"Sit up straight!" - we've all heard that command barked at us many times.
For years we've been told that good posture means standing tall, shoulders back and your spine straight as a rod.
But that might not actually be true. According to Dr Xand van Tulleken, a doctor and BBC presenter, much of what we think we know about posture is outdated.
In fact, trying to hold yourself bolt upright all day could do more harm than good, he told Morning Live.
As the end of summer looms and many people return to work and studying, here are his three suggestions to improve your posture and in turn help look after your back.
