Table 2.
Mean (SD), correlations and Bland-Altman output for Fitbit Zip and ActiGraph in school segments
| Fitbit Zip | ActiGraph GT3x | r | Bias | LoA | LuA | |
|---|---|---|---|---|---|---|
| Steps | ||||||
| Class time | 231.5 (298.2) | 206.2 (222.9) | 0.85** | 25.2 | − 209.6 | 260.3 |
| Physical education lesson | 2354.0 (1279.6) | 2008.7 (1172.5)** | 0.96** | 345.3 | − 163.8 | 854.4 |
| Recess | 472.2 (337.2) | 388.5 (268.2)** | 0.96** | 83.7 | −127.3 | 294.7 |
| MVPA (min) | ||||||
| Class time | 0.6 (2.5) | 0.9 (1.7)** | 0.24** | −0.3 | −4.0 | 3.3 |
| Physical education lesson | 17.8 (14.1) | 15.4 (9.1)* | 0.72** | 2.4 | −14.7 | 19.4 |
| Recess | 2.1 (4.3) | 2.4 (2.4)** | 0.56** | −0.3 | −6.4 | 5.8 |
| Sedentary time (min) | ||||||
| Class time | 37.5 (5.8) | 33.8 (6.5)** | 0.57** | 3.6 | −6.5 | 13.8 |
| Physical education lesson | 11.1 (9.8) | 13.7 (9.0)** | 0.85** | −2.6 | −10.4 | 5.2 |
| Recess | 5.5 (4.1) | 5.4 (3.9) | 0.87** | 0.1 | −3.7 | 3.9 |
Note: * P < 0.05, ** P < 0.001, LoA lower limits of agreement, LuA upper limits of agreement. Differences between two devices according to Wilcoxon Signed Rank test are presented in column “ActiGraph GT3x”