Smartphone addicts feel the pain now

Users of smartphones and tablet computers are starting to get high-tech blues, as increasing numbers of the tech savvy are coming down with ailments from "text neck" to "text thumb injury".

'The weight of an average human head is between 10 to 12 pounds (4.5 to 5.5 kilogrammes),' said Hutchful.

In an ideal posture, where a vertical line can be drawn from your ear through your shoulder, hip, knee and ankle, 'the weight is carried efficiently', he noted..

But if the head is constantly held forward to squint at a screen, then the unusual posture makes the head feel up to four times heavier, increasing strain across the whole body, he explained.

'Text neck' is in effect the latest manifestation of 'repetitive strain injury' (RSI), a condition which affects one worker in 50 in Britain.

RSI is the name given to a group of injuries affecting the muscles, tendons and nerves primarily of the neck and upper limbs. It is particularly prevalent among workers who spend long periods using computers and computer mouses.

It is a treatable condition, but experts warn it is essential not to ignore the early warning signs.

In France, RSI is the main cause of sick leave in the work place.

Emmanuelle Rivoal, a Paris-based physiotherapist and osteopath, is seeing an increasing number of patients who are paralysed by pain 'because they spend more than five hours a day in front of a screen.'

While stressing that he did not want to 'demonise smartphones', Hutchful offered some pointers for gadget aficionados to avoid injury, such as keeping smartphone use at under 40 minutes.

'Keep use to a minimum, take regular breaks and look at different ways of interacting,' such as voice recognition software for texting, he said.

Margo in Britain says the biggest at-risk group are children and teenagers, who are heavy users of the latest computers and phones.

'I know families where people communicate from one room to another via text messages,' she said. 'We have to put limits on this.'