Normal digital contribution to grip strength assessed by a computerized digital dynamometer.

A computerized digital dynamometer was used to assess the contribution of individual fingers to total grip strength in 100 hands from 50 randomly selected healthy subjects. The dynamometer simultaneously recorded force data from each digit (index, long, ring, and small) and cumulative grip directly to a laptop computer. The percentage contribution of each finger force to total grip force was calculated at three successive handle sizes for dominant and non-dominant hands. Individual digital contributions to total grip strength were approximately 25%, 35%, 26% and 15% for the index, long, ring, and small fingers respectively. This pattern was consistent irrespective of handle size, hand dominance, and grip strength.