From the study:
Sixteen male pain-free university students volunteered for this study. The trunk axial twisting was created by a torsion moment of 50 Nm for 10-min duration. The axial rotational creep was estimated by the transverse camera view directly on the top of the head. The visual analog scale in low back area was examined both in the initial and at the end of twisting. Each performed three trials of lumbar flexion-extension with the cycle of 5 s flexion and 5 s extension in standing before and after twisting. Surface electromyography from bilateral erector spinae muscles as well as trunk flexion performance was recorded synchronously in video camera. A one-way ANOVA with repeated measures was used to evaluate the effect of twist.
The results showed that there was a significant (p < 0.001) twist creep with rotational angle 10.5° as well as VAS increase with a mean value 45 mm. The erector spinae was active in a larger angle during flexion as well as extension after trunk axial twisting.
Sustained trunk axial twisting elicits significant trunk rotational creep. It causes the visual analog scale to have a significant increase, and causes erector spinae muscles to become active longer during anterior flexion as well as extension, which may be linked to the decrease of the tension ability of passive tissues in low back area, indicating a higher risk in developing low back pain.
This is a timely study for me as I just evaluated a new patient for low back pain with classic facet syndrome, (pain with extension, pain with side bending left, pain with rotation right, most pain with extension into the left quadrant, no pain whatsoever with flexion or slump tests). I see A LOT of people with low back pain and this is the first patient I had diagnosed with facet joint syndrome in years. Mostly facet joint irritation is secondary to a to degenerative disk disease, resultant from to too much spine flexion causing posterior disc prolapse and loss of disc height. This then brings the facet joints into close approximation with resultant arthritic changes. Only after the degenerative disc disease becomes advanced is spine extension solely provocative. This patient had none of that, and it only made sense when he later noted in passing that spends a fair amount of his work day sitting with his trunk rotated to the right, bingo.
This study relates in that researchers found trunk rotation sustained at end range just 10 minutes was enough to cause back pain in healthy subjects reaching 45 mm on a 100 mm scale (4.5/10). Trunk rotation afterwards increased a significant 10.5 degrees, which if sustained one would expect to only further increase pain. The study also noted they thought the rotation of the spinal discs increased compression and likely decreased hydration like wringing water from a wash cloth.
Also interesting from the study was they found erector spinae muscles to be active longer both during flexion and extension after the stretch than before. The researcher thought this was likely due to the rotation stretch decreasing passive structural support and putting them at a higher risk for the onset of developing low back pain. So the take home message is you really should not spend much, if any, time stretching your spine in rotation. Rather if your job or sport requires axial rotation, it’s a lot better if you pivot through your hips and your feet while you exercise to keep your spine strong and stable.
For the treatment of my patient if I were a follower of Williams I would have him stretch his knees to his chest and suggest he sit with his spine in a flexed posture regardless, unwittingly helping him herniate his lumbar discs. If I were a McKenzie practitioner I would also have him stretch away from the direction that causes pain, so in his case that would still be flexion, along with side bending right and rotation left stretches. I expect this would be entirely unnecessary as a spine does not need to be stretched in extremes of one direction to lessen stress from extremes of the other. Rather you just need to avoid the extremes. So most importantly I’m going to teach him to maintain a neutral spine during his workouts and to eliminate the prolonged spine rotation during his job through ergonomic changes. I’ll apply EMS to his abdominal and lumbar regions to eliminate pain in the short term, but also because there are no active exercises that work the abdominal muscles as well or intensely as EMS. Just as important is what I am not going to do, and that to have him lay on his back and rotate his hips from side to side and tell him it has to feel worse before it gets better.
As always, if you have any further questions or need for clarifications, please don’t hesitate to ask. Being aware that some of my blog ideas are contentious and occasionally a bit out of the field of my expertise, I encourage my readers to come forth with any questions/comments that are of interest or concern. Your comments are valued and welcomed.
Chad Reilly is a licensed physical therapist, located in North Phoenix, practicing science based medicine with treatment protocols unique and effective enough to proudly serve patients from Phoenix, Scottsdale, Mesa, Chandler, Tempe, Peoria, and Glendale.