Table 2.
Risk of Bias for Selected Studies.
| Study | Risk of Bias Domain | ||||||
|---|---|---|---|---|---|---|---|
| Randomization Process | Period or Carry-Over Effect |
Deviation from Intended Intervention | Missing Outcome Data | Measurement of Outcome | Selection of Reported Results | Overall Risk of Bias | |
| Beetroot Juice | |||||||
| Flueck et al. 2019 | Low | Low | Low | Low | Low | Low | Low |
| Caffeine | |||||||
| Flueck et al. 2014 | Low | Low | Low | Low | Low | Some concerns | Some concerns |
| Graham-Paulson et al. 2016 | Low | Low | Low | Low | Low | Some concerns | Some concerns |
| Flueck et al. 2015 | Low | Low | Low | Low | Low | Some concerns | Some concerns |
| Klimešová et al. 2017 | Low | Low | Low | Low | Low | Some concerns | Some concerns |
| Creatine | |||||||
| * Amorim et al. 2018 | Low | N/A | Low | Low | Low | Low | Low |
| Perret et al. 2006 | Low | Low | Low | Low | Low | Some concerns | Some concerns |
| Walter et al. 2000 | Low | Low | Low | Low | Low | Some concerns | Some concerns |
| Jacobs et al. 2002 | Low | Low | Low | Low | Low | Some concerns | Some concerns |
| Tarnopolsky et al. 1999 | Low | N/A | N/A | Low | Low | Some concerns | Some concerns |
| Fish Oil | |||||||
| Marques et al. 2016 | High | Low | Low | Low | Low | Some concerns | High |
| Vitamin D | |||||||
| Flueck et al. 2016 | High | N/A | Low | Low | Low | Low | High |
| Pritchett et al. 2019 | High | Low | Low | Low | Low | Some concerns | Some concerns |
| Protein and Amino Acids | |||||||
| Theis et al. 2020 | Low | N/A | Low | Low | Low | Low | Low |
* Amorim et al. (2018) also investigated vitamin D.