# Inferring the mobility of a middle Upper Paleolithic female skeleton from Caviglione (Liguria, Italy): Impact of trauma and mountainous terrain

Tony Chevalier, Thomas Colard

► To cite this version:

Tony Chevalier, Thomas Colard. Inferring the mobility of a middle Upper Paleolithic female skeleton from Caviglione (Liguria, Italy): Impact of trauma and mountainous terrain. Journal of Human Evolution, 2023, 184, pp.103428. 10.1016/j.jhevol.2023.103428. hal-04216930

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Inferring the mobility of a middle Upper Paleolithic female skeleton from Caviglione
(Liguria, Italy): Impact of trauma and mountainous terrain

Tony Chevalier<sup>a,*</sup>, Thomas Colard<sup>b,c</sup>,

<footnote><sup>a</sup> UMR 7194 HNHP, University of Perpignan via Domitia, EPCC-CERP de Tautavel, Avenue Léon Jean Grégory 66720 Tautavel, France.</footnote>

<footnote><sup>b</sup> UMR 5199 PACEA, University of Bordeaux, CNRS, MCC; Bâtiment B8, Allée Geoffroy Saint-Hilaire, CS50023, F-33615 Pessac, France.</footnote>

<footnote><sup>c</sup> Department of Oral and Maxillofacial Radiology, University of Lille, CHU Lille, F-59000 Lille, France</footnote>

<footnote>* Corresponding author.</footnote>

<footnote>E-mail address: tony.chevalier@univ-perp.fr (T. Chevalier).</footnote>
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# Inferring the mobility of a middle Upper Paleolithic female skeleton from Caviglione

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## (Liguria, Italy): Impact of trauma and mountainous terrain

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### Abstract

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Mobility and territory occupation, the participation of injured individuals in group activities, and the role of women in early human groups are crucial issues in human evolution.

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Previously, a biomechanical study showed evidence of several traumas to the upper limb of the well-preserved middle Upper Paleolithic (UP) female skeleton from Caviglione (Caviglione 1, Liguria, Italy) but did not characterize their impact on locomotor behavior.

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Furthermore, mobility in the European UP context is thoroughly documented in males but not in females. Therefore, we examined whether this trauma-affected female skeleton shows bone adaptation to high mobility, as expected in UP groups, and to frequent foot eversion and inversion, as expected given the mountainous area in which it was discovered. This study investigated the structural properties of the femur, tibia, fibula and first metatarsal to infer the mobility level and pattern of Caviglione 1. We analyzed the diaphyseal 'shape', robusticity, fibular cortical distribution and relative robusticity (fibula versus tibia). No substantial findings were derived from the first metatarsal. The fibular cortical distribution can discriminate 'active' (nomadic or settled) and recent sedentary human groups; these findings indicated Caviglione 1 belonged to the former. Interestingly, compared with ancient and recent sedentary humans and some UP individuals, Caviglione 1 had femurs with strong relative anteroposterior rigidity and robust tibias and fibulas reflecting an adaptation to extremely high levels of mobility. The very high relative fibular robusticity of Caviglione 1, higher than that of Middle UP males, is consistent with bone adaptation to frequent travel through mountainous terrain. Such fibular robusticity may also be a consequence of imbalance, due to upper limb traumas, when traveling downhill. These findings indicate that

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injured individuals may have participated in subsistence activities in past populations and
describe an UP female with bone adaptations to habitual high mobility, notably in
mountainous terrain.

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30 **Keywords:** Lower limb bones; Cross-sectional properties; Fibular robusticity; Gender-related behavior; Mountain mobility

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33 **1. Introduction**

Mobility is related to subsistence strategy (i.e., habitual activities) and other
fundamental cultural aspects in extant and past human populations (e.g., Kelly, 1992; Ruff et
al., 2015; Grove, 2016, 2018), as well as to various morphological and physiological
characteristics (Bramble and Lieberman, 2004; Raichlen and Gordon, 2011; Raichlen et al.,
2012; Raichlen and Polk, 2013; Albuquerque et al., 2015; Wallace and Garland, 2016). The
ability to exploit a territory is a strong marker of the adaptation of human societies to their
environment. This ability depends on both internal and external factors (e.g., Nathan et al.,
2008; Kuhn et al., 2016), such as cognitive abilities, knowledge transfer, technology,
population density, and physiological adaptation (inherited or not), as well as environmental
factors such as climatic and topographic constraints. The way in which habitual activities are
shared within human groups reflects social organization and cooperation (including mutual
assistance). Here, from the study of the middle Upper Paleolithic (MUP) female skeleton from
Caviglione, we investigated some of these critical aspects of human behavior by focusing on
gender-specific mobility, territory occupation and the functional adaptation of humans with
traumas.

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The well-preserved Caviglione 1 skeleton from Liguria, Italy, belongs to the richly
documented Italian Upper Paleolithic (UP) burials, which represent a major part of the
European UP sample (Fabbri and Giacobini, 2021). In 1872, Rivière discovered this skeleton in the Caviglione cave, one of the Grimaldi caves, that are all located within the same cliff (Rivière, 1872a, 1872b; Hurel, 2016). The cliff is known by different names depending on the language or patois used, such as Baousse Rousse or Balzi Rossi (Lumley, 2016a). This skeleton has been recently reassessed in a monograph (Lumley, 2016b), with a focus on the cranial and postcranial anatomy (Chevalier and Stalens, 2016; Chevalier et al., 2016; Guipert, 2016a, 2016b; Voisin and Stalens, 2016a, 2016b), body size (Chevalier, 2016), and trauma (Mafart et al., 2016). The female attribution (Mallegni, 1995 from G. Giacobini personal communication, contra Verneau, 1906) was confirmed (Bruzek et al., 2016), and the Gravettian burial was dated to approximately 24 000 cal BP from the *Cyclope neritea* shells of its headdress (Valladas et al., 2016). The biological age of Caviglione 1 was between 30 and 47 years old from the study of the cranial suture closure and dental wear (Lumley et al., 2016). Additionally, Chevalier (2019) revealed the residual effects of trauma on the biomechanical properties of the upper limb bones and proposed a new etiological interpretation from microtomographic analysis. Caviglione 1 suffered a left radius fracture, defined as a Galeazzi fracture, probably from a fall (Chevalier, 2019). Although the fracture had healed, the distal part of the radius was not aligned with the more proximal part. In addition, the humerus showed bone structure changes caused by an unidentified severe trauma to the right shoulder, which forced Caviglione 1 to become left-handed (Chevalier, 2019). However, biomechanical investigation of the lower limb bones is also needed to determine the lifestyle and living conditions of Caviglione 1 by determining her mobility pattern and to discuss the potential impact of the trauma on locomotion. The cross-sectional geometric (CSG) properties of UP human lower limbs and their dependence on mobility are well established and highlight the high level of mobility of the UP population (Holt, 2003; Ruff et al., 2006a, 2015; Ruff, 2018; Sparacello et al., 2018a). This background provides an
appropriate framework to examine whether Caviglione 1 displays the expected bone structure characteristics and mobility pattern in the UP context, which is predominantly composed of males with rare females (see Supplementary Online Material [SOM] Tables S1–S5). For example, the femoral MUP sample (the largest sample considering bone type) included 16 males and 4 females. As a result, the MUP mobility pattern reflects preferentially that of males.

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## 1.1. Determining Upper Paleolithic mobility from lower limb bones: The Ligurian context

The European UP population underwent a marked change in mobility following the Last Glacial Maximum (20 ka; Holt, 2003; Shackelford, 2007). Climatic shifts toward colder temperatures greatly impacted the subsistence behavior of UP human populations and reduced mobility. The human population in the Early Upper Paleolithic (EUP; 40–20 ka) was highly mobile and mobile to a greater extent than that in the late Upper Paleolithic (LUP; 20–10 ka). Mobility in the UP and Holocene has been extensively explored from assessments of the lower limb, including diaphyseal long bone shape (i.e., relative bending strength) and robusticity (i.e., bone strength relative to body size; see Ruff and Larsen, 2014, and Holt et al., 2018a, for a synthetic view). A decrease in midshaft cross-sectional femoral strength and an increase in circularity indicate a decrease in mobility; these bone structure changes were observed from the Early UP to Late UP and Mesolithic in European populations (Holt, 2003) and from the EUP to LUP in European, Asian, and African populations (Shackleford, 2007). By collecting a large European sample of modern humans in the context of major economic and social changes, Ruff et al. (2015) and Holt et al. (2018a) highlighted a significant decline in the femoral and tibial strength and shape ratio from the hunter-gatherers of the UP and Mesolithic to the more sedentary Holocene populations. These authors confirmed the decline in lower limb bone strength over time (Holt, 1999, 2003; Ruff, 2005; Ruff et al., 1993,

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2006b), persisting through the Iron/Roman period (ca. 2,000 years). The adoption of food production during the Neolithic was probably a driving force behind the decrease in mobility, leading to the major bone structure changes (Ruff et al., 2015). However, not all bones and biomechanical parameters show the same pattern of changes over time, and the change has not been linear (Holt et al., 2018a). Recently, Sparacello et al. (2018a) explored changes in the mobility pattern derived from lower limb characteristics during the Pleistocene-Holocene transition, based on European (and specifically Ligurian) samples as well as modern athletes.

The European sample exhibited no differences in the tibiofibular complex, an indicator of mobility (Shaw and Stock, 2009a; Rantalainen et al., 2010; Marchi and Shaw, 2011; Sparacello et al., 2018a), between the MUP (30–20 ka) and LUP (20–10 ka). Specifically, both groups exhibited a high mobility level. The multifactorial analyses indicated that neither group exhibited biomechanical characteristics similar to field hockey players or runners despite the supposedly more intensive exploitation of mountainous terrain by LUP individuals (requiring extensive foot eversion/inversion, as in field hockey players) and level terrain (the plain) by MUP individuals (requiring little foot eversion/inversion, as in runners). Within the Ligurian sample, found in a mountainous setting, the mobility patterns of the LUP and MUP groups were similar; however, a larger sample size is necessary for more robust interpretation (Sparacello et al., 2018a). To date, the well-preserved Ligurian skeleton of Caviglione 1 has not been included in such a study.

## 1.2. Investigating the mobility level and pattern in the Upper Paleolithic

Many factors, including physical behavior, can affect lower limb bone structure (e.g., Sparacello and Marchi, 2008; Pearson et al., 2014; Holt et al., 2018a). While mobility plays a major role in bone modeling, the unevenness of the terrain (Sparacello and Marchi, 2008; Holt and Whittey, 2019), variations in body size and body shape (Ruff, 2000; Shaw and
126 Stock, 2011; Pearson et al. 2014), workload (Holt et al., 2018a), genetic and hormonal factors,
127 and the influence of aging (Lovejoy et al., 2003; Pearson and Liebermann, 2004) might play a
128 crucial role in bone adaptation during an individual's lifespan. Additionally, bone properties
129 may be differentially influenced by changes in lifestyle; for example, femoral robusticity and
130 shape are differently affected by changes in the level of mobility (Sparacello and Marchi,
131 2008). Moreover, the same structural properties may provide distinct functional
132 interpretations in lower limb bones. Sparacello et al. (2018a) underlined the lack of significant
133 differences between the tibial shape ratio in EUP and LUP individuals, which contrasts with
134 the results of the femur shape ratio (see Holt, 2003). These results suggest that a combination
135 of variables and bones is conductive to a thorough interpretation of UP human mobility based
136 on lower limb analysis.

137 Most studies on human mobility in the UP and Holocene (e.g., Holt, 2003;
138 Shackelford, 2007; Ruff et al., 2015; Holt et al., 2018a, 2018b; Sparacello et al., 2018a) have
139 used the cross-sectional properties of weight-bearing long bones (the femur and tibia); the
140 fibula, considered a non- or poor-weight bearing bone (Takebe et al., 1984; McNeil et al.,
141 2009), is rarely included (Marchi et al., 2011; Sparacello et al., 2014, 2018a). The
142 biomechanical properties of MUP fibulas are presented only in Sparacello et al. (2018a), in
143 which all individuals are male (Barma Grande 2, 5 and 6; Bausso da Torre 1 and 2).
144 Moreover, the CSG properties of UP metatarsals have not yet been studied. Nevertheless, the
145 involvement of these bones in walking should prompt their inclusion in mobility studies. Both
146 bones (the fibula and first metatarsal) respond to distinct mechanical loads during locomotion;
147 therefore, they merit consideration when predicting mobility. The fibula is exposed to
148 different mechanical stresses generated by various foot movements. Foot eversion/inversion
149 occurs during frequent directional changes and when crossing uneven terrain (e.g.,
150 mountains); in field hockey players (Marchi and Shaw, 2011) and some Paleolithic and
Neolithic groups (Marchi et al., 2011; Sparacello et al., 2014, 2018a), these movements alter the biomechanical properties of the fibula (i.e., reinforce the fibula). Additionally, the first ray of the foot is a fundamental structure of the forefoot (Morton, 1935; Christensen and Jennings, 2009; Hansen, 2009). The first metatarsal in humans experiences high pressure during the push-off phase of bipedal walking, acting as a fulcrum for propulsion. The human foot exhibits high metatarsophalangeal joint angles (mean = 48°) during the stance phase of bipedal walking (Fernández et al., 2016), during which the head of the first metatarsal is directly (or indirectly, through a shoe) in contact with the ground and the metatarsal is subvertical to the ground. The ground reaction force at the metatarsal head produces significant diaphysis stresses that may generate functional adaptation. Indeed, Griffin and Richmond (2005) noted that CSG properties properly reflect the level of pressure experienced by the first metatarsal in the majority of activities. Macintosh and Stock (2019) highlighted the specific diaphyseal shape of the first metatarsal due to running activities, characterized by repetitive low impact loading. However, the other biomechanical parameters assessed from this foot bone showed no significant differences between runners, soccer players, rowers, and nonathletic individuals.

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## 1.3. *Aims of the study*

The comparative analysis of the MUP Caviglione 1 was not previously performed in UP CSG studies (see Holt, 2003; Shackelford, 2007; Ruff et al., 2015; Holt et al., 2018a, 2018b; Sparacello et al., 2018a). Our aim is to determine whether the biomechanical properties of the lower limb of Caviglione 1 (female with bone trauma) are consistent with previous UP cross-sectional results. Specifically, we investigate (1) whether this female exhibited the same high level of mobility as males, which comprise the majority of the UP sample; (2) whether she exhibited bone structure adaptations (i.e., bone modeling) to a
176 mountainous environment during its lifespan (the past environment, including a large coastal
177 plain in front of the Baousse Rousse cliff, differs from the present environment; Lumley,
178 2016a); and (3) whether Caviglione 1's upper limb bone pathologies impacted lower limb
179 bone structure and mobility. This is the first UP study to include the CSG properties of the
180 femur, tibia, fibula and first metatarsal, i.e., four bones experiencing distinct mechanical
181 loads, to investigate mobility (Fig. 1).

182 If Caviglione 1 exhibits an overall structural pattern highly similar to other UP
183 individuals, especially Ligurian UP individuals, we could deduce that sex and upper limb
184 trauma are not limiting factors for high levels of mobility, or at least that we have no proof of
185 the impact of trauma on mobility, and that locomotor behavior included the ability to cross in
186 mountainous terrain. This structural pattern should include high femoral and tibial robusticity
187 and shape indices compared to those of sedentary groups and high relative fibular robusticity,
188 as observed in extinct human groups living in mountainous regions.

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190 **2. Materials and methods**

2.1. *Caviglione 1 and comparative samples*

192 The femurs, tibias, fibulas and first metatarsals of the MUP Caviglione 1 female were
193 studied. They are housed in the Muséum national d'Histoire naturelle (MNHN), Paris. The
194 comparative sample was composed of MUP, LUP, Neolithic, Chalcolithic, and Bronze Age
195 individuals as well as recent modern humans (including modern athletes). Supplementary
196 information and details of the sample composition are presented in SOM S1 and Tables S1-
197 S6. Notably, the femoral and tibial samples, which are the most abundant, revealed the
198 scarcity of female representation, particularly for the period in question (i.e., UP). The UP
199 femoral sample was composed of 32 males and 13 females, and the UP tibial sample was
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composed of 29 males and 11 females (and individuals with undetermined sex). The MUP

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Ligurian sample was composed only of males, if we excluded Caviglione 1.

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## 2.2. *Microtomographic imaging and three-dimensional bone surface models*

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Seventy-three bones were scanned for this study. Two scanning platforms were used: the AST-RX (Paris, France) and ISIS4D (Lille, France) platforms. The Caviglione bones (n = 8) were scanned on the AST-RX platform of the Muséum National d'Histoire Naturelle (Paris, France) using a GE Sensing & Inspection Technologies phoenix|X-ray v|tome|x L240-180 µCT scanner. The isotropic voxel size reconstructions were 143.9 µm for femurs, 134.7 µm for tibias, 104.9 µm for fibulas and 69.0 µm for first metatarsals. Of the bones, 29 fibulas and 34 first metatarsals from the Holocene (Neolithic, Chalcolithic) were scanned with the ISIS4D X-ray platform (In Situ Innovative Set-ups) of the University of Lille, France, using an RX-Solution UltraTom µCT scanner. The isotropic voxel size reconstructions were 100.0–48.6 µm for fibulas and 49–40 µm for first metatarsals. The main parameters used for all acquisitions were: source voltage, 140 Kv; source current, 700µA; aluminum and copper filter; 3 frames averaging and helicoidal acquisition mode.

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Thirty-eight fibulas from recent modern humans, mainly part of Georges Olivier's collection (20th century), were previously scanned with the AST-RX platform (MNHN, France); some of these results were published in Chevalier and Tignères (2020). Microtomographic scans from Cro-Magnon, Abri Pataud and Baousso da Torre were made available by Sébastien Villotte (Villotte et al., 2017; Thibeault and Villotte, 2018). These scans included three tibias (4330/4333, 4332), two fibulas (4334, 4335) and one first metatarsal (4345) from Cro-Magnon; one fibula (58-2-37817) and one first metatarsal (63-2-1309) from Abri Pataud; and one first metatarsal from Baousso da Torre 1.

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Cross-sectional properties were extracted from bone surface models of femurs and tibias from Arene Candide (AC2, 3); fibulas from Arene Candide (AC1, 2, 3, 4 and 12) and Barma Grande (BG2, 5 and 6); and first metatarsals from Arene Candide (AC3-4, 13) and a recent human sample (n = 10). The Arene Candide surface models files were downloaded from www.morphosource.org, Duke University, with the agreement of Vitale Sparacello (Sparacello et al., 2018b). The Barma Grande surface models were made available by Vitale Sparacello and Nico Radi (Sparacello et al., 2018a). The first metatarsals of recent humans are part of the Stony Brook University collection and were downloaded from www.morphosource.org, Duke University, with permission of Biren Patel. Only for these individuals, biomechanical parameters were predicted based on solid sections from surface models (see below).

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## 2.3. *Cross-sectional geometric analysis*

The CSG analyses of bone diaphyses (femur, tibia, fibula, and first metatarsal) focused only on the midshaft cross-section (50%), except for the fibula, for which we also examined the distal cross-section (24%). This study provided new CSG properties for 213 cross-sections (SOM Tables S1–S5). The raw CSG properties from Caviglione 1 are presented in Table 1. The midshaft section was located with reference to the femoral and tibial biomechanical length (Trinkaus and Ruff, 2012), the fibular maximal length and the metatarsal interarticular length. When the bone was observed from a lateral perspective, the fibular distal cross-section was located at the junction between the line delimiting the proximal portion of the subcutaneous triangular area and the anterior border (SOM Fig. S1). We found that the distal cross-section was, on average, at 24% of the maximal length of the fibula (standard deviation: 2.7; n = 31), with 0% located at the most distal point. To calculate the relative fibular robusticity (the polar moment of area ratio [J] between the fibula and tibia, $J_{fib}/J_{tib}$), comparing

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the CSG properties between the fibula and tibia, the tibial midshaft (not the fibular midshaft) was used as the reference location (see additional comments in Section 2.6; SOM Fig. S2). Femoral, tibial, and fibular cross-sections were taken perpendicular to the diaphysis following anatomical orientation (for the fibular orientation see Chevalier and Tignères, 2020). For the metatarsals, the main axis was determined by the line passing through the center of the two articular surfaces, and sections were taken perpendicular to this axis. The selection of the cross-sectional location of fragmentary bones from the Cro-Magnon and Pataud sites is explained in SOM S2-S3. Cross-sections were selected with Avizo v. 7.1.0 (FEI Visualization Sciences Group, Hillsboro).

The biomechanical analyses focused on three kinds of indices: the ‘shape’ indices (second moment of area ratio, $I_x/I_y$ and $I_{max}/I_{min}$), robusticity indices (the standardized [std] polar section modulus [$Z_p$] and total area [TA]) and relative fibular robusticity. The ‘shape’ and robusticity indices and their mechanical interpretations are presented in Table 2 (Ruff, 2019). Standardizing TA by bone length allowed us to include individuals for whom body mass could not be estimated in the fibular robusticity comparison (see additional methodological information about the choice of indices in SOM S4). Mean values were used when both the right and left bones were available.

The ‘true’ or ‘medullary’ sections were predicted from ‘solid’ sections of surface models based on formulas described in previous studies for femur and tibia (Stock and Shaw, 2007; MacIntosh et al., 2013) and developed in this study for the fibula and first metatarsal (formulas in Table 3; sample and method in SOM S5). The individuals for whom CSG properties have been predicted have been mentioned before (see section 2.2). Comparison of the shape indices ($I_x/I_y$ and $I_{max}/I_{min}$ ratios) between fibular solid and medullary sections showed that differences in values were below, or slightly above, the percent error of prediction (%PE) and the percentage of the standard error of estimate (%SEE) calculated from
formula predictions. Consequently, we did not use the predicted values for the fibular shape
indices. We used the CSG directly measured from the solid section because the errors of
prediction are the same magnitude if we compare the shape indices only measured from the
solid section and the shape indices measured from the predicted true CSG properties based on
the solid section. This prediction concerned 4 fibulas from the MUP and 4 fibulas from the
LUP. The high percent error of prediction for Iₓ/Iᵧ at midshaft is discussed further given the
context in the Results section (section 3.3).

The cross-sectional properties were quantified with ImageJ v. 1.51q software (Schneider et al., 2012) with the plugin 'MomentMacro' (fae.johnshopkins.edu/chris-ruff/, provided for free download by Christopher Ruff). All statistical analyses were performed using PAST v. 2.14 and 4.08 (Hammer et al., 2001). To compare our dataset, we used the Shapiro-Wilk test for normally distributed data and the F test (for two groups) and Levene's test (for three groups) for data with equal variance. In terms of parametric tests, t tests and analyses of variance (ANOVAs, with Tukey's post hoc pairwise tests) were used to compare group means. In terms of nonparametric tests, the Mann-Whitney U test and Kruskal-Wallis test (followed by post hoc Mann-Whitney U tests with Bonferroni corrected *p*-values) were used to compare group medians. Statistical tests are feasible with samples containing at least three individuals. However, we believe that small sample sizes are inappropriate for comparison with statistical tests, as this favors anthropological overinterpretation given that the results depend strongly on fossil finds. Thus, statistical tests comparing the means and medians of groups were not performed unless at least one group contained at least ten individuals. Given our data, this subjective choice seems judicious, although we acknowledge that no choice is perfect. We used the 0.05 threshold (i.e., *p*-value <0.05) as an informative threshold and not as an absolute limit between two states (i.e., significant or not significant; Wasserstein and Lazar, 2016; Wasserstein et al., 2019).
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## 2.4. Body mass prediction

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Body mass (kg) estimates were predicted from the femoral head diameter (mm) of individuals represented by the femur, tibia and fibula according to the method proposed in Trinkaus and Ruff (2012; see additional information in SOM S6 for the Cro-Magnon and Arene Candide individuals). The body mass of Caviglione 1 was previously estimated in Chevalier (2016). In the present study, most of the first metatarsals were not associated with femurs belonging to the same individual, thus we proposed an alternative method. Body mass was predicted from the proximal dorsoplantar diameter of the first metatarsal according to De Groote and Humprey (2011). For consistency, all body masses used to quantify the metatarsal robusticity index were derived from the metatarsal diameter.

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## 2.5. Cortical thickness distribution pattern

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To determine the cortical thickness distribution, we measured the cortical thickness at each degree (for 360°) from an axis passing through the centroid of the medullary cavity with the 'Radial thickness measurements' plugin in ImageJ and developed by Robert Nshimirimana. We present the cortical thickness and relative cortical thickness, defined as the cortical thickness at each degree divided by the mean cortical thickness of the 360 values. The aim is to quantify local cortical bone reinforcement, which has been considered only descriptively previously (Chevalier and Lumley, 2022). Local reinforcement can be interpreted as the bone's reaction to mechanical stress. These data complement the more global approach with the relative second moment of area (e.g., $I_x/I_y$).

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## 2.6. Comparison with modern human athletes
In addition to comparison with past and recent populations, represented by dry bones, the bone structure properties of Caviglione 1 were compared with modern human athletes, drawing on data from Marchi and Shaw (2011), Sparacello et al. (2018a) and Macintosh and Stock (2019). The athlete sample was composed of cross-country runners and field hockey players, as well as nonathletic group (i.e., control group). The bones of runners and field hockey players are subjected to different mechanical load patterns. The frequent and abrupt directional changes in hockey players produce more mediolateral loading while the straight-ahead movements in runners favor anteroposterior loading (Shaw and Stock, 2009a; Marchi and Shaw, 2011). The two kinds of athletes were considered as highly mobile with repetitive low impact loading (See Macintosh and Stock, 2019), but hockey players more adequately reproduce the prehistoric human movements that can occur on uneven terrain. The CSG properties were from males except for the femoral and tibial shape indices ($I_{max}/I_{min}$), in which females were represented. To ensure consistency with the previously proposed methods and published data, we selected the left fibular cross-section of Caviglione 1 from the cross-section at the tibial midshaft (SOM Fig. S2) of Caviglione 1 (as the left leg was better preserved). From these new CSG properties, we measured and compared the shape ($I_x/I_y$ and $I_{max}/I_{min}$) and robusticity of the fibula and the relative fibular robusticity ($J_{fib}/J_{tib}$). The new fibular cross-section located at the tibial midshaft was at approximately 60% of the fibular maximal length. Based on this observation, we also included fibular CSG properties at 60% of the fibular maximal length for our recent human sample.

### 3. Results

The data used to compare the bone properties of Caviglione 1 with those of UP, Neolithic/Chalcolithic, Bronze Age individuals and recent individuals are presented in Tables 4–8 and Figures 1–9. In addition, individual data are presented in SOM Tables S1–S5, and
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subgroup means are presented in Table 5 and SOM Tables S7–S9. The CSG comparisons
with the athletes and the additional CSG properties of the left fibula of Caviglione 1 are
shown in Table 9. The results of statistical tests evaluating significant group differences are
provided in Tables 4–6 with details in SOM Tables S10–S13.

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Tables 5 and SOM Tables S1–S5 and S7 show the low proportion of females
compared with males, both in the data quantified for this study and in previous studies.

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3.1. *Femur*

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The femoral midshaft shape index (I<sub>x</sub>/I<sub>y</sub> ratio) of Caviglione 1 clearly was higher than the means of Neolithic/Bronze and recent humans (Fig. 3; Table 4). This high index is due to a strong posterior pilaster (SOM Fig. S3), which is common in early modern human femurs (e.g., Trinkaus and Ruff, 2012). The UP mean is also higher than the means of the Neolithic/Bronze and recent human groups (*p*-values < 0.0001). However, Caviglione 1 had a higher femoral shape index than the UP mean (and higher than the MUP and LUP means, as well as the male and female means in each subgroup) and was more similar to MUP males than females (Fig. 3; Table 5). Forty-three of the 50 UP individuals had a lower shape index than Caviglione 1. Furthermore, the shape index of Caviglione 1 was much higher than expected given the relationship between the femoral biomechanical length and the shape index (Fig. 4). The shape index of the Caviglione 1 femur was slightly below the mean of other MUP Ligurian femurs and very high compared to that of the LUP Ligurian sample (SOM Table S9).

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Caviglione 1 showed a higher value of femoral robusticity than the Neolithic/Bronze
and recent humans means (Fig. 3; Table 4). The femoral robusticity of Caviglione 1 was close
to the UP mean (Fig. 3; Table 4) which had the highest mean of all groups (*p*-value = 0.06).
The value of Caviglione 1 was particularly close to the LUP means, both male and female,
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was higher than the MUP mean, and notably higher than the MUP female mean (Table 5).

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However, the femoral robusticity of Caviglione 1 was far lower than that of the most robust femurs in the UP sample (e.g., the femurs from Cro-Magnon Alpha, Barma Grande 6, and Ohalo 2; SOM Table S1).

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Finally, the markedly high femoral robusticity and shape index ($I_x/I_y$ ratio) of Caviglione 1 and Liguria individuals contrasted with the gracile femurs and the low shape index found in many individuals of the Moravian sample, which included individuals from the Dolní Věstonice and Mladeč sites (SOM Table S1).

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## 3.2. Tibia

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The tibial shape index of Caviglione 1 ($I_{max}/I_{min}$ ratio), which was similar to the UP mean (*p*-value = 0.015), including the MUP and LUP means, and the Neolithic/Bronze mean (*p*-value = 0.027), was high compared to the recent humans mean (Fig. 3; Table 4). This tibial shape index contrasted greatly with the low indices of the only two MUP females. The difference in tibial shape index between Caviglione 1 and LUP females (represented by six individuals) was less marked (Table 5). Caviglione 1 had a tibial shape index similar to the Ligurian MUP mean and lower than the Ligurian LUP mean, which had particularly high shape indices (SOM Table S9). Note also that the tibial shape of Caviglione 1 is marked proximally by a prominent posterior pilaster (with anterolateral concavity and salient interosseous crest; SOM Fig. S4), which is attenuated at mid-diaphysis. This feature results in high platycnemic indices for both tibiae (right = 157.2; left = 168.5). Similar pilasters are frequently observed in UP tibiae (Trinkaus et al., 2022).

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The tibial robusticity of Caviglione 1 was higher than the UP mean and far higher than the Neolithic/Bronze and recent humans means (Fig. 3; Table 4). The average tibial robusticity of the MUP and LUP individuals was lower than that of Caviglione 1, who had a
tibial robusticity similar to that of MUP males (Table 5). The MUP sample, including only two females, showed very low value for the tibia of Dolní Věstonice 3. In the Ligurian context, the tibial robusticity of Caviglione 1 fell between the MUP and LUP means (SOM Table S9). We noted that some Ligurian MUP individuals had particularly robust tibias (e.g., Barma Grande 5 and 6; see also Cro-Magnon Alpha, in France; SOM Table S2).

Consequently, the tibial shape index ($I_{max}/I_{min}$ ratio) was similar between Caviglione 1 and the MUP mean from Liguria and Dolní Věstonice from Moravia (mean = 2.54; SD = 0.73); however, the latter sample had a very low tibial robusticity (mean = 72.2; SD = 15.9; SOM Table S2).

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### 3.3. *Fibula*

We assessed two fibular midshaft shape indices, the $I_x/I_y$ and $I_{max}/I_{min}$ ratios (Fig. 5; Table 6). The $I_x/I_y$ ratio of Caviglione 1 was very low compared to all the average of all samples (i.e., UP, Neolithic/Chalcolithic, recent humans). In other words, the cross-section of Caviglione 1 presented low expansion anteroposteriorly and particularly large expansion laterally (or posterolaterally). Recent humans presented the highest mean (*p*-value = 0.0344). However, each sample had substantial variation in this index. In UP individuals, low values were common in the Ligurian sample, in contrast to both indices in Cro-Magnon individuals (Alpha and Gamma; SOM Table S3). Caviglione 1 had a similar $I_x/I_y$ ratio to the Ligurian MUP and LUP means, except for the LUP Arene Candide 3 individual (SOM Tables S3 and S9). Arene Candide 3 greatly influenced the Ligurian LUP average given the small number of individuals in this sample. Although the prediction of some UP midshaft shape index ($I_x/I_y$) values depends on the predictive formula with a high %PE, the singular morphology of the UP fibula seems adequately represented by the singular predicted values. We considered there to be no major impact on the results and interpretation. The $I_{max}/I_{min}$ ratio of Caviglione 1, UP

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mean (*p*-value = 0.0009) and Neolithic/Chalcolithic mean (*p*-value = 0.0056) were higher
than the recent humans mean. The differences between the Iₓ/Iᵧ and Iₘₐₓ/Iₘₐₙ ratios were
marked in all samples except for recent humans, which indicated that strengthening mainly
occurred about the anteroposterior axis in recent humans.

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In the fibular UP sample, we had only two females (LUP). They presented a higher
mean (associated with high SD) for the midshaft I<sub>max</sub>/I<sub>min</sub> ratio than Caviglione 1, and a
similar robusticity (Table 5).

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The fibular distal shape indices also included two indices (Fig. 6; Table 6). The Iₓ/Iᵧ ratio of Caviglione 1 was slightly lower than the UP, Neolithic/Chalcolithic and recent humans means but similar to the total LUP sample mean and that of the MUP and LUP from Liguria (SOM Table S9). The Iₓ/Iᵧ ratio of Caviglione 1 was similar to the MUP mean, except for Cro-Magnon Gamma, who had an exceptionally high index that greatly influenced the MUP mean (SOM Table S4). Similar patterns were observed for the Iₘₐₓ/Iₘₐₙ ratio, but the differences between Caviglione 1 and the total UP sample (including MUP individuals but not LUP individuals), Neolithic/Chalcolithic individuals and recent humans were more marked. Furthermore, Caviglione 1 had an Iₘₐₓ/Iₘₐₙ ratio slightly lower than the Ligurian MUP mean but similar to the Ligurian LUP mean (SOM Table S9).

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The midshaft fibular robusticity was explored through the biomechanical index (Zp-
std) and the 'traditional' index (TA-std; Fig. 5; Table 6). The biomechanical index was
elevated in Caviglione 1 and UP mean (p-value = 0.0004) compared to the recent humans
mean. However, Caviglione 1 had a higher Zp-std value than the UP mean and was very close
to the maximal midshaft fibular robusticity value observed in the total sample (i.e., that of
Barma Grande 5; SOM Table S3). The mean of the fibular robusticity of MUP and LUP
individuals was similar (Table 5 and SOM Table S7). The traditional index showed a decline
in fibular robusticity (p-value = 0.0001) from UP and Neolithic/Chalcolithic individuals to

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recent humans (Table 6). In Figure 5, the differences are better identified between the recent humans mean and the UP (*p*-value = 0.025) and Neolithic/Chalcolithic (*p*-value = 0.0036) means, respectively. The traditional fibular robusticity of Caviglione 1 was similar to the UP mean (including each UP subgroup; SOM Table S7).

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The distal fibular robusticity (Zp-std) of Caviglione 1 was higher than the UP mean and markedly higher than the recent humans mean (Fig. 6; Table 6). However, the fibular robusticity of Caviglione 1 was similar to the MUP mean and substantially exceeded t the LUP mean (SOM Table S7). UP individuals exhibited high variation in robusticity. Among the UP individuals, Caviglione 1 showed an elevated robusticity similar to that of Arene Candide 1 and Barma Grande 5 and 6 (MUP individuals). The maximum fibular robusticity of recent humans was lower than that of Caviglione 1 (SOM Tables S4). The other distal fibular robusticity index (TA-std) was higher in Caviglione 1 and UP than in Neolithic/Chalcolithic and recent humans if we refer to the means (*p*-value = 0.5451 ; *p*-value = 0.0419, respectively; Fig. 6; Table 6). However, the TA-std value of Caviglione 1 was particularly close to the MUP mean (SOM Table S7), while LUP and Neolithic/Chalcolithic means had similar values of TA-std (*p*-value = 0.99).

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Caviglione 1 and UP individuals (i.e., Cro-Magnon 4334 and 4335, Pataud 58-2-37817, and Barma Grande 5) had substantially higher cortical thickness, with an impressive posterolateral thickness, than recent humans (Figs. 7 and 8). There were also large differences in the anterior and medial thickness between the Caviglione 1/UP mean and recent humans mean, but this difference was reduced after standardizing the cortical thickness (Fig. 7). The cortical thickness distribution of Caviglione 1 and the mean of UP individuals was markedly different from that of recent humans, for both standardized and unstandardized values. Specifically, recent humans showed similar cortical thicknesses at the three main locations (anterior, lateral and medial), while Caviglione 1 and UP individuals had predominant lateral

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thickening on average (Fig. 7). We discovered the same pattern as that in Caviglione 1 and most UP individuals (i.e., strong posterolateral or lateral thickening) in the Neolithic/Chalcolithic group. However, the mean value for these individuals highlighted a posterolateral thickness (unstandardized) that was lower than that in UP individuals and higher than that in recent humans, and the anterior and medial cortical thicknesses (standardized and unstandardized) were similar to those of recent humans. Finally, the major lateral cortical thickness in Caviglione 1 and UP and Neolithic/Chalcolithic individuals was associated with a lateral bulge. Cross-sectional observations indicated an obvious association between these two structurally related features and allowed us to infer such thickening from the solid cross-sections of 3D models that had sections without medullary cavities (see Arene Candide and Barma Grande individuals in Fig. 8). Furthermore, such features were generally distinguishable without measurements (although this precluded quantification). Based on these observations and data from µCT and surface scans, we determined that 92% of both UP individuals (including Caviglione 1; 11 out of 12 individuals) and Neolithic/Chalcolithic individuals (12 out of 13 individuals) and 13% of recent humans (6 out of 46 individuals) had predominant posterolateral cortical reinforcement (i.e., a midshaft lateral side with a strong bulge associated with high cortical thickness).

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### 3.4. Relative fibular robusticity (fibula versus tibia)

The relative fibular robusticity ($J_{fib}/J_{tib}$) of Caviglione 1 was greater than the mean of each sample (Neolithic, Iron Age, and Medieval), except for LUP females (Table 6). Overall, we observed that females exhibited higher robusticity than males in the Neolithic, Iron Age and Medieval samples; however, statistical comparison of group averages produced nonsignificant results ($p$-values > 0.3). Similarly, the LUP group exhibited high robusticity in females, but no statistical test was performed given the small sample size.
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Furthermore, the relative fibular robusticity ($J_{fib}/J_{tib}$) of Caviglione 1 substantially exceeded that of the Cro-Magnon Gamma and the Ligurian MUP and LUP means as well as the relative fibular robusticity of each Ligurian MUP individual; in particular, impressive differences between the value of Caviglione 1 and that of Barma Grande 2 and 6 and Baousso da Torre 2 were noted.

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### 3.4. First metatarsal

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The metatarsal shape ($I_x/I_y$) of Caviglione 1 was similar to the UP mean, especially MUP mean (Table 8; Fig. 9; SOM Table S9). Neolithic/Chalcolithic individuals and recent humans had a lower average shape index, i.e., more pronounced relative mediolateral to dorsoventral rigidity.

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The metatarsal robusticity of Caviglione 1 was high, similar to the recent humans mean and differing from the UP mean, including the MUP and LUP means (Table 8; Fig. 9; SOM Table S8). The metatarsal robusticity tended to increase from the UP to the recent human groups ($p$-value > 0.05).

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### 3.5. Caviglione 1 versus modern athletes

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The femoral shape index (i.e., $I_{max}/I_{min}$) of Caviglione 1 was greater than the mean values of female runners and the control group (Table 9). The tibia of Caviglione 1 was markedly more robust than modern human athletes (male runners and hockey players) and more sedentary people, with values more similar to those of male runners, based on means. The tibial shape index ($I_{max}/I_{min}$) of Caviglione 1 was similar to the female and male runner means, which presented the highest relative anteroposterior rigidity means out of athletes, control group individuals and other recent humans. Both the values of the fibular robusticity and relative fibular robusticity of Caviglione 1 were much higher than the athlete and

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sedentary group means which were composed only of males. The fibular shape index of
Caviglione 1 was high, similar to the (male) runners' mean, in terms of the relative maximal-
to-minimal moment of area. The relative anteroposterior-to-mediolateral moment of area of
Caviglione 1 was very low with respect to that of recent humans. Thus, Caviglione 1 might
have a fibula with a unique shape pattern resulting in low relative anteroposterior rigidity.
Although this observation remained valid regarding the samples quantified for this study
(which are isolated dry bones), it did not allow us to differentiate Caviglione 1 from athletes
(and the control group) for whom the protocols differed during the data acquisition (distinct
orientation of the fibula). Therefore, this latter shape index (I<sub>x</sub>/I<sub>y</sub>) was indicative only of the
distinction between athletes and the control group for which Marchi and Shaw (2011) found
no significant differences.

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535 **4. Discussion**

This study investigated the following main question: does Caviglione 1 (a female with clear bone trauma) exhibit the same structural pattern of the lower limb bones as the UP group, mainly composed of males? In other words, are her bones adapted to the same mechanical load pattern as her contemporaries, indicating that she had similar level and pattern of mobility?

Our findings revealed that the overall bone structure of Caviglione 1 was similar to
that of UP individuals, especially MUP males. Specifically, Caviglione 1 presented a
structural pattern of the lower limb bones that fit within the Ligurian pattern; although the
relative tibial rigidities of the Ligurian and Moravian bones was similar, the Ligurian bones
were more robust and had a higher relative femoral rigidity. Additionally, Caviglione 1 shared
many characteristics with Neolithic individuals and other individuals from close cultural
periods (i.e., Bronze and Chalcolithic individuals), but she differed dramatically from recent

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humans, regardless of their level and type of mobility. Therefore, her bone properties do not support a dramatic change in habitual locomotor behavior related to her sex or to her injuries. Indeed, the bone biomechanical properties of Caviglione 1's lower limb bones are associated with high mobility in UP groups (regardless of the terrain; e.g., Ruff et al., 1993, 2015; Holt, 2003; Holt et al., 2018a) and specifically with mountain travel (e.g., Sparacello et al., 2014, 2018a).

However, the unique structural pattern of Caviglione 1 merits further discussion concerning the following two points: (1) interpretation of the various characteristics of the thigh and leg bones regarding a specific level and pattern of mobility, as contradictions may arise when distinct biomechanical regions and variables are used, and (2) determination of gender-specific behavior and extension of the previous discussion regarding the impact of upper limb trauma on her habitual activities (Chevalier, 2019). These two points are discussed separately below. Here, we showed how the bone structure of the Caviglione 1 female might result from adaptation to (very) high mobility on both flat and mountainous terrain. The upper limb trauma appears to have had a nondeleterious influence on lower limb structure, and eventually on mobility, although the impact on mobility was difficult to assess considering the unknown timing of the trauma.

## 4.1. Level and pattern of mobility

The CSG properties of the Caviglione female indicated particularly that her femurs had a strong relative anteroposterior rigidity (i.e., high $I_x/I_y$ and $I_{max}/I_{min}$ ratios) and that her tibias were robust ($Z_p$-std); these characteristics were noticeable not only through comparison with Neolithic/Bronze individuals, athletes (male and female) and other recent humans but also with UP individuals that were predominately (approximately three-quarters) male. This high femoral shape index ($I_x/I_y$ ratio) and high tibial robusticity ($Z_p$-std) are expected in
Ligurian MUP individuals (Sparacello et al., 2018b). However, within this Ligurian MUP sample composed only of males, Caviglione 1 had a tibial robusticity lower than the most robust individuals. The femoral shape is often related to the level of mobility (Ruff and Hayes, 1983; Ruff, 1987; Stock and Pfeiffer, 2001; Holt, 2003; Sparacello and Marchi, 2008; Holt and Whittey, 2019), but the contribution of the body proportion to the femoral shape (the Iₓ/Iᵧ ratio) has been discussed in several studies (Ruff, 1995, 2000; Ruff et al., 2022; Shaw and Stock, 2011; Pearson et al., 2014; Sparacello et al., 2018a). Some authors have suggested that tropical-adapted bodies tend to have high relative anteroposterior rigidity and that, in contrast, a relatively broad body favors mediolateral strengthening (Holliday, 2002; Ruff et al., 2006b). Recently, Sparacello et al. (2018a) proposed that bone length could determine in part the midshaft femoral shape: the longer the femur is, the greater the Iₓ/Iᵧ ratio. The authors added that females tend to have shorter bone lengths and lower shape indices. Here, the Caviglione female presented a very high shape index and a long femoral biomechanical length; indeed, only 12 out of the 45 UP individuals had longer femurs than Caviglione 1. As shown in Figure 4, the shape indices of both femurs from Caviglione 1 were far higher than the expected values given the bone length, even within the UP sample. This finding suggests the potential for a (very) high level of mobility. The high tibial robusticity of Caviglione 1 supported this proposition, as high robusticity is generated by a high level of mobility (Stock, 2006; Shaw and Stock, 2009a; Shaw and Stock, 2013). Shaw and Stock (2009a) observed a decline in robusticity from runners to hockey players to the control group; however, all groups composed of males presented average values clearly lower than those of Caviglione 1 (see Sparacello et al., 2018a). Caviglione 1 exceeded the robusticity of an average modern athlete by approximately two standard deviations. In conclusion, Caviglione 1 was more mobile than modern athletes and the early agricultural population according to her femoral shape and tibial robusticity.
In contrast to the femoral shape and tibial robusticity, the tibial shape index ($I_{max}/I_{min}$) of Caviglione 1 was similar to the Neolithic/Bronze mean (and runners). This value was similar to the UP mean and high compared to the mean of 'sedentary' recent humans. The tibial shape is related to the terrestrial mobility level and pattern (Ruff and Hayes, 1983, Holt, 2003; Stock, 2006; Shaw and Stock, 2009a; Sparacello et al., 2014; Holt and Whittey, 2019).

A mobility pattern involving frequent foot eversion/inversion (as in hockey players) increases the tibial mediolateral bending rigidity (here, $I_{min}$), which produces a more rounded cross-section (i.e., a low $I_{max}/I_{min}$ ratio); in contrast, a high level of mobility with more stable foot movements (as in runners) increases the anteroposterior bending rigidity (here, $I_{max}$), which produces a more ovoid cross-section (i.e., a high $I_{max}/I_{min}$ ratio; Shaw and Stock, 2009a; Marchi et al., 2011). Incorporating the tibial shape with our proposal based on femoral shape and tibial robusticity, we can suggest that Caviglione 1 was highly mobile in flat terrain, such as coastal regions, but less than our previous comments suggested given the tibia shape index is less remarkable than the femoral shape index. From these features, we could suggest that Caviglione 1 was not accustomed to traveling through uneven terrain, although she was found in a mountainous area. However, we can attempt to explain the slightly distinct results from the tibia and the femur and propose an interpretation consistent with the findings of Sparacello et al. (2014) regarding Ligurian UP individuals and their relationship to mountains.

The tibia index in Caviglione 1, less notable than the femur index, could be due to the tibial mediolateral strengthening resulting from an adaptation to mountainous terrain. This adaptation would slightly reduce the relative anteroposterior rigidity of the tibia although this value remains high in Caviglione. Consequently, the exceptional level of mobility in Caviglione 1, notably in flat terrain (as indicated by the very high femoral shape index and tibial robusticity), would be associated with recurrent travel in mountainous terrain (as indicated by the 'moderately' high tibia index). However, the evidence for adaptation to
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mountainous terrain from the tibial shape needs to be strengthened. Our argument is based on
the relationship between the femoral and tibial shape, but they are weakly correlated (Pearson
et al., 2014).

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The fibula is also an important bone when discussing bone adaptation to mountainous terrain. Foot instability (as on uneven ground) increases the mediolateral stresses on the leg bones and impacts both fibular strength ($Z_p$-std) and relative fibular rigidity (the $J_{fibula}/J_{tibia}$ ratio; Funk et al., 2007; Marchi, 2007; Marchi and Shaw, 2011; Marchi et al., 2011; Sparacello et al., 2014) as well as, potentially, the fibular cortical distribution related to cross-sectional shape (e.g., $I_{max}/I_{min}$). In our present study, the midshaft cortical distribution seemed more indicative of 'active' groups, i.e., it grouped Caviglione 1 with UP and Neolithic/Chalcolithic individuals, separate from 'sedentary' recent humans. The fibular cross-sections of Dolní Věstonice individuals and the Tyrolean 'Iceman' confirmed this pattern (Ruff et al., 2006b; Trinkaus, 2006). Regarding fibular robusticity ($Z_p$-std and TA/bone length), that of Caviglione 1 was similar to the UP mean and higher than the Neolithic/Chalcolithic/Bronze mean and recent humans mean (including athletes). This result can indicate both a high level of mobility and travel through uneven terrain, since the UP hunter-gatherer sample was mainly composed of sites in mountainous regions (and almost none in hilly or plains regions). Here, the best property to infer the pattern of mobility is fibular relative robusticity because the comparison samples are composed of more diverse groups (see Tables 7–8) and because of the very high relative fibular robusticity of Caviglione 1. Indeed, only some Ligurian LUP and Neolithic individuals had values similar to those of Caviglione 1. The functional hypothesis suggests that Caviglione 1 was highly adapted to traveling in mountainous terrain based on the differences among hockey players (with higher values), runners and the sedentary control group (Marchi and Shaw, 2011), as some variations in the foot movements in mountainous terrain parallel those of hockey players. In addition,

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648 mountain-dwelling LUP, Neolithic and Iron Age groups from Liguria and Central Italia
649 exhibited more robust fibulas (based on means) than Medieval individuals who inhabited the
650 German plains (Sparacello et al., 2014). Logically, the low robusticity found in Medieval
651 fibulas could also be explained by a low mobility level, which contrasts with the high
652 mobility levels of LUP and Neolithic groups. However, the low fibular robusticity of
653 Medieval individuals living on plains is also remarkable compared to Iron Age group living in
654 mountainous terrain, although they have a similar level of mobility (i.e., low to moderate
655 mobility level; for classification of activity levels, see Sparacello et al., 2014).

656 Intriguingly, Caviglione 1 greatly differed from Ligurian MUP individuals in terms of
657 fibular robusticity (i.e., Jfibula/Jtibia) and, to a larger extent, differed from the fibular robusticity
658 of field hockey players (i.e., Jfibula/Jtibia and Zp-std). Sparacello et al. (2014) highlighted the
659 benefit of including fibular measurements in mechanical studies and the different ways to
660 interpret fibular morphology. They suggested that traveling downhill on rugged terrain and
661 traveling on level rugged terrain produce distinct ground reaction forces given the differences
662 in high impacts, which elucidates how to incorporate the biomechanical model of field hockey
663 players with our conclusions. When traveling downhill, the impact and braking force peaks
664 are greater than those when traveling across flat terrain. These observations are intuitive when
665 considering mountain travel; in mountain runners, when the slope increases, the force peak
666 increases (Gottschall and Kram, 2005). The effects of sloped walking on joint kinematics and
667 kinetics have been addressed in several studies (Schwameder et al., 2005; Lay et al., 2006;
668 Alexander and Schwameder, 2016) and are related to pain and injuries, notably during hiking
669 (Blake and Ferguson, 1993). Therefore, changes in ground reaction force would also impact
670 walkers, speed walkers, and individuals carrying loads downhill; runners would probably be
671 impacted to a greater extent. The fibular weight-bearing function differs according to the foot
672 position (Takebe et al., 1984; Goh et al. 1992; Thomas et al., 1993; Wang et al., 1996) and, to
an extent, the individual (Takebe et al., 1984). During the eversion and dorsiflexion of the
foot, which are experienced while traveling over level rough terrain and hilly or mountainous
terrain, delivered loads in the fibula are maximal, ranging from approximately 12% in the
neutral ankle position to 16-23% with a load level of 750 N (76.5 kg; Wang et al., 1996).
Furthermore, the percentage of loads carried by the fibula varies according to the total load:
the higher the total load is, the greater the proportion of load in the fibula, e.g., 12% of the
load in the fibula at the neutral ankle position (with 750 N) becomes 28% during dorsiflexion
at 1,000 N (102 kg), i.e., greater than 16-23% (Wang et al., 1996). Considering these fibular
biomechanical findings, we hypothesized that the level of stress produced by traveling
downhill, associated with eversion/inversion and plantar flexion/dorsiflexion movements,
explained the marked distinction in fibular robusticity between the Caviglione female and
male field hockey players. However, the age at which Caviglione 1 began to be subjected to
specific mechanical loads remains unknown and is a determining factor. We propose that
Caviglione 1 was subjected to greater locomotor loads than the other Ligurian MUP
individuals (only males), hypothetically due to more frequent, or intensive, travel in
mountainous areas. Femoral robusticity is also correlated with the type of terrain (Ruff, 1999;
Sparacello and Marchi, 2008; Holt and Whittey, 2019) as well as the level of activity (Holt
and Whittey, 2019). The femoral robusticity of Caviglione 1 was similar to the Ligurian MUP
and LUP means; therefore, it was not as distinctive as relative fibular robusticity.
Additionally, the other indices of fibular robusticity (Zp-std and TA/bone length) were similar
between Caviglione 1 and Ligurian MUP and LUP; however, Caviglione 1 had a higher distal
fibular robusticity than Ligurian LUP.

Finally, the Caviglione 1 female presented CSG values mainly similar to or higher
than those of males (largely represented in the comparative sample), both athletes and UP
individuals. Given that the bones of females may be less responsive to mechanical loading
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than those of males (Kannus et al., 1995; Haapasalo et al., 1996; Macintosh et al., 2017), the
lower limb bones of Caviglione 1 unequivocally experienced very high loading.

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## 4.2. Pathology and gender-related mobility

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Caviglione 1 exhibits major trauma of the upper limb; the timing of this trauma is unknown (Chevalier, 2019). This injury may have influenced the habitual behavior of this female. Chevalier (2019) described a helicoidal radial fracture of the left forearm that likely occurred during a fall on an outstretched hand during hyperpronation. This Galeazzi fracture had healed; indeed, the left arm was used preferentially for daily tasks given its robusticity, despite the valgus position of the distal part of the radius. Additionally, the right arm of this originally right-dominant female presents strong cortical and trabecular bone alterations due to an unknown traumatic event. Chevalier (2019) suggested that the right arm was most likely little used for habitual tasks following its injury, given its substantial loss of bone mass and the pattern of upper limb asymmetry. Determining the timing of these traumatic events within the lifespan of Caviglione 1 has not been possible and the influence of these injuries on locomotor activity has not been investigated until now. In the present study, we observed that the lower limb of Caviglione 1 exhibited the overall bone pattern of UP individuals related to high locomotor activity. Therefore, we have no evidence to suggest that these traumatic events modified the lower limb bone structure, either because they did not impact mobility or did not impact mobility for a sufficiently long period, or they did impact the mobility but we are unable to observe the consequences. The traumatic events might have taken place after the period of intense bone modeling occurring during growth (Forwood and Burr, 1993); therefore, the bone structure would have no longer been highly responsive to loading changes and would have preserved the overall structure that preferentially reflected the prepubertal activity level (see Murray and Erlandson, 2021). However, it should be noted that the upper
723 limb showed major structural changes following the trauma (Chevalier, 2019), indicating that
724 the bones of Caviglione 1 were still in a physiological condition to strongly react to loading
725 changes. Furthermore, Caviglione 1 presented some differences from the rest of the UP
726 sample (including other Ligurian MUP individuals); in particular, she differed in relative
727 fibular robusticity. Although the normal functional explanation is the strongest assumption, it
728 is possible that upper limb trauma decreased her balance during travel in mountainous terrain.
729 The movements that interfere with balance could have altered movement kinematics and
730 increased the impact of the foot against the ground. Such foot instability might have caused
731 the unique relative fibular robusticity. Some Mesolithic females from Liguria also present
732 high relative fibular robusticity as well as injury (Sparacello et al., 2018a). The Mezzocorona-
733 Borgonuovo individual shows a healed fibular fracture that could explain changes in lower
734 limb function. More interestingly, the Vatte di Zambana individual exhibits some deformities
735 of the upper limb; Sparacello et al. (2018a) do not dismiss a possible influence of such altered
736 upper limb function on mobility levels. The Vatte di Zambana individual had low femoral and
737 tibial robusticities, which supports Sparacello et al.'s hypothesis, but Caviglione 1 does not.
738 Finally, despite the serious developmental abnormalities that affect a large part of the
739 skeleton, Dolní Věstonice 15 participated in habitual group tasks and presented a lower limb
740 structural pattern consistent with a high level of mobility (Trinkaus et al., 2001). Studies of
741 Caviglione 1 (Chevalier, 2019 and the current study) failed to reject the involvement of
742 injured individuals in subsistence activities among past populations; however, this conclusion
743 does not preclude an influence of upper limb trauma on walking and related bone structure in
744 Caviglione 1.

745 Data from our study and those of Sparacello et al. (2018a), shown in Table 7, indicate
746 that females frequently present high relative fibular rigidity; differences in this value were
747 weakly supported by statistical tests. Insufficient sample size and the lack of females in some
groups have contributed to the difficulties of drawing conclusions. Sexual dimorphism of the lower limb has been studied with a large sample in Europe; the authors showed that UP males had higher mobility levels than females, probably due to hunting practices, that declined after the UP (Berner et al., 2018). In addition, Villotte et al. (2010) emphasized the effects of hunting practices in males by relating upper limb enthesopathies in the distal humerus to throwing practices. Here, we propose a hypothesis that future studies could test: the Caviglione female was typically involved in gathering in mountainous terrain that caused frequent or long displacements and, therefore, particular adaptation of the fibula relative to the tibia.

757

### 4.3. *Study limitations and perspectives*

When comparing human groups, confounding effects due to the influence of many factors on bone morphology make biomechanical interpretation difficult (e.g., Kannus et al., 1995; Ruff, 2000; Lovejoy et al., 2003; Pearson and Lieberman, 2004; Ruff et al., 2006a, 2006b; Sparacello and Marchi, 2008; Marchi and Shaw, 2011; Pearson et al., 2014; Berner et al., 2018; Holt et al., 2018a; Sparacello et al., 2018a; Holt and Whittey, 2019). For example, the more active an individual is, the greater the terrain affects their bone structure (Holt and Whittey, 2019), and the greater the femoral bone length influences the femoral diaphyseal shape (Sparacello et al., 2018a). In addition, the relationships of the tibial shape ratio with the terrain, gender-specific behavior and subsistence behavior are complex (Holt and Whittey, 2019): the tibial diaphyseal shape exhibits marked morphological changes with respect to the terrain in only agricultural groups, and these changes depend on gender (in contrast to hunter-gatherer and industrial/mechanized groups). Thus, the locomotor interpretation of a single individual (such as Caviglione 1) requires caution. However, given our data, it seems highly likely that this female had a high level of mobility, especially in mountainous terrain.
Human athletes offer a fundamental opportunity to develop biomechanical bases of interpreting the bone morphology of past human populations (Longman et al., 2020). Athletes specialize in sports that generate specific movements and mechanical loads. Their body size, athletic history (e.g., average of training hours per week; age at which training began) and sex are known. Therefore, biological anthropologists are particularly interested in comparing the properties of athlete bones (Shaw and Stock, 2009a, 2009b; Marchi and Shaw, 2011) to those of fossil bones (Shaw and Stock, 2013; Sparacello et al., 2014, 2018a; Chevalier and Lumley, 2022). However, as seen in the present study and in that of Sparacello et al. (2014), some very high values in past populations produce doubt regarding how to interpret the data accurately. Athletes are subject to specific training with muscular reinforcement that prepares the body to undergo the constraints of loads induced by their target activity. Therefore, although very useful, athletes do not represent perfect models. Applying this note of caution to our own study, the high mobility of Caviglione 1 appears supported by our data, but the extent of such a difference remains unclear: to what extent the difference in morphology reflects the difference in the level and pattern of mobility. This consideration does not call into question the well-established relationship between bone structure and physical activity, but we wonder whether the magnitude of the structural differences is at the same level as the magnitude of the differences in the activity performed. In other words, is there a linear relationship between structure and activity? How much of the abundance of bone mass in past populations is due to genetic and hormonal factors? Currently, the best way to interpret the remarkable mechanical parameters in UP individuals and Caviglione 1 (and Pleistocene hominins; Chevalier and Lumley, 2022) is to consider loading experienced during growth and development. The study of the tibial structure of athlete females supports the predominant influence of prepubertal activity on adult bone structure (Murray and Erlandson, 2021). A high level of physical activity produced at a young age, especially before puberty, is more prone to produce high
robusticity and specific bone shape than high loading experienced after puberty. Intense and repetitive loadings performed before becoming an adult is probably at the origin of the lower limb structure of Caviglione 1, even more so if the activity was carried out at an early maturational stage. As an example, the MUP Sunghir 2 individual shows high bone shape indices at approximately 12 years old (Trinkaus et al., 2014), similar to runners and soccer players for the femur and to the soccer players (but below the mean for runners) for the tibia according to the values in Murray and Erlandson (2021). Consequently, ontogenetic development in Pleistocene hominins should be systematically explored (when possible) which could also tell us about the functional and genetic influences on bone structure, notably if we incorporate very young individuals (e.g., Chevalier et al., 2021).

Finally, we included new investigations of the fibula and first metatarsal considering the UP context. The distal fibular shape ($I_{max}/I_{min}$ and $I_x/I_y$ ratios) and involvement of the first metatarsal seem disappointing when attempting to interpret the level and type of mobility. The limb tapering concept can be considered to explain these results. In this concept, the distal bones and distal part of bones are constrained by a drastic optimization between safety factors (e.g., fracture prevention) and tissue economy by minimizing bone production and energy required for movement, which means that these bone regions are less likely to adapt through the addition of bone mass, or to a lesser extent, when habitual loadings change or peak loading are higher than in other anatomical regions (Stock, 2006; Shaw et al., 2014; Nadell and Shaw, 2016; Saers et al., 2016). This concept can be used to explain the first metatarsal pattern, and we would expect an increase in trabecular anisotropy to compensate for the lack of diaphyseal adaptation (see Saers et al., 2016). The fibula pattern seems more complex to explain although robusticity decreases from the mid-diaphyseal to distal cross-section (Table 6) in agreement with the limb tapering concept. We could have expected no change in the fibula robusticity (i.e., no additional bone mass) and changes in the fibula shape
823 (i.e., redistribution of the bone mass), but we observed the opposite. Despite some
824 unsatisfactory results, the first metatarsal is often well preserved in an archeological context
825 and thus should be considered when analyzing the trabecular bone and more distal diaphyseal
826 sections, as its size and shape are less location dependent. In contrast, examining the
827 robusticity of the distal fibular region and the midshaft cortical distribution seems highly
828 promising for future studies. This combined approach may allow us to distinguish active
829 groups (e.g., UP and Neolithic/Chalcolithic individuals) from recent sedentary groups and, to
830 some degree, differentiate between highly mobile (UP) and sedentary (Neolithic/Chalcolithic)
831 groups. An isolated, or fragmentary, fibula can likely provide important results regarding
832 locomotor behavior based on the fibular index, TA/bone length (which confirms the Zp-std
833 analysis), and the cortical distribution pattern at midshaft. However, the sample size of some
834 groups was small in our current study; additional research is needed.
835

835

836 **5. Conclusion**

837 The lower limb bone structure of the Caviglione female is in line with the European
838 UP pattern, which was mainly defined from males. The various bones and mechanical
839 parameters studied lead to the definition of the level of mobility and the diversity of the
840 terrain traveled. The structural pattern of Caviglione 1 is consistent with a very high level of
841 mobility (e.g., from high femoral relative anteroposterior rigidity and robust tibia), notably in
842 flat terrain, and bone adaptation to frequent foot eversion/inversion movements (e.g., from
843 high relative fibular robusticity), as when walking in mountainous areas and uneven terrain.
844 Upper limb injuries do not appear to have had a notable impact on the lower limb bone
845 structure of Caviglione 1, which does not allow us to state that mobility was impaired. Some
846 exceptionally high robusticity indices relative to comparative samples, and, notably modern
847 athletes, lead us to reflect on the origin of such differences. In the Caviglione female,
848 activities resulting in frequent/long-distance travel in irregular terrain, and possibly slight imbalance due to upper limb trauma, might have generated high bone strain and produced a remarkable robusticity in the fibula. The age at which regular and specific physical activity begins can determine bone adaptation; unfortunately, this age remains undetermined for Caviglione 1. However, it is highly probable that the main structural characteristics of this skeleton were acquired during growth when bone modeling was very active, and thus, they likely reflect high loading experience related to intense mobility from a very young age.
849
850
851
852
853
854
855 Therefore, the timing of loading, level of mobility and type of terrain covered are the fundamental parameters that explain the remarkable lower limb structure in Caviglione 1 with respect to recent humans. Finally, new athlete models that include the bone properties of mountain walkers and runners, and new bone studies of immature Upper Paleolithic individuals could enhance future functional interpretations.
856
857
858
859
860

861 Acknowledgments

862 We thank Dominique Grimaud-Hervé (UMR 7194), Antoine Balzeau (UMR 7194), Martin Friess (UMR 7206), Aurélie Fort (MNHN) and Miguel García-Sanz (previously UMS 2700) for providing access to fossil and recent bones, to the µCT scan archives of the MNHN (Paris, France) and to AST-RX, plateforme d'Accès Scientifique à la Tomographie à Rayons X, UMS 2700 2AD Acquisition et Analyse de Données pour l'Histoire naturelle CNRS-Muséum National d'Histoire Naturelle (MNHN); Sébastien Villotte (UMR 5199) and Adrien Thibeault (UMR 5199) for sharing µCT data of Cro-Magnon and Abri Pataud individuals (project funded by the ANR Gravett'os, ANR-15-CE33-0004) and Baousso da Torre individual, and Véronique Laborde (MNHN) for granting access to the Cro-Magnon remains; Jérôme Hosdez (ISIS4D) and Pierre Marchandise (PMOI) for technical support while scanning at the ISIS4D X-ray platform (University of Lille, France), funded by the International Campus on Safety
and Intermodality in Transportation (CISIT), the Haut-de-France Region, the European Community, and the National Centre for Scientific Research (CNRS); Vitale Sparacello and Nico Radi for sharing bone surface models of Barma Grande individuals (image courtesy of Ministero della Cultura (MiC), Soprintendenza Archeologia, Belle Arti e Paesaggio per le province di Imperia e Savona, unauthorized reproduction forbidden), and Vitale Sparacello for sharing bone surface models of Arene Candide individuals (Soprintendenza Archeologia, Belle Arti e Paesaggio per la città metropolitana di Genova e le province di Imperia, La Spezia e Savona provided access to these data that originally appeared in Sparacello et al. (2018), the collection of which was funded by Marie-Curie European Union COFUND/Durham Junior Research Fellowship (under EU grant agreement number 267209), and by the Wolfson Institute for Health and Wellbeing, Durham, UK. The bone surface models of Barma Grande and Arene Candide individuals were downloaded from www.MorphoSource.org. We thank Biren Patel for sharing surface models of the first metatarsal (available on Morphosource); Christian Perrenoud (who led the excavation of the Tourelle site) and Henri Baills (who led the excavation of the Coma Francèze site); Francis Duranthon (MNHN, Toulouse) for providing access to the Grotte des Treilles collection and Guillaume Fleury (MNHN, Toulouse) for providing a friendly welcome during various visits. Microtomography acquisitions of the human remains were funded by the Regional Service of Archaeology of the Occitania Region (SRA, Occitanie, France) and the University of Perpignan via Domitia (BQR DéHom).

893

894

Declaration of competing interests

895

The authors declare that they have no conflicts of interest to disclose.

896

897

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1203
1204 **Figure captions**

1205 **Figure 1.** The lower limbs of Caviglione 1 (bones studied): femur, tibia and fibula (posterior 1206 view), first metatarsal (plantar view).

1207
1208 **Figure 2.** Cross-sections of the lower limbs of Caviglione 1: femur (Fem), tibia (Tib), fibula 1209 (Fib) and first metatarsal (Met). All cross-sections are located at the midshaft except for a 1210 distal cross-section of the fibula (see asterisk). Orientation is indicated for right bones.
1211

**Figure 3.** Box and whisker plots of the midshaft femoral and tibial properties in Caviglione 1 (red arrows) compared to those in Upper Paleolithic, Neolithic/Bronze and recent humans.

1212

1213

From bottom to top, the horizontal bars are the minimum value, first quartile, median value, third quartile and maximum value, without outliers; the cross is the mean value.

1214

1215

Abbreviations: LUP = late Upper Paleolithic; MUP = middle Upper Paleolithic.

1217

1218

**Figure 4.** Bivariate plots of femoral shape index ($I_x/I_y$) against femoral biomechanical length.

1219

1220

Least square regression (LSR): Shape index = 0.005 × biomechanical length – 0.9241, r = 0.52, *p* < 0.0001 (n = 199). References in SOM Table S1. Abbreviations: LUP = late Upper Paleolithic; MUP = middle Upper Paleolithic.

1222

1223

**Figure 5.** Box and whisker plots of the midshaft fibular properties in Caviglione 1 (red arrows) compared to those in Upper Paleolithic, Neolithic/Chalcolithic and recent humans.

1224

1225

From bottom to top, the horizontal bars are the minimum value, first quartile, median value, third quartile and maximum value, without outliers; the cross is the mean value. The small squares with a central point refer to LUP mean presented in Sparacello et al. (2018a); individual data were not specified for the 11 males and 2 females). Abbreviations: LUP = late Upper Paleolithic; MUP = middle Upper Paleolithic.

1230

1231

**Figure 6.** Box and whisker plots of the distal fibular properties in Caviglione 1 (red arrows) compared to those in Upper Paleolithic, Neolithic/Chalcolithic and recent humans. From bottom to top, the horizontal bars are the minimum value, first quartile, median value, third quartile and maximum value, without outliers; the cross is the mean value.

1235
1236 **Figure 7.** Mean values of cortical thickness at distinct location of the midshaft fibular cross-section. The cortical thickness distribution is shown by a line for each group. Values are measured at each degree, counterclockwise from the medial side. Abbreviations: NC = Neolithic and Chalcolithic; RH = recent humans; UP = Upper Paleolithic.

1240

1241 **Figure 8.** Midshaft fibular cross-section in Caviglione 1 and comparative samples. We selected sixteen younger individuals (18–42 years old) from the recent human sample. The red arrow shows the (postero)lateral bulge and thick cortical bone of Caviglione 1; these features are common in Upper Paleolithic and Neolithic individuals and rare in recent humans. Trinkaus et al. (2022) presented a more proximal midshaft cross-section for the fragmentary Cro-Magnon 4335, resulting in a more marked posterolateral bulge. The asterisk refers to the Barma Grande 5 cross-section at approximately 46% of the maximal fibular length. Abbreviations: AC = Arene Candide; BG = Barma Grande; CM = Cro-Magnon; Pt = Pataud; CAV = Caviglione; R = right; L = left.

1250

1251 **Figure 9.** Box and whisker plots of the midshaft first metatarsal properties in Caviglione 1 (red arrows) compared to those in Upper Paleolithic, Neolithic/Chalcolithic and recent humans. From bottom to top, the horizontal bars are the minimum value, first quartile, median value, third quartile and maximum value, without outliers; the cross is the mean value.

1255
100 mm

<figure><img src="image_2.png" /></figure>
Anterior

Lateral

Left

Right

<figure><img src="image_3.png" /></figure>

Fem

<figure><img src="image_4.png" /></figure>

<figure><img src="image_5.png" /></figure>

Fib

<figure><img src="image_6.png" /></figure>

<figure><img src="image_7.png" /></figure>

Tib

<figure><img src="image_8.png" /></figure>

Fib

<figure><img src="image_9.png" /></figure>

<figure><img src="image_10.png" /></figure>

Met

Dorsal

<figure><img src="image_11.png" /></figure>

Lateral

100 mm
Upper Palaeolithic

MUP Male

LUP Male

Neanderthlaeids

MUP Female

LUP female

Recent modern humans

Cirrhilienne (MUP female)

<figure><img src="image_12.png" /></figure>

<figure><img src="image_13.png" /></figure>

<figure><img src="image_14.png" /></figure>
<figure><img src="image_15.png" /></figure>

Holocephale

MUP

Ordinary LSR total sample

LUP

Cavignione

95% forecast
Lipid Palmitic

Nistatin/Chicorinato

Ferreti modernus Burmanus

MUP Male

LIP Male

Cerviglione (MUP female)

LIP Female

LIP Female

<figure><img src="image_16.png" /></figure>
☐ Upper Palateless

☐ Nodules/Chalcocite

☐ Recent amorphous barium

☐ LUP/Male

☐ LUP/Male

☐ Carcinome (LUP female)

<figure><img src="image_17.png" /></figure>
<figure><img src="image_18.png" /></figure>

<figure><img src="image_19.png" /></figure>

<figure><img src="image_20.png" /></figure>

Cerviglione

Upper Palermodi

Nasolabii/Chalaziformis

Recent humans
Recent humans

<figure><img src="image_21.png" /></figure>

Neolithic

<figure><img src="image_22.png" /></figure>

Upper Paleolithic

<figure><img src="image_23.png" /></figure>

CAY-R

59 mm

CAY-L
<figure><img src="image_24.png" /></figure>

Upper Palatal Fossa

Nasolabial/Cholinoepiglottal

Exenter modern humerus

MUP Male

LIP Male

Cervix (MUP formula)

<figure><img src="image_25.png" /></figure>

<figure><img src="image_26.png" /></figure>
# 1 Table 1

## 2 Cross-sectional geometric properties (CSG) of Caviglione 1 (femur, tibia, fibula and first metatarsal).<sup>a</sup>

<table><thead><tr><th>CSG location</th><th>Side</th><th>TA</th><th>CA</th><th>%CA</th><th>I<sub>x</sub></th><th>I<sub>y</sub></th><th>I<sub>x</sub>/I<sub>y</sub></th><th>I<sub>max</sub></th><th>I<sub>min</sub></th><th>I<sub>max</sub>/I<sub>min</sub></th><th>Z<sub>x</sub></th><th>Z<sub>y</sub></th><th>J</th><th>Z<sub>p</sub></th></tr></thead><tbody><tr><td>50% femur</td><td>R</td><td>673</td><td>496</td><td>73.7</td><td>47466</td><td>26207</td><td>1.81</td><td>47470</td><td>26203</td><td>1.81</td><td>2396</td><td>1821</td><td>73673</td><td>3696</td></tr><tr><td>50% femur</td><td>L</td><td>627</td><td>474</td><td>75.6</td><td>39617</td><td>23536</td><td>1.68</td><td>40157</td><td>22996</td><td>1.75</td><td>2112</td><td>1705</td><td>63153</td><td>3356</td></tr><tr><td>50% tibia</td><td>R</td><td>584</td><td>434</td><td>74.4</td><td>39343</td><td>20160</td><td>1.95</td><td>42200</td><td>17303</td><td>2.44</td><td>2364</td><td>1432</td><td>59503</td><td>3092</td></tr><tr><td>50% tibia</td><td>L</td><td>583</td><td>436</td><td>74.8</td><td>42051</td><td>17468</td><td>2.41</td><td>43484</td><td>16035</td><td>2.71</td><td>2370</td><td>1363</td><td>59519</td><td>3059</td></tr><tr><td>50% fibula</td><td>R</td><td>179</td><td>130</td><td>72.5</td><td>2186</td><td>3507</td><td>0.62</td><td>3928</td><td>1765</td><td>2.23</td><td>217</td><td>359</td><td>5693</td><td>554</td></tr><tr><td>50% fibula</td><td>L</td><td>168</td><td>121</td><td>71.7</td><td>2006</td><td>3293</td><td>0.61</td><td>3697</td><td>1602</td><td>2.31</td><td>210</td><td>338</td><td>5299</td><td>525</td></tr><tr><td>Distal fibula</td><td>R</td><td>157</td><td>103</td><td>65.9</td><td>2340</td><td>1163</td><td>2.01</td><td>2347</td><td>1157</td><td>2.03</td><td>262</td><td>168</td><td>3504</td><td>389</td></tr><tr><td>Distal fibula</td><td>L</td><td>155</td><td>98</td><td>63.5</td><td>2126</td><td>1192</td><td>1.78</td><td>2203</td><td>1115</td><td>1.98</td><td>235</td><td>165</td><td>3318</td><td>367</td></tr><tr><td>50% first metatarsal</td><td>R</td><td>174</td><td>76</td><td>43.7</td><td>1716</td><td>1539</td><td>1.12</td><td>1766</td><td>1489</td><td>1.19</td><td>203</td><td>202</td><td>3255</td><td>371</td></tr><tr><td>50% first metatarsal</td><td>L</td><td>171</td><td>71</td><td>41.4</td><td>1503</td><td>1528</td><td>0.98</td><td>1546</td><td>1484</td><td>1.04</td><td>196</td><td>204</td><td>3030</td><td>350</td></tr></tbody></table>

3 Abbreviations: R = right; L = left; TA = total area (mm²); CA = cortical area (mm²); %CA = percentage cortical area; I<sub>x</sub> = second moment of area about the mediolateral (ML) axis (mm⁴); I<sub>y</sub> = second moment of area about the anteroposterior (AP) axis (mm⁴); I<sub>max</sub> = maximal second moment of area (mm⁴); I<sub>min</sub> = minimal second moment of area (mm⁴); J = polar second moment of area (mm⁴); Z<sub>x</sub> = section modulus about mediolateral axis (mm³); Z<sub>y</sub> = section modulus about anteroposterior axis (mm³); Z<sub>p</sub> = polar section modulus (mm³).

4 about the mediolateral (ML) axis (mm⁴); I<sub>y</sub> = second moment of area about the anteroposterior (AP) axis (mm⁴); I<sub>max</sub> = maximal second moment of area (mm⁴); I<sub>min</sub> = minimal second moment of area (mm⁴); J = polar second moment of area (mm⁴); Z<sub>x</sub> = section modulus about mediolateral axis (mm³); Z<sub>y</sub> = section modulus about anteroposterior axis (mm³); Z<sub>p</sub> = polar section modulus (mm³).

5

6

7 a For the first metatarsal; ‘anteroposterior’ is dorsoventral. The distal fibula cross-section is approximately 24%.

8
9 Table 2

10 Cross-sectional geometric property parameters used in this study, with mechanical
11 interpretation (Ruff, 2019) and indices.ª

<table><thead><tr><th>Property</th><th>Abbreviation</th><th>Units</th><th>Mechanical interpretation</th><th>Standardization</th></tr></thead><tbody><tr><td>Total area</td><td>TA</td><td>mm²</td><td>—</td><td>TA-std = (TA/MBL)×100<sup>b</sup></td></tr><tr><td>Second moment of area about ML axis</td><td>I<sub>x</sub></td><td>mm<sup>4</sup></td><td>AP bending rigidity</td><td>—</td></tr><tr><td>Second moment of area about AP axis</td><td>I<sub>y</sub></td><td>mm<sup>4</sup></td><td>ML bending rigidity</td><td>—</td></tr><tr><td>Second moment of area ratio<sup>c</sup></td><td>I<sub>x</sub>/I<sub>y</sub></td><td>—</td><td>AP/ML bending rigidity</td><td>—</td></tr><tr><td>Maximum second moment of area</td><td>I<sub>max</sub></td><td>mm<sup>4</sup></td><td>Maximum bending rigidity</td><td>—</td></tr><tr><td>Minimum second moment of area</td><td>I<sub>min</sub></td><td>mm<sup>4</sup></td><td>Minimum bending rigidity</td><td>—</td></tr><tr><td>Second moment of area ratio<sup>c</sup></td><td>I<sub>max</sub>/I<sub>min</sub></td><td>—</td><td>Maximum/minimum bending rigidity</td><td>—</td></tr><tr><td>Polar second moment of area</td><td>J</td><td>mm<sup>4</sup></td><td>Torsional and average bending rigidity</td><td>—</td></tr><tr><td>Polar section modulus</td><td>Z<sub>p</sub></td><td>mm<sup>3</sup></td><td>Torsional and average bending strength</td><td>Z<sub>p</sub>-std = (Z<sub>p</sub>/(BM × BL))×1000<sup>b</sup></td></tr></tbody></table>

12 Abbreviations: std = standardized; BM = body mass (in kg); MBL = maximal bone length;

13 BL = bone length (biomechanical or maximal BL, according to the bone studied); ML =

14 mediolateral; AP = anteroposterior.

15 a For the first metatarsal, ‘anteroposterior’ (AP) is dorsoventral.

16 b Robusticity index

17 c Shape index

18

19 Table 3

20 Medullary versus solid cross-sectional properties: linear regression statistics for the fibula and first
21 metatarsal.

<table><thead><tr><th>Bone</th><th>CSG parameters</th><th>n</th><th>Slope</th><th>Intercept</th><th>r</th><th>p</th><th>%PE mean</th><th>%SEE</th><th>Medullary vs. solid<sup>a</sup></th></tr></thead><tbody><tr><td>Fibula</td><td>Z<sub>p</sub> 50%</td><td>34</td><td>0.84586</td><td>12.249</td><td>0.981</td><td>&lt;0.001</td><td>4.8</td><td>5.6</td><td>11.1</td></tr><tr><td>Fibula</td><td>Z<sub>p</sub> distal</td><td>31</td><td>0.85624</td><td>11.904</td><td>0.981</td><td>&lt;0.001</td><td>4.0</td><td>5.7</td><td>8.3</td></tr><tr><td>First metatarsal</td><td>Z<sub>p</sub> 50%</td><td>31</td><td>0.65434</td><td>9.170</td><td>0.945</td><td>&lt;0.001</td><td>7.0</td><td>8.0</td><td>47.6</td></tr><tr><td>Fibula</td><td>I<sub>x</sub>/I<sub>y</sub> 50%</td><td>38</td><td>0.81358</td><td>0.196</td><td>0.938</td><td>&lt;0.001</td><td>8.9</td><td>10.6</td><td>8.1</td></tr><tr><td>Fibula</td><td>I<sub>x</sub>/I<sub>y</sub> distal</td><td>38</td><td>0.97472</td><td>0.007</td><td>0.995</td><td>&lt;0.001</td><td>2.7</td><td>3.5</td><td>2.3</td></tr><tr><td>First metatarsal</td><td>I<sub>x</sub>/I<sub>y</sub> 50%</td><td>31</td><td>0.96696</td><td>-0.019</td><td>0.968</td><td>&lt;0.001</td><td>2.8</td><td>3.4</td><td>6.0</td></tr><tr><td>Fibula</td><td>I<sub>max</sub>/I<sub>min</sub> 50%</td><td>38</td><td>0.92181</td><td>0.099</td><td>0.992</td><td>&lt;0.001</td><td>2.3</td><td>3.7</td><td>2.8</td></tr><tr><td>Fibula</td><td>I<sub>max</sub>/I<sub>min</sub> distal</td><td>38</td><td>0.97202</td><td>0.012</td><td>0.995</td><td>&lt;0.001</td><td>2.6</td><td>3.3</td><td>3.2</td></tr></tbody></table>

22 Abbreviations: CSG = Cross-sectional geometric property; Z<sub>p</sub> = polar section modulus (mm<sup>3</sup>);

23 I<sub>x</sub> = second moment of area about the mediolateral axis (mm<sup>4</sup>); I<sub>y</sub> = second moment of area

24 about the anteroposterior axis (mm<sup>4</sup>); I<sub>max</sub> = maximal second moment of area (mm<sup>4</sup>); I<sub>min</sub> =

25 minimal second moment of area (mm<sup>4</sup>); %PE = prediction error (%); %SEE = standard error

26 of estimate (%).

27 a We calculated the difference between the medullary (or true) and solid cross-sectional
28 geometric as ([solid-medullary]/medullary) × 100.

29
30 Table 4

31 Midshaft femoral and tibial shape and robusticity of Caviglione 1 and comparative samples.<sup>a</sup>

<table><thead><tr><th>CSG parameters</th><th>Caviglione 1</th><th>Upper Paleolithic</th><th>Neolithic/Bronze</th><th>Recent humans</th></tr></thead><tbody><tr><td>Femur shape (I<sub>x</sub>/I<sub>y</sub>)<sup>b</sup></td><td></td><td></td><td></td><td></td></tr><tr><td>n</td><td>2</td><td>50</td><td>95</td><td>61</td></tr><tr><td>Mean</td><td>1.75</td><td>1.41</td><td>1.00<sup>c</sup></td><td>1.05<sup>c</sup></td></tr><tr><td>SD</td><td>0.09</td><td>0.28</td><td>0.21</td><td>0.23</td></tr><tr><td>Femur robusticity (Z<sub>p</sub>-std)</td><td></td><td></td><td></td><td></td></tr><tr><td>n</td><td>2</td><td>41</td><td>89</td><td>61</td></tr><tr><td>Mean</td><td>116.4</td><td>113.1</td><td>104.0<sup>c*</sup></td><td>105.5</td></tr><tr><td>SD</td><td>8.8</td><td>22.3</td><td>23.1</td><td>17.3</td></tr><tr><td>Tibia shape (I<sub>max</sub>/I<sub>min</sub>)<sup>b</sup></td><td></td><td></td><td></td><td></td></tr><tr><td>n</td><td>2</td><td>38</td><td>82</td><td>61</td></tr><tr><td>Mean</td><td>2.58</td><td>2.65</td><td>2.59</td><td>2.28<sup>c,d</sup></td></tr><tr><td>SD</td><td>0.19</td><td>0.58</td><td>0.68</td><td>0.51</td></tr><tr><td>Tibia robusticity (Z<sub>p</sub>-std)<sup>b</sup></td><td></td><td></td><td></td><td></td></tr><tr><td>n</td><td>2</td><td>35</td><td>75</td><td>61</td></tr><tr><td>Mean</td><td>119.2</td><td>107.1</td><td>87.5<sup>c</sup></td><td>84.6<sup>c</sup></td></tr><tr><td>SD</td><td>0.28</td><td>24.5</td><td>22.8</td><td>15.4</td></tr></tbody></table>

Abbreviations: CSG = Cross-sectional geometric property; I<sub>x</sub>/I<sub>y</sub> ratio = shape index, with I<sub>x</sub> (second moment of area about the mediolateral axis, mm<sup>4</sup>) and I<sub>y</sub> (second moment of area about the anteroposterior axis, mm<sup>4</sup>); I<sub>max</sub>/I<sub>min</sub> ratio = shape index, with I<sub>max</sub> (maximal second moment of area, mm<sup>4</sup>) and I<sub>min</sub> (minimal second moment of area, mm<sup>4</sup>); Z<sub>p</sub>-std = robusticity index, which refers to the polar section modulus (Z<sub>p</sub>, mm<sup>3</sup>) standardized for body size (bone length, mm; body mass, kg), i.e., Z<sub>p</sub>-std= Z<sub>p</sub>/(bone length × body mass; mm<sup>2</sup>/kg).

<sup>a</sup> References in SOM Tables S1 and S2.

<sup>b</sup> Difference between groups (without Caviglione 1) with *p*-values<0.05.

<sup>c</sup> Difference from Upper Paleolithic with Bonferroni-corrected *p*-values<0.05. Asterisks indicate *p*-values<0.05 without applied Bonferroni-correction.

<sup>d</sup> Difference from Neolithic/Bronze with Bonferroni-corrected *p*-values<0.05.

43
44 Table 5

45 Midshaft femoral, tibial and fibula shape and robusticity of middle Upper Paleolithic (MUP)
46 and late Upper Paleolithic (LUP) male and female groups.ª

<table><thead><tr><th rowspan="2">Variables</th><th rowspan="2">Caviglione 1</th><th colspan="3">MUP</th><th colspan="3">LUP</th></tr><tr><th>Total</th><th>Male</th><th>Female</th><th>Total</th><th>Male</th><th>Female</th></tr></thead><tbody><tr><td>Femur shape (I<sub>x</sub>/I<sub>y</sub>)</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>n</td><td>2</td><td>26</td><td>16</td><td>5</td><td>24</td><td>16</td><td>8</td></tr><tr><td>Mean</td><td>1.75</td><td>1.54</td><td>1.62</td><td>1.39</td><td>1.28<sup>b</sup></td><td>1.30</td><td>1.24</td></tr><tr><td>SD</td><td>0.09</td><td>0.25</td><td>0.27</td><td>0.14</td><td>0.25</td><td>0.26</td><td>0.25</td></tr><tr><td>Femur robusticity (Z<sub>p</sub>-std)</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>n</td><td>2</td><td>18</td><td>13</td><td>4</td><td>23</td><td>16</td><td>7</td></tr><tr><td>Mean</td><td>116.4</td><td>105.0</td><td>107.4</td><td>91.5</td><td>119.4<sup>b</sup></td><td>121.1</td><td>115.3</td></tr><tr><td>SD</td><td>8.8</td><td>25.3</td><td>26.1</td><td>19.2</td><td>17.7</td><td>15.0</td><td>23.6</td></tr><tr><td>Tibia shape (I<sub>max</sub>/I<sub>min</sub>)</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>n</td><td>2</td><td>19</td><td>16</td><td>2</td><td>19</td><td>13</td><td>6</td></tr><tr><td>Mean</td><td>2.58</td><td>2.67</td><td>2.79</td><td>1.87</td><td>2.62</td><td>2.78</td><td>2.29</td></tr><tr><td>SD</td><td>0.19</td><td>0.61</td><td>0.58</td><td>0.06</td><td>0.56</td><td>0.58</td><td>0.33</td></tr><tr><td>Tibia robusticity (Z<sub>p</sub>-std)</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>n</td><td>2</td><td>17</td><td>14</td><td>2</td><td>18</td><td>13</td><td>5</td></tr><tr><td>Mean</td><td>119.2</td><td>108.5</td><td>116.0</td><td>75.4</td><td>105.8</td><td>106.0</td><td>105.4</td></tr><tr><td>SD</td><td>0.28</td><td>33.3</td><td>30.4</td><td>36.3</td><td>12.3</td><td>10.6</td><td>17.6</td></tr><tr><td>Fibula shape (I<sub>max</sub>/I<sub>min</sub>)</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>n</td><td>2</td><td>8</td><td>7</td><td>-</td><td>13</td><td>11</td><td>2</td></tr><tr><td>Mean</td><td>2.27</td><td>2.49</td><td>2.56</td><td>-</td><td>2.29</td><td>2.24</td><td>2.54</td></tr><tr><td>SD</td><td>0.06</td><td>0.78</td><td>0.82</td><td>-</td><td>-</td><td>0.74</td><td>1.58</td></tr><tr><td>Fibula robusticity (Z<sub>p</sub>-std)</td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>n</td><td>2</td><td>6</td><td>6</td><td>-</td><td>13</td><td>11</td><td>2</td></tr><tr><td>Mean</td><td>20.8</td><td>16.1</td><td>16.1</td><td>-</td><td>17.2</td><td>16.5</td><td>20.7</td></tr><tr><td>SD</td><td>0.85</td><td>5.5</td><td>5.5</td><td>-</td><td>-</td><td>3.6</td><td>1.8</td></tr></tbody></table>

Abbreviations: I<sub>x</sub>/I<sub>y</sub> ratio = shape index, with I<sub>x</sub> (second moment of area about the mediolateral axis, mm<sup>4</sup>) and I<sub>y</sub> (second moment of area about the dorsoplantar axis, mm<sup>4</sup>);
I<sub>max</sub>/I<sub>min</sub> = shape index, with I<sub>max</sub> (maximal second moment of area, mm<sup>4</sup>) and I<sub>min</sub> (minimal second moment of area, mm<sup>4</sup>);
Z<sub>p</sub>-std = robusticity index, it refers to the polar section
modulus (Z<sub>p</sub>, mm<sup>3</sup>) standardized for body size (bone length, mm; body mass, kg), i.e., Z<sub>p</sub>-std= Z<sub>p</sub>/(bone length × body mass) in mm<sup>2</sup>/kg.

ª References in SOM Tables S1 and S2, and Sparacello et al. (2018a) for the fibula mean and standard deviation of LUP male and female; see SOM Table S7 for complementary data for male fibulas.

ᵇ Differences between MUP and LUP (without Caviglione 1) with *p*-values<0.05 (differences between MUP males and females or between LUP males and females always presented *p*-values>0.05).
59 Table 6

60 Midshaft and distal fibular shape and robusticity of Caviglione 1 and comparative samples.ª

<table><thead><tr><th>CSG parameters</th><th>Caviglione 1</th><th>Upper Paleolithic</th><th>Neolithic/Chalcolithic</th><th>Recent humans</th></tr></thead><tbody><tr><td><strong>Midshaft properties</strong></td><td></td><td></td><td></td><td></td></tr><tr><td>Fibula shape (I<sub>x</sub>/I<sub>y</sub>)<sup>b</sup></td><td></td><td></td><td></td><td></td></tr><tr><td>n</td><td>2</td><td>11</td><td>13</td><td>46</td></tr><tr><td>Mean</td><td>0.62</td><td>1.17</td><td>0.95</td><td>1.27<sup>d*</sup></td></tr><tr><td>SD</td><td>0.01</td><td>0.93</td><td>0.44</td><td>0.44</td></tr><tr><td>Fibula shape (I<sub>max</sub>/I<sub>min</sub>)<sup>b</sup></td><td></td><td></td><td></td><td></td></tr><tr><td>n</td><td>2</td><td>12</td><td>13</td><td>46</td></tr><tr><td>Mean</td><td>2.27</td><td>2.52</td><td>2.53</td><td>1.77<sup>c, d</sup></td></tr><tr><td>SD</td><td>0.06</td><td>0.71</td><td>0.86</td><td>0.45</td></tr><tr><td>Fibula robusticity (Z<sub>p</sub>-std)</td><td></td><td></td><td></td><td></td></tr><tr><td>n</td><td>2</td><td>10</td><td>—</td><td>27</td></tr><tr><td>Mean</td><td>20.8</td><td>16.5</td><td>—</td><td>10.1<sup>c</sup></td></tr><tr><td>SD</td><td>0.85</td><td>4.8</td><td>—</td><td>2.8</td></tr><tr><td>Fibula robusticity (TA-std)<sup>b</sup></td><td></td><td></td><td></td><td></td></tr><tr><td>n</td><td>2</td><td>9</td><td>13</td><td>46</td></tr><tr><td>Mean</td><td>45.2</td><td>44.2</td><td>36.8</td><td>30.1<sup>c, d</sup></td></tr><tr><td>SD</td><td>1.98</td><td>11.6</td><td>5.7</td><td>6.4</td></tr><tr><td><strong>Distal properties</strong></td><td></td><td></td><td></td><td></td></tr><tr><td>Fibula shape (I<sub>x</sub>/I<sub>y</sub>)</td><td></td><td></td><td></td><td></td></tr><tr><td>n</td><td>2</td><td>10</td><td>21</td><td>48</td></tr><tr><td>Mean</td><td>1.90</td><td>2.08</td><td>2.15</td><td>2.19</td></tr><tr><td>SD</td><td>0.16</td><td>0.68</td><td>0.77</td><td>0.77</td></tr><tr><td>Fibula shape (I<sub>max</sub>/I<sub>min</sub>)</td><td></td><td></td><td></td><td></td></tr><tr><td>n</td><td>2</td><td>10</td><td>21</td><td>48</td></tr><tr><td>Mean</td><td>2.01</td><td>2.28</td><td>2.27</td><td>2.40</td></tr><tr><td>SD</td><td>0.04</td><td>0.70</td><td>0.77</td><td>0.82</td></tr><tr><td>Fibula robusticity (Z<sub>p</sub>-std)</td><td></td><td></td><td></td><td></td></tr><tr><td>n</td><td>2</td><td>9</td><td>—</td><td>42</td></tr><tr><td>Mean</td><td>14.6</td><td>11.2</td><td>—</td><td>7.4<sup>c</sup></td></tr><tr><td>SD</td><td>0.64</td><td>4.2</td><td>—</td><td>2.1</td></tr><tr><td>Fibula robusticity (TA-std)<sup>b</sup></td><td></td><td></td><td></td><td></td></tr><tr><td>n</td><td>2</td><td>9</td><td>13</td><td>46</td></tr><tr><td>Mean</td><td>40.5</td><td>34.2</td><td>28.6</td><td>25.6<sup>c, d*</sup></td></tr><tr><td>SD</td><td>0.42</td><td>9.9</td><td>4.1</td><td>5.4</td></tr></tbody></table>

Abbreviations: CSG = Cross-sectional geometric property; I<sub>x</sub>/I<sub>y</sub> ratio = shape index, with I<sub>x</sub> (second moment of area about the mediolateral axis, mm<sup>4</sup>) and I<sub>y</sub> (second moment of area about the anteroposterior axis, mm<sup>4</sup>); I<sub>max</sub>/I<sub>min</sub> ratio = shape index, with I<sub>max</sub> (maximal second moment of area, mm<sup>4</sup>) and I<sub>min</sub> (minimal second moment of area, mm<sup>4</sup>); Z<sub>p</sub>-std = robusticity index, which refers to the polar section modulus (Z<sub>p</sub>, mm<sup>3</sup>) standardized for body size (bone length, mm; body mass, kg), i.e., Z<sub>p</sub>-std= Z<sub>p</sub>/(bone length × body mass; mm<sup>2</sup>/kg); TA-std = TA/maximal length (mm) with TA = total area (mm<sup>2</sup>).

68 a References in SOM Tables S3 and S4.

69 b Difference between groups (without Caviglione 1) with *p*-values<0.05.

70 c Difference from Upper Paleolithic with *p*-values<0.05; Bonferroni-correction was used if there were more than two groups.

72 d Difference from Neolithic/Bronze with Bonferroni-corrected *p*-values<0.05. Asterisks indicate *p*-values<0.05 without applied Bonferroni correction.
74 Table 7

75 Relative fibular robusticity of Caviglione 1 and comparative samples.

<table><thead><tr><th>Specimen/sample</th><th>Caviglione 1</th><th>Cro-Magnon<sup>a</sup></th><th>MUP<sup>b</sup></th><th>LUP<sup>b</sup></th><th>LUP<sup>b</sup></th><th>NEO</th><th>Iron Age</th><th>Medieval</th></tr><tr><th>Region</th><th>Liguria</th><th>Dordogne</th><th>Liguria</th><th>Liguria</th><th>European</th><th>Liguria</th><th>Central Italia</th><th>Germany</th></tr><tr><th>Terrain</th><th>Mountainous</th><th>Hilly</th><th>Mountainous</th><th>Mountainous</th><th>Various</th><th>Mountainous</th><th>Mountainous</th><th>Plain</th></tr><tr><th>Sex</th><th>F</th><th>M</th><th>M</th><th>M</th><th>M</th><th>F</th><th>M<sup>c</sup></th><th>F<sup>b</sup></th></tr></thead><tbody><tr><td>J<sub>fibula</sub>/J<sub>tibia</sub></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td><td></td></tr><tr><td>n</td><td>1</td><td>1</td><td>4</td><td>5</td><td>10</td><td>2</td><td>15</td><td>7</td></tr><tr><td>Mean</td><td>8.94</td><td>4.58</td><td>6.11</td><td>8.16</td><td>7.55</td><td>10.32</td><td>7.04</td><td>7.29</td></tr><tr><td>SD</td><td>—</td><td>—</td><td>0.96</td><td>2.87</td><td>2.26</td><td>0.37</td><td>1.77</td><td>1.99</td></tr></tbody></table>

76 Abbreviations: J<sub>fibula</sub>/J<sub>tibia</sub> = Relative polar second moment of area; F = female; M = male;

77 MUP = middle Upper Paleolithic; LUP = late Upper Paleolithic.

78 <sup>a</sup> Data from this study; Cro-Magnon named ‘Gamma’ in Thibeault and Villotte (2018).

79 <sup>b</sup> Data from Sparacello et al. (2018a), which includes the following MUP individuals: Barma Grande 2, 5, and 6 and Baousso da Torre 2 with relative fibular robusticity of 5.45, 7.54, 5.69 and 5.75, respectively.

82 <sup>c</sup> Data from Sparacello et al. (2014).

83

84

85 Table 8

86 Midshaft first metatarsal shape and robusticity of Caviglione 1 and comparative samples.<sup>a</sup>

<table><thead><tr><th>CSG parameters</th><th>Caviglione 1</th><th>Upper Paleolithic</th><th>Neolithic/Chalcolithic</th><th>Recent humans</th></tr></thead><tbody><tr><td>Metatarsal shape (I<sub>x</sub>/I<sub>y</sub>)</td><td></td><td></td><td></td><td></td></tr><tr><td>n</td><td>2</td><td>5</td><td>31</td><td>13</td></tr><tr><td>Mean</td><td>1.05</td><td>0.94</td><td>0.84<sup>b</sup></td><td>0.86</td></tr><tr><td>SD</td><td>0.10</td><td>0.09</td><td>0.11</td><td>0.09</td></tr><tr><td>Metatarsal robusticity (Z<sub>p</sub>-std)</td><td></td><td></td><td></td><td></td></tr><tr><td>n</td><td>2</td><td>5</td><td>30</td><td>13</td></tr><tr><td>Mean</td><td>8.05</td><td>6.76</td><td>7.47</td><td>8.37<sup>b</sup></td></tr><tr><td>SD</td><td>0.50</td><td>0.91</td><td>1.11</td><td>1.29</td></tr></tbody></table>

87 Abbreviations: CSG = cross-sectional geometric property; I<sub>x</sub>/I<sub>y</sub> ratio = shape index, with I<sub>x</sub> (second moment of area about the mediolateral axis, mm<sup>4</sup>) and I<sub>y</sub> (second moment of area about the dorsoplantar axis, mm<sup>4</sup>); Z<sub>p</sub>-std = robusticity index, it refers to the polar section modulus (Z<sub>p</sub>, mm<sup>3</sup>) standardized for body size (bone length, mm; body mass, kg), i.e., Z<sub>p</sub>-std= Z<sub>p</sub>/(bone length × body mass) in mm<sup>2</sup>/kg.

92 <sup>a</sup> References in SOM Table S5.

93 <sup>b</sup> Difference from Upper Paleolithic with *p*-values<0.05 without Bonferroni-correction.

94

95
96 Table 9

97 Cross-sectional geometric property comparisons between Caviglione 1 and recent humans, including
98 athletes and nonathletes.

<table><thead><tr><th rowspan="2">Specimens</th><th rowspan="2">Sex</th><th rowspan="2">n</th><th colspan="2">Femur</th><th colspan="2">Tibia</th><th colspan="2">Fibula</th><th colspan="2">Fibula vs tibia</th><th rowspan="2">Cross-section location for fibula</th></tr><tr><th>I<sub>max</sub>/I<sub>min</sub></th><th>Z<sub>p</sub>-std</th><th>I<sub>max</sub>/I<sub>min</sub></th><th>Z<sub>p</sub>-std</th><th>I<sub>max</sub>/I<sub>min</sub></th><th>I<sub>x</sub>/I<sub>y</sub></th><th>J<sub>fibula</sub>/J<sub>tibia</sub></th></tr></thead><tbody><tr><td>Caviglione 1 R/L</td><td>F</td><td>2</td><td>1.78</td><td>119.2</td><td>2.58</td><td>20.8</td><td>2.27</td><td>0.62</td><td>9.24</td><td>50% fibular length</td></tr><tr><td>Caviglione 1 L</td><td>F</td><td>1</td><td>—</td><td>—</td><td>—</td><td>19.3</td><td>2.37</td><td>0.81</td><td>8.94</td><td>50% tibial length</td></tr><tr><td>Hockey</td><td>M</td><td>17</td><td>—</td><td>92.27<sup>b</sup></td><td>2.22<sup>b</sup></td><td>11.97<sup>c</sup></td><td>2.22<sup>c</sup></td><td>1.87<sup>d</sup></td><td>6.18<sup>d</sup></td><td>50% tibial length</td></tr><tr><td>Runner</td><td>M</td><td>15</td><td>—</td><td>103.40<sup>b</sup></td><td>2.61<sup>b</sup></td><td>11.44<sup>c</sup></td><td>2.39<sup>c</sup></td><td>1.96<sup>d</sup></td><td>4.91<sup>d</sup></td><td>50% tibial length</td></tr><tr><td></td><td>F</td><td>18</td><td>1.50<sup>a</sup></td><td>—</td><td>2.53<sup>e</sup></td><td>—</td><td>—</td><td>—</td><td>—</td><td>—</td></tr><tr><td>Control</td><td>M</td><td>21</td><td>—</td><td>85.28<sup>b</sup></td><td>2.26<sup>b</sup></td><td>10.38<sup>c</sup></td><td>2.21<sup>c</sup></td><td>1.74<sup>d</sup></td><td>5.70<sup>d</sup></td><td>50% tibial length</td></tr><tr><td></td><td>F</td><td>37</td><td>1.36<sup>a</sup></td><td>—</td><td>2.02<sup>e</sup></td><td>—</td><td>—</td><td>—</td><td>—</td><td>—</td></tr><tr><td>Recent humans</td><td>—</td><td>61–27</td><td>—</td><td>84.60<sup>f</sup></td><td>2.28<sup>f</sup></td><td>10.1<sup>g</sup></td><td>1.77<sup>g</sup></td><td>1.27<sup>h</sup></td><td>—</td><td>50% fibular length</td></tr><tr><td>Recent humans</td><td>—</td><td>38–19</td><td>—</td><td>—</td><td>—</td><td>8.78<sup>h</sup></td><td>2.04<sup>h</sup></td><td>1.51<sup>h</sup></td><td>—</td><td>60% fibular length</td></tr></tbody></table>

99 Abbreviations: I<sub>x</sub>/I<sub>y</sub> ratio = shape index, with I<sub>x</sub> (second moment of area about the mediolateral axis, mm<sup>4</sup>) and I<sub>y</sub> (second moment of area about the anteroposterior axis, mm<sup>4</sup>);
100 I<sub>max</sub>/I<sub>min</sub> ratio = shape index, with I<sub>max</sub> (maximal second moment of area, mm<sup>4</sup>) and I<sub>min</sub> (minimal second moment of area, mm<sup>4</sup>);
101 Z<sub>p</sub>-std = robusticity index, it refers to the polar
102 section modulus (Z<sub>p</sub>, mm<sup>3</sup>) standardized for body size (bone length, mm; body mass, kg), i.e.,
103 Z<sub>p</sub>-std= Z<sub>p</sub>/(bone length × body mass) in mm<sup>2</sup>/kg; J<sub>fibula</sub>/J<sub>tibia</sub> = Relative polar second moment
104 of area; R = right; L = left; F = female; M = male.
105

106 <sup>a</sup> Data from Macintosh and Stock (2019).

107 <sup>b</sup> Data from Sparacello et al. (2014).

108 <sup>c</sup> Data from Sparacello et al. (2018a).

109 <sup>d</sup> Data from Marchi and Shaw (2011); I<sub>x</sub>/I<sub>y</sub> from athletes and control groups are only relevant
110 for comparison between these groups given that the scanning orientation is distinct from other
111 groups.

112 <sup>e</sup> Data from Macintosh et al. (2017).

113 <sup>f</sup> Data from Ruff et al. (2018); see details for the 61 individuals in SOM Table S2.

114 <sup>g</sup> Data from this study, see details in SOM Table S3.

115 <sup>h</sup> Data from Chevalier and Tignères (2020); see details in SOM Table S3.