Abstract: Exercise apparatus having a closed loop, hydraulic controller which provides a user selectable resistance to movement over an operating path. A restrictor valve assembly controls fluid flow in an exercise direction and includes a sealed valve body and a rotatable stem piece having a number of flow bores of differing relative dimension to a primary flow path. A pair of separable interlocking piston head pieces at a piston shaft control a reduced bypass resistance with return travel. Alternately disclosed modular frameworks, which include stationary and carriage portions, permit physical motion in relation to a measurement means which displays relative exertion.