Sitting is very bad for backs. Standing is very good. This is what many experts on the subject of computer ergonomics remind us every year. I think the whole logic behind this is simply that if your body becomes accustomed to sitting, your standing and walking posture will be "look" less human the longer this is done, which is already a good sign that something is wrong, never mind the pain that might already be a good indicator. So the alternative is to optimize your body for standing and walking, and then to sit in such a way such that it doesn't affect your standing and walking. Doing so won't hurt your back when you sit or walk, which proves the human body was not designed for sitting for hours at a time, but for upright movement. It's not something a person does that's bad, it's just the way the human body has evolved over the years.

The first problem I see with this report is that there is no mention of which chair was used and how long the subjects had to adjust to it. They probably had people sit down in a study-provided chair for a minute, then took the scans. It's possible the subjects didn't really get into as comfortable or realistic position as they could have, given a couple of weeks to adjust to the chair, or to bring their own.

Secondly, if one works out, they may be able to sit upright and still have great posture without slouching. It would be nice if a follow up study was done with subjects who work out regularly.

It would nice to know what the purpose of the chair was, as well--to allow users to sit in the "proper" way given measurements made by the manufacturer, or to compensate for the more realistic way a human might sit? I've read that car seats have been redesigned because of the discovery that people don't actually sit the same way as expected, though I don't recall if this was a comparison of American sitting habits between this decade to another, or that of Americans drivers compared to those of other countries.

Finally, the suggested solution should not have been to sit at 120-135 degrees, but to exercise regularly, weight train, and take frequent breaks.

I prefer standing when computing. For an elegant solution, you might want to look at Anthro carts; specifically the ones that adjust to standing height:

http://www.anthro.com/cpage.aspx?pid=200

Alternatively for the budget-minded, Phil Torrone pointed to this DIY for a stand-up desk a while back:

http://www.instructables.com/id/Stand-up-desk/

It isn't as though the medical community hasn't known this. I had a serious back injury over 10 years ago while still in high school. Semi-reclining to about 120 degrees is what my physical therapist suggested way back then.

Sitting upright puts a lot of pressure on your discs, but most people's back problems come from lack of strength in the abdomen, lower back, and "core" muscles connecting everything together. You can sit in whatever position you want so long as you keep in shape.

This is really interesting.

I've personally found the 120-135 degree angle the most comfortable.. I'd previously thought it was terrible for my back, perhaps not!

I've actually been looking for a way to use a laptop or PC comfortably while lying on a couch. Does anyone have any recommendations for this kind of usage?

An optical mouse is great because you don't need a flat surface. On-screen keyboard is also great if you really cant be f'ked. :P

I'm just in this position, I've my laptop on a small side table and I'm using a standard keyboard and a trackball. It's pretty comfortable.

The real problem with a 120-135 degree posture isn't the tendency to slide off, it's the tendency to slack off... and the difficulty of getting things accomplished from that posture.

I don't think the study has factored in the use of a keyboard. It's not as easy to type when you're reclined backwards - it adds extra stress to the wrists and triceps (assuming your still typing on the desk).

If you don't use the mouse a lot, it's easy to just set the keyboard in your lap.

The thing I hate about leaning back this far is having to bend your neck forward to see the monitor.

Great, so I worked on good posture during the last year for nothing.

I think the most entertaining thing about this article is that they quoted Dr. Bashir. I wonder how often people make jokes about that to him.

"reclining at 135 degrees can make sitting more difficult as there is a tendency to slide off the seat"

Exactly. Being suspended in a fluid tank might be awesome for the back but unfortunately some of us have to work while sitting at our desks.

I habitually put my feet on the edge of the desk at work. I find that I just can't stand the stress of other positions. I already have scoliosis; why should I make my suffering worse?

Can anyone recommend chairs that lean back this far?

I use Aerons. But I've been able to make every chair I've ever used do this. It's hilarious to me to see that I've been doing the right thing all along, after about 20 years of sitting in what everyone (including me) supposed was a preposterously unergonomic posture.

Yeah, I've always felt like a slouch. I sit exactly how they recommended. Any other posture became uncomfortable quickly.

Nice to know we were right all along eh? ;)

I slouch just a bit and it never bothers me. I also tend to fidget, get up a lot, switch positions. I don't sit still very well...

Sitting still is not a natural human state. Consider that the chair is a recent invention...

You are far from abnormal.

Just follow this guy's advice:

http://news.ycombinator.com/item?id=184930

and code from a beach chair in Brazil. ;-)

Just strap your laptop to the steering wheel and put the seat back.

I knew it! I feel entirely justified about my 'poor' seating posture now!