Abdollah V, Parent E, Battie M, MRI evaluation of the effects of extension exercises on the disc fluid content and location of the centroid of the fluid distribution, Musculoskeletal Science and Practice, 33, 67-70, 2017
This study looked at the immediate effect of extension in lying on disc fluid content and movement. It concluded that the exercises likely do not change the fluid content of the disc, but 'possibly influence fluid distribution within the discs favouring a more anterior position'
Al-Obaidi S, Anthony J, Dean E, Al-Shuwai N., Cardiovascular responses to repetitive McKenzie lumbar spine exercises, Phys Ther, Sep;81(9):1524-1533, 2000
Blood pressure and heart rate goes up in normal individuals when they perform repeated exercises as described by McKenzie.
Al-Obaidi SM, Asbeutah A, Al-Sayegh N, Dean E., To establish whether McKenzie lumbar flexion and extension mobility exercises performed in lying affect central as well as systemic hemodynamics: a crossover experimental study., Physiotherapy, 99:3:258-265, 2013
In healthy male volunteers repeated flexion and extension movements tend to increase the work of the heart, especially with more repetitions.
Alexander LA, Hancock E, Agouris I, Smith FW, MacSween A, The response of the nucleus pulposus of the lumbar intervertebral discs to functionally loaded positions., Spine, 32:1508-1512, 2007
First ever study using upright magnetic resonance imaging of effect of functional positions on movement of the nucleus pulposus (NP) in 11 volunteers. In sitting there was significantly less lordosis than prone lying and standing, and significantly more posterior migration of the NP than other positions.
Aota Y, Iizuka H, Ishige Y, Mochida T, Yoshihisa T, Uesugi M, Saito T, Effectiveness of a lumbar support continuous passive motion device in the prevention of low back pain during prolonged sitting., Spine, 32(23):674-677, 2007
Asymptomatic volunteers tested prolonged sitting with 1) no lumbar support, 2) static lumbar support, or 3) continuous passive motion lumbar support. There were significant differences between 1 and 2 / 3 in discomfort / pain, stiffness and fatigue, but no significant differences between 2 and 3
Astfalck RG, O'Sullivan PB, Straker LM, Smith AJ, Burnett A, Caneiro JP, Dankaerts W, Sitting postures and trunk muscle activity in adolescents with and without nonspecific chronic low back pain. An analysis based on subclassification., Spine, 35:1387-1395, 2010
Cross-sectional comparison of adolescents with and without back pain regarding posture and muscle activity, with no differences identified between groups. However flexion responders sat in more lordosis, and extension responders sat in more kyphosis, but muscle activity displayed no clear cut differences.
Bakker EW, Verhagen AP, Lucas C, Koning HJ, de Haan RJ, Koes BW., Daily spinal mechanical loading as a risk factor for acute non-specific low back pain: a case-control study using the 24-Hour Schedule, Eur Spine J., Jan;16(1):107-13, 2007
100 cases with acute back pain were compared by a blinded assessor with 100 controls using the 24-Hour Schedule, which quantifies spinal mechanical loading taking into account duration of activity, sagittal movement and loading status. There were no significant differences between cases and controls in predominant work postures. There were significant differences between the groups in hours in flexion and extension, with cases spending significantly more hours in flexion and significantly less likely to be in extended postures.
Bakker EWP, Verhagen AP, Lucas C, Koning HJCMF, Koes BW, Spinal mechanical load: a predictor of persistent low back pain? A prospective cohort study., Eur Spine J, 16:933-941, 2007
A prospective cohort study of 100 back pain patients who were reviewed at 6 months (N = 88) when 60% reported persistent back pain. Baseline factors were analysed for their association with back pain. Multivariate analysis found smoking and older age (protective) to be associated, while univariate analysis found the 24-hour schedule to be, this is a measure of spine mechanical load.
Beattie PF, Arnot CF, Donley JW, Noda H, Bailey L, The immediate reduction in low back pain intensity following lumbar joint mobilization and prone press-ups is associated with increased diffusion of water in the L5-S1 intervertebral disc., JOSPT, 40.256-264, 2010
20 patients with back pain who received extension mobilizations and extension in lying were monitored with MRI before and after, and classified as responders if there was a reduction in pain score of 2 or more. Responders demonstrated a mean increase in diffusion coefficient in the middle portion of the disc compared to a mean decrease in the non-responders.
Chiu C, Chuang T, Chang K, Wu C, Lin P, Hsu W, The probability of spontaneous regression of lumbar herniated disc: a systematic review, Clinical Rehabilitation, 29,2, 2014
This systematic review looked at the probability of spontaneous disc regression in the lumbar spine. Percentages were given for various types if disc herniations. Extrusions and sequestrations had the highest rates of regression
Dankaerts W, O'Sullivan P, Burnett A, Straker L., Differences in sitting postures are associated with nonspecific chronic low back pain disorders when patients are subclassified, Spine, Mar 15;31(6):698-704, 2006
An examination of the sitting posture of back pain patients, analysed as non-specific or according to a novel classification system, and non-back pain controls. There was no difference in sitting posture between controls and un-differentiated back pain patients; however there were significant differences between sub-groups and controls. Flexion pattern patients, with a directional preference for extension, had a more kyphotic sitting pattern than controls; and active extension pattern patients, who had a directional preference for flexion had a more lordotic sitting posture than controls.
Edmondston SJ, Song S, Bricknell RV, Davies PA, Fersum K, Humphries P, Wickenden D, Singer KP., MRI evaluation of lumbar spine flexion and extension in asymptomatic individuals., Man Ther, Aug;5(3):158-64, 1999
Between flexion and extension there was anterior displacement of the nucleus pulposus of 6.7%, this was significant at L1/2, L2/3 and L5/S1. Displacement did not occur in 30% of discs.
Fazey PJ, Song S, Monsas A et al, An MRI investigation of intervertebral disc deformation in response to torsion., Clin Biomech, 21;538-542, 2006
MRI investigation of 3 asymptomatic women showing that in most instances extension caused anterior deformation of nucleus, flexion posterior deformation, and left rotation deformation to the right.
Fazey PJ, Takasaki H, Singer KP, Nucleus pulposus deformation in response to lumbar spine lateral flexion: an in vivo MRI investigation., Eur Spine J, 19(7):1115-20, 2010
A novel MRI method derived from pixels and the effect lateral flexion is described; in 95% of healthy subjects the nucleus pulposus was displaced away from the direction of lateral flexion.
Fredericson M, Lee SU, Welsh J, Butts K, Norbash A, Carragee EJ, Changes in posterior disc bulging and intervertebral foraminal size associated with flexion-extension movement: a comparison between L4-5 and L5-S1 levels in normal subjects., Spine J, 1:10-17, 2001
MRI of 3 volunteers with no history of back pain; clear trend for flexion to cause greater posterior bulging and extension to reduce posterior bulging. Intervertebral foramina increased in flexion and decreased with extension.
Geldhof E, De Clercq D, De Bourdeaudhuij I, Cardon G, Classroom postures of 8-12 year old children, Ergonomics, 50(10):1571-1581, 2007
Pupils (N = 105) were observed to spend 85% of classroom time sitting, 28% of which was flexed forward and 91% of time was static. Children who spent more time sitting flexed forward reported significantly more low back pain.
Key S, Adams MA, Stefanakis M., Healing of painful intervertebral discs: implications for physiotherapy. Part 2-pressure change therapy: a proposed clinical model to stimulate disc healing., Phys Ther Rev, 18:34-42, 2013
Narrative review about the possible cause of discogenic pain, relating to inflammatory pain in the acute stage. Suggesting that physical therapy should aim to stimulate healing, as in other connective tissue problems, with loading, by stimulating cells, boosting metabolite transport, discouraging adhesion formation and preventing re-injury.
May S, Nanche G, Pingle S, High frequency of McKenzie's postural syndrome in young population of non-care seeking individuals., J Man Manip Ther, 19:48-54, 2011
In a population under 30 years of age 138 were approached to participate in a questionnaire and 100 agreed to participate; of these 66 appeared to have postural syndromes, and they were asked to attend a physical examination, of which 37 consented. Of these 31 met the criteria for postural syndrome, with the syndrome being significantly associated with sustained loading and abolition of pain on posture correction. Symptoms were mostly, but not only, spinal, and mostly, but not only, provoked by sustained sitting.
Munster M, Brismee JM, Sizer P, Browne K, Dewan B, Litke A, Pape J, Sobczak S, Can 5 minutes of repetitive prone press-ups and sustained prone press-ups following a period of spinal loading reverse spinal shrinkage?, Physio Theory and Pract., Online Feb, 2018
This study demonstrated that both repeated and sustained extension increased lumbar spinal height and speculated that this strategy may have some preventative value
Murphy S, Buckle P, Stubbs D, Classroom posture and self-reported back and neck pain in school children., Applied Ergonomics, 35:113-120, 2004
The sitting posture and self-reported pain was measured in 66 school children, mean age 13. Significant associations were found between self-reported spine pain and: lesson length, sustained trunk or neck flexion, and time working at the desk
Nairn BC, Chisholm SR, Drake JDM., What is slumped sitting? A kinematic and electromyographical evaluation., Manual therapy, 18:498-505, 2013
Twelve asymptomatic males were assessed. Slumped sitting was associated with posterior pelvis rotation, near-end range flexion of the mid and lower thoracic spine, and mid-range flexion of the upper thoracic and lower lumbar spine. Muscle activity decreased in the slump sitting posture.
Nakashima H, Yukawa Y, Suda K, Yamagata M, Ueta T, Kato F, Abnormal Findings on Magnetic Resonance Images of the Cervical Spines in 1211 Asymptomatic Subjects, Spine, 40,6,392-398 , 2015
In this asymptomatic population disc bulging was seen frequently, increasing between the ages of 20 and 50. Even those in their 20s had a high proportion of disc bulging. Cord compression increased after the age of 50
Nazari J, Pope MH, Graveling RA., Reality about migration of the nucleus pulposus with in the intervertebral disc with changing postures., Clin Biomech, 27:213-217, 2012
Magnetic resonance images of lumbar spines of 25 asymptomatic volunteers in different postures, which showed that the length of the nucleus pulposus (NP) changed in different postures rather than actual migration of the NP.
O'Keefe M, Dankaerts W,O'Sullivan P, O'Sullivan L, O'Sullivan K, Specific flexion-related low back pain and sitting: comparison of seated discomfort on two different chairs., Ergonomics, 56:4:650-658, 2013
In 21 participants, whose low-back pain was aggravated by sitting and better with standing, two sitting positions were trialled. Back pain was significantly more in those who sat on the normal office chair compared to those who sat on anterior-tilted seat (increased lordosis).
O'Sullivan P, Dankaerts W, Burnett A et al, Evaluation of the flexion relaxation phenomenon of the trunk muscles in sitting., Spine, 31;2009-2016, 2006
In 24 healthy volunteers neutral lordotic sitting posture facilitated multifidus and internal oblique muscles, whereas slumped sitting caused a significant decrease in their activity. Activity of erector spinae varied during slumped sitting in some it increased and in some it decreased.
O'Sullivan PB, Grahamslaw KM, Kendell M, Lapenskie SC, Moller NE, Richards KV., The effect of different standing and sitting postures on trunk muscle activity in a pain-free population., Spine, Jun 1;27(11):1238-44, 2001
Compared to erect sitting and standing most trunk muscle activity is significantly less in slumped sitting or standing.
O'Sullivan PB, Mitchell T, Bulich P, Waller R, Holte J, The relationship between posture and back muscle endurance in industrial workers with flexion-related low back pain., Man Ther, 11:264-271, 2006
24 workers with back pain provoked by flexion activities compared with 21 healthy workers had: significantly reduced muscle endurance, increased posterior pelvic tilt and sat closer to their end range of lumbar flexion.
Powers CM, Beneck GJ, Kulig K, Landel RF, Fredericson M, Effects of a single session of posterior-to-anterior spinal mobilization and press-up exercise on pain response and lumbar spine extension in people with non-specific low back pain., Phys Ther, 88:485-493, 2008
Comparison of the effects, on short-term pain scores on extension in standing and extension range as measured by MRI, in 30 patients with back pain randomised to a single session of spinal mobilisation or extension in lying. There were significant improvements in both pain and range in both groups, but no significant differences between the groups.
Pynt J, Higgs J, Mackey M, Seeking the optimal posture of the seated lumbar spine., Physio Theory & Pract, 17;5-21, 2000
A review of the literature on the optimal sitting posture for spinal health, based mostly on cadaveric studies, but some clinical studies. They conclude that the arguments in favour of a kyphotic sitting position are not substantiated by research; and that a lordotic position, interspersed with regular movement, is the optimal sitting posture and assists in preventing back pain.
Scannell JP and McGill SM, Disc Prolapse: Evidence of Reversal with Repeated Extension, Spine, Volume 14, Number 4, pp. 344-350, 2009
Porcine cadaver study of cervical spine - loading in flexion produced nucleus prolapse in 11 of the 18 specimens. In 5 of the 11 the prolapse was reduced with repeated loading into extension.
Shin G, Mirka G, An in vivo assessment of the low back response to prolonged flexion: Interplay between active and passive tissues., Clinical Biomechanics, 22(9):965-971, 2007
Smart KM, Blake C, Staines A, Doody C., The discriminative validity of nociceptive, peripheral neuropathic, and central sensitization as mechanism-based classifications of musculoskeletal pain., Clin J Pain, 27:655-663, 2011
464 patients with low-back pain were assessed using a standardised assessment protocol, assigned a mechanism-based classification according to their clinical experience, which was then checked against the protocol criteria: 55%, 22%, and 23% were classified as nociceptive, peripheral neuropathic and central sensitization respectively. Nociceptive, in other words mechanical pain, was very strongly associated with localized pain, clear aggravating and easing factors, and less strongly with intermittency of pain. Peripheral neuropathic pain was very strongly associated with dermatomal pain and positive nerve movement tests; whereas central sensitization was strongly associated with: disproportionate aggravating and easing factors, diffuse painful palpation, and psychosocial symptoms.
Takasaki H, Comparable effect of simulated side bending and side gliding positions on the direction and magnitude of lumbar disc hydration shift: in vivo MRI mechanistic study, J Man Manip Ther, 32:2:101-108, 2015
The study compared the effect of side gliding to side bending in the lumbar spine on disc hydration. Side gliding produced comparable effects to side bending on lumbar disc hydration
Takasaki H, May S, Fazey PJ, Hall T., Nucleus pulposus deformation following application of mechanical diagnosis and therapy: a single case report with magnetic resonance imaging., J Man Manip Ther, 18:153-158, 2010
Case study in which symptom resolution coincided with change in MRI findings from baseline to one month with use of MDT therapy.
Tsantizos A, Ito K, Aebi M, Steffen T, Internal strains in healthy and degenerated lumbar intervertebral discs., Spine, 30.2129-2137, 2009
Cadaver study looking at the effects of degeneration and loading on nucleus pulposus deformation. The nucleus migrated to the opposite side of bending direction regardless of loading and significantly more in degenerated discs.
Womersley L, May S., Sitting posture of subjects with postural backache, J Manipulative Physiol Ther, Mar-Apr;29(3):213-8., 2006
Nine students were classified as postural backache (history of mild backache but no functional disability) and 9 as control (no history of backache). Postural activity was recorded over 3 days and relaxed sustained sitting posture observed with computerised video analysis. The postural backache group had significantly longer periods of uninterrupted sitting and sat with greater flexion when relaxed.
Zou J, Yang H, Miyazaki M, Mosishita Y, Wei F, McGovern S, Wang J, Dynamic Bulging of Intervertebral Discs in the Degenerative Lumbar Spine, Spine, 34(23):2545-2550, 2009
On a kinematic MRI non-degenerated discs moved posteriorly in flexion and anteriorly in extension. However more degenerated discs behaved much less predictably, and extension may lead to posterior disc bulging.