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A new study in the Journal of Strength and Conditioning Research follows up with a group of competitive masters cyclists seven years after the original study showing that they had abnormally low bone density. The cyclists now have an average age of 57, and 89.5% of them meet the criteria for osteopenia or osteoporosis. In comparison, only 61.1% of a group of matched controls meet the same criteria.
It’s still not entirely clear why cyclists seem to have poor bone density. Obviously cycling is a non-weight-bearing, non-impact activity, so they’re not getting any bone benefits from their time in the saddle. But it appears that their cycle training makes them less likely to do any weight-bearing activity even compared to non-athletic controls who don’t do any training at all. Another possibility is that they’re sweating out too much calcium, hindering bone formation and repair. This study doesn’t do much to clear up the mystery, but it does show that this is a real effect, not just an artifact of the general skinniness of cyclists — otherwise the equally skinny control group would show the same effects.
One important note: four of the 19 cyclists in the group started weight training during the seven-year interval, and they were able to slow their rate of bone loss. It’s another reminder to everyone whose main sports is something like cycling or swimming: you need to do something that stresses your bones, either through sharp impacts or the torque applied by strength training.