Biologia

review article

Endurance running and the evolution of Homo
Dennis M. Bramble1 & Daniel E. Lieberman2
1 2

Department of Biology, University of Utah, Salt Lake City, Utah 84112, USA Peabody Museum, Harvard University, Cambridge, Massachusetts 02138, USA...........................................................................................................................................................................................................................

Striding bipedalism is a key derived behaviour of hominids that possibly originated soon after the divergence of the chimpanzee and human lineages. Although bipedal gaits include walking and running, running is generally considered to have played no major role in human evolution because humans, like apes, arepoor sprinters compared to most quadrupeds. Here we assess how well humans perform at sustained long-distance running, and review the physiological and anatomical bases of endurance running capabilities in humans and other mammals. Judged by several criteria, humans perform remarkably well at endurance running, thanks to a diverse array of features, many of which leave traces in the skeleton. Thefossil evidence of these features suggests that endurance running is a derived capability of the genus Homo, originating about 2 million years ago, and may have been instrumental in the evolution of the human body form.

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ost research on the evolution of human locomotion has focused on walking. There are a few indications that the earliest-known hominids were bipeds1,2, and there is abundantfossil evidence that australopithecines habitually walked by at least 4.4 million years (Myr) ago3,4. Many researchers interpret the evolution of an essentially modern human-like body shape, first apparent in early Homo erectus, as evidence for improved walking performance in more open habitats that came at the expense of retained adaptations in the australopithecine postcranium for arboreallocomotion (for example, refs 5–8). Although the biomechanics of running, the other human gait, is well studied, only a few researchers (see refs 9, 10 for example) have considered whether running was a mode of locomotion that influenced human evolution. This lack of attention is largely because humans are mediocre runners in several respects. Even elite human sprinters are comparatively slow, capable ofsustaining maximum speeds of only 10.2 m s21 for less than 15 s. In contrast, mammalian cursorial specialists such as horses, greyhounds and pronghorn antelopes can maintain maximum galloping speeds of 15–20 m s21 for several minutes11. Moreover, running is more costly for humans than for most mammals, demanding roughly twice as much metabolic energy per distance travelled than is typical for amammal of equal body mass12. Finally, human runners are less manoeuvrable and lack many structural modifications characteristic of most quadrupedal cursors such as elongate digitigrade feet and short proximal limb segments. However, although humans are comparatively poor sprinters, they also engage in a different type of running, endurance running (ER), defined as running many kilometres over extendedtime periods using aerobic metabolism. Although not extensively studied in non-humans, ER is unique to humans among primates, and uncommon among quadrupedal mammals other than social carnivores (such as dogs and hyenas) and migratory ungulates (such as wildebeest and horses)13,14. Here, we review the evidence for and impact of ER in human evolution. We begin with a discussion of the mechanicaldifferences between walking and running, and how well humans perform at ER compared to other mammals. We then review what is known about the key structural specializations thought to underlie human ER capabilities, the extent to which they may be features that evolved originally for bipedal walking, and the evidence for their appearance in the hominid fossil record. We conclude by outlining some...