The impact of terrain on lower limb bone structure

Abstract

Objectives: Lower limb diaphyseal geometry is often used to evaluate mobility in past populations. Diaphyseal dimensions such as high shape (I X /I Y ) indices generally thought to reflect high mobility may also result from walking over rough terrain. This study investigates the possible effects of terrain on lower limb diaphyseal cross-sectional geometric dimensions. Materials:The sample (N = 3,195) comprises adult skeletons from Europe, Africa, North America, and Asia, spanning from around 30,000 BP to mid-twentieth century.Methods: Femoral and tibial shape and bending/torsional strength dimensions were gathered either as part of a previous project or were generously provided by researchers. Local terrain for each site was quantified with ArcGIS mapping software using geographic coordinates and USGS elevation data, and characterized as flat, hilly, or mountainous.Results: Analysis of variance shows significant differences (p < .05) in midshaft femoral and tibial shape ratio and relative bending/torsional strength among the three terrain categories, with more AP oriented diaphyseal shapes and greater relative strength in hilly and mountainous groups, even after correcting for the effect of subsistence. As expected, the impact of terrain is much more marked for hunter-gatherers and agriculturalists than for more mechanized recent populations. Interestingly, the effect of terrain is confounded in higher latitude individuals that exhibit increased ML bending strength, probably reflecting larger body breadth.Discussion: This study underscores the mechanical significance of traveling over rough terrain and highlights the complex interactions of mobility, terrain, and body shape that contribute to shaping lower limb bone diaphyseal structure. K E Y W O R D Scross-sectional geometry, lower limb, robusticity, terrain

Adapting in the Arctic: Habitual activity and landscape interaction in Late Holocene hunter‐gatherers from Alaska

“…Overall, these results are consistent with previous studies that demonstrated increased femoral and tibial areas and second moments of area as well as greater A‐P/M‐L bending rigidity in the lower limb of hunter‐gatherers with higher terrestrial mobility, and specifically, higher mobility across rugged terrain (Cameron & Stock, 2018; Holt, 2003; Holt et al, 2018; Holt & Whittey, 2019; Macdonald et al, 2009; Ruff, 1999; Stock & Pfeiffer, 2001, 2004). Several examples are of particular relevance to the results reported from Alaska.…”

“…Elevated mobility increases A‐P bending of the lower limb bones (see Ruff et al, 2015 and references therein), and thus an increase in the ratio (Cameron & Stock, 2018; Hill et al, 2016; Larsen et al, 1996; Ruff et al, 1984; Ruff & Larsen, 1990, 2014). Greater relative A‐P bending rigidity is also found in regions with rugged terrain (Cameron & Stock, 2018; Holt, 2003; Holt & Whittey, 2019; Marchi, 2008; Marchi et al, 2011; Ruff, 1999; Stock & Pfeiffer, 2004). Sexual dimorphism in these bone shape indices may be used to differentiate logistical and residential mobility patterns (Ruff, 1987, 1999).…”

“…Variation in terrain also influences intensity of bone strain (Ruff, 2019). Populations who traversed rugged terrain have greater bone rigidity and strength in the lower limb, while those with reduced intensity of activity from regions with flatter terrain have reduced rigidity/strength (Cameron & Stock, 2018; Holt, 2003; Holt et al, 2018; Holt & Whittey, 2019; Marchi, 2008; Marchi et al, 2011; Ruff, 2019; Ruff & Holt, 2018). Taken together, these results suggest that the contextual study of long bone cross‐sectional properties is a useful adjunct to understanding patterns of behavior and landscape usage in past populations.…”

Sex differences in diet and life conditions in a rural Medieval Islamic population from Spain (La Torrecilla, Granada): An isotopic and osteological approach to gender differentiation inal‐Andalus

“…Males show a significant positive correlation between FMS (femoral shape) of both sides and δ 15 N values (Table 5). Anteroposteriorly elongated femora can be linked to both greater mobility and habitual walking on rough terrain (Agostini et al, 2018; Holt & Whittey, 2019; Marchi et al, 2006). In La Torrecilla, the daily short‐distance or seasonal long‐distance driving of livestock to nearby mountainous areas (Malpica Cuello, 2012) was probably carried out by a subset of the male population.…”

Femoral neck and shaft structure in Homo naledi from the Dinaledi Chamber (Rising Star System, South Africa)

“…Biomechanical appendicular properties, in particular cross-sectional geometric properties, have been shown to vary with activity (Ruff et al, 1994(Ruff et al, , 2006Warden et al, 2005Warden et al, , 2014Marchi et al, 2006;Sparacello and Marchi, 2008;Shaw and Stock, 2009a, b;Sparacello et al, 2018), terrain properties (Ruff, 1999;Marchi, 2008;Sparacello et al, 2010;Holt and Whittey, 2019), age (Ruff and Hayes, 1988;Bouxsein et al, 1994;climatically-induced body proportions (Pearson, 2000a;Stock, 2006), ontogeny (Cowgill et al, 2010;Cowgill, 2014), chronological context (Pearson, 2000a;Trinkaus and Ruff, 2012;Friedl et al, 2016;Marchi et al, 2019), hormones (Wang et al, 2004;Travison et al, 2008) and genetic factors (Pearson, 2000a;Lovejoy et al, 2003). When examining hominin remains, all of these aspects become relevant, and appropriate comparisons should be made based on presumed shared characteristics (i.e., activity, climate, and chronological context).…”