Numerous studies have shown the particular interest of the maximal grip strength recording in the framework of general health or on the changes of functional capacities during occupational exposure or as an effective index of the hand function recovery after an injury or an episode of musculoskeletal disorder. This work has two objectives: 1) to recall the grip strength (Fp) recording methodology and to allow the expression of the Fp recorded with the most common dynamometers in Fp equivalent with the Jamar apparatus which is the reference dynamometer; 2) to propose Fp reference values for a working population.

A first experiment was conducted to compare the Fp recorded with 5 different dynamometers on 37 young and active subjects (20 women, 17 men). The mean Fp and their prediction models were computed from the Fp recorded in a large sample of more than 1800 French workers (597 women, 1206 men) aged between 17 and 62.

The results show that the Bettendorff dynamometer recordings are almost the same as those recorded with the Jamar. The Collin and the My-Gripper apparatus allow an accurate Fp recording. The Martin vigorimeter is slightly less accurate but the comfort of its grip makes it adapted for populations suffering from hand osteoarthritis.

The mean Fp and, in brackets, their standard deviation, recorded in the working population, are, for the dominant hand 303 (55) N for women and 515 (91) N for men. In the non-dominant hand these figures are 271 (51) N for women and 477 (83) N for men. Grip strength is significantly (p < 0.001) related to gender (women/men ratio = 0,59), to age (decrease per ten years equals 14 N for women and 24 N for men), to the body mass index (decrease of 5 N by BMI unit) and to squared forearm circumference. From this last relationship, the ratio of grip strength to squared forearm circumference is proposed as a tonic index.

At last, three prediction models of Fp are proposed which allow dominant and non-dominant hand and the mean of both hands Fp calculations. These models explain at least 72 percent of the Fp variance and could be practical goals of an efficient rehabilitation.