However, findings from a recently released study in Medicine & Science in Sport & Exercise (MSSE) indicate that high-intensity cycling could be a good bone-strengthening exercise for people who can’t do high-impact exercise.
The study, undertaken by Canadian exercise scientists, had participants do six by one-minute intense intervals, at 90 percent maximum, followed by a one-minute rest period repeated six times.
The scientists found that sprint-interval training had a significant effect on key bone turnover and formation markers among a group of recreationally active men, but not specifically cyclists. This led the authors to conclude that high-intensity cycling could enhance bone strengthening.
Therefore, if intervals can build bone, why then does cycling continue to get a bad rap? Sport science and orthopedic researcher and former pro racer Dr Aaron Smathers, who was diagnosed with low bone density, has done a fair bit of research on the topic of cycling and brittle bones.
He confirmed that the science of bone density is complicated and that there is much we don’t yet know, but there are some key factors we do know.
One is that our body size plays a big role. Research has found that body mass, especially muscle mass, is the biggest factor that influences bone-mineral density. This makes perfect sense because it is common knowledge that bone strain from muscle or impact helps with bone density.
The lightest cyclists have the lowest bone density, but bone density was also found to be site specific. This means that you build more bone in places with more muscle mass and in areas that work the hardest.
Therefore, in cyclists, the femurs in the upper leg would probably be the strongest, while your torso bones would be the weakest. It could then be said that sprinters, in cycling, have solid femurs, weak hips and a fragile spine?
“Another interesting phenomenon that seems unique to road cycling,” says Dr Smathers, “is that there appears to be some mechanism that is causing more resorption or loss of bone during the turnover cycle.”
In simple terms, this means that although you are creating all these positive factors, the end result is still negative; almost like a catch 22. So, while high-intensity cycling bursts will create stronger bones, the catch is that competitive cyclists want to be as light as possible, not lift weights and rest when they are not riding.
Therefore, it appears that non-competitive, heavier, recreational cyclists who are willing to do a few high-intensity bursts in training sessions will be ‘healthier, with stronger bones’ than the competitive ones. Suggestions then for the recreational riders are to do some other things like weights, cross-training or just a few high-intensity bursts in your cycling training.
Some advice from Dr Smathers is as follows:
• Go for a bone scan. If you have a family history of osteoporosis, are an endurance cyclist, seem to break bones easily or have any reason to suspect you might have diminished bone density, get a bone scan. It’s quick and easy.
• Incorporate all-year-round strength training a couple of times a week, if you are not already doing this. A strong core makes you better on the bike.
• Do some sprints, even if it is in the base or winter training phase. It will help preserve fast-twitch muscles and top-end fitness as well.
• Get on a MTB or cross bike, if you are a roadie, and mix it up. Research shows that mountain bikers have significantly stronger, denser bones, most likely due to the full-body strain and impact that comes from riding over rugged terrain. In addition, it can also help improve your bike-handling skills.