title: The coefficient of variation as a measure of sincerity of effort of grip strength, Part I: the statistical principle.
abstract: The coefficient of variation (CV) is a widely used measure of sincerity of effort of grip strength despite contradictory research findings and lack of empirical support in the literature. The purpose of this study was to investigate whether the CV is an appropriate measure of sincerity of effort. One hundred forty-six uninjured volunteers underwent a series of grip strength tests. The mean, standard deviation (SD), and CV of repeated strength trials were calculated, and paired comparisons were conducted between maximal and submaximal efforts. While the mean of maximal trials was significantly greater, there were no differences in SD between maximal and submaximal trials. Therefore, the increased CV associated with submaximal effort was an artifact of reduced torque rather than an indicator of a true increase in variability. Consequently, the CV is not an appropriate measure of sincerity of effort of grip strength.
authors.affiliation: Department of Occupational Therapy, College of Health Professions, University of Florida, Gainesville 32610, USA. oshechtm@hp.ufl.edu
authors.forename: O
authors.initials: O
authors.lastname: Shechtman
mesh_terms: D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D005260:Female; D018737:Hand Strength; D006801:Humans; D008297:Male; D005082:Physical Exertion; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity