Measurement and prediction of single and multi-digit finger strength

Abstract

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.

Maximum isometric finger pull forces

“…In addition, the bracing allowed with the contralateral arm, and the different arm postures used, may have also contributed to the higher current values. It is also possible that the edge on the aluminum bar, in DiDomenico and Nussbaum (2003) may have been sharper than the thin ring used here. This would have resulted in large contact stress and may have inhibited higher force production.…”

“…Studies isolating individual digit contributions to finger pull strength have been rare in the literature. DiDomenico and Nussbaum (2003) examined strength during various single and multi-finger tasks. They had one condition, called the "distal pad pull", which can be compared to the current study.…”

“…As previously mentioned, there are a number of manufacturing tasks that require the finger(s) to be used as a tool to hook and pull various parts. To our knowledge, DiDomenico and Nussbaum (2003) have conducted one of the only studies of finger pulling, but that study was limited to pulling with only one finger. The purpose of the current study was to determine maximum finger pull forces for a variety of conditions that do not involve pinches and have not been presented previously in the literature.…”

Effect of fabrication stages and cementation on the marginal fit of CAD-CAM monolithic zirconia crowns

“…cement (Adhesor Carbofine; SpofaDental) according to the manufacturer's instructions. The crowns were seated with a rocking motion 53 and maximum index finger pressure (180-degree distal pad press) of a young adult male (50 N) 54 as in the clinical situation. 48 During setting, a static standardized force (40 N) directed onto the central fossa of the crown parallel to the vertical axis of the tooth was applied on each specimen for 5 minutes.…”

Haptically assisted chemotaxis for odor source localization

“…This torque is transmitted to the upper bar using a toothed belt with a speed ratio of 2:1. Given the motor, belt transmission, and the 40 mm bar, the estimated force applied to the user is of 2.5 N, which is sufficient to be perceived by the user [19] but less than the typical force that an individual can exert [18]. The angular displacement of the upper bar translates into the corresponding track velocity.…”