Muscle-to-Bone Ratio in Collegiate Female Athletes in Low and High Impact Sports

The purpose of the present study was to compare the muscle-to-bone ratio in National Collegiate Athletic Association Division I female athletes (<i>n</i>=387) to those in age-matched controls (<i>n</i>=209). In addition, we examined the muscle-to-bone ratio in low and high impact sports. Total and regional lean soft tissue, fat mass, and bone mineral content were determined by dual X-ray absorptiometry. The muscle-to-bone ratio was calculated by dividing lean soft tissue by bone mineral content. Athletes were categorized by sports: basketball (<i>n</i>=66), cross-country (<i>n</i>=49), diving (<i>n</i>=17), soccer (<i>n</i>=69), softball (<i>n</i>=71), swimming (<i>n</i>=93), and volleyball (<i>n</i>=22). There were significant differences between controls and athletes for total lean soft tissue, fat mass, and bone mineral content. When the total muscle-to-bone ratio in athletes was compared to that in controls, there were no significant differences; however, there were significant differences in the regional muscle-to-bone ratio. Low impact sports (i.e., diving and swimming) had significantly higher total and regional muscle-to-bone ratios than high impact sports (i.e., cross-country, basketball, volleyball, softball, and soccer). The differences identified between sports in total and regional muscle-to-bone ratios may be a result of sport-specific impact and mechanical strain affecting the balance between the muscle and the bone. This study provides insights into how training-induced body composition impacts the balance between the tissues in female athletes.