Step 5: Walk More!

The Desk Warriors Guide to Building a Healthy Back! 5/10

http://www.youtube.com/watch?v=JPq3bk4uRBw

My biggest pet peeve is seeing people spend minutes searching for a close parking spot; driving up and down the rows of cars when they could have easily parked a hundred yards away and walked. Not only are these rats wasting time, they are wasting a fossil fuels, contributing to global warming, wasting money, wasting energy, stressing out about their parking spot and greatly increasing their risk of being in a car accident. O yea, and they are spending more time SITTING when they could have gotten off their lazy asses and gotten a small dose of some exercise medicine.

While some may find walking to be a chore or laborious exercise, others get great relief from walking. Walking speed may have something to do with the above dichotomy. Strolling, or walking slowly reduces spine motion and statically loads the spine. This contributes to the same overloading of tissues that we’ve discussed earlier, and thus pain in the associated tissues. I feel this pain as I aimlessly meander after my girlfriend while she bounces between various female clothing stores while shopping at the mall.

Faster, more purposeful walking results in greater more cyclic spinal movement. This cyclic movement migrates the forces to more tissues. This is hypothesized to be part of the reason why a quicker walking pace is more restorative to the spine. Also, arm swinging (from the shoulder, not the elbow) as in the faster walking clips has been shown in studies to reduce spinal compression by up to 10%. (Callaghan, Patla, McGill, 1999) All other factors being the same, arm swinging from the shoulder, not elbow results in lower lumbar spine torques, muscular activity, and loading.

Get outside and walk people!

Walking is often a first step in various rehabilitations. Studies show walking to be a positive cofactor in prevention of LBP (low-back pain), and more successful recovery from LBP (Nutter, 1988). Besides reducing compressive forces, torques and muscular activity, the light reciprocal muscular activation is hypothesized to not only migrate tissue load but to increase circulation and bloodflow to the area. Tissues heal in correlation with the amount of bloodflow or nutrients they recieve. Think of walking as nutrition to your lumbar spine and the rest of your body for that matter.

Some may find relief simply from changing their morning routine. When we sleep, fluids accumulate in and around the discs. (we are often up to 1cm taller in the mornings) This intradiscal fluid build-up increases pressure in the back, manifesting as a stiff lower back. (ever notice how much more difficult it is too tie your shoes first thing in the morning?) Putting on and tying the shoes in the morning is always harder than at night for this exact reason. Snook and colleagues (1998) found that avoiding forward bending postures upon awakening is very effective in reducing symptoms in a group of back-troubled individuals. This would mean avoiding sitting or performing work where you frequently bend over or forward in the morning is prudent for those with LBP. Forward-bending stresses on the ligaments and discs are higher in the first two hours after rising, requiring less loading or degree of bending to induce injury. (McGill, 2007.) Again, take the dog for a walk, take yourself for a walk, cook and eat standing up. Avoid flexion while your discs are fully juiced.

Desk Warriors, I urge you to pace around in between bouts of sitting. Stand and walk as you take cell-phone calls. (I personally feel more in charge and clear headed when I stand or pace while on the phone) Purposefully walk between tasks. Park farther away from work rather than wasting time and mental energy fighting for the closer spots. Take a brisk walk first thing in the morning on an empty stomach. You will burn fat efficiently and allow for the release of intradiscal fluid pressure. Good luck!

Callaghan, J.P, Patla A.E., and McGill, S.M., (2001) Low back joint loading and kinematics during standing and unsupported sitting. Ergonomics, 44 (4): 373-381

McGill, (2007) Low Back Disorders. Human Kinetics, Champaign Illinios. P. 155.

Nutter, P. (1988) Aerobic exercise in the treatment and prevention of low back pain. State of the Art Review of Occupational Medicine, 3: 137.

Snook, S.H., Webster, B.S., McGarry R.W., Fogleman, M.T., and McCann, K.B. (1998) The reduction of chronic nonspecific low back pain through the control of early morning lumbar flexion: A randomized controlled trial. Spine 23 (23): 2601-2607.

Step 2: Sit Better!

The Desk Warriors Guide to Building a Healthy Back! 2/10

By reading part 1 of The Desk Warriors Guide to Building a Healthy Back, we know that sitting for prolonged periods is something to be avoided. But what are we to do when sitting can't be avoided? After all, our jobs, our livelihoods are now spent hunched over computers. We can't all earn a living on our feet like pro-athletes, dancers or even bartenders for that matter. We have to sit at a desk and work.

This begs the question, what is the most optimal seated posture?

I will first address the myth about "proper" posture. When we sit with "proper" posture, our feet flat on the floor, our knees and hips at 90', the spine long and upright; the head and chest up and our lumbar curve maintained we are actually damaging our lumbar spines. This may be aesthetic sitting posture or proper school boy/girl posture, but according to my man Stuart McGill it is only tolerable for 10 minutes max and should not be attempted further.

"Ideal" Sitting Posture Try to sit unsupported like our man with the "ideal" posture for 10 minutes...

If you take us up on the "ideal" seated posture challenge, what will happen is you will engage your core muscles to the point of fatigue. As discussed in the previous post, engaging the core muscles results in a shortening of the muscles, thus spinal compression. The hip angle of 90* with core compression results in increased compression of the spine, thus increased intradiscal pressures (pressure on your discs). Take a moment to stand up tall and feel your core muscles. Feel the muscles in your lower back and the muscles that surround your waist. You shouldn't feel a great deal of muscular tension. When standing upright, you are designed to elicit the smallest amount of muscular effort. The curvature of your lumbar spine bears the brunt of your weight and only perturbations during movement should result in greater core muscular activity.

So when engaged in prolonged sitting, we want to find ourselves in a position where like standing, the core musculature is at a minimal tone or effort. The typical seated posture or worse, the forward bending seated posture compresses the vertebrae in a manner that sends the disk posteriorly (backwards) This causes a posterior annulus strain of the disk while (center of the disk bursting through the annular layers of the disk leading to bulging and eventually herniated discs). We now know that the outer layers of the annulus fibrosus are innervated (containing nerves) This means that delamination, as occurs when the nucleus of the disc bursts through annular layers (bulging disc) causes pain without impinging on the larger sciatic nerve as previously thought. Further prolonged sitting leads to creep in the posterior passive tissues, which is essentially loosened spinal ligaments allowing for more shearing movement on the spine. This is bad. Think of the mechanism of grating cheese, that is anterior posterior shear, not something you want going on in your low-back.

Now we've deduced that sitting with "ideal" posture or a hip angle of 90* is not a good long-term seated posture.We guessed that leaning forward and increasing the hip angle is even worse because it accelerates the rate of all the above jargon happening in your spine (as viewed below or here). So let's get to the meat and potatoes. How can we sit longer and not destroy our spines and health in the process?

The above T-bone steak looking thing is an illustration of your vertebral discs. The center or nucleus migrating posteriorly as intradiscal pressures increase in various postures.

Now you smart ones out there probably took a good look at the above picture above and hypothesized that since

laying down has the least amount of intradiscal pressures via relaxed musculature, that a more reclined posture is

optimal.

You would be correct. However, a back angle of anything less than 135* can't really be considered sitting since you are closer to laying down. Assuming we have to be at a desk/work station in a seated position, the ideal posture is one in which muscle activation is lowest via support (back of chair or lumbar support), maintenance of the normal lumbar curve and one in which we can change position easily.

The reason we need to change positions easily and regularly is to not overload any one tissue. Tissue loads need to be migrated from tissue to tissue in order to minimize the accumulated microtrauma of any one tissue. Think about it, you fidget for a reason. You are spreading the microtraua from tissue to tissue. McGill recommends changing postures very often. Atleast every ten minutes.

The chair is not helping the situation. Chairs are designed by architects, not biomechanists. Ideally, you would want a chair with a great deal of lumbar support. The Nottingham chair is one that supports the lumbar spine and aims to keep a posture more congruent with standing, thus sparing the spine. Standing desk stations are also a great way to preserve the spine. But yes, the Nottingham chair is expensive and unstylish and standing desk stations have their problems as well.

So when forced to sit for long periods of time. We want a chair that supports the entire back, rather than doing all the work ourselves via the core musculature and contributing to spinal compression in a flexed posture (contributing to discogenic pain). We want to be able to mimic normal standing posture as best as possible so a chair that supports the normal lumbar curvature is essential. If your work chair does not do this, simply buy a lumbar support. Arm rests also alleviate spinal compression, so use them when you get the chance. Most importantly, we want a chair with the ability to recline. The more the better. The optimal seated position would be in a lazy boy, but as most desk warriors aren't afforded this luxury, we must aim to achieve this recumbent position via lumbar support and reclining our chairs. Again, I reiterate that any position must be changed eventually to promote circulation and to spread the microtrauma to various tissues, thus our reclined lumbar supported position must to be changed regularly.

The least compressive the posture, the longer it can be tolerated. So Desk Warriors, arm yourselves with an arsenal of appropriate desk postures. Change the angle of your back via more or less lumbar support or varying degrees of reclination. Shift your weight to your right, then your left. Sit with your legs crossed, left and right. Cross your legs with your lean on. Essentially be mindful of maintaining your neutral lumbar spine while shifting into a variety of comfortable positions.

This stance on postural shifting can also be applied to sleep. No one sleeps in any one position and they shift subconsciously. They do this because it's our way of our body spreading the stresses to different tissues as we should do when we sit, stand, lie etc…

In conclusion, the ideal posture for prolonged sitting is a reclined ~135 back angle posture where our natural lumbar, thoracic and cervical curves are preserved. However, we learned that after a certain exposure, no position is safe and that we must find a variety of Desk Warrior poses to serve our productivity needs.

Callaghan, J.P., and McGill S.M. (2001) Low back joint loading and kinematics during standing and unsupported sitting. Ergonomics, 44 (4): 373-381

And of course the books cited in Step 1: Sit Less