Figure 3
Experimental setup for isometric arm-shoulder force tasks in 24 directions. The subject has the arm in a splint, which is connected to a force transducer. Subjects must bring the arm force driven red cursor into the blue target area, which indicates force direction (n = 24 directions) and force magnitude. The exerted force, perpendicular to the humerus long axis, is recorded together with EMG to measure the activity of 10 individual shoulder muscles.