Which setting of the dynamometer provides maximal grip strength?

The purpose of this study was to determine which setting of the clinical dynamometer produced maximal grip strength and to correlate that setting with characteristics of the individual. Using a computerized isometric dynamometer, the maximal grip strength was determined in 288 normal asymptomatic hands in 4- to 78-year-old individuals at five dynamometer size settings. The majority of hands (256, or 89%) had a maximal grip strength at setting II. Mean body weight and mean height were lower in the group that had a maximal strength at or equal to setting I than in those individuals with maximal setting II and above. However, no clear significant correlation between body mass or hand size and maximal setting was evident. Those with a maximal grip at setting III or IV did not have larger hands or other features that differed from those with maximal settings at II. If measured at setting II only, maximal grip strength would have been underestimated in about 10% of individuals, but the error was small, ranging from 2% to 24%. Since no feature was identified that predicted maximal grip strength setting, it is recommended that grip strength of all patients should be routinely measured at setting II, irrespective of age, weight, or hand dimensions.