Spinal hydration, multifidus, spacemen and bedrest

The fact that 50% of (western) astronauts get back pain when they return from space missions, has added to our knowledge of back pain.

It seems that space flight and lounging around in bed whining (aka bedrest) results in an increased incidence of low back pain. This has been associated with abnormal lengthening of the spine, atrophy of spinal musculature increased intervertebral disc (IVD) height and area, and altered IVD composition.

As a trainee therapist, I was always told to pay attention to the suggestion that fully hydrated discs (which elongate the spine) from a night of bed rest can increase stress in the “annulus”: by three times during morning bending activities. That’s why I don’t recommend spinal flexion within the 1st few hours after waking up. If you get up and do lots of spinal wiggling. Pack it in!

It was always assumed that inactivity and pain produced muscle atrophy: the reality is that some muscles get bigger and their activation increases in fact there is greater atrophy in the spinal extensor muscles (think multifidus) than in the flexor muscles (think Psoas)

Interestingly after bed rest, It takes 28 days for the psoas muscle to return to its pre-bed-rest size and changes in the multifidus muscle were still evident at 90 days after a return to normal activities. This differential atrophy of the muscles during bed rest has also been linked to the development of LBP

The effects of prolonged bed rest on the lumbar IVDs are similar to spaceflight. The length of the lumbar spine has been shown to increase which is thought to be due to discs imbibing fluid in combination with flattening of the lumbar lordosis This may also have biomechanical consequences on the ability of the disc to distribute load and have been associated with LBP incidence after bed rest

Bailey and her space cadets have now come down on the side of multifidus atrophy, rather than intervertebral disc swelling, associated strongly with lumbar flattening and increased stiffness.

so, spare a thought for your multifidus

Obviously, from an andrewstemler.com point of view, you want to “assume its everything”, but add this drill to build up your multifidus

whatever drill or therapy you do in your session, commit to moving well for the rest of the day

so, how can you make your back pain go away?

for FREE, do the drills above and join my mailing list

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McGill, S.M., Axler, C.T. (1996) Changes in spine height throughout 32 hours of bedrest. Archives of Physical Medicine and Rehabilitation. 77(10), 1071-1073.

Urban, J.P.G., Holm, S., Maroddas, A., Nachemson, A. (1982) Nutrition of the intervertebral disc: Effect of fluid flow on solute transport. Clinical Orthopaedics.170, 296-302.

(Adams, M.A, Dolan, P., Hutton, W.C. (1987) Diurnal variations in the stresses on the lumbar spine. Spine. 12(2), 130-137. showed that fully hydrated discs from a night of bed rest tend to show a 3x increase in annulus stresses during morning bending activities ) 

According to Natarajan RN, ( Andersson GB. The influence of lumbar disc height and cross-sectional area on the mechanical response of the disc to physiologic loading. Spine. 1999;24:1873–1881.)

Hides, et al.The effects of rehabilitation on the muscles of the trunk following prolonged bed rest Eur Spine J. 2011 May; 20(5): 808–818.Published online 2010 Jul 1. PMCID: PMC3082685 PMID: 20593204

F Bailey  et al 2018: From the international space station to the clinic: how prolonged unloading may disrupt lumbar spine stability Spine 2018 Jan;18(1):7-14. doi: 10.1016/j.spinee.2017.08.261. Epub 2017 Sep 28.

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