Abstract: An ankle exerciser (10) is disclosed for permitting isokinetic exercise of the ankle joint of the user. The foot of the user is secured to a foot plate (54) by a strap (124). The foot plate is capable of motion about three mutually perpendicular axes (X--X, Y--Y, Z--Z), with one axis corresponding to the axis of pivotal motion of the ankle joint in dorsel and plantar flexion. The motion about each axis is restricted by a double acting fluid cylinder (64, 82, 104). Individual metering valves (160, 162, 164) are provided for restricting flow between the chambers of the cylinders and a reservoir (152) to selectively determine the desired resistance to motion. Pressure gauges (154, 156, 158) are associated with each of the fluid cylinders to indicate the force exerted by the user resisted by the particular fluid cylinder. In a second embodiment, an ankle exerciser (250) is provided for exercising both ankles of the user. The foot plates (282, 284) are provided with straps to secure the feet of the user thereon.