Is Sitting The New Smoking?
It’s a bit of a bold statement but it did get your attention. So… is sitting really killing us? When our Walton chiropractors are with patients at the Pro Chiro clinic, they often get asked to explain and demonstrate correct sitting posture. We therefore thought it was a good idea to write this post to try and help everyone understand this topic more clearly.
There is no doubt that sitting has become routine in today’s society. On average we sit for almost 10 hours a day! (1). We know that prolonged sitting and a sedentary lifestyle will increase your risk of many health conditions, particularly heart diseases, not to mention the stress and strain it places onto your muscles and joints. It’s no secret then that sitting is a significant risk factor for developing low back pain. Low back pain is the number one global health burden and creates a tremendous economic strain world-wide.
The Mechanics of Sitting
When we sit, our spine is forced into a flexed position and the pelvis tilts posteriorly (backwards), leading to a loss of the natural low back curve (lordosis). This places higher forces on parts of the low back such as the ligaments, joint capsules and the posterior fibres of the intervertebral disc. The majority of this pressure is localised to the L5/S1 and L4/L5 spinal segments (2). These are the most common locations for a lumbar disc herniation.
Sitting for as little as 20 minutes has been shown to increase ligament laxity and delay our protective muscle reflexes. These reflexes support the segments of the spine during movement, so this reflex delay could potentially lead to injury (2).
Creep
Creep is the term used for this gradual change in tissue properties. When placed under a constant load, some of the structures in the spine will slowly deform. For example, when sitting in a fully slouched position, your upper body (head, arms and trunk) acts as a constant force on the lower back. Some parts of the spine (ligaments, joint capsules and muscles) are going to stretch and lengthen. This reduces the tension placed on other parts of the spine (mainly the vertebrae and discs). The result of this is that some of the sensory receptors in the muscles and joints of the spine take longer to activate. In return, there is a slower activation of the muscles and decreased overall strength.
Just imagine this poorly controlled or “lazy” support system suddenly being placed under high demand, such as going to the gym or doing some sort of extreme physical activity (or perhaps just everyday activities). Can you see how this can increase your chances of injuring yourself?
Travel and Work
There are two common reasons why we may be sitting for long periods that are generally beyond our control:
• Work – Sitting at work in the office is becoming more and more common. We have to work, so what can we do about this?
• Travel – Particularly in the car, travelling for prolonged periods sometimes cannot be avoided and often we go from sitting in the car to sitting down at work!
Office chairs have been shown to put you into an overly slouched position (2). Most car seats are designed for the 50th percentile male (3). Therefore most seats are totally inappropriate for the rest of the population. They also provide little or no support for the low back. Additionally it has been shown that a fixed low back support that is the wrong shape or size can contribute to pain generation and discomfort (4). In other words they can make the problem worse!
Low Back Supports
Low back supports and seating aids have been developed for both office chairs and car seats. These supports aim to promote a better sitting posture. Some aim to make you sit upright, such as a tilted wedge to sit on. The purpose of this is to maintain the natural low back curve. Replacing your regular office chair with a dynamic office chair or a stability ball is another solution. This was originally thought to keep the spine in a more active and supported position.
However, studies have actually found that these methods can result in increased soreness due to increased muscle activity and fatigue (2). Similarly, studies done on stability ball\’s showed they led to an increased level of low back pain. This was in addition to no significant difference in muscle activity, spinal loads and overall spinal posture when compared to sitting in an office chair (5).
Passive Supports
There are passive lumbar supports that place direct pressure on the lumbar spine, allowing for increased extension locally. This attempts to relax the back muscles while maintaining the natural low back curve. Some researchers have looked at spine posture and discomfort while driving. They found that when participants were given the choice to select the amount of low back support they thought would be most comfortable, all participants selected at least some amount of support.
However, even though participants were comfortable in the short term, pain was still not avoided in the long term when driving up to two hours (6). In other words, lumbar supports and correctly fitted chairs can be good for pain in the short term, but have little or no benefit for prolonged sitting.
Essentially, chair features are fairly limited as they only influence posture locally at the point of contact. At the end of the day, as long as you are sitting, the spine is still in flexion. Therefore the stresses and strain associated with flexion will still be placed onto your back!
Standing Desks
So, what about standing? Surely that’s the answer! This concept has certainly gained a lot of traction in recent years. But not so fast…. Just as sitting places a flexion force through the spine, standing places the spine into extension. Studies are finding that low back pain caused by standing can commonly develop from as little as 15-45mins of static standing (7). What’s more, low back pain associated with static standing without previous injury is a predictor for the development of long term low back pain (7).
Standing at work can definitely help reduce time spent sitting still. This translates to less upper back and neck pain, plus there is evidence that suggests an overall increase in job productivity. However, without the proper training and advice in the transition to a sit-to-stand work station, problems are arising.
There is also evidence to suggest that standing causes an increase of discomfort of the upper limbs, especially the wrist. This is due to the different bio-mechanical loads at a computer station when changing from sitting to standing (it’s not simply a matter of standing up!). Also, 50% of people reported that their low back pain persisted, with only temporary relief from sitting, and immediately returned again when standing.
So it seems that simply shifting from a prolonged sitting position to a prolonged standing position is not the answer either.
Summary
To sum it all up, there is no perfect sitting posture and there is no one simple solution. The take home message however is to avoid any static posture for long periods of time.
We also need to try to reduce our overall sedentary behaviours. If you have to sit, be sure to move often. The same goes for standing! Once again, movement is the key! If you\’re in the car, being able to adjust and move the supports can help. Better yet, stopping and actually getting out of the car is helpful for stopping pain from sitting.
Take home points and recommendations:
• We are designed to move! It is important to reduce overall sedentary times.
• Perform low level physical activity at work.
• ANY sitting posture is going to put strain on the spinal structures and can potentially cause pain.
• Take regular rest breaks to encourage movement, try not to sit in that same posture for longer than 20 mins.
• For an 8-hour work day, a 1:1 ratio of sitting for 4 hours to standing/walking/other activities for the other 4 hours can be recommended.
• Change postures before you feel pain. Workers who changed position more often, even if the total sitting time was the same had better health outcomes.
• Static STANDING places the spine into extension and can therefore also cause pain.
• If you get low back pain while standing, start with more sitting time. Slowly build to a longer time standing. Start with 20 minutes standing, then sit for 40 minutes. Repeat this throughout the day.
• When transitioning to a sit-stand desk, it is essential to have the proper training and education to achieve a reduction in discomfort.
• An adjustable monitor is necessary when moving between sitting to standing as the ergonomics of a computer work station will change when moving between the two postures.
• It may be beneficial to participate in a stabilisation-based exercise program targeting trunk and hip strength, plus seeking manual treatment for low back pain as appropriate.
How We Can Help
This last point is where we can help you! The sports chiropractors at Pro Chiro are expertly trained to help you overcome back pain and prevent further episodes. Our goal is to help everyone in the community live their lives the way they want without any pain, as your Walton chiropractor. If you have any questions, feel free to contact us here. We also have a Facebook page where our Walton chiropractor provides health tips and advice.
References
1) Diana De Carvalho, Diane Grondin & Jack Callaghan (2017). The impact of office chair features on lumbar lordosis, intervertebral joint and sacral tilt angles: a radiographic assessment, Erganomics, 60:10, 139-1404.
2) Kolich, M (2003). Automobile seat comfort: Occupant preferences vs. anthropometric accommodation, Applied Erganomics, 51, 193-207.
3) Reed, M and Schneider, L (1996). Lumbar support in auto seats: Conclusions from a study of preferred driving posture (SAE Technichnical Paper 960478). Warrendale, PA: SAE International.
4) Michael Holmes, Diana De Carvalho, Thomas Karakolis and Jack Callaghan (2015). Evaluating Abdominal and Lower-Back Muscle Activity While Performing Core Exercises on a Stability Ball and a Dynamic Office Chair, Human Factors, 57:7, 1149-1161.
5) Diana E. De Carvalho and Jack Callaghan (2015). Spine Posture and Discomfort During Prolonged Simulated Driving with Self-Selected Lumbar Support Prominence, Human Factors, 57:6, 976-987.
6) Jack Callaghan, Diana De Carvalho, Kaitlin Gallagher, Thomas Karakolis and Erika Nelson-Wong (2015). Is Standing the Solution to Sedentary Office Work? Ergonomics in Design, 20-24.
Helping you live life the way you want through sports chiropractic care. Pro Chiro is a Walton chiropractor clinic providing sports chiropractic care. If you are experiencing pain or injuries, we can help.
