Laid-back sitting

A few people have asked about the 135 degree sitting angle mentioned in my RSI Day message (see below). It does sound odd and I think 135 degrees is quite ambitious, but I've just taken a photo of myself at my desk and I reckon I get an angle of about 115 degrees between my spine and my thighs (measured very accurately using a protractor held up to the screen!).

Give it a go!