“…4 By contrast, hemiparetic reaches exhibit systematic misdirection 5 and a lack of hand-path smoothness (1,6) that can coincide with an increased frequency of terminal corrective submovements. 7 Two neuromotor deficits have been implicated as contributing to the lack of hand trajectory smoothness post-stroke: abnormal management of interaction torques (5,8; c.f., 9) and an increased variability in the generation of muscle force 10 that is related to muscle weakness. 11 With recovery, hand trajectory smoothness progressively increases; 6,12 this trajectory smoothing corresponds to a gradual reduction in the third time derivative of hand displacement (i.e., hand trajectory jerk) (c.f., 13).…”