Fig. 2.

Recorded data from a single subject: 0.5 s of filtered EMG and force collected during the different tasks with stimulation. Darker lines represent the muscles and loads (force and moments) related to the task performed. Fx and Fy are horizontal forces applied in the x (+ve forward)- and y (+ve rightward)-directions, respectively. Mz is the moment generated about the z-axis (+ve down) during left yaw axial rotation tasks in fixed conditions. Head-free and -fixed conditions are represented as open and shaded heads, respectively. Accompanying arrows indicate the direction of load applied by the subject in fixed conditions.