Byting us where it hurts

Computers may be more ergonomically harmful than previously supposed, a sizeable study by health and safety software developers Wellnomics has found.

The Christchurch-based company - the only New Zealand company represented within US-based research funding organisation the Office Ergonomics Research Committee (OERC) - recently conducted an analysis of the behaviour of nearly 50,000 computer users across 95 organisations in Europe, North America and Australasia and found earlier national and international ergonomic studies based on self reporting were likely to be between 40 and 100 per cent inaccurate. The reason: computer users consistently over-estimate the amount of time they spend on a computer at work a day.

Wellnomics discovered this by conducting observational studies based on "odometer" software installed in the computers of workers. The software recorded keystrokes, mouse clicks and time spent at the computer and showed the average office worker uses their computer for 12.4 hours a week or 2.4 hours a day over a five-day working week. Only 12 per cent of users had average computer use exceeding 20 hours per week, with less than 1 per cent exceeding 30 hours per week by working beyond standard business hours.

"We have [computer use] guidelines set at around five or six hours a day in various countries, based on self-reporting studies which have now been found to be inaccurate.

The reality is the current level of injuries is coming from far lower levels of computer use than first thought. If we are seeing high incidences of computer related RSI with average work computer use of only 2.4 hours a day, then new guidelines need to be developed urgently," says Dr Kevin Taylor, director for Wellnomics.

While Taylor is wary of stating what these guidelines should be, he says existing recommendations around computer use may put people in a higher risk zone for RSI and MSD-related injuries than previously thought.

With younger generations using computers for long hours of leisure and social communication as well as study and work, and employers encouraging employees to use web chats and mobile computers, RSI injuries are now present in people just entering the workforce.

This, along with the study's findings, mean employers might like to reassess which users could be considered high computer users, he says.

"There are about 50 different risk factors that contribute to musculoskeletal disorders but, with computers, the risk is in how much people use the computer compared with how often they take a break. Most people think in terms of chairs and desks when they think of ergonomics but even if the [external] ergonomics are excellent, if you put computer use in your risk model, then the threshold for [RSI and MSD] risk is lower than what [was] thought," says Taylor.

Wellnomics' findings were presented at the 2007 PREMUS international scientific conference for musculoskeletal disorders (MSDs) held in Boston.

Taylor says one of the most important discussion areas arising from the findings is how to approach guidelines set by governments and corporations for safe amounts of computer usage. He says the level of computer mouse use is also more important than the number of keystrokes as an indicator of RSI risk, because there is a scientific consensus that it is not repetitive actions like typing that cause most RSI injuries, but the static posture and muscle tension required when using a mouse.

Other data collected in the research included which applications were used the most and which types of computing users spent the most time doing.

Email unsurprisingly took first place, using 28 per cent of total computing time, with internet browsing in second place at 18 per cent and word processing at 15 per cent. Meanwhile, users in the study spent just under half of all work computer time (46 per cent) online, either for email or internet browsing or using online applications or web portals.

Taylor says one limit to the study is that it covers only work environments - it's hard to say whether people who suffer from computer related RSI injuries have also used their home computer for long hours.

Interestingly, there were significant differences in average computer use between users in different countries, suggesting differences in cultural attitudes towards work hours and perhaps computer use.

UK users put in the most hours (16.8 per week) and recorded the highest number of keystrokes an hour of computer use, followed by users in the US and Australia with 14.5 and 13.6 hours a week respectively. But the number of keystrokes a user an hour in the Netherlands was a third less that of UK and Australian users.

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