In particular, the popularity of text messaging -- known as "thumb culture" -- is being blamed for the new phenomenon of the problem.

Because of instant delivery and low charge, text messages have rapidly become one of the most popular means of communication among young people.

Figures show that in 2002, 90 billion text messages were sent through China Mobile and China Unicom, about 246 million per day on average, rising to 300 million a day during the outbreak of severe acute respiratory syndrome (SARS).

Besides now young people are paying for their messaging mania.

Tang Xiaoyan describes herself as a text message addict. Working in the Beijing branch of a Chengdu-based cultural communications firm, she has no relatives in Beijing and lives farfrom her friends, so text messages are her major entertainment.

Tang says her monthly expenditure on text messages ranges from 150 to 200 yuan (18.3 to 24.4 US dollars). During the SARS crisis,the firm suspended business so she stayed at home and spent more time on her phone.

However, Tang recently found she had sore thumbs. "It's gettingworse day by day," she says.

A doctor told her she wrote too many text messages and her tendons were injured.

Wang Heping, a senior doctor with the Renmin Hospital of Gansu Province, said, "I have received four cases of tenosynovitis this year, and I believe there are more people who haven't seen a doctor."

Thumbs might be hurt by pressing the phone keypad too much, tooquickly and on a very small space, Wang said.

"To keep your thumbs healthy, the best way is to write less messages and do more physical exercise," he said.

(People's Daily July 17, 2003)