Related Experiment Video
Updated: Mar 9, 2026
An Instrumented Pull Test to Characterize Postural Responses
Published on: April 6, 2019
Accuracy of distraction based lifting criteria for the identification of insincere effort utilizing the under loading
Robert Townsend1, Shane Bell1, John Harry2
1University of Memphis, Memphis, TN, USA.
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.
