FIG. 4.

Moments exerted on the handle under different external torques. A: local moment of thumb ($m_Z^{\mathit{th}}$). B: VF local moment ($m_Z^{\mathit{vf}}$). C: moment of a VF couple [$m_Z^{\mathit{vf}\left(C\right)}$]. D: moments of VF F_X [$M_Z^{\mathit{vf}\left(X\right)}$]. Averaged data across trials and subjects are presented with SE bars (the error bars are too small to be seen for most data points). Note the different scales in the panels.