Table 5. Intervention effects on physical activity according to group allocation.
| Intervention (N = 96) | Control (N = 148) | |||||||||
|---|---|---|---|---|---|---|---|---|---|---|
| Outcome | Baseline | Mid-intervention | Within-group change | Baseline | Mid-intervention | Within-group change | Adjusted difference in changea | 95% CI | p-value | ConditionalICC |
| Physical activity level (cpm)b | 394 372–417 | 462 435–491 | 73 (111) | 386 364–409 | 428 403–455 | 47 (133) | 5 | -30–41 | 0.77 | Class: 0.04 |
| Overall MVPA (minutes/day)b | 44.9 41.9–48.3 | 55.2 51.2–59.6 | 11.4 (17.2) | 44.5 41.6–47.7 | 51.5 48.2–55.1 | 7.4 (17.4) | 1.2 | -3.9–6.3 | 0.64 | Class: 0.04 |
| All school time (cpm)b | 465 436–496 | 492 461–525 | 29 (152) | 405 382–429 | 422 393–453 | 30 (156) | 1 | -62–63 | 0.98 | Class: 0.24 |
| All school time MVPA (%)b | 6.7 6.2–7.3 | 7.3 6.7–7.9 | 0.7 (2.8) | 5.9 5.5–6.3 | 6.4 5.8–6.9 | 0.9 (2.9) | -0.3 | -1.5–0.9 | 0.63 | Class: 0.25 |
| Class time (cpm)b | 291 271–312 | 288 268–309 | -2 (108) | 25 9 243–277 | 250 231–271 | 0.9 (131) | 6 | -53–64 | 0.86 | Class: 0.42 |
| Class time MVPA (%)b | 3.6 3.3–4.0 | 3.7 3.3–4.0 | 0.0 (2.0) | 3.2 2.9–3.5 | 3.1 2.8–3.5 | 0.2 (2.3) | 0.0 | -1.0–1.0 | 0.98 | Class: 0.37 |
| Recess (cpm)b, c | 903 822–992 | 982 893–1080 | 89 (462) | 691 631–757 | 690 619–769 | 52 (458) | 112 | -84–308 | 0.26 | School: 0.12. Class 0.04 |
| Recess MVPA (%)b, c | 14.3 12.8–15.9 | 15.7 13.9–17.7 | 1.8 (8.2) | 10.7 9.6–11.9 | 10.6 9.2–12.3 | 1.6 (9.4) | 1.2 | -3.2–5.6 | 0.59 | School: 0.17. Class: 0.07 |
Baseline, follow-up and within-group changes are unadjusted values while between-group comparisons are adjusted. All physical activity values were skewed hence baseline and mid-intervention values are presented as geometric means with 95% CI ratios. Changes are presented as means with SD for within group-changes and means with 95% CI for between group changes.
a Estimates are the unstandardized beta-coefficients (control coded as zero, intervention coded as 1) from linear mixed models with the change in outcome adjusted for baseline value of outcome, gender and grade level. If a random effect did not improve the model fit, ordinary least squares regression was used.
b Between-group difference in change is further adjusted for class cluster as a random effect.
c Between-group difference in change is further adjusted for school cluster as a random effect.
CI: confidence interval, MVPA = moderate to vigorous physical activity, CI = confidence interval, ICC: Intraclass correlation coefficient.