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

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 ≥0.75, a Kappa value ≥0.60, and a percentage of absolute agreement of ≥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.