Disclosed is a para-bi-cycling knee joint prosthesis for interconnecting a prosthetic lower leg and a prosthetic thigh, the knee joint prosthesis including an upper body portion configured to support a socket adapter, for connection with a prosthetic thigh; a lower body portion extending from the upper body portion and configured to connect with a prosthetic lower leg; a pair of ball bearings mounted on ends of a pivot shaft, the pivot shaft forming un upper part of the lower body portion, the upper body portion having left and right upper body portions, each configured to receive the external surface of one of the bearings, thus enabling rotation between the upper and lower body portions; the rotation allowing for flexion between the upper and the lower body portions of at least 140 degrees; and the upper body portion having an extended surface configured to engage a complementarily-shaped surface of the lower body portion, to prevent the backward rotation of the knee joint.