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Zorrilla-Revilla G, Volpe SL, Prado-Nóvoa O, Howard KR, Laskaridou E, Marinik EL, Ramadoss R, Davy KP, García-González R. Far from the walking pace. Ecological and evolutionary consequences of the suboptimal locomotion speeds in non-adult humans. Am J Hum Biol 2024:e24138. [PMID: 39016420 DOI: 10.1002/ajhb.24138] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2024] [Revised: 07/05/2024] [Accepted: 07/10/2024] [Indexed: 07/18/2024] Open
Abstract
INTRODUCTION Locomotion activities are part of most human daily tasks and are the basis for subsistence activities, particularly for hunter-gatherers. Therefore, differences in speed walking-related variables may have an effect, not only on the mobility of the group, but also on its composition. Some anthropometric parameters related to body length could affect walking speed-related variables and contribute to different human behaviors. However, there is currently little information on the influence of these parameters in nonadult individuals. METHODS Overall, 11 females and 17 male child/adolescents, 8-17 years of age, volunteered to participate in this cross-sectional study. Five different pace walking tests were performed on a treadmill to calculate the optimal locomotion speed (OLS) and U-shaped relationship between the walking energy expenditure and speed (χ2 cost of transport [CoT]) (i.e., energetic walking flexibility). RESULTS The mean OLS was 3.05 ± 0.13 miles per hour (mph), with no differences between sexes. Similarly, there were no sex differences in walking flexibility according to the χ2 CoT. Body height (p < .0001) and femur length (p < .001) were positively correlated with χ2 CoT; however, female child/adolescents mitigated the effect of height and femur length when walking at suboptimal speeds. CONCLUSION Consistent with prior observations in adults, our findings suggest that anthropometric parameters related to body stature are associated with reduced suboptimal walking flexibility in children and adolescents. Taken together, these results suggest that children and adolescents can adapt their pace to the one of taller individuals without a highly energetic penalty, but this flexibility decreases with increasing body size.
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Affiliation(s)
- Guillermo Zorrilla-Revilla
- Laboratorio de Evolución Humana, Universidad de Burgos, Burgos, Spain
- Department of Human Nutrition, Foods, and Exercise, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, Virginia, USA
- CIAS-Research Centre for Anthropology and Health, University of Coimbra, Coimbra, Portugal
| | - Stella L Volpe
- Department of Human Nutrition, Foods, and Exercise, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, Virginia, USA
| | - Olalla Prado-Nóvoa
- Department of Human Nutrition, Foods, and Exercise, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, Virginia, USA
| | - Kristen R Howard
- Department of Human Nutrition, Foods, and Exercise, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, Virginia, USA
- Graduate Program in Translational Biology, Medicine, and Health, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, Virginia, USA
| | - Eleni Laskaridou
- Department of Human Nutrition, Foods, and Exercise, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, Virginia, USA
| | - Elaina L Marinik
- Department of Human Nutrition, Foods, and Exercise, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, Virginia, USA
| | - Rohit Ramadoss
- Department of Human Nutrition, Foods, and Exercise, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, Virginia, USA
| | - Kevin P Davy
- Department of Human Nutrition, Foods, and Exercise, Virginia Polytechnic Institute and State University (Virginia Tech), Blacksburg, Virginia, USA
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Mitteroecker P, Fischer B. Evolution of the human birth canal. Am J Obstet Gynecol 2024; 230:S841-S855. [PMID: 38462258 DOI: 10.1016/j.ajog.2022.09.010] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/02/2022] [Revised: 09/07/2022] [Accepted: 09/07/2022] [Indexed: 03/12/2024]
Abstract
It seems puzzling why humans have evolved such a small and rigid birth canal that entails a relatively complex process of labor compared with the birth canal of our closest relatives, the great apes. This study reviewed insights into the evolution of the human birth canal from recent theoretical and empirical studies and discussed connections to obstetrics, gynecology, and orthopedics. Originating from the evolution of bipedality and the large human brain million years ago, the evolution of the human birth canal has been characterized by complex trade-off dynamics among multiple biological, environmental, and sociocultural factors. The long-held notion that a wider pelvis has not evolved because it would be disadvantageous for bipedal locomotion has not yet been empirically verified. However, recent clinical and biomechanical studies suggest that a larger birth canal would compromise pelvic floor stability and increase the risk of incontinence and pelvic organ prolapse. Several mammals have neonates that are equally large or even larger than human neonates compared to the size of the maternal birth canal. In these species, the pubic symphysis opens widely to allow successful delivery. Biomechanical and developmental constraints imposed by bipedality have hindered this evolutionary solution in humans and led to the comparatively rigid pelvic girdle in pregnant women. Mathematical models have shown why the evolutionary compromise to these antagonistic selective factors inevitably involves a certain rate of fetopelvic disproportion. In addition, these models predict that cesarean deliveries have disrupted the evolutionary equilibrium and led to new and ongoing evolutionary changes. Different forms of assisted birth have existed since the stone age and have become an integral part of human reproduction. Paradoxically, by buffering selection, they may also have hindered the evolution of a larger birth canal. Many of the biological, environmental, and sociocultural factors that have influenced the evolution of the human birth canal vary globally and are subject to ongoing transitions. These differences may have contributed to the global variation in the form of the birth canal and the difficulty of labor, and they likely continue to change human reproductive anatomy.
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Affiliation(s)
- Philipp Mitteroecker
- Unit for Theoretical Biology, Department of Evolutionary Biology, University of Vienna, Vienna, Austria.
| | - Barbara Fischer
- Unit for Theoretical Biology, Department of Evolutionary Biology, University of Vienna, Vienna, Austria
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3
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Rodríguez J, Hölzchen E, Caso-Alonso AI, Berndt JO, Hertler C, Timm IJ, Mateos A. Computer simulation of scavenging by hominins and giant hyenas in the late Early Pleistocene. Sci Rep 2023; 13:14283. [PMID: 37770511 PMCID: PMC10539305 DOI: 10.1038/s41598-023-39776-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/08/2023] [Accepted: 07/31/2023] [Indexed: 09/30/2023] Open
Abstract
Consumption of animal-sourced food is an important factor in broadening the diet of early hominins, promoting brain and body growth, and increasing behavioural complexity. However, whether early hominins obtained animal food by scavenging or hunting large mammals remains debated. Sabre-toothed felids have been proposed to facilitate the expansion of early Homo out of Africa into Europe 1.4-0.8 Ma by creating a niche for scavengers in Eurasia as the carcasses abandoned by these felids still contained abundant edible resources. In contrast, it has been argued that the niche for a large scavenger was already occupied in Eurasia by the giant hyena, preventing hominins from utilising this resource. This study shows that sabre-toothed felids generated carcasses rich in edible resources and that hominins were capable of competing with giant hyenas for this resource. The simulation experiments showed that maintaining an optimum group size is essential for the success of the hominin scavenging strategy. Early hominins could outcompete giant hyenas only if they could successfully dispute carcasses with them. Thus, in the presence of a strong competitor, passive scavenging is essentially the same as confrontational scavenging.
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Affiliation(s)
- Jesús Rodríguez
- National Research Center On Human Evolution (CENIEH), Paseo Sierra de Atapuerca 3, 09002, Burgos, Spain
| | - Ericson Hölzchen
- Chair for Business Informatics 1, Trier University, Behringstraße 21, 54296, Trier, Germany
- German Research Center for Artificial Intelligence (DFKI). Smart Data and Knowledge Services - Cognitive Social Simulation, Trier University, Behringstraße 21, 54296, Trier, Germany
| | - Ana Isabel Caso-Alonso
- Facultad de Ciencias. Edificio de Biología, Universidad Autónoma de Madrid. C/ Darwin, 2. Campus de Cantoblanco, 28049, Madrid, Spain
| | - Jan Ole Berndt
- German Research Center for Artificial Intelligence (DFKI). Smart Data and Knowledge Services - Cognitive Social Simulation, Trier University, Behringstraße 21, 54296, Trier, Germany
| | - Christine Hertler
- The Role of Culture in Early Expansion of Humans (ROCEEH), Senckenberg Research Institute, Senckenberganlage 25, 60325, Frankfurt Am Main, Germany
- The Role of Culture in Early Expansion of Humans (ROCEEH), Heidelberg Academy of Sciences, Karlstraße 4, 69117, Heidelberg, Germany
| | - Ingo J Timm
- Chair for Business Informatics 1, Trier University, Behringstraße 21, 54296, Trier, Germany
- German Research Center for Artificial Intelligence (DFKI). Smart Data and Knowledge Services - Cognitive Social Simulation, Trier University, Behringstraße 21, 54296, Trier, Germany
| | - Ana Mateos
- National Research Center On Human Evolution (CENIEH), Paseo Sierra de Atapuerca 3, 09002, Burgos, Spain.
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Grunstra NDS, Betti L, Fischer B, Haeusler M, Pavlicev M, Stansfield E, Trevathan W, Webb NM, Wells JCK, Rosenberg KR, Mitteroecker P. There is an obstetrical dilemma: Misconceptions about the evolution of human childbirth and pelvic form. AMERICAN JOURNAL OF BIOLOGICAL ANTHROPOLOGY 2023; 181:535-544. [PMID: 37353889 PMCID: PMC10952510 DOI: 10.1002/ajpa.24802] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 05/27/2023] [Accepted: 06/11/2023] [Indexed: 06/25/2023]
Abstract
Compared to other primates, modern humans face high rates of maternal and neonatal morbidity and mortality during childbirth. Since the early 20th century, this "difficulty" of human parturition has prompted numerous evolutionary explanations, typically assuming antagonistic selective forces acting on maternal and fetal traits, which has been termed the "obstetrical dilemma." Recently, there has been a growing tendency among some anthropologists to question the difficulty of human childbirth and its evolutionary origin in an antagonistic selective regime. Partly, this stems from the motivation to combat increasing pathologization and overmedicalization of childbirth in industrialized countries. Some authors have argued that there is no obstetrical dilemma at all, and that the difficulty of childbirth mainly results from modern lifestyles and inappropriate and patriarchal obstetric practices. The failure of some studies to identify biomechanical and metabolic constraints on pelvic dimensions is sometimes interpreted as empirical support for discarding an obstetrical dilemma. Here we explain why these points are important but do not invalidate evolutionary explanations of human childbirth. We present robust empirical evidence and solid evolutionary theory supporting an obstetrical dilemma, yet one that is much more complex than originally conceived in the 20th century. We argue that evolutionary research does not hinder appropriate midwifery and obstetric care, nor does it promote negative views of female bodies. Understanding the evolutionary entanglement of biological and sociocultural factors underlying human childbirth can help us to understand individual variation in the risk factors of obstructed labor, and thus can contribute to more individualized maternal care.
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Affiliation(s)
- N. D. S. Grunstra
- Department of Evolutionary Biology, Unit for Theoretical BiologyUniversity of ViennaViennaAustria
- Mammal CollectionNatural History Museum ViennaViennaAustria
| | - L. Betti
- School of Life and Health SciencesUniversity of RoehamptonLondonUK
| | - B. Fischer
- Department of Evolutionary Biology, Unit for Theoretical BiologyUniversity of ViennaViennaAustria
| | - M. Haeusler
- Institute of Evolutionary MedicineUniversity of ZurichZurichSwitzerland
| | - M. Pavlicev
- Department of Evolutionary Biology, Unit for Theoretical BiologyUniversity of ViennaViennaAustria
| | - E. Stansfield
- Department of Evolutionary Biology, Unit for Theoretical BiologyUniversity of ViennaViennaAustria
| | - W. Trevathan
- School for Advanced ResearchSanta FeNew MexicoUSA
| | - N. M. Webb
- Institute of Evolutionary MedicineUniversity of ZurichZurichSwitzerland
- Institute of Archaeological Sciences, Senckenberg Centre for Human Evolution and PalaeoenvironmentEberhard‐Karls University of TübingenTübingenGermany
| | - J. C. K. Wells
- UCL Great Ormond Street Institute of Child Health, Population, Policy and Practice Research and Teaching ProgrammeChildhood Nutrition Research CentreLondonUK
| | - K. R. Rosenberg
- Department of AnthropologyUniversity of DelawareNewarkDelawareUSA
| | - P. Mitteroecker
- Department of Evolutionary Biology, Unit for Theoretical BiologyUniversity of ViennaViennaAustria
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5
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Wiseman ALA. Three-dimensional volumetric muscle reconstruction of the Australopithecus afarensis pelvis and limb, with estimations of limb leverage. ROYAL SOCIETY OPEN SCIENCE 2023; 10:230356. [PMID: 37325588 PMCID: PMC10265029 DOI: 10.1098/rsos.230356] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 08/30/2022] [Accepted: 05/24/2023] [Indexed: 06/17/2023]
Abstract
To understand how an extinct species may have moved, we first need to reconstruct the missing soft tissues of the skeleton, which rarely preserve, with an understanding of segmental volume and muscular composition within the body. The Australopithecus afarensis specimen AL 288-1 is one of the most complete hominin skeletons. Despite 40+ years of research, the frequency and efficiency of bipedal movement in this specimen is still debated. Here, 36 muscles of the pelvis and lower limb were reconstructed using three-dimensional polygonal modelling, guided by imaging scan data and muscle scarring. Reconstructed muscle masses and configurations guided musculoskeletal modelling of the lower limb in comparison with a modern human. Results show that the moment arms of both species were comparable, hinting towards similar limb functionality. Moving forward, the polygonal muscle modelling approach has demonstrated promise for reconstructing the soft tissues of hominins and providing information on muscle configuration and space filling. This method demonstrates that volumetric reconstructions are required to know where space must be occupied by muscles and thus where lines of action might not be feasible due to interference with another muscle. This approach is effective for reconstructing muscle volumes in extinct hominins for which musculature is unknown.
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Mateos A, Rodríguez J. EVOBREATH. Datasets for evolutionary bioenergetics research on anthropology. Data Brief 2023; 47:108955. [PMID: 36879607 PMCID: PMC9984409 DOI: 10.1016/j.dib.2023.108955] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2022] [Revised: 01/25/2023] [Accepted: 02/01/2023] [Indexed: 02/08/2023] Open
Abstract
Human bioenergetics has been incorporated into the palaeobiology of human ancestors during the last years to broaden our understanding of Human Evolution. The hypotheses based solely on the taxonomy and phylogenetic relationships of the fossil record, cannot easily explain many of the questions about the physiology of past humans. Data on the energetics and physiology of recent humans, together with comprehensive analyses of body proportions and body composition in relation to human metabolism, are needed to understand the evolutionary constraints of hominin ecophysiology. Furthermore, specific datasets including energetic data from modern humans are required to model hominin palaeophysiology. EVOBREATH Datasets were gradually developed since 2013 to store and manage all the data obtained in the Research Programs on Experimental Energetics developed by the Palaeophisiology and Human Ecology Group and the Palaeoecology of Mammals Group of the National Research centre on Human Evolution (CENIEH, Burgos, Spain). All experimental tests were developed either in the CENIEH BioEnergy and Motion Lab (LabBioEM) or in the field, using mobile devices. Datasets include quantitative experimental data related to human anthropometry (Height, Weight, all postcranial dimensions and segments, including hands and feet, and computation of anatomical indices), body composition (fat mass, fat-free mass, muscular mass, body water), and energetics (resting metabolic rate and energetic expenditure in different physical activities, oxygen consumption (O2) and carbon dioxide (CO2) production measured breath-by-breath) obtained in multiple studies with in vivo subjects of different ages (adults, adolescents and children) and both sexes (n = 501). These datasets are useful to optimize the time-consuming process of generating experimental data and to facilitate their reuse by the scientific community. Researchers can readily employ the datasets in their own research endeavours.
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Affiliation(s)
- Ana Mateos
- National Research Center on Human Evolution (CENIEH). Paseo Sierra de Atapuerca 3, 09002 Burgos, Spain
| | - Jesús Rodríguez
- National Research Center on Human Evolution (CENIEH). Paseo Sierra de Atapuerca 3, 09002 Burgos, Spain
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7
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Avni HL, Shvalb N, Pokhojaev A, Francis S, Pelleg-Kallevag R, Roul V, Hublin JJ, Rühli F, May H. Evolutionary roots of the risk of hip fracture in humans. Commun Biol 2023; 6:283. [PMID: 36932194 PMCID: PMC10023703 DOI: 10.1038/s42003-023-04633-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2022] [Accepted: 02/27/2023] [Indexed: 03/19/2023] Open
Abstract
The transition to bipedal locomotion was a fundamental milestone in human evolution. Consequently, the human skeleton underwent substantial morphological adaptations. These adaptations are responsible for many of today's common physical impairments, including hip fractures. This study aims to reveal the morphological changes in the proximal femur, which increase the risk of intracapsular hip fractures in present-day populations. Our sample includes chimpanzees, early hominins, early Homo Neanderthals, as well as prehistoric and recent humans. Using Geometric Morphometric methods, we demonstrate differences in the proximal femur shape between hominids and populations that practiced different lifestyles. We show that the proximal femur morphology is a risk factor for intracapsular hip fracture independent of osteoporosis. Changes in the proximal femur, such as the shortening of the femoral neck and an increased anterolateral expansion of the greater trochanter, are associated with an increased risk for intracapsular hip fractures. We conclude that intracapsular hip fractures are a trade-off for efficient bipedal walking in humans, and their risk is exacerbated by reduced physical activity.
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Affiliation(s)
- Hadas Leah Avni
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, 6997801, Israel
- The Shmunis Family Anthropology Institute, the Dan David Center for Human Evolution and Biohistory Research, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Nir Shvalb
- Mechanical Engineering Department, Ariel University, Ariel, 40700, Israel
| | - Ariel Pokhojaev
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, 6997801, Israel
- The Shmunis Family Anthropology Institute, the Dan David Center for Human Evolution and Biohistory Research, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, 6997801, Israel
- Department of Oral Biology, The Maurice and Gabriela Goldschleger School of Dental Medicine, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Samuel Francis
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, 6997801, Israel
- The Shmunis Family Anthropology Institute, the Dan David Center for Human Evolution and Biohistory Research, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Ruth Pelleg-Kallevag
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, 6997801, Israel
- The Shmunis Family Anthropology Institute, the Dan David Center for Human Evolution and Biohistory Research, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, 6997801, Israel
- Zefat Academic College, Zefat, Israel
| | - Victoria Roul
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, 6997801, Israel
- The Shmunis Family Anthropology Institute, the Dan David Center for Human Evolution and Biohistory Research, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, 6997801, Israel
| | - Jean-Jacques Hublin
- Chaire de Paléoanthropologie, CIRB (UMR 7241 - U1050), Collège de France, Paris, 75231, France
- Max-Planck Institute for Evolutionary Anthropology, Leipzig, 04103, Germany
| | - Frank Rühli
- Institute of Evolutionary Medicine, University of Zurich, Zurich, CH-8057, Switzerland
| | - Hila May
- Department of Anatomy and Anthropology, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, 6997801, Israel.
- The Shmunis Family Anthropology Institute, the Dan David Center for Human Evolution and Biohistory Research, Sackler Faculty of Medicine, Tel Aviv University, Tel Aviv, 6997801, Israel.
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Sylvester AD, Lautzenheiser SG, Kramer PA. A review of musculoskeletal modelling of human locomotion. Interface Focus 2021; 11:20200060. [PMID: 34938430 DOI: 10.1098/rsfs.2020.0060] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 06/15/2021] [Indexed: 01/07/2023] Open
Abstract
Locomotion through the environment is important because movement provides access to key resources, including food, shelter and mates. Central to many locomotion-focused questions is the need to understand internal forces, particularly muscle forces and joint reactions. Musculoskeletal modelling, which typically harnesses the power of inverse dynamics, unites experimental data that are collected on living subjects with virtual models of their morphology. The inputs required for producing good musculoskeletal models include body geometry, muscle parameters, motion variables and ground reaction forces. This methodological approach is critically informed by both biological anthropology, with its focus on variation in human form and function, and mechanical engineering, with a focus on the application of Newtonian mechanics to current problems. Here, we demonstrate the application of a musculoskeletal modelling approach to human walking using the data of a single male subject. Furthermore, we discuss the decisions required to build the model, including how to customize the musculoskeletal model, and suggest cautions that both biological anthropologists and engineers who are interested in this topic should consider.
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Affiliation(s)
- Adam D Sylvester
- Center for Functional Anatomy and Evolution, The Johns Hopkins University School of Medicine, 1830 E. Monument Street, Baltimore, MD 21205, USA
| | - Steven G Lautzenheiser
- Department of Anthropology, University of Washington, Denny Hall, Seattle, WA 98195, USA.,Department of Anthropology, The University of Tennessee, Strong Hall, Knoxville, TN 37996, USA
| | - Patricia Ann Kramer
- Department of Anthropology, University of Washington, Denny Hall, Seattle, WA 98195, USA
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9
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Zorrilla-Revilla G, Rodríguez J, Mateos A. Gathering Is Not Only for Girls : No Influence of Energy Expenditure on the Onset of Sexual Division of Labor. HUMAN NATURE-AN INTERDISCIPLINARY BIOSOCIAL PERSPECTIVE 2021; 32:582-602. [PMID: 34570339 DOI: 10.1007/s12110-021-09411-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Accepted: 07/23/2021] [Indexed: 11/24/2022]
Abstract
In some small-scale societies, a sexual division of labor is common. For subadult hunter-gatherers, the onset of this division dates to middle childhood and the start of puberty; however, there is apparently no physiological explanation for this timing. The present study uses an experimental approach to evaluate possible energetic differences by sex in gathering-related activities. The energetic cost of gathering-related activities was measured in a sample of 42 subjects of both sexes aged between 8 and 14 years. Body mass and other anthropometric variables were also recorded. Our results show that the energetic differences in the simulated gathering activities depend only on body mass. Both sexes expend a similar amount of energy during locomotion activities related to gathering. Discarding the energetic factor, the sexual division of tasks may be explained as an adaptation to acquire the skills needed to undertake the complex activities required during adulthood as early as possible. Carrying out gathering activities during childhood and adolescence could be favored by the growth and development cycles of Homo sapiens. Moreover, if most of the energetic costs of gathering activities depend on body mass, the delayed growth in humans relative to other primates allows subadults to practice these tasks for longer periods, and to become better at performing them. In fact, this strategy could enable them to acquire adults' complex skills at a low energetic cost that can be easily subsidized by other members of the group.
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Affiliation(s)
| | - Jesús Rodríguez
- National Research Center On Human Evolution (CENIEH), 09002, Burgos, Spain
| | - Ana Mateos
- National Research Center On Human Evolution (CENIEH), 09002, Burgos, Spain.
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Vidal-Cordasco M, Rodríguez J, Prado-Nóvoa O, Zorrilla-Revilla G, Mateos A. Locomotor Economy and Foraging Ecology in Hominins. JOURNAL OF ANTHROPOLOGICAL RESEARCH 2021. [DOI: 10.1086/715402] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/03/2022]
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Sylvester AD, Lautzenheiser SG, Kramer PA. Muscle forces and the demands of human walking. Biol Open 2021; 10:bio058595. [PMID: 34279576 PMCID: PMC8325943 DOI: 10.1242/bio.058595] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2021] [Accepted: 05/20/2021] [Indexed: 12/22/2022] Open
Abstract
Reconstructing the locomotor behavior of extinct animals depends on elucidating the principles that link behavior, function, and morphology, which can only be done using extant animals. Within the human lineage, the evolution of bipedalism represents a critical transition, and evaluating fossil hominins depends on understanding the relationship between lower limb forces and skeletal morphology in living humans. As a step toward that goal, here we use a musculoskeletal model to estimate forces in the lower limb muscles of ten individuals during walking. The purpose is to quantify the consistency, timing, and magnitude of these muscle forces during the stance phase of walking. We find that muscles which act to support or propel the body during walking demonstrate the greatest force magnitudes as well as the highest consistency in the shape of force curves among individuals. Muscles that generate moments in the same direction as, or orthogonal to, the ground reaction force show lower forces of greater variability. These data can be used to define the envelope of load cases that need to be examined in order to understand human lower limb skeletal load bearing.
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Affiliation(s)
- Adam D. Sylvester
- Center for Functional Anatomy and Evolution, The Johns Hopkins University School of Medicine, 1830 E. Monument Street, Baltimore, MD 21205, USA
| | - Steven G. Lautzenheiser
- Department of Anthropology, University of Washington, Denny Hall, Seattle, WA 98195, USA
- Department of Anthropology, The University of Tennessee, Knoxville, Strong Hall, Knoxville, TN 37996, USA
| | - Patricia Ann Kramer
- Department of Anthropology, University of Washington, Denny Hall, Seattle, WA 98195, USA
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12
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Grunstra NDS, Zachos FE, Herdina AN, Fischer B, Pavličev M, Mitteroecker P. Humans as inverted bats: A comparative approach to the obstetric conundrum. Am J Hum Biol 2019; 31:e23227. [PMID: 30810261 PMCID: PMC6492174 DOI: 10.1002/ajhb.23227] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/19/2018] [Revised: 02/03/2019] [Accepted: 02/06/2019] [Indexed: 01/19/2023] Open
Abstract
OBJECTIVES The narrow human birth canal evolved in response to multiple opposing selective forces on the pelvis. These factors cannot be sufficiently disentangled in humans because of the limited range of relevant variation. Here, we outline a comparative strategy to study the evolution of human childbirth and to test existing hypotheses in primates and other mammals. METHODS We combined a literature review with comparative analyses of neonatal and female body and brain mass, using three existing datasets. We also present images of bony pelves of a diverse sample of taxa. RESULTS Bats, certain non-human primates, seals, and most ungulates, including whales, have much larger relative neonatal masses than humans, and they all differ in their anatomical adaptations for childbirth. Bats, as a group, are particularly interesting in this context as they give birth to the relatively largest neonates, and their pelvis is highly dimorphic: Whereas males have a fused symphysis, a ligament bridges a large pubic gap in females. The resulting strong demands on the widened and vulnerable pelvic floor likely are relaxed by roosting head-down. CONCLUSIONS Parturition has constituted a strong selective force in many non-human placentals. We illustrated how the demands on pelvic morphology resulting from locomotion, pelvic floor stability, childbirth, and perhaps also erectile function in males have been traded off differently in mammals, depending on their locomotion and environment. Exploiting the power of a comparative approach, we present new hypotheses and research directions for resolving the obstetric conundrum in humans.
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Affiliation(s)
- Nicole D. S. Grunstra
- Department of Theoretical BiologyUniversity of ViennaViennaAustria
- Mammal CollectionNatural History Museum ViennaViennaAustria
| | - Frank E. Zachos
- Mammal CollectionNatural History Museum ViennaViennaAustria
- Department of Integrative ZoologyUniversity of ViennaViennaAustria
| | | | - Barbara Fischer
- Konrad Lorenz Institute for Evolution and Cognition ResearchKlosterneuburgAustria
| | - Mihaela Pavličev
- Cincinnati Children's Hospital Medical CenterCincinnatiOhio
- Department of PediatricsUniversity of Cincinnati College of MedicineCincinnatiOhio
- Department of PhilosophyUniversity of CincinnatiCincinnatiOhio
| | - Philipp Mitteroecker
- Department of Theoretical BiologyUniversity of ViennaViennaAustria
- Konrad Lorenz Institute for Evolution and Cognition ResearchKlosterneuburgAustria
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