You know how your mother has been telling you for years to sit up straight and you’ve been telling that to your kids (if you have kids). Leif Parsons has a piece in today’s Times about research that may debunk the notion that anything other than sitting up straight is bad for your back.

Despite its persistence, that
advice is wrong. Parents may insist that sitting up straight with your
thighs parallel to the ground is the best way to sit, but a long list
of studies has shown that that position increases stress on the lumbar
disks in your lower back.

Thirty years ago, scientists first
showed this by inserting needles into the backs of volunteers and
measuring the amount of pressure created by various seating positions.
They found that a reclining position was ideal, placing the least
strain on the back and minimizing pressure that could lead to back
problems. Since then, multiple studies have confirmed that finding.

But
it was only in 2006 that scientists produced direct visual evidence. In
a study that used new magnetic resonance imaging machines that allow
people to sit instead of lie down, a team of researchers at the
University of Aberdeen in Scotland looked at 22 volunteers who sat in
three positions. The first two positions, sitting upright and sitting
with the body hunched forward, produced the greatest spinal disk
movement, causing the internal disk material to misalign. The third
position, in which the subjects reclined at a 135-degree angle with
their feet planted on the floor, created the least strain.

According
to the study, any position in which a person leans back, opening the
angle between the thighs and the back, is preferable to sitting up
straight.

THE BOTTOM LINE Sitting upright at a 90-degree angle strains your back; leaning back places less pressure on the spine.