Measurement and prediction of single and multi-digit finger strength

Hand and finger strength has direct application in the design of human-machine interfaces involving the whole hand or single digits. Limited finger strength data is available, however, particularly for practical situations such as pinching and poking. A study was conducted in which strength in a variety of couplings was collected from 100 participants, in order to enhance and supplement the existing literature. Differences between couplings, gender, and age groups were evaluated. Strength was significantly higher for multi-digit couplings as compared with single digit couplings (p < 0.05). In addition, female strength was approximately 70% of male strength across all couplings. No significant differences were found between three age groups ranging from 18 to 40 + years old. Multiple regression models were used to determine whether finger strength could be predicted from other strength measures and anthropometry. Regression results suggest that finger strength can be predicted with only moderate accuracy using these variables (R2-adj: 0.45 - 0.64; standard error: 12 - 19 N). Such models are easy to implement, however, and begin to overcome the limitations of direct finger strength measurements.