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

Abstract

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. The hand-grip strengths of 476 healthy adult subjects were tested using the electronic (Grippit; AB Detektor, Goteborg, Sweden) and hydraulic (Jamar; Smith and Nephew, Memphis, TN) dynamometers. 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. The study yielded population reference ranges of peak, average, and final strength over a 10-second grip assessment using an electronic dynamometer. Results from the Grippit and Jamar dynamometers are similar; however, the dynamometers cannot be interchanged. The Grippit provides information about endurance and fatigue of grip over 10 seconds, showing differences between right- and left-dominant adults.