Variability in forelimb bone strains during non-steady locomotor activities in goats

Abstract

SUMMARYThe purpose of this study was to investigate the effects of non-steady locomotor activities on load predictability in two goat forelimb bones and to explore the degree to which bone curvature influences load predictability. We measured in vivo bone strains in the radius and metacarpus of juvenile goats performing a variety of natural behaviors in an outdoor arena and compared these strain magnitudes and loading patterns with those measured during steady-state treadmill locomotion. We sought to test two hypotheses: our first hypothesis expects an increase in the variability of strain magnitude and pattern during outdoor non-steady behavior when compared to treadmill locomotion. Our second hypothesis was that the curved radius experiences higher peak strains but less variability during non-steady activities than the straighter metacarpus. We found that unsteady, outdoor locomotion generally caused more variable strain patterns (consistent with the first hypothesis), but not more variable strain magnitudes, than treadmill locomotion in both bones. During outdoor locomotion, higher magnitude strain events in the radius showed more constrained loading patterns than in the metacarpus (consistent with the second hypothesis). In addition to the radius experiencing significantly greater bending strains compared to the straighter metacarpus, these results support the idea of a trade-off between increased predictability of loading pattern and increased bending-induced strain. Strain magnitudes recorded during both outdoor and treadmill locomotion showed a lognormal frequency distribution, but the outdoor bone strain distributions had a greater range because they included high magnitude loading events that did not occur during steady treadmill locomotion.

Locomotor variation and bending regimes of capuchin limb bones

“…To capture the loads associated with locomotion in a natural habitat, our efforts should clearly be focused on trying to expand the range of activities solicited in a laboratory experimental environment. Nonlinear locomotion is a particularly important activity that has been widely neglected in vertebrate locomotor studies (but see Burr et al, 1996;Walter, 2003;Demes et al, 2006;Carlson and Judex, 2007;Jindrich et al, 2007;Moreno et al, 2008). The advice by Dickinson et al (2000) to ''leave the straight and narrow'' in laboratory studies of locomotion is still highly relevant.…”

“…As a result, strain studies can convey the potentially biased impression of rather stereotypic loading regimes of limb bones. To date, only one study has explored bone deformation experienced during nonsteady locomotor activities that tried to mimic the natural behaviors of a quadruped.This study, performed on goats, found that outdoor locomotion encompassing jumps, turns, runs up and down a ramp, decelerating and accelerating bouts, produced more variable strains in the radius and metacarpal than steady state treadmill locomotion of the same animals (Moreno et al, 2008).An understanding of the loading regimes of bones is important for interpreting morphological variation. A widely held notion is that the shapes of long bone diaphyses reflect aspects of habitual bone loading (e.g., Pauwels, 1948;Lovejoy et al, 1976;Ruff and Runestad, 1992;Ruff et al, 2006).…”

Utility of osteon circularity for determining species and interpreting load history in primates and nonprimates

“…In studies that have sought to estimate chronological age or classify fragmentary or complete limb bones FIG URE 1 Load-Complexity Categories (modified from Skedros, 2012). This scheme is based on data from various sources (Biewener and Dial, 1995;Biewener et al, 1996;Blob and Biewener, 1999;Burr et al, 1996;Carrano and Biewener, 1999;Carter et al, 1980;Coleman et al, 2002;Cristofolini et al, 1996;Demes et al, 1998;Drapeau and Streeter, 2006;Goldman et al, 2003;Gross et al, 1992;Judex et al, 1997;Kalmey and Lovejoy, 2002;Lambert, 1971;Lanyon, 1974;Lanyon and Bourn, 1979;Lanyon et al, 1975Lanyon et al, , 1982Lee, 2004;Lieberman et al, 2004;Main, 2007;Main and Biewener, 2004;Milgrom et al, 2000;Moreno et al, 2008;Peterman et al, 2001;Pidaparti and Turner, 1997;Rubin and Lanyon, 1985;Rubin et al, 1996Rubin et al, , 2013Ruff et al, 2006;Skedros, 2002;Skedros and Baucom, 2007;Skedros et al, 1996Skedros et al, , 1999Skedros et al, , 2003aSkedros et al, , 2006Skedros et al, , 2008Skedros et al, , 2012Su et al, 1999;…”

The mechanical consequences of load bearing in the equine third metacarpal across speed and gait: the nonuniform distributions of normal strain, shear strain, and strain energy density

“…Another significant limitation of this study lies with the use of a treadmill to control speed and gait, which inherently confines the induced strain environment compared with unconstrained ambulation in a field, including rapid acceleration/deceleration and changes in direction. A recent study in pygmy goats assessed whether strains induced in the metacarpus and radius vary between treadmill gait and outdoor activity when the goats were chased in an outdoor enclosure (20). While strain distributions across the cortex were not determined in that study, the attachment of gauges on 3 surfaces enabled the authors to assess the frequency distribution of peak strains at each gauge site.…”