Unlike swimmers, their hands are used for other things such as holding a camera, or some other tool. If you have ever tried to do a few laps in a swimming pool using only your legs you probably found it quite difficult to go from one place to another in a short time. If a diver tries to use their arms for movement it becomes exhausting. If the fin is the proper length, is not too heavy, has the proper flexibility, and fits the foot correctly then the dive can be quite pleasurable. In the many years of selling diving equipment, Deep-Six has found only a few brands to meet these exacting criteria.
Some divers kick from the knees and there is very little movement at the hip.
Propulsion is so severely reduced, and energy is expended so rapidly the dive is not enjoyable. If the power of the kick originates from the hip, with very little bending at the knee, the diver is propelled forward with incredible efficiency. There are two general models of fins for the diver. One covers the entire bottom of the foot as well as the heel. The second type has an adjustable strap in the heel end of the fin.