Validity of the fingertip-to-floor test and straight leg raising test in patients with acute and subacute low back pain: a comparison by sex and radicular pain.

OBJECTIVE To use self-reported disability (Roland-Morris Disability Questionnaire [RMDQ]) to assess the criterion validity of straight leg raising (SLR) test and flexion range of motion (ROM) (fingertip-to-floor test) before and after stratification by sex and presence/absence of radicular pain. DESIGN Cross-sectional study. SETTING Outpatient physical therapy clinic. PARTICIPANTS Subjects with acute/subacute low back pain with (n=40) and without (n=35) radicular pain. INTERVENTIONS Not applicable. MAIN OUTCOME MEASURES We examined the relationship between RMDQ (reference variable) and SLR test and fingertip-to-floor test. The sample was stratified by presence/absence of radicular pain (categorized by the dichotomous slump test). RESULTS In the entire sample, fair correlations were found between both physical impairment tests (ie, SLR test and flexion ROM) and self-reported disability (.27.44). After stratification by sex, the correlation between RMDQ and flexion ROM and between RMDQ and nonside-specific SLR test increased in women but decreased in men. In those with radicular pain, good correlations were found between RMDQ and flexion ROM (r=.68 for men and r=.70 for women), and moderate correlation was found between the RMDQ and SLR tests of the affected side in women (r=.60), but only fair correlation was found between the RMDQ and SLR tests of the affected side in men (r=.28). CONCLUSIONS After stratification by sex and presence/absence of radicular pain, the present study supports a good validity of the fingertip-to-floor test for both men and women with radicular pain. The SLR test, however, was of less value as an indicator of self-reported disability after stratification, especially for men.