BBC Learning English.

We hear family members and teachers telling us to "sit up straight" and "stand tall", but do they say that because an erect posture is more aesthetically pleasing, or is it the key to a pain-free back?

It's commonly believed that 'slump' sitting or 'slouch' standing damages our spines.

But, is slouching really that bad?

Meghan Markowski, physiotherapist at Harvard-affiliated Brigham and Women's Hospital, says that a poor posture can lead to neck pain and back problems.

She also links it to other problems like poor balance, headaches and breathing difficulties.

Meghan says we should aim for an upright spine position and to avoid flexing and arching our backs.

But, if you're a sloucher, there may be some good news coming from the last two decades of research…

In an article called "Sit Up Straight: Time to Re-evaluate", physiotherapist Diane Slater and colleagues review the current research and conclude that there is no strong evidence that slouching aggravates back pain, or even that a perfect posture exists.

Instead, they argue that differences in our spinal curvatures are a fact of life, and that our backs are stronger than we think.