How much time do you spend in front of the computer? Do you sometimes feel like you need a back massage after work? Have you ever wondered if your back pain is related to your posture at work?
These questions have been subjects of scientific studies all over the world. A person who spends more than half a day at work sitting with poor posture is at risk of developing lower pain or leg pain (sciatica). This trend is also observed among truck drivers and heavy machine operators.
The spinal column is composed of vertebrae (bones) and intervertebral discs. The disc fits between two vertebrae to allow better movement, lubrication, and shock absorption. In the lower back (lumbar region), there are 5 vertebrae. Of these 5 vertebrae, the last vertebrae is connected to the sacrum, which forms a joint with the pelvis.
What happens when you sit for a long time?
Intervertebral discs deform over time as a result of poor posture and movement. In a seated position, the discs are under 10% more stress compared to a standing position.
When seated, a load is carried from the neck to the lower back by each vertebrae. The spine is able to adapt to the seated position, but it has its limitations. The longer we sit, the more the discs are compressed. After 4 hours in a static seated position, this distortion of the disc is much greater and the disc begins to “flatten.” This change is mostly observed between the 4th and 5th vertebrae in the lower back (L4-L5). Imagine the impact on your body over several days, months, and even years. Static sitting can increase the risk of a bulging disc and herniation.
What happens when you are exposed to vibrations?
Some people work in environments where their bodies are exposed to vibrations. For example, the vibrations may come from tractors, trains, trucks, and helicopters. Vibrations may also be from machinery such as those used in dental care or in the pharmaceutical industry. When we are seated, the vibrations transfer from the seat or arm to the rest of the body. Certain parameters, such as the intensity, duration, and the frequency of vibrations, increase the risk of developing sciatica or back pain. In addition to the vibrations, the workers are often seated with poor posture, either with a twisted back or with more weight on one side than the other.
Simple solutions to protect your back
Are you seated all day? Do not panic! One way to prevent back pain while sitting is to move a little every 15 minutes. What kind of movements can you do? It is not necessary to get up. You can simply reposition yourself on your chair while making sure that you are comfortable. Light stretches while sitting may also help. These readjustments can take a few seconds and will help your back over time.
In an ideal world, a cylindrical cushion would support the lower back. If you shop around, you can find a lumber roll support that fits nicely on the back of a chair. This support allows you to keep a space between the back of the chair and the upper back while keeping a straight posture. With a relaxed upper back, the shoulders are less rounded and the neck is less stiff.
Occasionally, some occupations may require working in poor posture, such as a dental hygienist or a seamstress. As much as possible, keep your abdominal muscles (core muscles) contracted. The deep abdominal muscles act as a corset or belt since they attach with the low back muscles. When these muscles are engaged, they provide an increased stability in the lower back despite being in a poor seated posture.
Article written by Lisa Zhu, physiotherapist
Billy, G. G., Lemieux, S. K., & Chow, M. X. (2014). Lumbar Disc Changes Associated with Prolonged Sitting. PM&R, 6(9), 790-795.
Lis, A. M., Black, K. M., Korn, H., & Nordin, M. (2007). Association between sitting and occupational LBP. European Spine Journal, 2, 283-298.