Details

Autor(en) / Beteiligte

• Francis, Shelby L
• Morrissey, Joanna L
• Letuchy, Elena M
• Levy, Steven M
• Janz, Kathleen F

Titel

Physical Activity Tracking in Iowa Bone Development Study Youth: Alignment by Biological versus Chronological Age

Ist Teil von

• Medicine and science in sports and exercise, 2012-05, Vol.44 (5S), p.655-655

Erscheinungsjahr

2012

Quelle

RCN full-text journals@Ovid

Beschreibungen/Notizen

• PURPOSE: To compare the tracking of childhood and adolescent objectively-measured physical activity (PA) using peak height velocity (PHV) as a predicted measure of biological age (BA) versus chronological age (CA, yr). To investigate whether known gender differences in PA trajectories were altered after aligning by BA instead of CA. METHODS: The Iowa Bone Development Study has collected longitudinal ActiGraph data at ages 5, 9, 11, 13, and 15 yr. To be included in this analysis, participants had to have worn an accelerometer at least two measurement periods (N = 112 girls; N = 96 boys). Spearman correlation coefficients were used to determine two-year intervals of tracking of moderate to vigorous PA (MVPA) before and after maturity (PHV). Gender-specific MVPA trajectories were compared using mixed models with autoregressive residual covariance. RESULTS: Moderate two-year tracking associations were present, except the -1 yr PHV to +1 yr PHV in boys. The mixed models indicate MVPA was highest at age 5 and then declined in girls. Boys' MVPA increased until 9 yr and then decreased at a faster rate than girls. A significant interaction between age and gender confirmed the different trajectories. By 2.5 to 3 yr post PHV girls and boys had similar levels of MVPA. CONCLUSIONS: Exploring opportunity, availability, and support of MVPA in boys and girls may help explain why levels are decreasing with age. Further research into the immediate time period surrounding PHV appears warranted in boys.