Execution:
- Patient is standing upright and barefoot with the feet 30cm apart
- The examiner marks one line 5cm below the line of the iliac crests and another one 10cm above so that the distance from the bottom to the top line is 15cm
- The patient is then asked to bend forward and the distance between the two lines is measured again
Positive Outcome: The distance between the lines is the amount of lumbar flexion. In the Bath Ankylosing Spondylitis Metrology Index (BASMI), a mild flexion limitation is assumed if the distance is >4cm, moderate from 2-4cm and severe for a distance <2cm
| Study | Reliability | Sn | Sp | LR+ | LR- |
| Calvo-Gutiérrez et al. (2016) | Inter-rater ICC=0.76 | NA | NA | NA | NA |
| Davis et al. (2007) | Inter-rater ICC=0.96 | NA | NA | NA | NA |
| Haywood et al. (2004) | Inter-rater ICC=0.90 | NA | NA | NA | NA |
| Maksymowynch et al. (2006) | Inter-rater ICC=0.97 | NA | NA | NA | NA |
| Viitanen et al. (2000) | Inter-rater ICC=0.96 | NA | NA | NA | NA |
| Comment: The original Schober shows acceptable construct validity for inferring the extent of structural damage when assessing patients with ankylosing spondylitis. | |||||
