Effects of subject position on measurements of flexion, extension, and lateral flexion of the spine.

Effects of subject positions on range and repeatability of thoracic and lumbar forward flexion, extension, and lateral flexion were studied. Inclinometric methods were used, and 27 subjects were measured by two trained testers. No great differences in repeatability and range of movements were found between measurements in different positions, but according to the results and convenience of performance, the following positions could be recommended: forward flexion in a sitting position, extension while lying on an examination table with arms braced ahead, and lateral flexion close to a wall and facing it.