, we were able to achieve press-up extensions which felt much better with a "posterior innominate glide" during movement).
Visual feedback was utilized during core progressions with bent knee fall-outs (keeping laser centered on ceiling during exercise), quadruped pointers (again keeping center once in pelvic neutral) as well as functional tasks. The patient had mentioned that hugging her husband was consistently painful (as her husband was tall and her back would hurt as it extended to hug).
Heres a quick vid on functional task in pelvic neutral/slight post tilt during exercise:
pelvic positional awareness during functional tasks
At her 7th session, the patient was pain-free with ADL, had mild soreness after 1hr soccer game lasting only half an hour, and had returned to all exercise classes.
Exercise with pelvic control is a great way to modify. It doesn't mean that it needs to be utilized for life, but as a means to allow tissue desensitization and continue fatiguing muscles and getting a work-out, as opposed to avoiding exercise because positions are painful.