The Problem With Sitting...Problems Associated with Long Term Seated Postures
By Charles Staley, B.Sc, MSS
Director, Staley Training Systems
Perhaps the most common oversight made by bodybuilders and other athletes is failing to consider the risks of day-to-day, non-training activities.
Typically, most trainees will be very careful about their form when exercising (which comprises at most, 20% of all activities in any one given day) yet totally ignore the potential consequences of other activities which make up a much greater portion of our lives. When problems arise, blame is usually assigned to the training activity.
One position that everyone spends a considerable amount of time in is sitting. Given this fact, it would seem prudent to study this postural position, and in particular, it's effects on the spine. People are usually surprised to learn that pressures on the vertebral disks are higher when sitting than when standing or even lying down. In fact, some experts suggest that interdiscal pressure when seated is up to 11 times greater than lying down. This risk is particularly insidious because sitting is not normally associated with back pain, whereas standing often is!
How Sitting Results in High Loads to the Vertebral Disks
Many people who, having had the experience of back pain while standing for long periods of time, and the subsequent relief that comes from sitting, have difficulty understanding just how sitting can place undue pressure to the vertebral disks. In order to understand this concept better, let's have a look at the following:
1). First, the distinction must be made between the back muscles and the vertebral disks. When you stand for long periods, the disk pressure is relatively low, but you nevertheless feel pain, which is a result of fatigued lowback muscles.
2). Increased pressure on the disks in and of itself does not necessarily result in immediate pain. Thus, we are often unaware of this pressure, which in the long term can lead to deformative changes in the disks.
3). Now to the real mystery— how can sitting create higher intradiscal pressure than standing? It's because, when standing, your bodyweight is distributed over a wide variety of structures, including muscles, tendons, ligaments and joints. Upon sitting down, however, the abdominal "corset" relaxes, which causes a majority of your bodyweight to load the disks. As we mentioned earlier, you probably will not feel any pain at all when this happens. But over the long term, the constant, increased load upon the disks can result in a multitude of problems, from impinged nerve roots to degenerative osteoarthritic changes.
Since sitting is inescapable for most of us the best advice is 1) to limit time spent sitting as much as possible, and 2), design your workplace (which includes, but is not limited to your chair) with the following in mind:
- Chairs with lumbar supports (sufficient to maintain, but not exaggerate the normal lordosis, or sway, of the spine have been shown to result in lower interdiscal pressures than chairs without these supports.
Chairs with armrests also reduce pressure on the disks.
Sitting in an reclined position (120 degrees seems optimal) lowers disc pressure, so make sure your chair allows you to alternate positions!
Since keeping the knees close together makes you more prone to "slumping," choose a chair that is wide enough to keep your knees apart. Also, you sit at a desk for long periods of time, make sure that it allows you enough space to open your knees.
When selecting a chair, adjustability is crucial. This is because people come in different shapes and sizes, have have unique needs for their work-station set-up. An adjustable chair will ensure that you can optimize your own workstation for the best possible ergonomic effect.
At your work-station, your chair/desk arrangement should be such that your forearms rest on the desk, elbows at a 90 degree angle and close to your sides— this position reduces stress on the trapezious and surrounding muscles of the upper back and neck.
- If you work with a computer monitor, or anything else that you visually refer to often, keep it straight ahead and at eye level— if your focal point is lower than this, it sets you up for a rounded, slumped forward posture.
Remember— virtually all postural related spinal disorders are preventable!
Although the dangers of sitting for prolonged periods of time may not seem like a pressing issue at the moment, over the years it has a cumulative effect on the spine— just take a look at many older people who have acquired debilitating hunchbacks and other deformities from lifetimes spent in poor posture.