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In the wake of the column comparing elliptical training to running, I got a very interesting e-mail from Gary Rothbart, a Toronto personal trainer. He said, in part:
I feel that the fitness community has done a great disservice to the average person. One of the most important factors with respect to avoiding osteoporosis is high impact activities… The difference between running and the use of non-impact machines is great when taking into the long term implications on bone density.
That makes a lot of intuitive sense. To be honest, that’s something I expected to find when I started researching this story — but I didn’t. That doesn’t mean it’s not true, but I wasn’t able to find solid evidence that it is. One point worth noting is that the elliptical is still very much a weight-bearing activity, even if jarring impacts are reduced. In this article from the Washington Post from a few years ago, a scientific advisor to the U.S. National Osteoporosis Foundation makes that point:
[…] A workout on an elliptical machine provides no-impact, weight-bearing exercise: While your bones are supporting your weight, your feet are not striking the ground, as they do when you walk or run. So are you missing bone benefits by giving up the impact? If so, not much, [Creighton University professor Robert] Recker said. The bone density benefit from an elliptical machine workout is comparable to that from a run of equal time.
As far as I can tell, he’s drawing that conclusion from an absence of research, rather than specific studies showing it to be true. There is, however, some relevant research on bone density that I came across while researching an upcoming piece for Canadian Running. According to this article from the current issue of Medicine & Science in Sports & Exercise, “Generally, strength- and powertrained athletes have higher BMD [bone mineral density] than endurance-trained athletes, and male long-distance runners have been reported to have lower BMD than controls.” I followed up the references, and found several studies dating as far back as the 1980s confirming that serious runners seem to have lower bone density than sedentary people. The mechanism for this still isn’t understood.
So what can we conclude from all this? It’s still hard for me to believe that running isn’t a bit better for bone density than alternate activities like the elliptical — though, as a runner, I may be biased. But given the mixed messages above, I don’t feel we’re at a point where I could recommend against using the elliptical for bone density reasons. Of course, there may well be other research out there that I missed. If so, please let me know!
Perhaps the reason long distance runners have lower BMD is due to their bone size.
Most long distance runners are tall and skinny (ectomorph body type) and therfore have smaller lighter bones than the average person to start with.
The question is if long distance running is the cause of lower BMD or if the type of people who take up long distance running are natuarlly and biologically more predisposed to having a lower BMD. On the flip side long distance running could be too much of a good thing and after a point too much running causes depletion of calcium from high bone turnover!
Thanks for the comment, Dave — you’re absolutely right about that. In fact, shortly after this blog post was written, a new study from the University of Missouri came out that said exactly that: runners seem to have lower bone density because their bodies are smaller. Here’s a link to a Jockology column I wrote that mentions the study:
“Pamela Hinton and her colleagues at the University of Missouri compared runners, cyclists and resistance-trained men. While the resistance group did have the greatest bone density, the differences were only relative: The runners were leaner, but their bones were just as strong for their body size…”
Interesting topic being discussed here. While I think there is validity to the comments that the elliptical machine is not as useful in developing bone mass as is impact-bearing activities such as running, relative to the amount of exercise the average North American does every year, it is still effective. Inactivity is the biggest risk factor to poor health condition.
Sebastien Rahman
Toronto Personal Trainer
I agree, Sebastien. First of all, bone health is just one among many outcomes that you have to consider in designing an exercise program, so it would be a mistake to toss out elliptical just because it’s not the “best” bone developer. And secondly, the more research I read about bone health, the more I get the sense that it’s a mistake to think just about “jarring impacts” for building bones. Having strong muscles applies stress to bones, triggering growth — so elliptical is bound to have some positive impacts for the typical sedentary person.