Table 2. Phase 2 clinical and physiological characteristics, and exercise performance.
| Standard Group | Incentive Group | |||
|---|---|---|---|---|
| Pre | Change at End of Phase | Pre | Change at End of Phase | |
| BMI, kg/m2 | 33.6 ± 6.8 | 0.0 ± 1.4 | 34.6 ± 6.9 | 1.3 ± 4.2 |
| BMI, percentile | 97 ± 4 | 0 ± 2 | 98 ± 3 | 0 ± 1 |
| Body fat, % | 42.6 ± 6.3 | -1.1 ± 3.9 | 44.0 ± 6.8 | -0.8 ± 4.5 |
| Fat-free mass, kg | 49.9 ± 9.4 | 0.9 ± 2.7 | 51.6 ± 11.6 | 0.9 ± 2.9 |
| Waist circumference, cm | 103 ± 15 | -2 ± 5 | 105 ± 16 | 2 ± 5 |
| VO2peak, ml/kg FFM/min | 33.9 ± 6.2 | 4.6 ± 8.9 | 39.0 ± 9.7 | -0.7 ± 6.7 |
| Steps per day | 5,265 ± 2,199 | -115 ± 2,641 | 6,042 ± 2,508 | -2,078 ± 2,599 |
| Glucose, mmol/l | 5.1 ± 0.4 | 0.0 ± 0.3 | 5.2 ± 0.4 | 0.0 ± 0.4 |
| Insulin, pmol/l | 110.0 ± 80.3 | 2.8 ± 77.8 | 114.7 ± 67.5 | 24.6 ± 75.1 |
| iHOMA2 (%S) | 67.3 ± 34.8 | -5.9 ± 62.2 | 62.2 ± 31.4 | -6.2 ± 34.5 |
| HbA1c (%) | 5.3 ± 0.2 | 0.2 ± 0.2 | 5.5 ± 0.2 | 0.0 ± 0.2 |
| Exercise sessions performed | — | 16 ± 11 | — | 19 ± 17 |
| Total MVPA time, h | — | 8.0 ± 5.5 | — | 12.4 ± 11.1 |
| MVPA time per exercise session, minutes | — | 29 ± 6 | — | 38 ± 11§§ |
| MVPA time in moderate intensity range, % | — | 63 ± 18 | — | 62 ± 22 |
| Payments for exercise, USD$ | — | 64 ± 43 | — | 106 ± 89§ |
Values shown as mean ± SD. Pre-values correspond to measurements performed at the end of Phase 1, before Phase 2 exercise commenced. BMI, body mass index; VO2peak, peak oxygen uptake during aerobic fitness test; FFM, fat-free mass; iHOMA2, integrated homeostatic model of assessment; HbA1c, hemoglobin A1c; MVPA, moderate-to-vigorous activity. The Standard group had 11 girls, 9 boys; mean age 14.0 ± 2.0 years at the start of Phase 2. The Incentive group had 12 girls, 14 boys; mean age 14.6 ± 2.8 years at the start of Phase 2.
§ Difference between groups, p < 0.05.
§§ Difference between groups, p < 0.01