Mechanisms for the functional differentiation of the propulsive and braking roles of the forelimbs and hindlimbs during quadrupedal walking in primates and felines.

Published

Journal Article

During quadrupedal walking in most animals, the forelimbs play a net braking role, whereas the hindlimbs are net propulsive. However, the mechanism by which this differentiation occurs remains unclear. Here, we test two models to explain this pattern using primates and felines: (1) the horizontal strut effect (in which limbs are modeled as independent struts), and (2) the linked strut model (in which limbs are modeled as linked struts with a center of mass in between). Video recordings were used to determine point of contact, timing of mid-stance, and limb protraction/retraction duration. Single-limb forces were used to calculate contact time, impulses and the proportion of the stride at which the braking-to-propulsive transition (BP) occurred for each limb. We found no association between the occurrence of the BP and mid-stance, little influence of protraction and retraction duration on the braking-propulsive function of a limb, and a causative relationship between vertical force distribution between limbs and the patterns of horizontal forces. These findings reject the horizontal strut effect, and provide some support for the linked strut model, although predictions were not perfectly matched. We suggest that the position of the center of mass relative to limb contact points is a very important, but not the only, factor driving functional differentiation of the braking and propulsive roles of the limbs in quadrupeds. It was also found that primates have greater differences in horizontal impulse between their limbs compared with felines, a pattern that may reflect a fundamental arboreal adaptation in primates.

Full Text

Duke Authors

Cited Authors

  • Granatosky, MC; Fitzsimons, A; Zeininger, A; Schmitt, D

Published Date

  • January 22, 2018

Published In

Volume / Issue

  • 221 / Pt 2

PubMed ID

  • 29170258

Pubmed Central ID

  • 29170258

Electronic International Standard Serial Number (EISSN)

  • 1477-9145

International Standard Serial Number (ISSN)

  • 0022-0949

Digital Object Identifier (DOI)

  • 10.1242/jeb.162917

Language

  • eng