Figure 2.

Parallel coordinates characterize the high-dimensional structure of a feasible activation spaces. Consider four points (i.e., muscle activation patterns) from the polygon that is a feasible activation space (A). The activation level for each muscle (i.e., the coordinates of each point) are sewn across three vertical parallel axes (B). As is common when evaluating muscle coordination patterns, each point can also be assigned a cost as per an assumed cost function. The associated cost for each muscle activation pattern can also be shown as an additional dimension. We show three representative cost functions (C). Activation levels are bound between 0 and 1, and costs are normalized to their respective observed ranges.