In a majority of studies on grasp, only normal forces were measured and only when a zero torque was exerted on a hand-held object. This study concerns finger force vectors during the torque production tasks. Subjects (n=8) stabilized a handle with an attachment that allowed for change of external torque from -1.5 to 1.5Nm. Forces and moments exerted by the digit tips on the object were recorded. At the large (>-0.375Nm) supination torques the index/middle and ring/little pairs of fingers generated oppositely directed tangential forces. The index and middle finger produced forces in a downward direction and therefore did not support the load. At a zero torque and pronation torques, the middle, ring and little fingers produced forces along nearly the same direction. The vector of the index finger force was always directed differently from the vectors of other finger forces, the angles ranged from 19°30′ to 47°40′. The points of force application were systematically displaced with the torque, with the exception of the little finger. Tangential finger forces contributed substantially to the total torque exerted on the hand-held object.
|Number of pages||5|
|Journal||Journal of Biomechanics|
|State||Published - Nov 1 2003|
Bibliographical noteFunding Information:
The authors are grateful to Dr. Zong-Ming Li, Robert Gregory and Todd Pataky for insightful comments on earlier versions of the manuscript. This study was partly supported by NIH Grants NS-35032 and AG-18751.
- Finger forces
ASJC Scopus subject areas
- Orthopedics and Sports Medicine
- Biomedical Engineering