Sports Participation, Exercise Intensity, and Bone Mineral Status in Chinese Adolescents pp. 49-63
Authors: Afrooz Afghani and C. Anderson Johnson
Abstract: Introduction/Purpose: Physical activity has been recognized to be an important determinant of bone gain or maintenance during adulthood. However, the role of mechanical loading on the pediatric skeletal system is less understood. The present study was conducted to address the role of leisure physical activity, sports team participation, and intensity of sports on skeletal mass of Chinese adolescents. Methods: A total of 166 girls and 300 boys between the ages of 10 and 16 participated in this study. Bone mineral density (BMD) and content (BMC) of the forearm and the heel (os calcis) were measured using dual energy x-ray absorptiometry (DXA). Leisure physical activity and sports team participation were determined using standard questionnaire. The Compendium of Physical Activities was used to determine intensity of sports. Results: After controlling for age, body mass index (BMI), and grip strength, there were no significant differences among groups of leisure activity in any of the bone mineral measures. In girls, there were also no significant differences among groups of sports teams. However, in boys, sports team participants had significantly greater BMD and BMC at the forearm and the heel. Adjusted means and SEM for forearm BMC were 3.11 ± 0.035 versus 3.36 ± 0.048 (p<0.001) for non-participants and participants, respectively. For heel BMC, adjusted means and SEM were 2.33 ± 0.037 versus 2.48 ± 0.051 (p<0.05). High intensity sports participants had significantly greater forearm (p<0.01) and heel (p<0.05) BMD and BMC than the boys who reported no sports membership. Conclusion: This study supports the role of mechanical loading or exercise on the skeletal system of Chinese adolescent boys. Interventions designed for the purpose of maximizing peak bone mass in children and reducing the risk for osteoporosis later in life should focus on sports team membership in high intensity type of exercises.