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.
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.
Comments
http://cyclingframes.blogspot.com
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!
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.