title: Brief communication: could Kadanuumuu (KSD-VP-1/1) and Lucy (AL 288-1) have walked together comfortably?
abstract: The estimated lower limb length (0.761-0.793 m) of the partial skeleton of Australopithecus afarensis from Woranso-Mille (KSD-VP-1/1) is outside the previously known range for Australopithecus and within the range of modern humans. The lower limb length of KSD-VP-1/1 is particularly intriguing when juxtaposed against the lower limb length estimate of the other partial skeleton of A. afarensis, AL 288-1 (0.525 m). A sample of 36 children (age, >7 years, trochanteric height = 0.56-0.765 m) and 16 adults (trochanteric height = 0.77-1.00 m) walked at their self-selected slow, preferred, and fast walking velocities, while their oxygen consumption was monitored. Lower limb length and velocity were correlated with slow (P < 0.001, r(2) = 0.44), preferred (P < 0.001, r(2) = 0.55), and fast (P < 0.001, r(2) = 0.69) walking velocity. The relationship between optimal velocity and lower limb length was also determined and lower limb length explained 47% of the variability in optimal velocity. The velocity profile for KSD-VP-1/1 (slow = 0.73-0.75 m/s, preferred = 1.08-1.11 m/s, and fast = 1.48-1.54 m/s) is 36-44% higher than that of AL 288-1 (slow = 0.53 m/s, preferred = 0.78 m/s, and fast = 1.07 m/s). The optimal velocity for AL 288-1 is 1.04 m/s, whereas that for KSD-VP-1/1 is 1.29-1.33 m/s. This degree of lower limb length dimorphism suggests that members of a group would have had to compromise their preferences to walk together or to split into subgroups to walk at their optimal velocity.
authors.affiliation: Departments of Anthropology and of Orthopaedics and Sports Medicine, University of Washington, Seattle, WA 98195-3100, USA. pakramer@u.washington.edu
authors.forename: Patricia Ann
authors.initials: PA
authors.lastname: Kramer
mesh_terms: D000293:Adolescent; D000328:Adult; D000818:Animals; D000885:Anthropology, Physical; D001696:Biomechanical Phenomena; D049628:Body Size / Q000502:physiology*; D002648:Child; D005269:Femur / Q000033:anatomy & histology*; D005580:Fossils; D015186:Hominidae / Q000033:anatomy & histology* / Q000502:physiology*; D006801:Humans; D016014:Linear Models; D035002:Lower Extremity / Q000033:anatomy & histology; D008875:Middle Aged; D016138:Walking / Q000502:physiology*