Abstract: An active, patient-implementable, angular range-of-motion recovery practice, and associated structure, usable with respect to a knee including, from a methodologic point of view, (a) a occupying a sitting position, (b) by such occupying, defining a common swing plane for the upper and lower leg, (c) supporting the foot for back-and-forth, defined-swing-plane, rolling-contact motion over and in contact with an underlying motion-guidance surface, with such motion taking place generally within the defined swing plane, and (d) then swinging the lower leg in a fore-and-aft manner within the defined plane. The structure of the invention includes a rolling-motion traveler for supporting the underside of a patient's foot during practice of the invention, and a cooperative instruction set describing proper patient use of the traveler.