ABSTRACT
Scientifi c studies of human movement traces their origins back to the 17th century and include work up through the early 20th century. By the 19th century it had been realized that individual angular joint motion along with the translations of individual segments and the whole-body mass was necessary to fully characterize human motion. Th is hierarchical viewpoint allows the human body to be visualized
as a system of joints and limbs with both active and passive loading members. It has, however, only been within the last century that true measurement, and therefore quantifi cation, has been achieved.
