Brokaw EB, Murray T, Nef T, Lum PS. Retraining of interjoint arm coordination after stroke using robot-assisted time-independent functional training. J Rehabil Res Dev. 2011;48(4):299-316.DOI:10.1682/JRRD.2010.04.0064

Figure 10. Contrast between time-independent functional training (TIFT) and Dus-chau-Wicke methods for trajectory advancement. Current point on tra-jectory is A. Points B and C are two possible movements in joint space. Gray and dotted arrows point to resulting advancement points on trajec-tory for two methods. Because current point on trajectory determines location of haptic walls, energy injection into limb is possible in Dus-chau-Wicke method, while TIFT mode is passive. Note that for point C, Duschau-Wicke method allows advancement along trajectory even when shoulder is rotating in wrong direction. Since TIFT method does not allow moving backward in trajectory, movement to point C does not change current point on trajectory. TIFT mode only allows progression for movements to right and above thin black lines.