Optimal Jamar dynamometer handle position to assess maximal isometric hand grip strength in epidemiological studies.

Purpose Hand grip strength is an indicator of general muscle strength that is measured using a hand dynamometer. In some studies, a subject's grip strength is taken to be the maximal grip strength achieved from measurements taken at several different dynamometer handle positions. However, little is known about the influence of these different positions on the measured grip strength. The aim of the study was to identify one standard handle position that could be used to assess the grip strength of all subjects. Methods Grip strength was assessed with a hand dynamometer (Jamar Plus+; Sammons Preston, Rolyon, Bolingbrook, IL). Each participant's grip strength was measured 3 times in each of 5 different handle positions with each hand. The best position for each participant was defined as the position at which they achieved maximal grip strength. Results The mean (± standard deviation) age of the 50 participants was 41 (± 13) years. Maximal grip strength was 43.7 (± 12.4) kg for all participants; 55.0 (± 10.2) kg for men and 35.4 (± 5.2) kg for women. Handle position 2 was the best position for 70% of participants. The mean difference between the grip strength achieved by each participant at handle position 2 and that achieved at each participant's best position was 0.8 (± 1.78) kg. Conclusions Our results show that measurements taken at a single standard handle position are sufficiently accurate to assess grip strengths for all subjects. We therefore recommend handle position 2 as the standard position for measuring grip strength with the Jamar Plus+ hand dynamometer. Clinical relevance The assessment of grip strength with the Jamar Plus+ dynamometer is easier and faster if a single, standard handle position is used rather than multiple different positions. As well as providing accurate results, a single, standard handle position also reduces fatigue and increases the comparability of results between subjects.