An exercise assembly useful in training a bicyclist for increased speed includes a pair of elastic straps adjustable in their length to stretch between the rear axle of the bicycle and the bicyclist's respective thighs. The strap attachment to the thighs is effected by a corresponding pair of adjustable elastic hoops that are limited in their elastic expansion by fabric strips attached to each of the hoops at loosely spaced intervals. A set of elastomeric wraps may be further interposed between the thighs and the hoops to expand the contact area and therefore the shear load capacity of the engagement to limit any axial translation of the engagement along the thigh. When not in use the straps can be attached to the bicycle frame both when implemented as a stationary bicycle or when on the road.