Body posture and mode of locomotion in early Pleistocene hominids.

Assumptions concerning the carriage of fossil primates play a considerable role in most discussions of human evolution. Such assertions may be reliable to a very high degree, since there exists a causal relationship between mechanical stresses acting in a bone during locomotion and its shape and structure. The stresses in a bone are determined by relatively few characteristics: the relative forces of the muscles, lengths of their lever arms, as well as points of application and directions of external forces. Whereas the former can be assumed to have certain values and then be treated as known factors, the latter depend on the body’s posture and the method of locomotion of the animal in question. Analyses of this type are used to improve our knowledge about Early Pleistocene hominids from East and South Africa. The investigation is based primarily on the foot and leg bones from Olduvai Gorge.