Any animal that can go from zero to 40 mph in three strides must have a very specialized body. The cheetah is so built for speed, it really can't do much else. A cheetah's speed starts with aerodynamics. Its slender body, small head, flattened rib cage and long, thin legs minimize air resistance. It typically only weighs about 125 pounds (57 kg), so its muscles don't have that much weight to carry.