The 81st Annual Meeting of the American Association of Physical Anthropologists (2012)

Revisiting the human obstetrical dilemma: effect of pelvic rotation stride length


Department of Anthropology, University of Cincinnati

Saturday 3:15-3:30, Galleria North Add to calendar

Here we focus on stride length as the major component of gait economy to explore key factors within the locomotor chain that contribute to stride length, introducing a new pelvic rotation model to compare gait performance of the obstetric/locomotor pelvis of females with the locomotor pelvis of males. We investigated anthropometrics and 3D kinematics at 1.25 ms-1 and 1.75 ms-1. Although females have larger pelves relative to body mass (male 3.44+/0.42, female 4.32+/-0.55, P<0.001) and maintained 50% larger values knee angles, they did not demonstrate different dynamic segment excursions of the lower limb from males. Although walking with absolutely shorter limbs, females match speed with males of greater limb length without differing in limb kinematics. Pelvic rotation differed by sex at both speeds (male 11.7 [5.0], 22.3 [5.2]; female 17.6 [4.3], 22.3 [5.3], P<0.002, P<0.002). Females generated greater hip translation (0.046 [0.02], 0.069 [0.02], P<0.0006) and shorter stride lengths (1.385 [0.08], 1.282 [0.08], P<0.0006). However, dimensionless stride length was greater in females at both speeds (1.46 [0.08], 1.57 [0.07], P<0.007). For their leg length, females obtained longer strides suggesting that travel distance is achieved with proportionally less limb length in females exploiting the inherent capacity of their relatively wide hips to increase leg swing with each gait cycle. Finally, our new model was a better predictor of stride length than a limb-based model, explaining 91% of the variance in males (r2=0.91, P<0.001) and 92% in females (r2=0.92, P<0.001). Comparison of the sexes showed that females experience the largest pelvic effect.

This research was supported by the University of Cincinnati

comments powered by Disqus