Figure 3. Right knee flexion angle obtained from COM (light gray solid line with circles), DVP (dark gray solid line with squares) and manual tracking (black solid line) during a full cycle of the “Elliptical machine” exercise. For DVP and COM, straight lines at the bottom of the plot represent the frames in which all the visible markers were tracked automatically (solid segments), and those requiring manual interventions for at least one marker (dotted segments).