PSYCHOMETRIC CHARACTERISTICS AND CLINICAL USEFULNESS OF PHYSICAL PERFORMANCE TESTS IN PATIENTS WITH LOW-BACK-PAIN

Study Design, The psychometric properties and clinical use of a batter y of physical performance measures were tested on 44 patients with low back pain and 48 healthy, pain-free control subjects. Objectives, Rel iability, validity, and clinical use of nine physical performance meas ures were evaluated, Summary of Background Data. Although physical per formance measures have potential use in evaluation, treatment planning , and determination of treatment outcome, there is sparse systematic i nvestigation of their reliability, validity, and clinical use. Methods . Forty-Four subjects with low back pain and 48 healthy pain-free subj ects participated, the following physical performance measures were te sted: distance walked in 5 minutes; 50-foot walk at fastest speed; 50- foot walk at preferred speed; 5 repetitions of a sit-to-stand task; 10 repetitions of a repeated trunk flexion task; timed up-and-go task; u nloaded forward reach task; loaded forward reach task; and Sorensen fa tigue test. Subjects were assessed twice on 2 days. Results. All measu res had excellent intertester reliability (intraclass correlation coef ficient [ICC](1.1) >0.95). Test-retest (within Session) reliability wa s adequate for all measures (ICC1.1 >0.83) except repeated trunk flexi on (ICC1.1 >0.45) in the low back pain group. Test-retest (day-to-day) reliability ranged between 0.53 and 0.88 in the low back pain group a nd between 0.46 and 0.76 in the control group. Day-to-day reliability improved when the averages of two trials of repeated trunk flexion and sit-to-stand was used (0.76-0.91 low back pain group and 0.62-0.89 co ntrol group). Results of a multivariate analysis of variance showed a significant effect of group (F-10,F-65 = 3.52, P = 0.001). Results of univariate analyses showed significant group differences on all measur es except the 50-foot walk at preferred speed and unloaded forward rea ch. Self-report of disability was moderately correlated with the perfo rmance tasks (r = 0.400 to -0.603). Conclusions. The results provide s upport for the use of these physical performance measures as a complem ent to patient self-report.