Sitting Up Straight: Is it really the best for your back?

Judd's note: We've all been told that sitting or standing up nice and straight is good for posture. But what about when you're seated for a lengthy time? Is placing a chair at a 90-degree angle really the best for your back? Matt Ford thinks not. Read on.....

A new study conducted at the Woodend Hospital in Aberdeen, Scotland reveals some information that may surprise you. It seems that sitting up straight, with your legs parallel to the floor forming a 90-degree angle with you back, is not all that good for you. This posture puts a large amount of pressure on one's lower lumbar discs. The high stress on the discs can, and often does, lead to lower back pain, which is the second most common cause of doctor and hospital visits in the US, behind only the flu and colds.

If this proper posture is not best, then what is? Apparently sitting with a 135-degree angle between your lower back and thighs is the preferred posture positioning for your aching back. This is about the angle that is formed between your thighs and back when sitting in a La-Z-Boy type chair--another reason to love them.

As one will obviously say, a reclined seating position does not lend itself well to working on a computer, which is often done sitting up straight or, even worse according to the study (and being done by me at this very moment) leaning forward. A way to achieve this 135o posture is to raise the back of the chair so that you keep your feet on the ground, but open the angle between your back and your thighs, thus minimizing back pain.

However, as anyone well versed in ergonomics will tell you, keeping one position for extended periods of time is bad, so getting up and stretching or walking is always healthy.

This study was carried out using a new type of magnetic resonance imaging (MRI) technique. Traditional MRI machines require the patient to lie down in a closed tube: this position lets the spine be fully relaxed and doesn't allow it to be imaged under stress.

By using newer MRI machines with new capabilities, doctors were able to conduct a study to image 22 healthy patients while they were sitting up, examining their spines under normal stress loads. The 135-degree angle they found confirmed a 30 year old study that examined pressures in peoples back by placing needles in there to measure the pressure at various locations. They too found an ideal, low pressure, angle of 135.

This angle is the form your body will take in the absence of external forces, such as floating in water or an astronaut in zero G. While this position is not practical to sit in all day, experts suggest that you try to sit in a partially reclined position when work allows, while on the phone and not using the computer is an example offered. It seems good, now defined as reclined, posture today can save you a lot of pain in the future.