Table 1.
Mean (S.D.) age (years) | 12.0 (1.6) |
Mean (SD) body mass index (kg/m2) | 19.0 (3.3) |
Mean (SD) age at menarche (years) | 11.8 (1.0) |
% Post-menarcheal | 44.1% (n=3008) |
% Underweight | 8.6% (n=570) |
% Overweight or obese | 19.8% (n=1309) |
% Disordered eating | 2.5% (n=169) |
% Maternal history of low bone density or osteoporosis | 10.4% (n=707) |
Hours per week of moderate or vigorous activitya | |
< 1 hour/week | 0.2% (n=12) |
1–3.9 hrs/wk | 3.4% (n=222) |
4–7.9 hrs/wk | 14.0% (n=918) |
8–11.9 hrs/wk | 19.9% (n=1310) |
12–15.9 hrs/wk | 18.8% (n=1239) |
16–19.9 hrs/wk | 15.0% (n=988) |
20–24.9 hrs/wk | 11.2% (n=734) |
> 25 hrs | 15.7% (n=1033) |
Mean (SD) hours/week of non impact activity | 4.7 (3.3) |
Mean (SD) hours/week of intermediate impact activity | 2.2 (2.4) |
Mean (SD) hours/week of high impact activityb | 5.2 (4.1) |
Sum of basketball, baseball, biking, dance/aerobics, hockey, running, swimming, skating, skateboarding, soccer, tennis, cheerleading, lifting weights, volleyball, and karate.
Sum of basketball, running, soccer, tennis, cheerleading, and volleyball.