TABLE 1.
Descriptive characteristics of the girls (n = 248) at baseline and 2 years as well as the change in these variables over the 2-year period.
| Baseline | 2 Year | Change | P | |
|---|---|---|---|---|
| Age (yrs) | 10.7 ± 1.1 | 12.8 ± 1.1 | 2.1 ± 0.1 | <0.001 |
| Maturity offset (yrs) | −1.1 ± 1.0 | 0.7 ± 1.0 | 1.8 ± 0.3 | <0.001 |
| Height (cm) | 145 ± 9.9 | 157 ± 9.2 | 12.2 ± 3.8 | <0.001 |
| Body mass (kg) | 38.7 ± 9.5 | 49.8 ± 11.9 | 11.1 ± 4.8 | <0.001 |
| BMI (kg/m2) | 18.3 ± 3.0 | 20.0 ± 3.6 | 1.8 ± 1.6 | <0.001 |
| Femur length (cm) | 34.3 ± 3.1 | 36.8 ± 2.6 | 2.5 ± 1.5 | <0.001 |
| Tibia length (cm) | 33.2 ± 2.9 | 36.3 ± 2.6 | 3.1 ± 1.3 | <0.001 |
| Total body lean mass (kg) | 25.7 ± 5.0 | 32.1 ± 5.6 | 6.4 ± 2.4 | <0.001 |
| Total body fat mass (kg) | 10.9 ± 5.7 | 15.2 ± 7.5 | 4.3 ± 3.5 | <0.001 |
| Total body percent fat (%) | 27.3 ± 8.5 | 29.5 ± 8.2 | 2.1 ± 4.5 | <0.001 |
| Calf muscle density (mg/cm3) | 79.0 ± 1.3 | 79.8 ± 1.2 | 0.8 ± 1.5 | <0.001 |
| Thigh muscle density (mg/cm3) | 76.4 ± 1.6 | 77.5 ± 1.5 | 1.1 ± 1.5 | <0.001 |
| Calf MCSA (mm2) | 3208 ± 583 | 4364 ± 923 | 659 ± 292 | <0.001 |
| Thigh MCSA (mm2) | 3590 ± 711 | 4384 ± 872 | 792 ± 488 | <0.001 |
| Physical activity | 5322 ± 4670 | 5183 ± 4204 | −140 ± 5306 | 0.678 |
Values are presented as mean ± SD. BMI = body mass index; MCSA = muscle cross-sectional area. P values represent paired samples t-Test for difference between the baseline and 2-year study visit.