Objectives: Users of hand-held vibratory tools report reductions in grip strength and manual dexterity. This study quantified the test-retest repeatability of grip strength and manual dexterity tests, investigated effects of gender and age, and determined normative measures in different subject groups.

Methods: A total of 72 subjects in four groups (both genders and two age ranges) participated: men and women aged 18 to 25 years and 45 to 55 years. Grip strength was measured with a hand-held dynamometer, and dexterity measured with the Purdue pegboard. We assessed repeatability using one subject group (18 to 25-year-old men) who attended over three successive weeks.

Results: Repeated measures of grip strength were correlated for both hands and for each combination of weekly tests (P=0.01), and there were no significant changes in strength over weeks. Repeated measures of dexterity were correlated in both hands (P=0.01) for all test combinations, except between weeks 1 and 3 in the non-dominant hand (P=0.15). Further analysis suggested an improvement in dexterity, consistent with a practice effect. In both age groups, grip strength of the men was significantly greater than that of the women (P<0.01), but there were no gender differences in dexterity scores (P>0.1). There were no significant effects of age for either grip strength or dexterity (P>0.1).

Conclusions: Both tests showed sufficient repeatability, with no age effect on either grip or manual dexterity (between approximately 20 to 55 years), although a decline in grip and dexterity is expected at greater ages. Dexterity scores were similar in both genders for the groups studied. Grip strength was greater in men. Occupational effects might exist for both tests, irrespective of any occupational disorder, and might be reflected in increases or decreases in grip strength and dexterity.