EN
Subjects were required to track a target consisting of two vertical bars moving with either a constant or a sinusoidally modulated speed an osciloscope scren with a joystick-controlled light-spot.Either target size or velocity of the target movement(velocity quided tasks), varied throughout different tasks determined by subject's performance.The target's initial movement period was either 2 or 3 seconds.The following parameters were studied: time on-terget intervals, time off-target intervals, number of tracking errors, heart rate and tracking error incidence over the cardiac cycle.Time on-target intervals were longer for the velocity quided tasks then for the size quided ones.The same was true for time off-terget intervals.Values for both types of intervals decreased gradually over the fixed sequence of tasks for velocity but not for size quided tasks.Heart rate was higher in the size quided task.Tracking error incidence did not depend on the phase of cardiac cycle.