Site-Specific Bone Differences and Energy Status in Male Competitive Runners and Road Cyclists: Bone in Runners and Cyclists

ABSTRACT The interaction between mechanical loading and energy availability on bone health in male endurance athletes merits further investigation. The purpose of this study was to compare bone status in male competitive runners and road cyclists and to investigate the influence of energy availability on bone mineral density (BMD). 18 competitive runners and 19 road cyclists (20-50 years) participated in this study. Areal BMD (aBMD) and body composition were assessed by dual energy x-ray absorptiometry (DXA). Volumetric bone variables at the 4% and 66% tibia sites were assessed by pQCT. Energy availability (EA, 7-day dietary and exercise logs) and resting metabolic rate (RMR, open circuit spirometry) were measured as indicators of energy status. Bone loading history, calcium intake, and training history were assessed by questionnaires. After adjusting for age, runners had significantly greater (p