FACTORS INVOLVED IN PHYSICAL MATURITY IN BOYS AND GIRLS
Nogueira, R. C., Weeks, B. K., & Beck, B. R. (2013). Sex-specific relationships between physical activity, maturity, calcium, and bone, muscle and fat in peripubertal children. Medicine & Science in Sports & Exercise, 45(5), Supplement abstract number 163.
This study examined the gender-specific relationships between physical activity, biological maturity, and calcium consumption and indices of musculoskeletal health in a cohort of healthy pre- and peri-pubertal girls and boys (N = 330). Maturity was defined as years from the age of peak high-velocity growth; determined from height, weight, and sitting height. Historical physical activity was derived from the Bone-specific Physical Activity Questionnaire. Calcium consumption was determined from the Australian Children and Adolescent Eating Survey. Markers of musculoskeletal health, including calcaneal broadband ultrasound attenuation, whole body, lumbar spine, femoral-neck, and trochanteric bone mineral density, lean mass, and percent fat (%fat), tibial volumetric density at the 4% site and cortical thickness at the 38% site were measured.
There were no gender differences in any variable except peak high-velocity growth, which was greater in boys. The Bone-specific Physical Activity Questionnaire score was greater in girls. Peak high-velocity growth predicted variance in whole-body bone mineral density, lumbar spine bone mineral density, %fat, and lean mass for boys. Peak high-velocity growth predicted roughly the same degree of variance in whole-body bone mineral density, lumbar spine bone mineral density, and a slightly greater amount of trochanteric bone mineral density, and lean mass for girls. It also explained the variance in femoral-neck bone mineral density and calcaneal broadband ultrasound attenuation. Tibial cortical thickness was related to peak high-velocity growth for both genders. Tibial volumetric density at the 4% site was related to peak high-velocity growth only for girls. Neither calcium nor physical activity explained variance in any musculoskeletal variable for either sex in the regression models.
Implication. Maturity, defined as years from age of peak height velocity growth, largely accounts for variance in bone, fat, and muscle status in both male and female pre- and peri-pubertal children, while physical activity and calcium are not significantly influential. Some gender differences exist.
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