Computerworld — An expensive ergonomic chair won't do any good unless it's properly adjusted by a trained professional, according to a study in the Journal of Occupational and Environmental Medicine .

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Prompted by a move to a new headquarters facility, World Bank researchers designed a study involving two groups of employees. Both groups were given ergonomic office furniture and information on how to set it up, but one of the groups also received personalized setup by a professional ergonomist.

The ergonomics effort reduced the aches, pains and eyestrain produced by office work -- but only for the employees whose workstations were set up and adjusted by an ergonomist, according to the study, led by World Bank health consultant Jasminka Goldoni Laestadius.

The reduction in painful symptoms was clearly related to improved work postures, the researchers said.

"This really isn't a surprise. People are not intuitive ergonomists, otherwise there would never be any problems or injuries," said Alan Hedge , director of the Human Factors and Ergonomics Laboratory at Cornell University, in an interview.

Proper adjustments require an observer who can see what changes are needed, he said, just as an athlete needs a coach to evaluate his technique and suggest improvements.

"Simply giving people ergonomic products with some educational materials is like giving a teenager a car with an instruction book and then expecting them to be a safe driver," Hedge said.