Ergometric exercise device 10 comprises a foot-operable drive including drive elements in the form of foot-driven pedals 18 mounted via pedal cranks 20 to opposite sides of a drive wheel 22. A flywheel 24 with a magnetic rim (Fig 6, 38) is coupled to the drive wheel 22 via a gear mechanism 26. The exercise device 10 has a brake device (Fig 6, 40) in the form of one or more permanent magnets (Fig 6, 44a,44b) mounted for movement by means of a motor (Fig 6, 42) towards and away from the magnetic rim (38) of the flywheel 24 to selectively adjust a braking force applied to the flywheel 24. There is a measuring unit for measuring drive force or torque and a measuring device for measuring cadence. A command module receives the measurements, calculates performance parameters for the user and controls the movement of the permanent magnets (44a, 44b) relative to the magnetic rim (38) of the flywheel 24, in order to alter the braking force and thereby adjust the performance parameters so that they conform with a predetermined performance profile.
