give propulsion to the bicycle the pedal will be further towards the rear of the bicycle that means that the bicycle rider 39 s leg will be angled further back as he is pushing the pedal down there is a biomechanical advantage for the rider to push down on the pedal with his leg angled somewhat backwards because he is able to use his weight to better advantage and also because he is able to more efficiently use the powerful hamstring muscles in the back of the leg it should be clear from fig1 that the nearer the lengths of the second linkage arms 11 are to the lengths of the first linkage arms 10 the closer the path of the pedals 12 is to a straight line as the lengths of the second linkage arms 11 are lengthened the pedals 12 follow a wider elliptical path therefore the length of the second linkage arms 11 can be selected to provide an elliptical path of pedals 12 that gives the best biomechanical advantage to the bicycle rider an advantage of the present invention is that it can be easily retrofited onto any standard bicycle the spindle 9 can be any standard bicycle spindle or can be a specially made spindle which is manufactured to fit into a standard bicycle.