As kids, everyone's mom reminds them to 'sit up straight.' Is sitting up straight better for me than being relaxed?
Why do we think that it's a good thing to sit up straight? It might be because we assume that it's good for the back.
However, according to a study by Scottish and Canadian researchers, exactly the opposite is true. Sitting up straight, as it turns out, is actually bad for your back! The researchers used a positional MRI scanner, which allows patients to move around during a scan, to look at the spines of 22 subjects in a variety of sitting positions. The worst position for the back turned out to be sitting straight up. The upright position put puts a lot of pressure on the spine, and causes the vertebrae to move around. If the vertebrae move too much, a slipped disc can result, causing a lot of pain and often requiring surgery to fix.
The best position for the back, according to the study, was leaning back at an angle of about 135 degrees. Picture a clock-face reading a quarter after ten o'clock, with the short hand being your back.
Now, keep in mind that this study was done on adults, not kids. Also, a sample of 22 people is a pretty small sample. It's probably not true for everyone that sitting up straight is harmful, or that leaning back is better for your back. However, at the very least, it seems to be the case that sitting up straight is not always best for the back.