Why do we want to measure the properties of the body? What good will it do us to know these things? Why should we care about the properties of the body?
Knowing the properties of the body opens up a world of possibilities. Using the knowledge of these properties allows us to design treatments and special tools to be used on the body. It also will allow the design of applications to be used inside the body, like artifical hearts and valves or internal rods and screws to help support broken bones. Leg braces can also be designed when the stresses, strains, and other properties of the legs are known.
Knowing the properties of the body not only allow us to desing equipment, it also allows for the creation of mathematical models that describe the motion and the properties of the body depending on ceartain variables. Some examples of these models can be seen in the reference articles.