Descriptive characteristics of the study population at baseline in each study phase, mean ± SD or N (%)
| Control group | Intervention group | |||
| Characteristic | N | Mean±SD or % | N | Mean±SD or % |
| Age (year) | 39 | 15.7 (1.0) | 45 | 16.0 (1.4) |
| Gender | ||||
| Female | 38 | 97.4% | 43 | 95.5% |
| Male | 0 | 0% | 0 | 0% |
| Other | 1 | 2.6% | 2 | 4.4% |
| Race | ||||
| White | 25 | 64.1% | 40 | 88.9% |
| Black | 0 | 0% | 0 | 0% |
| Asian | 3 | 7.7% | 1 | 2.2% |
| More than one race | 8 | 20.5% | 3 | 6.7% |
| Unknown/not reported | 3 | 7.7% | 1 | 2.2% |
| Years running track | 39 | 3.4 (2.1) | 45 | 3.4 (2.0) |
| Age menarche | ||||
| Never menstruated | 1 | 2.6% | 0 | 0% |
| 11 years or younger | 6 | 15.4% | 7 | 15.6% |
| 12–14 years | 30 | 76.9% | 36 | 80.0% |
| 15 years or older | 2 | 5.1% | 2 | 4.4% |
| Regular periods | ||||
| Yes | 23 | 59.0% | 31 | 68.9% |
| No | 8 | 21.1% | 4 | 8.9% |
| Not sure if regular | 7 | 18.4% | 9 | 20.0% |
| Prefer not to answer | 1 | 2.6% | 1 | 2.2% |
| Oral contraceptive use | ||||
| Yes | 1 | 2.6% | 5 | 11.1% |
| No | 38 | 97.4% | 40 | 88.9% |
| Diagnosed eating disorder | ||||
| Yes | 4 | 10.3% | 5 | 11.1% |
| No | 35 | 89.7% | 40 | 88.9% |
| Diagnosed BSI history | ||||
| Yes | 4 | 10.3% | 11 | 24.4% |
| No | 35 | 89.7% | 34 | 75.6% |
| History of low BMD | ||||
| Yes | 0 | 0% | 0 | 0% |
| No | 39 | 100% | 45 | 100% |
BMD, bone mineral density; BSI, bone stress injury.