Dec. 3, 2001 -- Your back is killing you, but you have to get those groceries out of the car. You lift carefully. You go slowly. You try not to hurt yourself, but OW! You do.
How could you have re-injured your back? You were being so careful. And that was the problem, according to a report in the current issue of the journal Spine.
"People with back pain guard the injured area by using more muscles than they need to. The more muscles they use, the greater the load there is on the spine," says William Marras, PhD, director of the Ohio State University biodynamics laboratory, in a news release.
Marras and colleagues analyzed the way 22 people with lower-back pain lifted things. To make sure they didn't get hurt, they lifted only light objects. The researchers then calculated what would have happened if these people had lifted heavier weights. They compared the findings to similar analyses of 22 healthy people.
People with back pain tried to avoid using hurt muscles. In doing so, they used different muscles and put a lot more strain on their backs than did normal people.
"When people apply all those extra muscles, it's as if they're pushing down on the short end of a seesaw and trying to lift something on the far end," Marras says. "They exert more force -- to little effect."
Lifting slowly only increases the time that the spine has to endure all that extra force. It actually increased the danger of lifting for people with back pain.
"Bottom line -- you can send people back to work after a back injury, but you have to be very careful about what you have them do," Marras says.
The findings also suggest that physical therapy for back pain shouldn't just focus on regaining back strength. It should also focus on proper use of back muscles.