Researchers Say Lifting Isn't Bad for the Back
Don't go so easy on your back.
In a surprising study, researchers say regular lifting is not necessarily bad for your back, and they argue that not taking it so easy on the spine might help to ward off back pain.
Disc degeneration is one of the most common causes of low back pain, but little is known about why discs fail. One theory is that having a physically demanding job that requires regular lifting may be a primary risk factor.
An international team of researchers set out to test that theory by gathering information on 44 sets of male twins. They were identical twins, so they shared exactly the same genes, but they were included in the study because one weighed significantly more than the other, an average of 17 pounds more.
Their theory was that, all genes being equal, having to carry around more body weight each day might damage spinal discs, which were measured by magnetic resonance imaging (MRI) scans.
What they found, however, was the opposite. The heavier twins had healthier spines, with about 6 percent higher bone density and less disc degeneration than their lighter sibling.
“Physical loading is beneficial for the muscular skeletal system. It’s good for bones, it’s good to make muscles and ligaments stronger,” says study author Tapio Videman, MD, PhD, a professor in the University of Alberta's Faculty of Rehabilitation Medicine in Edmonton, Canada.
Dr. Videman and his team say they hope their study results change the minds of people who think disc degeneration is caused by moderate lifting since they say they’ve discovered this type of routine activity actually does the opposite – slightly slows disc degeneration.
“If you have gradually increased your [lifting] levels, your body has probably adapted to those loads in a reasonable way and our findings don’t find that type of lifting or increased weight will increase disc degeneration,” explains Michele Crites Battié, PhD, another study author and professor in the University of Alberta's Faculty of Rehabilitation Medicine.
Battié says their findings only hold true with physical loading up to a certain limit. They say it is an entirely different situation when it comes to unusual or extreme heavy lifting.
“If you are not trained for a certain activity and you do something that is very demanding, that may have a very different effect,” Battié says. “I would guess that if your repetitions are too great and if the load is too great, there is likely a point when that becomes a negative thing for your skeletal system.”
Gunnar Andersson, MD, PhD, is an orthopedist at Rush University Medical Center in Chicago who specializes in back pain and injuries. He’s written 250 academic papers and more than 150 books and book chapters on the topic. He says this is a well-done study that it is interesting because it contradicts previous studies that have shown body weight and the type of job you do have an effect on the development of disc degeneration.
“It’s not like this is the definitive study on the subject, but it is an important study because it points out the importance of the genes,” Dr. Andersson says. “I think the problem in the past has been that people have viewed disc degeneration as being specifically caused by work or caused by body weight and other factors. The reality is while all of those are probably important, it seems that the genetic factors are even more important. And so, whether or not you are going to have disc degeneration depends to a larger degree on your gene pool than on what you do.”
He says the downsides of this study are that it followed a small group of participants and they’re all male. It also only looked at L1-L4 discs.
“So I think what we have to do is be a little bit careful about how to interpret it,” he says.
But the research team says they hope their findings reassure patients who have been afraid to regularly lift things.
“If you have back pain, I would say don’t be afraid of moderate activity and some mild to moderate lifting," Battié says. “Don’t go out of your way to exacerbate those symptoms. But if we are talking about people who might be afraid they are damaging the underlying structure of their spine, the disc, thru routine lifting you probably don’t have to worry about that.”
The study was published in the January 2010 issue of The Spine Journal. Next the research team plans to use the study group of twins to look at the effects of different loading conditions not just on disc degeneration, but also on pain.
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