Steve Infanti
Scripps Howard News Service Q: I suffer from chronic lower-back pain and it seems like it is always the same spot. I'm very careful and slowly lift heavy objects. Any ideas on why this may be a constant problem? A: An important factor in recurring back injury is our natural tendency to avoid using hurt muscles, according to researchers from Ohio State University. William Marras, professor of industrial, welding and systems engineering, and his colleagues discovered that people tend to compensate for back injuries by using many inappropriate muscles in place of the muscles that hurt. "People with back pain guard the injured area by using more muscles than they need to," Marras said. "The more muscles they use, the greater the load there is on the spine." For instance, injured people may employ muscles in their abdomen or sides or other, uninjured back muscles, even though these muscles are not necessary for lifting. The study revealed that people with back injuries unknowingly inflict twice as much twisting force on their spine, and 1.5 times as much compressive force as uninjured people, when lifting the same object. Over time, greater loads on the spine lead to more serious back injuries, such as disc degeneration, which require surgery. What's more, lifting objects slowly, as injured people also tend to do, only intensifies the harm. "Moving slowly just increases the length of time the spine has to endure those extra forces," Marras said. Marras directs Ohio State's Biodynamics Laboratory, where he and his colleagues conducted this study to compare how people with and without back injuries use their muscles. Across the country in 1999, more than 420,000 people missed work because of back injury. Each lost an average of six days on the job, according to the U.S. Bureau of Labor Statistics. (Send questions about health, fitness or nutrition to Steve Infanti, A Fit Life, 216 Henderson Blvd., University Park, PA, 16802, or e-mail to SCInfanti@compuserve.com.)
| 
