Abstract
Adaptation to bipedal running occupies a central place among the biological adaptations that have enabled the development of efficient predation on medium to large mammals. Among primates, humans are the only ones with a real aptitude for endurance running, thanks in particular to a thermoregulatory system that relies heavily on sweating. It was probably with Homo erectus, around two million years ago, that this adaptation to running was fully expressed for the first time . The changes in behavior that accompanied this adaptation were only a few years before the first representatives of the Homo genus left Africa and were now able to survive in a variety of environments. By this time, hominins with body proportions close to those of present-day humans were already present. The anatomical changes that led to this new adaptive model involved lengthening the lower limbs and stabilizing the head and trunk during running. The latter is facilitated by transformations in the nuchal and dorsal musculature, and by an evolution of the inner ear better able to control the relative movements of head and body during running. Skeletal modifications to the spine and pelvis reduce mechanical stress, while the foot and calf become capable of absorbing mechanical shocks more effectively, thus acting as a spring in every stride. Increased venous circulation in the neurocranium also improves thermal regulation of the brain.
