Measuring grip strength in normal adults: Reference ranges and a comparison of electronic and hydraulic instruments

Purpose: To determine reference ranges for peak, average and final adult grip strength over 10 seconds by using an electronic dynamometer, and to compare results from hydraulic and electronic dynamometers. Methods: The hand-grip strengths of 476 healthy adult subjects were tested using the electronic (Grippit; AB Detekor, Goteborg, Sweden) and hydraulic (Jamar; Smith and Nephew, Memphis, TN) dynamometers. Results: Age- and gender-specific reference ranges for the Jamar and Grippit dynamometers are presented. Bland - Altman analysis of the differences between the results obtained using the 2 instruments revealed a bias (mean difference) of 22 N (Jamar - Grippit) and limits of agreement of -86 to 129 N (mean +/- 2 SD), which indicates that grip measurements may vary by up to 215 N between instruments. Conclusions: The study yielded population reference ranges of peak, average and final strenght over a 10-second grip assessment using an electronic dynamometer. Results from the Grippit and Jamar dynamometers are similar; however, the dynamometer cannot be interchanged. The Grippit provides information about endurance and fatigue of grip over 10 seconds, showing differences between right- and left-dominant adults. Copyright (C) 2004 by the American Society for Surgery of the Hand.