Spinalis chair - opinion?

[McHrozni]

Hello all

I tried a Spinalis chair at work today, and it was an ... interesting experience. It encourages active sitting by forcing you to remain upright. My back felt as if I was exercising, so there is something to it.

http://www.spinalis.us/

The manufacturer claims this trains your spinal muscles to support your spine while sitting, which in turn greatly reduces injuries to spine in later life. Since my mom had surgery a few years back for discus hernia, I was thinking of buying one or two.
The catch is that they're ridicolusly expensive ($900-2600 or 600-1300€), so buying one to try it out isn't an option for my psyche :) Does anyone have any experience with them or knows enough about the underlying principle? The manufacturer offers a bunch of rave reviews by a bunch of people I've never heard of, which is normal. :)

Thanks in advance :)

McHrozni

[casebro]

I think I would find it very tensing. Two discs fixed by two procedures, and I find that when I sit on any thing that my back has no confidence in, causes my back to tense up. YMMV. But the spring looks like a gimmick to me. Sitting on a ball might be good as exercise, for a short time?

[svenax]

I haven't tried that one, but something similar. I have some friends who all swear by the Swopper (www . swopper . com), a chair attached to a spring that bounce up and down as well as flex sideways. I can use one for maybe ten minutes, then my back is shot. I need support, not exercise when sitting.

[McHrozni]

I haven't tried that one, but something similar. I have some friends who all swear by the Swopper (www . swopper . com), a chair attached to a spring that bounce up and down as well as flex sideways. I can use one for maybe ten minutes, then my back is shot. I need support, not exercise when sitting.

Aha. Well, this one does not bounce up and down, the spiral (it's not a spring) is there just to provide the flex. I sat on it for about 20 minutes and, as I said, my back felt as if I was exercising - tired, but quite good.

Thanks for the opinions :)

McHrozni

[JuWlz]

I'm not familiar with that particular chair, but the thing that helps your back most is balance. Movement in a chair (i.e. rocking forward and backwards easily with you) combined with a forward tilting seat whilst working (to reduce the backward pull on the pelvis by the hamstrings - which for most of us have shortened over the years) allow sitting to be as much like walking as possible. And walking, not sitting, is what our bodies have evolved to do. In evolutionary terms, we're still hunter-gatherers.

For scientific research into forward tilting work seats, see Home Sedens - The Seated Man (http://www.acmandal.com/).

Movement in a chair triggers the body's balance mechanisms, and so adds to the concept of forward sloping seats to make them easier to use. Have a look at anything you can find by Peter Opsvik (http://opsvik.no) (e.g. Hag (http://www.haginc.com/web/dynamic-ergonomy-us.aspx) or Varier (http://varierfurniture.com/Collections) chairs - the former LOOK like office chairs; the latter are based on rocking bases made of laminated beech) - and in my opinion are much smoother and more natural to use. My personal favourites for sitting at a desk or table (depending on situation) are the Actulum (http://varierfurniture.com/Collections/Human-instruments/Actulum) and Thatsit (http://varierfurniture.com/Collections/Human-instruments/Thatsit-balans-R/%28language%29/eng-GB). I also have his Gravity (http://varierfurniture.com/Collections/Human-instruments/Gravity-balans-R) chairs in my lounge, which are supremely comfortable and versatile ;-).

Opsvik's answer to the question of what is the best sitting position is somewhat glib, but very true: "The next one". i.e. it's the movement, rather than any particular position, that keeps your back healthy.

Balancing on the points of the pelvis (in the same way that you do when you're walking) is much easier to do than "sitting up straight", which involves a lot of muscle power and is tiring. And while you're concentrating on working, sitting up straight through muscle power is just too difficult to do - you have to pay too much attention to it. Sitting with your back supported whilst at a desk actually encourages slumping (through the upper back, if not the lower). Yes, most people have got used to being supported (mostly with the pelvis in an unbalanced position, i.e. rolling over backwards, which puts a strain on the lower back). If you allow the pelvis to roll over backwards, and then support the lumbar area, you actually set up some quite powerful shearing forces between the top of the (non-upright) pelvis and the lower spine. Balancing the pelvis upright allows the lumbar curve to be natural.

Balanced sitting may take a bit of practice, and most people will have to re-learn how to sit in balance, but a rocking, forward tilting seat encourage that balance, and it's not difficult to learn, and once learned, you don't need to pay any significant attention to maintaining it. To find the points of your pelvis, sit on your hands (palms upwards) and tilt your pelvis until you're digging the points of it into your fingers most sharply. From there, close your eyes, and rock forwards and backwards on the points of the pelvis, making the rocking movements smaller and smaller, until you're virtually still. At this point you SHOULD be upright. However, allow for the fact that most people PERCEIVE that they're upright when they're actually leaving backwards slightly. (To confirm this, get somebody to connect a video camera to a TV and give you live feedback from a side view.) Don't forget you had to learn how to balance to ride a bike too. If you're a horse-rider, you won't find this at all difficult or unnatural.

Balance works because the body finds movement less tiring than stillness. As a quick illustration hold both arms out by your side at shoulder level. Keep one of them still, and move the other one around, keeping it more-or-less at shoulder level. See which ones feels tired first. Balance is continual adjustment of position (think of a tightrope walker, as an extreme example - not one you probably want to test while concentrating on something else though!). A bicycle or motorbike is a less extreme example. Lose the movement, and you lose the balance. Sitting on a chair with your feet underneath your hips on the ground gives you a more stable, yet still balanced basis for your working position.

You can find more (general) advice on sitting at a desk here (http://www.backinaction.co.uk/advice-sitting).

The cheapest solution that combines movement with forward tilting and balance is to sit on an exercise ball (of the correct height for your legs), and with your desk height adjusted to elbow height when seated on the ball. Of course, being spherical, a ball needs to be as wide as it is high, which can be impractical. Putting the ball in a frame makes it more practical - it won't roll away when you stand up, and you can get the same height from a smaller diameter ball, which means you don't have to straddle quite as much.

Note that the principle of adjusting the desk to your on your chair of choice holds true whatever you sit on: adjust the chair to you, not to your desk, and adjust the desk to the correct height for you on your chair (which will vary depending on what you're sitting on). This can usually be done pretty cheaply using blocks of the appropriate height under the legs of the desk. Most people tend to adjust the chair to the desk, and if you're tall, that just means that either your legs are crumpled uncomortably underneath you, or your knees have to be higher than your hips, losing the forward tilt and balance.

Tilting your work surface towards you (if you write, rather than using a computer) will also help to discourage slumping.

Julie