Dr Vybarr Cregan-Reid investigates what the last 250 years has done to our backs. What is it about modern life that has promoted back pain, especially lower back pain, from a rarity to the number one cause of pain and disability in the world?

In the remote Kenyan Village of Pemja, Dr Cregan-Reid meets people with such excellent backs that they are the subject of international study. He hears from pain-wracked workers in Nairobi whose backs today are a pale version of those of their grandparents' and at the London Design museum he comes face-to-face with the artefact that has done most to weaken our backs - the chair.

Chairs with backs are now so ubiquitous it is reckoned there are around 10 for each of us but as recently as 1800 they were a rarity. Not that we have much choice but to sit down today. At the start of the 19th Century fractions of one per cent of people sat down for a living but today three quarters work in offices or drive for a living. We put our spines into positions they were not designed to sustain for hours on end.

He discusses with Australian academics their research which claims that half of back pain is in the mind and why simple movement is probably more effective than surgery, manipulation and powerful painkillers in getting to the bottom of back pain.

(Photo: A woman rubs her lower back. Credit: Getty Images)