Test–Retest Reliability of the Isernhagen Work Systems Functional Capacity Evaluation in Healthy Adults

Abstract

Aim of this study was to investigate test-retest reliability of the Isernhagen Work System Functional Capacity Evaluation (IWS FCE) in healthy subjects. The IWS FCE consists of 28 tests that reflect work-related activities such as lifting, carrying, bending, etc. A convenience sample of 26 healthy subjects participated in the study. The subjects' mean age was 34.9 years. Two FCE sessions were held within a 2-3 week interval. Descriptives per session, Intra Class Correlations (ICC), limits of agreement, Cohen's Kappa, and percentage of agreement were calculated where appropriate. An ICC of > or =0.75, a Kappa value > or =0.60, and a percentage of absolute agreement of > or =80% were considered acceptable reliability. Acceptable reliability was demonstrated for seven out of nine tests (78%) of the material handling group and the shuttle walk test based on ICC analyses only. Sixteen out of 17 criterion and ceiling tests (94%) showed acceptable reliability based on Kappa values and percentage of agreement. Of these 17 tests, 8 were eligible for further analysis, and of those 8 tests the reliability of one test was acceptable based on ICC analyses (13%). In conclusion, the test-retest reliability of the material-handling group is acceptable. Crude analyses of the ceiling and criterion tests reveal acceptable test-retest reliability of most, but not all, tests.