Is sitting up straight really ergonomic?

This recent article on the BBC website suggested that sitting up straight to work wasn't actually as good for your back as previously suggested.

…an interesting report suggesting the low-strain result of slouching, we're sure that the results are right, but what about the conclusions in the article?  The report could easily be misinterpreted

The posture may be OK for relaxing (isn’t this what this is all about?), but for all those people working on a computer at a desk, it can raise other problems:

• Viewing distance to the computer screen is much increased in this position, making great demands on visual acuity. This posture makes the person lift their head, whereas, with an upright posture the head is more naturally balanced. For many people, there will be  a tendency to strain the head forward, creating more trouble in the neck than it saves in the lower back.
• This is particularly true of those who wear varifocal glasses, since the increased viewing distance prompts a view through a higher part of the lens, which in turn forces the head more forward
• It’s difficult to hold the arms outstretched for any length of time, so this seating posture needs to be combined with a lower desk, moved close in to the body – which limits freedom to fidget around. Everyone agrees (do they?) that regular movement is good!

The illustration shows a chair with what appears to be a good lumbar support. I would predict a very different result if the chair had been a canvas deck-chair, where the lumbar region has to be supported by the body’s own musculature.

Most of us have seen, heard of or tried the “kneeling” chair, designed to reduce the angle between pelvis and thighs. This has only a marginal success, not because the reduced pelvic angle is bad – it isn’t, but most “kneeling” chair designs actually limit freedom to move the legs as widely as an “ordinary” one. People with weak knees also suffer from the load on their knees

So, for most of us, an upright posture will still be the all-round winner for the working environment. As Ergonomists, we will probably continue to encourage people to sit upright when working and, critically, to keep up with breaks and changes in posture.