Abstract
Currently, there are no universally accepted assessment methods for detecting insincere
effort during grip strength testing. We examined the validity of the slopes of the
force-time curve (during force-generation and force-decay phases) as indicative of
sincerity of effort. Thirty healthy subjects performed both maximal and submaximal
grip strength trials. The test administrator was blinded as to the nature of the effort.
A force-time curve was generated for each individual trial. The slopes of the force-generation
phase and the force-decay phase were calculated. Both slopes were significantly steeper
for the maximal than the submaximal efforts (p≤0.0001). Sensitivity and specificity analyses revealed that the slope of the force-generation
phase was a more effective assessment of sincerity of effort for women, whereas the
slope of the force-decay phase was a more effective assessment for men. The most notable
finding was that for the force-decay phase, for slope cutoff values of −0.75 and −1.0,
none of the men who exerted maximal effort were mistakenly identified as exerting
a submaximal effort, whereas only 7% of the men who exerted submaximal effort were
incorrectly identified as exerting a maximal effort. Thus, the slopes of the force-time
curve are valid and effective in detecting sincerity of effort in healthy subjects.
This study represents the first step in establishing the feasibility and validity
of a new sincerity of effort assessment using the slopes of the force-time curve.
Future research is needed to establish the validity and effectiveness of this sincerity
of effort assessment in people with hand injury.
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JHT Read for Credit
Quiz: Article #048
Record your answers on the Return Answer Form found on the tear-out coupon at the back of this issue. There is only one best answer for each question.
- #1.The data showed
- a.only steeper force-generation curves for maximal efforts than submaximal efforts
- b.only steeper force-decay curves for maximal efforts than submaximal efforts
- c.both steeper force-generation and force-decay curves for maximal efforts than submaximal efforts
- d.both steeper force-generation curves and force-decay curves for submaximal efforts than maximal efforts
- a.
- #2.The data suggested that for indicating sincerity of effort
- a.force-generation curves were better for women, and force-decay curves were better for men
- b.force-generation curves were better for men, and force-decay curves were better for women
- c.force-generation and force-decay curves were equally valid for both men and women
- d.force-generation and force-decay curves were invalid for both men and women
- a.
- #3.In detecting sincerity of effort, force-time curves were found to be
- a.impractical for research purposes
- b.practical for clinical practice
- c.effective and valid for a patient population
- d.effective and valid in healthy subjects
- a.
- #4.In considering specificity and sensitivity, it is better to err in the direction of
- a.the highest sensitivity without regard to specificity
- b.higher sensitivity and lower specificity
- c.lower sensitivity and higher specificity
- d.the highest specificity without regard to sensitivity
- a.
- #5.The following number of men who actually exerted a sincere effort were identified as giving a submaximal effort
- a.1
- b.0
- c.5
- d.7
- a.
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© 2007 Hanley & Belfus. Published by Elsevier Inc. All rights reserved.
