Abstract
OBJECTIVE: To develop and establish the reliability, validity, measurement error, and minimum detectable change of a novel 30-second fast-paced walk test (30SFW) in persons with knee osteoarthritis (OA) that is easy to administer and can quantify walking performance in persons of all abilities. METHODS: Twenty females with symptomatic knee OA (mean age [SD] 58.30 [8.05] years) and 20 age- and sex-matched asymptomatic controls (57.25 [8.71] years) participated in the study. Participants completed questionnaires of demographic and clinical data, the Knee Injury and Osteoarthritis Outcome Score (KOOS), and the 36-item Short Form Health Survey (SF-36) followed by 30SFW performance. Participants returned 2-7 days later and performed the 30SFW again. RESULTS: The knee OA group reported function that was worse than controls (all KOOS subscales; P < 0.0001). The 30SFW intrarater and interrater reliability were excellent [ICC ((2,1)) = 0.95-0.99]. Knee OA participants walked a shorter distance in the 30SFW than controls (mean [SD]: OA 44.4 m [9.5 m]; control 58.1 m [7.8 m]; P < 0.0001). Positive strong correlations were found between the 30SFW and the KOOS-Activity of Daily Living, SF-36-Physical Functioning, and SF-36-Physical Health Composite scores (P < 0.0001). A nonsignificant, weak correlation between 30SFW and SF-36-Mental Health scores was present (r = 0.32, P = 0.05). CONCLUSION: The 30SFW has excellent intrarater and interrater reliability. The 30SFW demonstrated excellent known groups, convergent, and discriminant validity as a measure of short-distance walking ability in persons with knee OA. Clinicians and researchers should consider using the 30SFW to quantify walking ability in persons with knee OA and assess walking ability change.