Table 2:
Black and Downs checklist for methodological quality of studies
| Authors and year of publication | Reporting | External validity | Internal validity - bias | Internal validity - confounding | Total | Percent (%) | Quality | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
|
| ||||||||||||||||||
| 1 | 2 | 3 | 5 | 6 | 7 | 10 | 11 | 12 | 16 | 18 | 20 | 21 | 22 | 25 | ||||
| Messier et al. 1990 (38) | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 0 | 0 | 1 | 9 | 60 | M |
| Radin et al. 1991 (23) | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 9 | 60 | M |
| Powers et al. 1999 (20) | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 0 | 1 | 11 | 73 | H |
| Duffey et al. 2000 (37) | 1 | 1 | 1 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 12 | 80 | H |
| Levinger et al. 2007 (36) | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 0 | 0 | 0 | 11 | 73 | H |
| Paoloni et al. 2010 (11) | 1 | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 0 | 0 | 0 | 9 | 60 | M |
| Saad et al. 2011 (15) | 1 | 1 | 0 | 0 | 0 | 0 | 0 | 1 | 0 | 0 | 1 | 1 | 0 | 0 | 0 | 5 | 33 | L |
| Silva et al. 2015 (10) | 1 | 1 | 1 | 0 | 0 | 0 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 1 | 12 | 80 | H |
| Esculier et al. 2015 (35) | 1 | 1 | 1 | 0 | 0 | 1 | 1 | 1 | 2 | 1 | 1 | 1 | 1 | 0 | 0 | 12 | 80 | H |
Abbreviations: H: high, M: medium, L: low