Monday, May 10, 2010

Cycling and bone loss

I think I've had something up about this before (just checked and it was a couple of years ago....). OK - few of us will cycle at the levels of a professional in terms of the hours in the saddle, still it is interesting to bear in mind if you are thinking about exercising to maintain bone density. Cycling is not the best choice.

Then again....of course it isn't: we were designed to move around on two feet not on a bike. (Another one for the paleo concept?)

Bone Status in Professional Cyclists

Professional cycling combines extensive endurance training with non weight-bearing exercise, two factors often associated with lower bone mineral density (BMD). Therefore BMD was measured with dual-energy x-ray absorptiometry in 30 professional road cyclists (mean (SD) age: 29.1 (3.4) years; height: 178.5 (6.7) cm; weight: 71.3 (6.1) kg; %fat mass: 9.7 (3.2)%; V˙O2max: 70.5 (5.5) ml·kg−1·min−1) and in 30 young healthy males used as reference (28.6 (4.5) years; 176.5 (6.3) cm; 73.4 (7.3) kg; 20.7 (5.8)%). Adjusting for differences in age, height, fat mass, lean body mass, and calcium intake by ANCOVA, professional cyclists had similar head BMD (p=0.383) but lower total body (1.135 (0.071) vs. 1.248 (0.104) g·cm−2; p<0.001), arms (0.903 (0.075) vs. 0.950 (0.085), p=0.028), legs (1.290 (0.112) vs. 1.479 (0.138); p<0.001), spine (0.948 (0.100) vs. 1.117 (0.147) g·cm−2; p<0.001), pelvis (1.054 (0.084) vs. 1.244 (0.142), p<0.001), lumbar spine (1.046 (0.103) vs. 1.244 (0.167), P<0.001), and femoral neck BMD (0.900 (0.115) vs. 1.093 (0.137), p<0.001) compared to reference subjects. Professional cycling appears to negatively affect BMD in young healthy and highly active males, the femoral neck being the most affected site (−18%) in spite of the elevated muscle contractions inherent to the activity.

9 comments:

Ron said...

Wolff's Law states that a tissue will respond to force placed on it. In this case the lack of force. The bike has little to no weight bearing force the bones require to grow. Force placed on the bone will stimulate the bone to grow. Which is funny since swimming is even worse on bone mineral density as the bones are receiving traction due to buoyancy. The body is funny.

Jim Nariel said...

Nopt so much worried about my bones but more interested in shedding some weight (i.e fat. Happy to continue cycling

http://cyclingframes.blogspot.com

Mike said...

@Jim: Then you should be doing weight bearing resistance training in a high intensity intermittent fashion---You'll shed weight quicker and more effectively, AND increase bone density, to many only two of the many benefits.

While I completely endorse doing something one loves (I'm a very passionate mountain biker), I also believe in training smartly and effective, since time is always of the essence. I've seen great male cyclists unable to lift 50 pounds of weight over their heads, or jump higher than a few inches. That's not really conducive to being effective at LIFE.

@Chris: Always posting a broad range of provocative material. Keep up the great work, mate!

williebr said...

The blog is back! Nice to see you posting regularly again.

Steven Rice said...

I hate criticizing anything that gets people moving, especially outdoors, but I agree that cycling is very limited as a fitness pursuit. Besides lacking essential weight-bearing stimulation, there are a limited number of large muscles moving in a single constrained pattern. Worst from my perspective as a bodyworker is that it puts people in a terrible posture and exacerbates the exact harmful position they are in when sitting at a desk or in a car.

More on my post Happy Bike to Work Day

In summary, biking is great when balanced with other exercise activities, but not so good by itself.

Erlyn3 said...

So is swimming still OK?

Steven Rice said...

I'd say that both swimming and cycling are not just OK, but great. However, as with any exercise, understand their shortcomings and use other training methods to compensate. You can't get around the fact that the design of the human body and demands of life require dealing with gravity.

Anonymous said...

While cycling by itself may not be the best choice for maintaining bone density I have to believe that it's still better than sitting in a chair in front of a computer or television all day. If the bicycle is what gets someone up and moving then it's all good, right?

Anonymous said...

Maybe too much steroids, which promote osteoporosis and is frequent among cyclists...