.

             The flexion component is not to be ignored when referring to the frog's kinematics1. Indeed, a joined boned in the lower area of the leg, namely the tibiofibula, is important if one is to ensure that the leg is able to rotate at a sufficient rate to promote the body forward. In other words, a joint tibia and fibula is the guarantee of a moving mechanism.

             The front legs in a frog are much more similar to those of a man. Indeed, the frog has, just like man, one upper arm bone, the humerus, and one lower arm bone, joined in frogs into the radioulna. The radioulna has the same functional explanation as the tibiofibula and is perhaps best used in swimming. On the other hand, the existence of a single humerus bone is adapted to the position that a frog takes after the leap. In this sense, the humerus bone needed to exist on its own and be very solid, because the almost perpendicular position in which it has to remain after the leap is done. Swimming again intervenes here as well. The long humerus provides for an excellent spread and can increase speed in the water as the frog swims. .

             If we look at these two types of bones, the leg bones and the 'arm' bones, we may see that these have gradually adapted themselves to the requirements of the frog's outer environment. The frog relies greatly in its movement on land on jumping, short leaps that are able to carry it speedily in the area around the pond. .

             On the other hand, much of a frog's time is spent in the pond, in water hence. Moving around fast in the aquatic environment is essential, because it means the frog can avoid possible natural predators, such as aquatic birds, and, additionally, it can pursue its own food sources in proper timing.

             The metacarpals and the metatarsals follow along this pattern as well. Both have been adapted to swimming and can be barely differentiated. The metacarpals and the metatarsals are long, with a skin in-between the fingers that is intended to provide the characteristics of a paddle and to facilitate the movement in the water, as well as an increased speed in the aquatic environment.