Fig. 2

Representative trials for each lifting/humeral rotation direction combination for each group. Solid lines are the isometric humeral rotation joint torques (Nm; External Rotation (+) in the top panels, Internal Rotation (+) in the bottom panels) indicated by the left y-axis. Dashed lines are the vertical position of the robot (cm; 0 indicating midpoint between ceiling (+) and floor (−) limits) during the task indicated by the right y-axis. The starting position of the vertical position on the left two plots was 5 cm illustrating the participant beginning in contact with the ceiling limit. Similarly, the starting position of the vertical position on the right two plots was −5 cm illustrating the participant beginning in contact with the floor limit. The vertical black line indicates the transition cues (visual and verbal) from the single-task to the dual-task