A stationary exercise device comprises pedals mounted via cranks to opposite sides of a drive wheel; a flywheel with a magnetic rim coupled to the drive wheel; a brake with a motor and one or more permanent magnets mounted for movement relative to the magnetic rim; a measuring unit for measuring at least one of the drive force applied via the drive wheel and the related torque; a measuring device for measuring cadence; and a command module. The command module uses measurements from the measuring unit and the measuring device to calculate a performance parameter and compares the performance parameter against a predetermined performance profile. The command module also can control the motor to move the permanent magnets relative to the magnetic rim to adjust the braking force applied and thereby adjust the performance parameter to conform with the performance profile.