Abstract des Autors

Purpose: Male athletes who were runners (N=12), cyclists (N=14), or both (N=13) were compared with nonexercising age-matched controls (N=23) for total and regional bone mineral density (BMD). All athletic subjects had competed for a minimum of 3 yr and trained for a minimum of 4 h/wk. Runners undertook no cycling and cyclists undertook no running training. Methods: All subjects were scanned for whole body and L1-L4 spine BMD using a Hologic QDR 1000W scanner (Hologic Inc., Bedford, MA). Results: There were no differences in age, height, weight, body mass index (BMI), %fat, or hours of training between any of the athletic groups (P>0.05), although compared with controls, runners and cyclists had lower body mass index (P<0.01) and all athletic groups had lower %fat (P<0.001). Compared with controls, runners had greater total and leg BMD (P<0.05), cyclists had reduced spine BMD (P=0.05), and athletes of the "both" group had greater total (P<0.05) and arm BMD (P<0.01). Conclusion: Running is associated with increased bone density, particularly in the leg, whereas cycling is associated with a mild decrease in bone density in the spine. In athletes who do both, running exerts a stronger influence than cycling. Verf.-Referat