Do you worry about bone density?
 

I've been reading some of these articles about cyclists having low bone density. My dad and his mother have both dealt with osteoporosis so I worry about it for myself. I realize most of those articles looked at cyclist who put in gobs of miles, but I'm wondering if any of you take any steps to try and avert loosing bone mass. I like that by commuting I can get exercise without going to the gym, but some people say to lift weights to build bone mass.

Do you do anything in this regard?

I've heard this mentioned before, but I guess I don't know what causes it. If it's just that it's non-weight-bearing than replacing driving with riding should have no effect. Is there more to it than that?

I do strength and conditioning workouts 3 times per week. I have my own 300 pound barbell, kettlebells and gymnastic rings. I train at home or outside. There is no need for gym membership. It's a lot cheaper to buy your own stuff and excercise at home. I've heard about cycling and bone density but I don't know if it's true or not. The main reason why I strength train is because I want to maintain my fitnness.

There is some evidence to support the claim, but it becomes a problem with the long-distance cyclists more than anyone else; cycling doesn't promote bone strength because so little weight is actually carried by the bones -- if you STOOD on the pedals the whole time, it'd be a different story.

I began to 'worry' about this in early 2010, while recovering from a cracked ankle (2nd broken bone in just over two years), and started to supplement with calcium/vit. D. No definitive way to tell if it's done any good, but I haven't broken a bone since. Being on your feet a lot will negate any problems cycling may cause, and my job is 'on the feet for 8'.

I bet it affects more people riding lightweight bicycles than people riding heavy bikes since the later must push harder on the pedal to move the bike

Your "theory" doesn't make any sense. I am sure all those pro racers with their light bikes pedal much harder then an average commuter on their heavy bike...A 30 pound commuter bike will not increase your bone density anymore then a 19 pound race bike, it doesn't matter how hard you pedal... The only way to increase bone density is through weight training, plyometrics and sprint running.

i box and stickfight, with associated training. i figure i'm good.

you push hard to beat inertia and inertia is related to mass and change of motion, not speed, F=ma. Speed and acceleration are not the same. An average commuter is heavier and has an heavier bike and tend to stop at red lights and must beat inertia every time he/she must reach his/her average speed from no velocity. But... pro racers usually have a more intense training.
I noticed though that bicycle weight has a huge impact on how hard you push on the pedal when some lightweight people i know told me they couldn't handle my heavy bike for long due to the bicycle weight. 120 pounds on a 70 pounds bike is not the same as 220 pounds on the same 70 pounds bike.
The weight ratio of the bike in the first case is 36%
in the other case it is 24%

Have you tried to ride a 200 to 300 pounds bike with groceries + 220 pounds of rider weight on a 5 to 10% up hill on a big gear ratio?
you don't necessarely need weight training.

erig, the point is not how much effort you put out. The problem, people theorize, is that your body is not supporting its own weight. Unless you have that 200 lbs of groceries on your back and you are out of the saddle the entire time, it is not helping you.

Astronauts lose bone mass in space because there is never any pressure on their bones, so basically, the bones atrophy.

I don't quite understand the way weight bearing on a bike differs from standing. Cyclists absolutely put huge forces on their legs, but the force on a cyclists hips is much less than say a runner..... I don't understand the mechanism, but bone loss in professional cyclists is very real.

People also theorize that it has to do with exercising with a calorie deficit. Professionals clearly can't feed their bodies enough calories to make up for what they expend during a long race. The body could be pulling nutrients from other parts of the body to make up for that. Hence bone loss.

I was hoping to find some people who have really looked into this issue and dealt with it. Speculation really doesn't help anything. But, my question was 'do people worry about bone loss' and it seems the answer so far is "No."

You pedal to accelerate, but you also pedal to stay at constant speed. Different kinds of friction apply a force backward and you need to apply an equal force forward to stay at constant speed. And friction increases nonlinearly with speed, which is why it's so hard to maintain say 25 mph even on flat ground. You can look up power output for pro racers, and it's very high. As long as you're pedaling at the same cadence, higher power means higher torque (and higher force).

what i can see is that
force travels from feet to hips via legs' bones but on a bicycle because the angle hips-femur is not the same as when someone run or walk hips tend to handle flexion rather than pressure.

http://www.t-nation.com/img/photos/2...-structure.jpg

The other thing is that when someone walk or run, their is an impact on the hips from the feet on the ground which tends to reinforce bone structure. On a bicycle, on the other hand there isn't much impact
What i can see as well is that on a bicycle the pressure of the pedal is on the fore foot and because the foot acts as a spring some energy is dissipated
when you walk or run the pressure/impact is on the back of the foot or the side depending on if you tend to pronate, suppinate or have a more neutral footstep.
Another thing i see is that on a bike with spd type pedal at some time the pressure become negative when the cyclist move up his/her foot

How many people ride 300 pound bikes up 10% grade ?? . It's a recipe for disaster which will kill and destroy your knees...I much rather prefer deadlifts, squats , power cleans and plyometric jumps. I also commute on a fixed gear which provides more resistence then a freewheel bike.

i have been doing this for years and i haven't had any problem yet and i had an achille tendon rupture when i was younger. I believe that as long as i keep riding i won't have any trouble as my bones are used to.

i agree but you agree that the average joe will have a bike less clean (which means more friction), not as efficient (cheaper gears), probably some larger tires and an heavier bike than a pro racer. Because of all that i couldn't say which one has to handle more friction. I know for sure that the average joe will weight more and will be heavier than some pro racer.

Does the average commuter cyclist have greater bone density then a pro racer ?? , because they ride a heavier bike.

You can eliminate all those unknowns by just comparing power output. For roughly similar cadence and crank length, power is a measure of force. Amateur cyclists can't achieve the power elites can, based on power meter results.

Amateur cyclists and average joe is not exactly the same but it's quite close. I will be sure when the 400 pounds average albert will fail short though. Until then i must believe you, ;)

I'm a high mileage cyclist (500,000 miles). I drove my heel bone through the tibia/fibula a decade ago. When the X-ray came up, the orthopedic surgeon, one of the team physicians for the Sacramento Kings, called the entire staff in to marvel at the densest bones he had ever seen. If I worry at all about bone density, it is to be concerned that I am dragging excess weight up every hill.

My take on it is this: bones will grow denser in response to damage. Damage is inflicted by stress. Most folks focus on muscle output or weight bearing as primary stress, but I think that may be mistaken. The stress that is relevant for weight-bearing activities for bone density is the micro-fracture causing slamming of the feet into the ground, such as is experienced in basketball. I think I get a similar level of stress by riding full out on crappy roads. The bike bounces, as do my lower legs.

It would be interesting to compare track cyclists' bone density to that of off-road racers, particularly if one can find off-roaders who have good form (less upper body use and more shock absorption from the legs). Maybe that can't be done anymore since the off-road folks are all on suspension bikes.

Interesting point. I wonder against whom did the studies compare the cyclists. Were they comparing cyclists with other athletes, or with people not much into sports? In other words, is that cycling just does not help strengthening the bone as some other sports do, or it decreases bone density so that cyclists are worse off than couch potatoes?

I wonder if part of the culprit has to do with the fact that people who frequently ride bicycles tend to walk less. I used to walk a lot until taking up bike riding. Now to go anywhere more than 10 blocks away (half mile?), I go by bike.

Regarding the low weight-bearing nature of cycling, what about the wrists? I ride hybrid with flat bar and I feel my wrists are supporting considerable weight during a long ride (very sore). However when I had a bone density scan of my wrists, the result was below normal bone density.

There was a study that had people jump up and down 30 times daily. Doing so increased bone density and appeared to be protective for osteoporosis. If you're worried jump up and down 30 times or go running a fe days a week.

You have three points of contact with the bike -- bar, pedals, saddle. Between the three, 100% of your weight is divided (unevenly). I've read that 50-60% of your weight is routinely carried on the saddle, about 30% on the pedals, and the rest on the bar. I can't link to that, since I don't remember where I read it, so all I have to go on is my admittedly imperfect memory.

I had a bone scan a few years ago and was shocked to hear that I had decreased bone density in my spine. In addition to cycling I've done marathons and half marathons for the last 18 years. The bone scan pushed me into upping my weight training in the gym, along with taking calcium supplements.

Different bodies will have different results, but you do need some sort of weight-bearing exercise to stress your bones in order to prevent bone loss as you get older.

Jumping excercises are called Plyometric training. They are very effective if done correctly.

Weight bearing exercise. You do not have weight bearing on you on a bike. Your weight is bearing on the bike. Get off the bike and run, do yoga, play basketball...these will make you bear your weight. Remember high impact/low impact aerobics? The impact is on YOUR body. Stop trying to say that biking is weight bearing. It is NOT. Pro cyclists have know for years that this is an issue in their sport. Why is it being debated on here?

Cycling is NOT weight-bearing exercise. If you want to have healthy bones for years and years, do WEIGHT BEARING EXERCISE in addition to your cycling!

Suggestion for study: test the bone density of those who live on the top floor of a walk-up building and carry their bikes with heavy chain- and U-locks down- and upstairs daily.

Bicycling isn't usually a weight-bearing activity, so if you want to keep bones healthy and be all-round fit, you need to get off the bike and do other things. (We've all seen our share of pot-bellied "serious" cyclists.) I go to a rock climbing gym twice a week, do some stretching and strength training every day, and try to go on a 7-10 mile walk at least once a week or so. (I tried running, but running along with daily bicycle commuting turned out to be a good way to injure myself...)