Analyzing injury risks on the job.

• Position: Back injury risks

Researchers have identified five factors that can help determine whether industrial workers are at risk for debilitating back injuries. Calculating risk based on these factors is about three times more likely to pinpoint unsafe work settings as is the standard method used by the Occupational Safety and Health Administration OSHA), according to William Marras, professor of industrial systems engineering and of physical medicine and rehabilitation, Ohio State University. The five factors are: * How often a worker lifts. * How rapidly the individual moves to the right or left from the trunk (or midsection). * How quickly he or she twists at the trunk. * How far forward a person bends when lifting. * The "load moment," calculated by multiplying the weight of the object being lifted by its distance from the spine.

"Standard models used by OSHA have stressed the importance of the weight of the objects handled by workers," Marras explains. "But we've found that it's a combination of these five factors that are key to understanding - and preventing - on-the-job lower back injuries." Most probably are due to repetitive wear and tear. Workers don't commonly injure themselves suddenly, but, instead, the cumulative effect of repetitive tasks "really adds up. Like the straw that broke the camel's back, these cumulative traumas can wear down your spine."

He conducted his on-site studies with a device he invented called the lumbar motion monitor (LMM). a lightweight replica of the...