Nichols, JF and Rauh, MJ. Longitudinal changes in bone mineral density in male master cyclists and nonathletes. J Strength Cond Res 25(3): 727-734, 2011-This study tracked changes in bone mineral density (BMD) over a 7-year period in competitive male master cyclists (n = 19) and nonathletes (n = 18). Participants completed health/exercise history and food frequency (for calcium intake) questionnaires and underwent BMD testing by dual-energy X-ray absorptiometry. At initial and 7-year assessments, there was a consistent pattern of lower BMD in cyclists compared to nonathletes at all bone sites measured. Repeated measures analysis of covariance adjusted for changes in body mass index, lean mass, calcium intake, and exercise habits indicated a significant interaction at the total body site, indicating greater BMD decline in cyclists than nonathletes (p < 0.05). Among all study participants, those who reported participating in weight training or impact exercise since the baseline assessment lost significantly less BMD at the spine and femoral neck compared to participants who reported no weight training/impact exercise since baseline (p < 0.05). A significantly greater percentage of cyclists than nonathletes met the International Society of Clinical Densitometry criteria for osteopenia or osteoporosis at baseline (84.2% vs. 50.0%) and at follow-up (89.5% vs. 61.1%, p < 0.05). Further, 6 of the 19 (31.6%) cyclists who had osteopenia at baseline became osteoporotic, compared to 1 (5.6%) of the nonathletes. The high percentage of male master cyclists with low BMD, combined with a high risk for fracture from falls associated with competitive cycling, warrant attention among this population. Coaches and health professionals interacting with cyclists need to promote alternative exercise such as weight training, plyometrics, or other high impact activity as a complement to cycle training to help minimize bone loss in this population.