Active Leisure Protects Against Repetitive Strain Injury

VANCOUVER, British Columbia, March 30 -- An active lifestyle away from work protects against on the job upper-body repetitive strain injury, found researchers here.

In a large population-based survey in Canada, people with an active leisure-time lifestyle were 16% less likely to report having work-related repetitive strain injury, according to C.R. Ratzlaff, a doctoral candidate at the University of British Columbia.

On the other hand, analysis of data from the 2003 Canadian Community Health Survey showed that participation in leisure activities with a heavy upper-body load -- such as baseball, hockey, or golf -- wasn't associated with increased risk of repetitive strain injury, Ratzlaff and colleagues reported in the April issue of Arthritis Care & Research.

"This finding provides evidence for a hypothesis that an active lifestyle outside of work may protect against work-related repetitive strain injury, adding another potential health benefit to leisure-time physical-activity participation," the authors said.

The data came from a Canadian cross-sectional survey of 134,072 respondents, ages 12 and older. The analysis was limited to the 58,622 participants reporting work-related injuries during the year before the survey.

Of those, the researchers found, 5.9% reported upper-body repetitive strain injury. In a multivariate analysis, a range of factors were found to be associated with repetitive strain injury, including:

• Female sex. Compared with men, they had a 68% increased risk of repetitive strain injury. The odds ratio was 1.68, with a 95% confidence interval from 1.52 to 1.85.
• Obesity. The odds ratio was 1.25, with a 95% confidence interval from 1.11 to 1.42.
• Work-related stress. Compared with those who said they had low stress at work, high stress increased the risk of repetitive strain injury by 44%. The odds ratio was 1.44, with a 95% confidence interval from 130 to 1.58.
• Age. Compared to those under 30, those between 30 and 49 had a 29% increase in risk, while those 50 and over had a 26% decrease in risk. The odds ratios were 1.28 and 0.74, respectively, with 95% confidence intervals from 1.03 to 1.57 and from 0.64 to 0.88.
• All the associations were statistically significant at P<0.01.

But the key finding, the researchers said, was that - compared with those with an inactive lifestyle - those whose leisure was filled with sports and other physical activities had a 16% reduction in the risk of repetitive strain injury.

The odds ratio was 0.84, with a 95% confidence interval from 0.75 to 0.95, which was significant again at P<0.01.

The researchers suggested that leisure-time physical activity "may improve musculoskeletal health in sedentary workers by offsetting muscle weakness and tightness in the upper body."

For those whose work itself is physically active, they said, it may be that the leisure activity increases "balance of movement and muscle activity" more than the repetitive loads seen at work.

They noted that the study is cross-sectional and can't determine cause and effect. One competing hypothesis is that people with repetitive strain injury are simply less active outside of work because of their injuries.

On the other hand, the researchers said, most upper-body repetitive strain injuries involve the wrist and hand, which would not limit such physical activities as walking or cycling.