Skeletal Loading: Lean and Bone Mass Development in Young Elite Male Gymnasts, Swimmers, and Nonathletes Aged 6–24 Years

Abstract

Background: Exercise optimizes peak bone mass accrual, particularly if the loading is high magnitude and distributed in abnormal directions. Little is known about the influence of early intense training in sport during peak bone mass accrual, especially in boys. Methods: Ninety-eight males aged 6–24 years (gymnasts, swimmers, and controls) completed the bone-specific physical activity questionnaire and a 7-day exercise diary. Dual-energy X-ray absorptiometry determined bone mineral properties of the total body (less head) and lumbar spine (LS, L1–L4) and total lean mass. Subgroup analyses were conducted for juniors (prepubescent), adolescents (11–16 y), and seniors (17–24 y). Results: Lean mass was positively associated with total body less head and LS bone outcomes in all 3 age groups (R2 = .632–.770, P < .05), and bone-specific physical activity questionnaire scores were associated with LS bone mineral density in adolescents and seniors (R2 = .440 and .591, P < .05). Senior gymnasts had significantly higher LS bone mineral density (in grams per square centimeter) and Z-scores than swimmers (P = .004) and controls (P = .012). Conclusions: Elite gymnastics is associated with superior peak bone mass accrual in young males. The benefits appear more pronounced during young adulthood compared with prepuberty, potentially reflecting an extended time course for bone adaptation.