Electronic Supplementary File 1.
Quality assessment results.
| Study | Selection bias | Measurement and outcome bias | Data presentation | |||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Author, date) | Q1 | Q2 | Q3 | Q4 | Q5 | Selection bias (Maximum=5) | Q6 | Q7 | Q8 | Q9 | Q10 | Q11 | Q12 | Measurement and outcome bias (maximum = 7) | Q13 | Q14 | Data presentation (maximum = 2) | Total Score |
| 1. Bussey et al, 2016 | Y | N | Y | Y | Y | 4 | Y | Y | Y | N | Y | N | Y | 5 | Y | Y | 2 | 11 |
| 2. Cooper et al, 2016 | Y | N | Y | Y | Y | 4 | Y | Y | Y | N | Y | N | Y | 5 | Y | Y | 2 | 11 |
| 3. Cai et al, 2015 | N | N | N | Y | Y | 2 | Y | Y | Y | N | Y | N | Y | 5 | Y | Y | 2 | 9 |
| 4. Sutherlin et al, 2015 | Y | N | Y | Y | Y | 4 | Y | Y | Y | N | Y | N | Y | 5 | Y | Y | 2 | 11 |
| 5. Penney et al, 2014 | Y | N | Y | Y | Y | 4 | Y | Y | Y | N | Y | N | Y | 5 | Y | Y | 2 | 11 |
| 6. Yahia et al, 2011 | Y | Y | Y | Y | Y | 5 | Y | Y | Y | N | Y | N | Y | 5 | Y | Y | 2 | 12 |
| 7. Arab et al, 2010 | Y | N | Y | Y | Y | 4 | Y | Y | Y | N | Y | N | Y | 5 | Y | Y | 2 | 11 |
| 8. Kendall et al, 2010 | N | N | Y | Y | Y | 3 | Y | Y | Y | N | Y | N | Y | 5 | Y | Y | 2 | 10 |
| 9. Marshall et al, 2010 | Y | Y | Y | Y | Y | 5 | Y | Y | Y | N | Y | N | Y | 5 | Y | Y | 2 | 12 |
| 10. Tsai et al, 2010 | Y | N | Y | Y | Y | 4 | Y | Y | Y | N | Y | N | Y | 5 | Y | Y | 2 | 11 |
| 11. Marshall et al, 2009 | Y | N | N | Y | Y | 3 | Y | Y | Y | N | Y | N | Y | 5 | Y | Y | 2 | 10 |
| 12. Bernard et al, 2008 | Y | Y | Y | Y | Y | 5 | Y | Y | Y | N | Y | N | Y | 5 | Y | Y | 2 | 12 |
| 13. Lee et al, 1995 | N | Y | Y | Y | Y | 4 | Y | Y | Y | N | Y | N | Y | 5 | Y | Y | 2 | 11 |
| 14. Nourbakhsh et al, 2002 | Y | Y | Y | Y | Y | 5 | Y | Y | Y | N | Y | N | Y | 5 | Y | Y | 2 | 14 |
| TOTAL Score & Percentage Yes | 79 | 36 | 86 | 100 | 100 | 100 | 100 | 100 | 0 | 100 | 0 | 100 | 100 | 100 | ||||
Q1. Was the study population clearly specified, defined and adequately described?
Q2. Where both groups drawn from the same population (selected from similar populations and including the same time period)?
Q3. Were both groups comparable for age, sex, BMI/weight?
Q4. Was muscle strength described for LBP group?
Q5. Was an attempt made to define LBP and control group characteristics?
Q6. Did the method description enable accurate replication of the measurement procedures?
Q7. Was the measurement instrument clearly defined, valid, reliable, and adequately described?
Q8. Was a system for standardizing movement instructions reported?
Q9. Were assessors trained in standardized measurement procedure?
Q10. Did the same assessors test those with and without LBP?
Q11. Were assessors blinded as to which group subjects were in?
Q12. Was the same assessment procedure applied to those with and without LBP?
Q13. The results of between-group statistical comparisons are reported for at least one key outcome"?
Q14. Point estimates and measures of variability are provided for at least one key outcome for those with and without LBP?