Short screen breaks are key to reducing injuries

Short, strategically spaced rest breaks can reduce eyestrain and musculoskeletal discomforts for video display terminal operators without decreasing productivity, according to a recent official study.

The report was conducted by the US National Institute for Occupational Safety and Health and published in the scientific journal Ergonomics.

A Field Study of Supplementary Rest Breaks for Data-entry Operators by Dr Traci Galinsky compared results under two rest-break schedules for a group of 42 data-entry operators employed by the Inland Revenue Service.

Under one schedule, the operators worked their regular daily schedule, including two 15-minute rest breaks, one in each half of the work shift.

In the other schedule, the conventional breaks were supplemented with four five-minute breaks spaced throughout the day, giving 20 extra minutes of break time.

The conventional schedule comprised a 15-minute break after two hours' work, a 30-minute lunch break after four hours' work, and a second 15-minute break after six hours. The supplementary schedule involved a five-minute break after one hour's work. The 15-minute break remained after two hours' work. A further five-minute break was taken after three hours, with the 30-minute lunch break four hours from start time. A five-minute break was introduced an hour-and-a-half after lunch. Later came the normal 15-minute mid-afternoon break, while the final five-minute break was taken an hour before quitting work.

Under the supplementary schedule, the workers consistently reported less eye soreness, visual blurring and upper-body discomfort.

Moreover, "increases in discomfort of the right forearm, wrist and hand over the course of the work week under the conventional schedule were eliminated under the supplementary schedule. These beneficial effects were obtained without reductions in data-entry performance," says the report.

In short, quantity and quality of work were comparable under both schedules, measured by numbers of keystrokes and accuracy in typing data from paper forms into the computer.

"Adding short breaks through the day may relieve cumulative discomforts from repetitive motions and static postures in a way that conventional break schedules do not," concluded the National Institute for Occupational Safety and Health.

In a comment equally pertinent to the Irish workplace, institute director Dr Linda Rosenstock said that, with the move to a service economy, increasing numbers of workers were employed in visual display terminal-intensive jobs. "It is encouraging that practical steps exist for improving job quality and perhaps reducing the risk of musculoskeletal injuries from these growing numbers of workers".

According to the report: "Accumulation of discomfort in several body parts was significantly attenuated by providing frequent opportunities to recover from the fatigue imposed by static postures and repetitive motions.

"It is particularly noteworthy that supplementary rest breaks reduced discomfort in the neck and shoulders, as these body parts have not appeared to benefit in previous studies utilising workstation design interventions."

Researchers also found that "small day-to-day increases in discomfort in the right forearm, wrist and hand" when workers broke only for the conventional rest periods "were significantly offset" when workers took the extra five-minute breaks during their daily working schedule.

As well as decreasing musculoskeletal discomfort, the additional short breaks "also led to decreased levels of eye soreness and visual blurring", says the report.

Previous studies found improved productivity in workers who took regular short breaks. While this study found no such improvements in job performance, "inspection of the data indicates that the mean keystroke was actually higher (although not significantly) under the supplementary schedule than under the conventional schedule".

So although workers worked a shorter period, they were just as productive.

The report emphasises that "the supplementary rest break schedule did not have any negative impact on worker performance. Furthermore, interviews with worksite managers indicated that no disruption of work processes was associated with the supplementary rest break schedule nor with the study in general, and all of the productivity goals (`program completion dates') were met on schedule throughout the duration of the study".

Participants in the study systematically rated their levels of discomfort and other feeling states such as cheerfulness, energy, tension and fatigue. They were instructed to note any instances in which how they felt was influenced by non-job factors, such as playing sports, gardening or medications. Overall "mean ratings of discomfort were relatively low, and mean changes in ratings produced by statistically significant rest break effects and interactions were small . . . However, the importance of what appear to be modest effects should not be under-emphasised."

jmarms@irish-times.ie