Convex hull estimation of mammalian body segment parameters

Obtaining accurate values for body segment parameters (BSPs) is
fundamental in many biomechanical studies, particularly for gait analysis.
Convex hulling, where the smallest-possible convex object that surrounds a
set of points is calculated, has been suggested as an effective and
time-efficient method to estimate these parameters in extinct animals,
where soft tissues are rarely preserved. We investigated the effectiveness
of convex hull BSP estimation in a range of extant mammals, to inform the
potential future usage of this technique with extinct taxa. Computed
tomography scans of both the skeleton and skin of every species
investigated were virtually segmented. BSPs (the mass, position of the
centre of mass and inertial tensors of each segment) were calculated from
the resultant soft tissue segments, while the bone segments were used as
the basis for convex hull reconstructions. We performed phylogenetic
generalised least squares and ordinary least squares regressions to
compare the BSPs calculated from soft tissue segments with those estimated
using convex hulls, finding consistent predictive relationships for each
body segment. The resultant regression equations can therefore be used
with confidence in future volumetric reconstruction and biomechanical
analyses of mammals, in both extinct and extant species where such data
may not be available.