Fig. 8.
DH manipulation. a Normal forces of the thumb and VF versus the handle acceleration in the horizontal direction. A representative trial, the load was 13.8 N, the frequency was 2 Hz, representative subject. The range of the internal force fluctuations was approximately 7.0 N, from 10.0 to 17.0 N. b The phase angles between the normal force of the thumb and the handle acceleration (circular histogram). Note that this graph is only valid for the selected direction of the coordinate axes. c The thumb normal force–VF normal force phase angle (circular histogram)