Quote Originally Posted by damnable View Post
It's not just a matter of consuming more calcium, it's encouraging and calcium to be absorbed and to be incorporated into bone.

Higher impact and high strength (eg, jogging and weights) encourage the building of bone, whereas lower impacts activitites such as cycling don't stress the bone so much and don't have as much of an effect.

Although I do like that you are an advocate of cross training.

Thinking about it now, low impact sports for overweight people may be the equivalent of higher impact sports for a more average weighted person, simply becuase there is more weight behind the movement. These are just my thoughts and I am not sure if they have been proven.

And also, cycling is better than nothing!
Actually the best test for this, would be to take 100 people, 25 who cycle, 25 who run, 25 who do walking (including hiking, and other walking based exercises), and 25 who do couch surf. Then compare the bone density numbers. My guess is that highest bone density would be the runners, next would be the walkers, close behind or even to the walkers would be cyclists, and far behind both would be the couch surfers. The real question, is, what is the median bone density for the average person, in a certain age group, do other factors affect this, such as diet, sex, weight and general fitness level?

A cyclist has a much lower muscle mass then a power lifter, but actually has a higher muscle mass then a couch potato, is this a similar thing, it's not that cyclists have lower bone density then average, but that runners have higher bone density then average.