A major turning point in human phylogenetic development occurred with the transition of Hominidae (anthropoid humans) from four-leg stance to two-leg stance. There are two different theories about the cause as well as the time of this transition. A widely adopted view is that the transition from four-leg stance to two-leg stance occurred about 3.5 million years ago when, as the result of the increased brain mass, the capacity for the construction and utilization of tools for hunting and food preparation was obtained. In the absence of fossils to support tlus theory, an alternative view was developed according to which the transition occurred much earlier, about 10 million years ago, due to the altered social and behavioral patterns(l), Whatever the cause of its initiation, the adoption of biped stance and locomotion must have had distinct advantages over quadruped stance for the survival of these early humanoids.

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Adriaan Stichting
H.J. Stam (Henk) , C.J. Snijders (Chris)
Erasmus University Rotterdam
Erasmus MC: University Medical Center Rotterdam

Hoogvliet, P. (1997, March 26). Lower extremity movements in frontal plane balance control during one-leg stance. Retrieved from http://hdl.handle.net/1765/18019