Reliability and agreement of 5 Ergo-Kit functional capacity evaluation lifting tests in subjects with low back pain

OBJECTIVE: To assess interrater reliability and agreement of 5 Ergo-Kit functional capacity evaluation lifting tests in subjects with low back pain (LBP). DESIGN: Within-subjects design, with 2 repeated measurements. SETTING: Academic medical center in The Netherlands. PARTICIPANTS: Twenty-four subjects (10 men, 14 women) with LBP. INTERVENTIONS: Not applicable. MAIN OUTCOME MEASURE: Five Ergo-Kit lifting tests (2 isometric, 3 dynamic) were assessed on 2 occasions (t1, t2), by 2 different raters (R1, R2). The interval between the test sessions was 3 days. Interrater reliability level was expressed with the intraclass correlation coefficient (ICC), and the level of agreement between raters with the standard error (SE) of measurement. RESULTS: ICCs means (reliability) of isometric and dynamic Ergo-Kit lifting tests ranged from .94 to .97, and SE of measurement values (agreement) ranged from 1.9 to 8.6 kg. CONCLUSIONS: There was good reliability and agreement between raters of the isometric and dynamic Ergo-Kit lifting tests in subjects with LBP, which supports the use of these tests to assess functional lifting capacity.