Research ArticlesCOEFFICIENT OF VARIATION IN MAXIMAL AND FEIGNED STATIC AND DYNAMIC GRIP EFFORTS1Dvir, Zeevi PhD, LLB2 Author Information 1 From the Department of Physical Therapy, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Israel. 2 All correspondence and requests for reprints should be addressed to: Department of Physical Therapy, Sackler Faculty of Medicine, Tel Aviv University, Ramat Aviv, Israel 69978. American Journal of Physical Medicine & Rehabilitation 78(3):p 216-221, May 1999. Buy Abstract The purpose of this study was to investigate the validity of the coefficient of variation as an identifier of feigned grip effort. Seventeen healthy female aged 20 to 25 yr participated in the study. Maximal and feigned efforts were measured isometrically and isokinetically (concentric and eccentric) using the Jamar and KinCom dynamometers, respectively. Findings indicated that, in all situations, the coefficient of variation derived from the maximal effort was significantly (P < 0.0001) lower than that derived from the feigned effort. However, the extent of overlapping between the two was sufficiently large to render the test sensitivities very low. Consequently, regardless of the measurement method, the coefficient of variation is not a valid tool for identifying feigned grip effort in healthy subjects. © 1999 Lippincott Williams & Wilkins, Inc.