BACKGROUND: Distraction based material handling tests are used to measure effort during functional capacity evaluations. OBJECTIVE: To identify validity of effort using the under loading method with the XRTS Lever Arm. Classification of effort between the two sessions (100 effort and estimated 50 effort) was compared with current validity criteria. METHODS: Fifty healthy and asymptomatic subjects were tested under two conditions (100 effort and an estimated 50 effort). Comparisons were made between percent changes from crate lifts to lever arm lifts from three starting heights (0.25 m, 0.38 m and 0.051 m). RESULTS: During the 100 effort sessions, no subject had a mean percent change >20, a majority of lift comparison >25 or a single lift comparison >30. The specificity of the current validity criteria is 100. The under loading method of using the XRTS lever arm was 20 sensitive in identifying an equivocal or invalid test result when subjects gave an estimated 50 effort. CONCLUSIONS: The results indicate the under loading method of distraction based testing is very specific but lacks sensitivity in identifying feigned weakness with asymptomatic, non-injured individuals. The high specificity of the test should eliminate concern of having a false positive for insincere effort during functional testing.
- Functional capacity evaluation
- cross-reference testing
- percent change