Figure 1
On/off centers in the phase planes of the ankle (top), knee (middle), and hip (bottom). Vertical and horizontal axes represent angular position and velocity, respectively; positive sign represents ankle dorsiflexion, knee extension, and hip anteflexion. Dark blue and light blue circles represent the centers of on-area and off-area, respectively, for all trials (80 samples for each muscle). Gray background represents an anatomically indirect joint-muscle relationship (e.g., MG cannot actuate the hip directly).
