Figure 2. Kinematic determinants of intention choice.

Panel (A) (obtained from ³⁰*) represents the frontal and lateral view of the marker positions used to characterize kinematics of grasp-to-pour and grasp-to-drink actions. Additional markers (not used to compute the variables of interest) were placed on the metacarpal and proximal interphalangeal joints of the thumb, the proximal interphalangeal joint of the index finger, and the proximal interphalangeal joint and the tip of the little finger. Panel (B) shows the relative importance of kinematic parameters (with respect to normalized movement duration) in determining the intention choice. The wrist height is defined as the z-component of the rad marker; the dorsum plane is defined on the local frame of reference (F_local) determined by using the markers rad, ind₁, and lit₁; the wrist horizontal trajectory corresponds to the x (left-right) component of the rad marker; the finger plane is defined as x, y, and z components of the thumb – index plane that passes through the markers thu₀, ind₃, and thu₄; z-index is defined as the z-coordinate of ind₃ marker with respect to F_local. *The image of Panel A was obtained from an open access article distributed under the terms of the Creative Commons Attribution (CC BY) License (https://creativecommons.org/licenses/by/4.0/). CC BY License permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Compared to the original image, no changes were made.