An automated physical therapy system comprising two leg components, each of said leg components optionally moving alternatively above and below a base plane, thereby simulating a swimming motion in the legs of a user. The system provides a unique hemodynamic effect, i.e. blood from one of the user's legs above the base plane is displaced by gravity into the rest of the body, while blood from the user's other leg disposed below the base plane is displaced in that leg by gravity. Said hemodynamic effect is advantageous because the net hemodynamic effect is zero, i.e. blood displaced into the rest of the user's body is roughly equivalent to blood displaced into the user's other leg, allowing use of the system by users who are at risk if a large amount of blood is displaced in the user's heart or other internal organs.
