Abstract: A gymnastic bicycle includes a device for regulating the physical effort necessary for tilting handlebars with respect to a chassis during exercises simulating rowing, together with a vibrator formed by a lever having one end permanently connected to the articulation of the handlebar tube with respect to the chassis. The other end of the lever has a roller capable of contacting a polygonal surface which rotates as a result of pedalling. The polygonal surface forms part of or is closely linked to an inertia flywheel which constitutes a power accumulator and pedalling regulator. Contact or separated positions of the roller with respect to the polygonal surface are obtained by a control knob fixed to a shaft provided at its free end with two axially spaced surfaces which, on rotation of the knob and shaft, alternately contact a plate, thereby pivoting the lever with respect to the chassis of the bicycle.