Table 4.
Risk of bias assessed by Cochrane Risk of Bias tool.
| Studies | Sequence generation | Allocation concealment | Blinding participants |
Blinding of outcome assessment | Incomplete outcome data | Selective outcome reporting | Sampling bias |
|---|---|---|---|---|---|---|---|
| Chaddock-Heyman et al. (2013)* | Unclear | Unclear | High | Unclear | Low | Low | Low |
| Chaddock-Heyman et al. (2018)* | Low | Low | High | Low Blinded research team |
Low | Low | Low |
| Chen et al. (2016) | Unclear | N/A Cross-over design |
High | Unclear | Unclear | Low | Low |
| Chu et al. (2017) | Unclear | N/A Cross-over design |
High | Unclear | Unclear | Low | High 100 % boys |
| Chuang et al. (2015) | Unclear | N/A Cross-over design |
High | Unclear | Low | Low | High 85 % boys |
| Davis et al. (2011) | Low Stratified |
Low | High | Low Blinded assessors |
Low | Unclear Not reported for subsample |
Low |
| Drollette et al. (2018)* | Low Balanced by sex, race, IQ, SES & VO2; Coin flipping |
Unclear | High | Low Blinded staff members |
Low | Low | Low |
| Hillman et al. (2009) | Unclear | N/A Cross-over design |
High | Unclear | Unclear | Low | Unclear |
| Hillman et al. (2014)* | Low Coin flipping |
Low | High | Low Blinded assessors |
Low | Low | Low |
| Huang et al. (2018) | Low Counterbalanced |
Unclear | High | Unclear | Low | Low | High 100 % boys |
| Hung et al. (2016) | Unclear | N/A Cross-over design |
High | Unclear | Low | Low | High 100 % boys |
| Kamijo et al. (2011) | Unclear | Unclear | High | Unclear | Low | Low | Low |
| Kim and So (2015) | Unclear | Unclear | High | Unclear | Low | Low | Low |
| Krafft, et al. (2014c) | Low Balanced by sex, race, school |
Low | High | Unclear | Low | Low | High 100 % black |
| Krafft et al. (2014c) | Low Balanced by sex, race, school |
Low | High | Unclear | Low | Low | High 90 % black |
| Krafft et al. (2014b) | Low Balanced by sex, race, school |
Low | High | Unclear | Low | Low | High 94 % black |
| Lee et al. (2017) | Low Block randomization |
Unclear | High | Unclear | Low | Low | High 100 % boys |
| Lind et al. (2019) | Low | N/A Cross-over design |
High | Unclear | Low | Low | Low |
| Ludyga et al. (2019)* | Low | Unclear | High | Low Blinded assessors |
Low | Low | Unclear |
| Mierau et al. (2014) | Unclear | N/A Cross-over design |
High | Unclear | Low | Low | High 100 % boys |
| Pontifex et al. (2013) | Unclear | N/A Cross-over design |
High | Unclear | Unclear | Low | High 70 % boys |
| Pontifex et al. (2018) | Low Counterbalanced |
N/A Cross-over design |
High | Unclear | Low | Low | Low |
| Schaeffer et al. (2014) | Unclear | Low | High | Unclear | Unclear | Low | High 95 % black |
| St Louis Deschenes et al. (2015) | Unclear | N/A Cross-over design |
High | Unclear | Unclear | Low | Low |
| Xiong et al. (2018) | Unclear | Unclear | High | Unclear | Low | Low | Low |
| Wollseiffen et al. (2018) | Unclear | N/A Cross-over design |
High | Unclear | Unclear | Low | Low |
Abbreviations: N/A, not applicable; * Outcome measures were preregistered in clinical trial registers.