Consistency of sincere and feigned grip exertions with repeated testing.

Our purpose was to test the hypothesis that feigned exertions would show greater variability in both force and electromyograms than would sincere exertions over repeated testing sessions. Eleven normal subjects made sincere and feigned exertions while performing the five-handle position Jamar grip test. The subjects were tested 6 times in a 3- to 5-week period. Contrary to the hypothesis, feigned exertions did not show greater variability than sincere exertions. Both sincere and feigned exertions were highly consistent over the six sessions. However, the sincere and feigned exertions did differ in the patterns of force and electromyogram on the five-handle position test. These results and those of previous studies suggest that clinicians should use more than one type of test when testing suspected malingerers.