Lower Limb Peak Power and Cortical and Trabecular Bone Strength in the General Population

Muscular fitness has been associated with several health-related outcomes including bone health. However, evidence on this relationship considering sport participation is scarce. PURPOSE: To examine associations between several expressions of muscular fitness and bone speed of sound (SoS) in young people of both sexes according to current sport participation (ATHL-athletes engaged in formal competition vs. Non-ATHL non-athletes). METHODS: Participants were 184 boys (11.1-18.9 yrs old; 90 athletes) and 198 girls (12.2-18.8 yrs old; 45 athletes) at and above the age of peak height velocity (PHV). Bone SoS evaluation was conducted by quantitative ultrasound (QUS) at the distal radius (R-SoS) and midshaft tibia (T-SoS) of the non-dominant limbs. Muscular fitness included the handgrip strength (HG), the vertical jump (VJ), agility (shuttle-run 4x10m), and speed (20-m sprint test). All statistical analyzes were performed separately for boys and girls and adjusted for maturity (yrs from the age of PHV), body mass index (WHO z-BMI), and daily calcium intake. RESULTS: The ANCOVA revealed superior muscular fitness in athletes compared to non-athletes (p <0.05) in both sexes, with the exception of HG strength in which no differences were observed. There were no dissimilarities in bone SoS between the athletes and non-athletes, except for the tibia in which the male athletes showed lower SoS than the non-athletes (ATHL: 3743.78 ± 8.90m/s vs. Non-ATHL: 3775.33±8.71m/s, p=0.013). In both sexes, multiple linear regression showed a greater number of muscular fitness predictors of bone SoS in non-athletes than in athletes: in non-athletes, the HG strength associated with the T-SoS (β=5.36, p=0.002) and the speed with the R-SoS (β=-58.97, p=0.001) in girls and the VJ height (β=3.01, p=0.017) and speed (β=-71.69, p=0.022) associated both with the T-SoS in boys. In athletes, HG strength associated with R-SoS (β=1.99, p=0.049) in girls and the sprint associated with the T-SoS (β=-65.78, p=0.020) in boys. CONCLUSION: Despite higher values of muscular fitness, athletes did not reveal higher bone SoS than non-athletes and showed less associations between these variables. In young people, muscular fitness appeared to be a better marker of bone health in non-athletes compared to athletes. 2481 Board #145 May 31 11:00 AM 12:30 PM Relationship Of Physical Activity With Bone Parameters In Young Hispanic Girls Diego W. Blew, Vinson R. Lee, Robert M. Blew, Jennifer W. Bea, Victoria L. Bland, Scott B. Going. University of Arizona, Tucson, AZ. (No relationships reported) Increased levels of moderate-to-vigorous physical activity (MVPA) are associated with enhanced bone mass/density development in non-Hispanic children, which may prevent osteoporosis later in life. This relationship has not been established in Hispanic females; as osteoporosis rates increase, an understanding of this relationship across populations is vital. PURPOSE: To determine the impact of MVPA on bone density, content, structure and strength in young Hispanic girls. Copyright © 2019 by the American College of Sports Medicine. Unauthorized reproduction of this article is prohibited.