PURPOSE: To control the reaction force conforming to muscular power of a training person, to reduce a noise, and to make the device compact by filling the inside of a case with an electric viscous fluid, so that a voltage applied between electrode can be controlled.

CONSTITUTION: A muscular power training device consists of a base 1, a supporting leg 2, a muscular power strengthening device 3 for the lower half part of the body, a muscular power strengthening device 4 for the upper half part of the body and a controller 5. The muscular power strengthening device 3 and the muscular power strengthening device 4 are connected to a reaction force adjusting device 6 in the controller 5. In the reaction force adjusting device 6, a piston 8 is provided in the inside of a case 7, a pair of electrodes 16, 17 are provided through an electric insulator 15 on the inside surface opposed by placing a communicating passage 10 of the piston 8, and the inside of fluid chambers 9a, 9b is filled with an electric viscous fluid. When a voltage is applied between the electrodes 16, 17, viscosity of the electric viscous fluid increases, and a loop resistance of the fluid in the communicating passage 10 increases. The voltage between the electrodes 16, 17 is varied by operating an operating part 5a of the controller 5, and a load resistance of the reaction force adjusting device 6 connected to the muscular power strengthening devices 3, 4 is adjusted.