Contributions of Mt and Mn to the total moment for a typical trial, where (a) the external moment is 0.6 Nm. In this example, both the Mn and Mt remain constant. The regression coefficient between the thumb and VF tangential forces for this example is 1.68. The total moment applied by the fingers is slightly less than the external torque probably due to friction. In (b), a different subject, the external moment is −0.4 Nm, and in this example, in contrast, Mt changes significantly during the trial, requiring Mn to also change to maintain a constant overall moment. For this example, the regression coefficient between the thumb and VF tangential forces is 0.95.