Sit upright or Sit relaxed
What does the current evidence say?
If you are on a desk job and if you ever had an episode of back pain, you may have been advised to avoid slouching or to sit/stand upright. You perhaps may have come across this infographic of what an ‘ideal posture’ should look like, or some health professional may have recommended you to assume an upright posture while you stand/ sit. Ergonomically designed chairs are very popular in office settings and, they are believed to protect our spine. But this posture advice went too far to the extreme that upright sitting /standing postures are “standard’ for everyone, even to people without back pain.
Could sitting upright truly prevent back pain? Is there evidence to support this belief?
Erect posture is widely recommended for yonks to protect our spine health. This concept has stemmed from two different schools of thought and their treatment approaches. Basically, a group of medical pioneers believed kyphosis when sitting is good whereas others argued lordosis is the best for our spine. Recently we have also seen people advocate for a neutral spine when sitting and standing.
Before going any further, real short information about spinal curvatures-what are they?
We are born like this with kyphotic curvature, we develop normal curvatures as we grow older, and eventually, we become kyphotic.
Quick fact 1: Lot many people don’t have these curvatures and it is not abnormal.
It is believed that slouched sitting or sitting with a hump in our back creates an imbalance in weight distribution on our spine, weakens spinal & trunk musculature, and discs are loaded incorrectly- all this overtime creates cumulative strain in our spinal bones and compresses spinal nerves consequently resulting in pain.
Does slouching load spinal discs improperly?
Animal experiments and human cadaveric studies showed that improper loading of spinal bones leads to deformation in spinal discs. These experiments were conducted on alive mouse tails (tail is part of its spine that has bones and discs like humans), and spines of human cadavers showed that when those spines are mechanically compressed in a way that mimics a typical person likely would do in a real-life, those discs in between spinal bones displayed changes such as dehydration and thinning (changes in disc height) due to abnormal pressure changes. These results are applied as predictions in real life that when humans slouch persistently our discs would deform and cause discomfort and back pain and sciatica (i.e., pain that travels from the lower back to 1 or both legs).
However, we have evidence to the contrary. When we slouch those observed changes (like disc height changes, pressure difference) in the discs perhaps are true but those so-called deformations are not pathological (i.e., not capable of causing pain). Those disc pressure changes happen in everyday life for a purpose. That is the disc’s way of transporting nutrition in and out, as they don’t have a full blood supply.
Quick fact 2: Blood vessels and blood supply are essential to transport nutrition and remove waste contents from our body structure.
When there is limited blood supply, discs have two processes for staying alive - diffusion & fluid flow. Pressure changes within the discs happen when we move, sit, squat, lift, bend, lie down, etc., These constant pressure changes push waste products from the disc outwards and take nutrition inwards when it is relaxed. So, these normal, everyday changes in the discs are unlikely to be associated with pain and long-term damage.
Animal and cadaveric studies benefited humans in a great many fields invaluably. But there are some limitations on how these results should be interpreted, especially in this biomechanical context.
What this means is animal and human spinal discs vary a lot - the type of the cell that makes the disc, size of the disc, how they are loaded (as they are quadrupeds, they don’t load their spine as humans). Hence the predictions or hypotheses from animal studies comes with some limitations and that they cannot be directly applied to human- at least in this biomechanical context.
Spinal DISC- what are they?
We have discs in between our spine bones that transfer our body weight. They function as a suspension system.
They are tough!!
People compare discs commonly to a soft material like gel/cushion/ doughnut with a jam in the middle, when they get compressed things inside squish out causing damages. Whilst this simplification of anatomy to a common man has good intentions, but they pose potential harmful effects on a layperson. I suppose the person could not possibly relax when they imagine things ooze out from the disc when getting compressed!!
In reality, discs aren’t soft; they are, in fact, tough & elastic, and can be compared to rubber tyres that allow getting compressed yet able to recoil. There is a blog about discs, for those who are interested. [Disc bulge or herniation from acute injuries is a different story, we only discuss here under the context of relaxed sitting]
Does slouching cause spinal muscle weakness?
Another common reason proposed to avoid slouching is that this posture weakens spinal musculature and the elastic features of ligaments that support spinal joints will be compromised. Consequently, these soft tissue compromise imposes more strain on spinal joints leading to pain in the lower back. A study done on 20 pain-free people supports this view and it reported that in erect standing/sitting we use spinal muscles better than in slouched sitting and standing. Though it can be argued gradual spinal muscle weakness from slouched sitting exposes the spinal joints to cumulative strain, we don’t know whether there is any causal relationship between muscle weakness and future back pain episodes.
A study done on 50 people with back pain did not find any specific trends of spinal muscle group weakness in the participants. Interestingly, people with back pain exhibit more spinal and trunk muscle activation than people without back pain.
What this means is that people with chronic back pain aren’t relaxed and they hold the muscle uptight to an extent that spinal muscles limit free movement of spinal joints causing even more pain. [There are other reasons why this happens- like fear avoidance behaviour and learning associated behaviour].
Slouching and Disc Degenerative Disease (DDD) otherwise known as arthritis of disc
Often in clinical practice, these disc degenerative disease is associated with back pain. Hence the recommendation is to maintain proper alignment in our spine to prevent degeneration of the disc. However, there is no evidence to prove that upright sitting will prevent disc degeneration. But we have evidence that contrasts this common misconception. In this study, they compared X-rays of people living in the city to tribal people who predominantly squat when they sit, which causes slouching in their spine. The tribal population has significantly less degenerative changes in their spine when compared to city dwellers.
What this means is regardless of how we sit, discs undergo normal age-related changes which is a part of our aging process, and they are not always associated with pain.
Quick fact 3: Disc degeneration cannot be prevented. For example, can we prevent from getting grey hair?
This study found that over 3000 people have different types of degeneration in their spine, but are pain-free. What this means is DDD/arthritis of the disc is not always associated with pain.
So, if degeneration in the disc is not always associated with pain do you really need to spend your energy in assuming upright posture especially that has no evidence to back up the claim that sitting upright is good for our spine?
Posture and social/cultural meanings
Sitting postures or in general, any posture we assume has so many meanings in different social and cultural contexts. This goes back to 5000 years of evolutionary history, of who gets to sit, how to sit & stand, how to rise from sitting. Human behavioural experts or soft skill trainers would say ‘stand or sit as you mean it’. Sitting upright shows you are confident, you are keen; slouching perhaps carry meaning that you aren’t engaged enough. Therefore, in office settings or when you are in an interview, to win people’s attention you are expected to assume an erect posture. Besides this, there is no scientific evidence in favour of sitting upright would protect our spine.
Ergonomics is a huge multi-million-dollar business that of course made our work life easy - computer desks, manual labour devices, and a great many other devices! But, at end of the day, an office chair is any type of chair which, as long as you feel comfortable, is an appropriate chair for you!
Is there a best sitting posture?
The short answer is no.
‘The best posture is your next posture’, as Peter O Sullivan says.
It is not slouched sitting that causes back pain but a sedentary lifestyle and a whole myriad of factors that could cause back pain- see in this picture.
If your lifestyle is sedentary - increase your physical activity gradually, if you are predominantly an office-based worker stand up and move from desk regularly at least every 20-30 mins and, more importantly, stop worrying about sitting posture.
Sit in any posture that you feel comfortable- slouch, sit with crossed legs, sit upright, and use any comfortable chair that should do the job.
That’s all for now!! If you have come this far thanks for your time. If you like this piece, why not share it with your friends.
P.S. My Running update: I recently completed 5K mark. Going great and I’m pleased with my progress.
Useful article.. nice one to share..
nice article, thanks for sharing...