Anthropology, University of Cincinnati
Saturday Morning, Ballroom C
A fundamental change associated with bipedalism was the evolution of a lumbar lordosis. Recent research suggests that unlike early hominins and modern humans, Neandertals were hypolordotic. Absence of a lordosis in Neandertals is surprising given both the evolutionary and biomechanical relevance of the lumbar curve in bipedal locomotion. To better understand the function of the reduced lumbar lordosis in Neandertals, I kinematically assessed movements of the lumbopelvic complex in human subjects walking with an experimentally reduced lordosis. Subjects posteriorly tilted the pelvis to achieve a reduced lordotic curve, simulating the Neandertal hypolordosis. Segment angles of the lower back, pelvis, and hind limb were calculated from 3D motion capture data. Kruskal-Wallis tests were performed to identify significant differences between conditions in static posture and dynamic gait.
Subjects achieved a posterior pelvic tilt (normal mean 12.1º, experimental mean -0.58º, p < .05) and a reduced lordosis (normal mean 27.9º, experimental mean 19.5º, p = .275) in quiet stance. Overall, posterior tilt increased the mean lordosis during walking (+6.6º, p < .0001). It appears that a reduction in lordosis is difficult to sustain during locomotion, hinting at the fundamental need for the lumbar lordosis. Hypolordotic strides were reduced in length and associated with a less extended knee (p < .0001). The gait kinematics of experimentally induced hypolordosis in modern bipeds, combined with the relatively short legs of Neandertals, suggest that Neandertals were less efficient bipeds than modern humans and thus likely expended greater energy in their foraging and hunting efforts.
University of Cincinnati and The Charles Phelps Taft Research Center at the University of Cincinnati