spinconn

I have read several times that cyclists who do large mileage need to do resistance training and supplement their diet to prevent loss of bone density. The explanation given makes sense to me if cyclists are compared to folks who do other kinds of exercise, but not when compared to the majority of people, most of whom do not exercise at all. Is it possible that cycling is worse for bone density than being a couch potato?

GhostRider62

Everything is possible.

work4bike

I don't know, but I think it's possible, simply because cyclists are stressing their body and forcing it to draw from areas of the body that are not as stressed, as opposed to someone that just sit around, but again I don't know.

However, that's not to say that cycling will result in bone loss, period. If combined with weight training leads to an overall stronger body. And of course, eat your greens.

BTW, I'm 58 and have been cycling for over 30-years and I have zero back issues. However, I've always used weight training to keep the body strong. Your musculoskeletal system is your armor.



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GhostRider62

Osteoporosis is very common for all old people.

Despite what you read, it can be reversed to a some degree. I had a T Score -2.8 and 18 months later it was something like +0.3. Some anatomical areas improved more and some less than others.

Resistance training per se isn't helpful, sharp impact loads like hiking with a pack in rocky, hilly terrain is the easiest. Supplements are also helpful

Daniel4

Don't confuse yourself. Bottom line is that being a regular cyclist is better than being a couch potato.

And definitely do some weight training exercises.

RChung

Possibly, but I don't read the exercise guidelines for osteopenia that way: I think what that means is that while cycling (and swimming) aren't the best ways to strengthen bones, they're not counter-productive (i.e., they're not worse than couch-surfing). In addition, since they mention walking and climbing stairs, I take their recommendation as saying that low-power cycling on flat ground isn't in that class, but that moderately high resistance cycling as in hill-climbing might be. We can calculate the average pedal force it would take to climb a steep hill at various combinations of gradient, bike speed, and gearing, so while the forces are often lower than stair-climbing, if done at moderately high effort (especially if standing on the pedals) they can be higher than walking slowly. I guess what I'm saying is that these exercises aren't separated by a bright well-defined line, they're arrayed along a spectrum, and that some activities overlap depending on how you do them.

Carbonfiberboy 

I'll start by linking to two studies:.
https://bmjopensem.bmj.com/content/4/1/e000449
https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3230645/.

So it's complicated. It looks like it's hours of cycling per week dependent. 6-8 hours, probably fine. If you ride really a lot, even weight training won't make much difference. In any case, being a cyclist has a pretty good chance of being worse for your bones than being a couch potato. A few years ago, I did some calculations estimating calcium losses through sweat while riding. It didn't seem to me like that would be the source of bone loss, but these scientists disagree.

I was diagnosed osteoporotic after about 20 years of endurance cycling in the PNW. During most of that time, I did heavy strength training about 9 months of the year + hiked and backpacked. If you've never had a DEXA scan, you have no idea whether you have a bone loss issue or not. I haven't broken a bone since I was 21, when I fractured a couple ribs bouncing off moguls while downhill training, though I have been down on the bike several times. I'm pretty good at falling, maybe from having done so much Alpine skiing. "If you're not falling, you're not learning." - CFB.

My doctor also doubts the sweat loss theory. In her opinion, it's more likely, at least in my case, to be dysfunctional osteoblasts for no obvious reason.

Studies of bone remodeling have concluded that ground reaction forces are the most important. Jumping is really good, especially jumping down from some small height. The mechanistic model says it takes about 10% of the breaking strength of a bone to cause remodeling. Muscle forces add to the ground reaction force so that the force on a bone can be as much as 4X the ground reaction force. Thus that 10% is not an impossible or unreal estimate.

RChung

I'm not terribly fond of this study design or analysis, but this was just published: https://journals.lww.com/acsm-msse/F...d_Risk.20.aspx

downtube42

Exploratory analyses indicated that low BMD is associated with low body mass index, fracture incidence, lack of bone-specific physical activity, and low energy availability in active career elite cyclists.

Seems like the bold text (my bold) is significant, possibly as important as their status as elite cyclists, and not pertinent to many of us.

Carbonfiberboy 

This is another interesting look at it:
https://marciaruns.com/2020/08/17/ru...tipping-point/

RChung

Yeah, I noticed that, too. But in a larger sense, the original question that started off this thread was about cycling in comparison with couch potatoes, and this study didn't look at the general population -- by design, they only looked at fairly active cyclists so we don't know whether cycling is better or worse for BMD than doing nothing.

Carbonfiberboy 

I believe that was addressed in the second link in post 7. Perhaps you missed it. Apparently BND in cyclists is inversely proportional to hours/week over some uncertain limit.

RChung

Well, I didn't dig into the individual studies but the summary sez the prospective studies apparently didn't compare with sedentary controls. Of the 4 cross-sectional studies (which are a lower level of evidence), 3 showed no difference between sedentary controls and cyclists; and the overall conclusion is that the evidence is mixed. So I'm not going to sit on my couch thinking that it's going to give me stronger bones.