Health experts in Britain are warning that children who regularly send text messages to their friends on mobile telephones, are at risk of developing repetitive strain injury.
According to the Chartered Society of Physiotherapists, regular texting using just a thumb to type could cause pain and swelling in the tendons and possibly long-term injury.
As more children acquire mobile phones, and phones get smaller, they are at risk of a condition more commonly linked to desk-bound adults.
Bronwyn Clifford, of the Association of Chartered Physiotherapists in Occupational Health and Ergonomics, says the thumb is not a very dexterous digit and though it is good for grasping it is not good for repetitive movement.
The symptoms of RSI include tingling, numbness, weakness, loss of movement, muscle spasm and shooting pains.