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Sample records for tardigrada biomechanics morphogeometry

  1. Inorganic ion composition in Tardigrada

    DEFF Research Database (Denmark)

    Halberg, Kenneth Agerlin; Larsen, Kristine Wulff; Jørgensen, Aslak

    2013-01-01

    composition and total osmotic concentration of five different species of tardigrades (Echiniscus testudo, Milnesium tardigradum, Richtersius coronifer, Macrobiotus cf. hufelandi and Halobiotus crispae) using high-performance liquid chromatography and nanoliter osmometry. Quantification of the ionic content....... Concentrations of most inorganic ions are largely identical between active and dehydrated groups of R. coronifer, suggesting that this tardigrade does not lose large quantities of inorganic ions during dehydration. The large osmotic and ionic gradients maintained by both limno-terrestrial and marine species...... are indicative of a powerful ion-retentive mechanism in Tardigrada. Moreover, our data indicate that cryptobiotic tardigrades contain a large fraction of unidentified organic osmolytes, the identification of which is expected to provide increased insight into the phenomenon of cryptobiosis....

  2. Diversity and distribution of Tardigrada in Arctic cryoconite holes

    Czech Academy of Sciences Publication Activity Database

    Zawierucha, K.; Ostrowska, M.; Vonnahme, T.R.; Devetter, Miloslav; Nawrot, A.P.; Lehmann, S.; Kolicka, M.

    2016-01-01

    Roč. 75, č. 3 (2016), s. 545-559 ISSN 1129-5767 Institutional support: RVO:60077344 Keywords : Buchanbreen * Hansbreen * glacial biome * Svalbard * Tardigrada * unique species Subject RIV: EH - Ecology, Behaviour Impact factor: 1.451, year: 2016

  3. Area, depth and elevation of cryoconite holes in the Arctic do not influence Tardigrada densities

    Czech Academy of Sciences Publication Activity Database

    Zawierucha, K.; Vonnahme, T.R.; Devetter, Miloslav; Kolicka, M.; Ostrowska, M.; Chmielewski, S.; Kosicki, J.Z.

    2016-01-01

    Roč. 37, č. 2 (2016), s. 325-334 ISSN 0138-0338 Institutional support: RVO:60077344 Keywords : Arctic * cryoconite holes * ecology * glaciers * Svalbard * Tardigrada Subject RIV: EH - Ecology, Behaviour Impact factor: 0.636, year: 2016

  4. Tardigrada of the Caribbean island of Dominica (West Indies

    Directory of Open Access Journals (Sweden)

    Juliana G. Hinton

    2013-05-01

    Full Text Available In June 2009 we surveyed the terrestrial Tardigrada of Dominica, the most northerly of the Windward islands of the Lesser Antilles in the Caribbean sea. Out of 112 moss, lichen, liverwort and leaf litter samples, 35 had tardigrades, representing 10 genera and 25 species or species groups. This survey increases the number of species reported from Dominica from 3 to 25, more than the total recorded from any other West Indian island. Twelve species found in Dominica are cosmopolitan or belong to cosmopolitan species groups. Eight species are new to the fauna of the West Indies, one is new to the fauna of the Americas, and at least one is endemic to Dominica.

  5. Diversity and distribution of Tardigrada in Arctic cryoconite holes

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    Krzysztof Zawierucha

    2016-06-01

    Full Text Available Despite the fact that glaciers and ice sheets have been monitored for more than a century, knowledge on the glacial biota remains poor. Cryoconite holes are water-filled reservoirs on a glacier’s surface and one of the most extreme ecosystems for micro-invertebrates. Tardigrada, also known as water bears, are a common inhabitant of cryoconite holes. In this paper we present novel data on the morphology, diversity, distribution and role in food web of tardigrades on Arctic glaciers. From 33 sampled cryoconite holes of 6 glaciers on Spitsbergen, in 25 tardigrades were found and identified. Five taxa of Tardigrada (Eutardigrada were found in the samples, they are: Hypsibius dujardini, Hypsibius sp. A, Isohypsibius sp. A., Pilatobius recamieri, and one species of Ramazzottiidae. H. dujardini and P. recamieri were previously known from tundra in the Svalbard archipelago. Despite the number of studies on Arctic tundra ecosystems, Hypsibius sp. A, one species of Ramazzottiidae and Isohypsibius sp. A are known only from cryoconite holes. Tardigrade found in this study do not falsify the hypothesis that glaciers and ice sheets are a viable biome (characteristic for biome organisms assemblages - tardigrades. Diagnosis of Hypsibius sp. A, Isohypsibius sp. A, and species of Ramazzottiidae with discussion on the status of taxa, is provided. To check what analytes are associated with the presence of tardigrades in High Arctic glacier chemical analyses were carried out on samples taken from the Buchan Glacier. pH values and the chemical composition of anions and cations from cryoconite hole water from the Buchan Glacier are also presented. The current study on the Spitsbergen glaciers clearly indicates that tardigrade species richness in cryoconite holes is lower than tardigrade species richness in Arctic tundra ecosystems, but consists of unique cryoconite hole species. As cryoconite tardigrades may feed on bacteria as well as algae, they are primary

  6. The Tardigrada Register: a comprehensive online data repository for tardigrade taxonomy

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    Łukasz Michalczyk

    2013-05-01

    Full Text Available In this paper we present the Tardigrada Register (www.tardigrada.net/register: a free, comprehensive, and standardised online data repository for tardigrade taxonomy. We outline key problems of the modern tardigrade systematics and we propose the Register as a potential solution to some of them. We then describe the idea, structure and works of the service and discuss challenges it may face. However, most importantly, we hope to convince fellow Tardigradologists that sharing their data via the Register will benefit the entire community of the contemporary and future tardigrade researchers.

  7. MicroRNAs and phylogenomics resolve the relationships of Tardigrada and suggest that velvet worms are the sister group of Arthropoda.

    Science.gov (United States)

    Campbell, Lahcen I; Rota-Stabelli, Omar; Edgecombe, Gregory D; Marchioro, Trevor; Longhorn, Stuart J; Telford, Maximilian J; Philippe, Hervé; Rebecchi, Lorena; Peterson, Kevin J; Pisani, Davide

    2011-09-20

    Morphological data traditionally group Tardigrada (water bears), Onychophora (velvet worms), and Arthropoda (e.g., spiders, insects, and their allies) into a monophyletic group of invertebrates with walking appendages known as the Panarthropoda. However, molecular data generally do not support the inclusion of tardigrades within the Panarthropoda, but instead place them closer to Nematoda (roundworms). Here we present results from the analyses of two independent genomic datasets, expressed sequence tags (ESTs) and microRNAs (miRNAs), which congruently resolve the phylogenetic relationships of Tardigrada. Our EST analyses, based on 49,023 amino acid sites from 255 proteins, significantly support a monophyletic Panarthropoda including Tardigrada and suggest a sister group relationship between Arthropoda and Onychophora. Using careful experimental manipulations--comparisons of model fit, signal dissection, and taxonomic pruning--we show that support for a Tardigrada + Nematoda group derives from the phylogenetic artifact of long-branch attraction. Our small RNA libraries fully support our EST results; no miRNAs were found to link Tardigrada and Nematoda, whereas all panarthropods were found to share one unique miRNA (miR-276). In addition, Onychophora and Arthropoda were found to share a second miRNA (miR-305). Our study confirms the monophyly of the legged ecdysozoans, shows that past support for a Tardigrada + Nematoda group was due to long-branch attraction, and suggests that the velvet worms are the sister group to the arthropods.

  8. An attempt to revisit the global biogeography of limno-terrestrial Tardigrada

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    Philip J.A. PUGH

    2007-09-01

    Full Text Available The major increase in distribution records of limno-terrestrial tardigrades over the last ten years has enabled us to reassess the global biogeography of the Tardigrada using cluster analysis, principal components analysis and parsimony analysis of endemism (PAE. Although the new clustergram topology shows a close correlation with those we originally presented in 1998, the PAE outputs warrant a radical reinterpretation of the results as they imply that the Laurasian fauna is derived and the Gondwanan groups basal. The distribution of endemic tardigrade genera and families provides some support for this argument though the findings should be viewed with some caution as PAE has its detractors and has not been previously applied on a 'global' scale.

  9. Area, depth and elevation of cryoconite holes in the Arctic do not influence Tardigrada densities

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    Zawierucha Krzysztof

    2016-06-01

    Full Text Available Water bears (Tardigrada are known as one of the most extremophile animals in the world. They inhabit environments from the deepest parts of the oceans up to the highest mountains. One of the most extreme and still poorly studied habitats which tardigrades inhabit are cryoconite holes. We analysed the relation between area, depth, elevation and tardigrades densities in cryoconite holes on four glaciers on Spitsbergen. The mean (±SD of cryoconite area was 1287.21±2400.8 cm2, while the depth was on average 10.8±11.2 cm, the elevation 172.6±109.66 m a.s.l., and tardigrade density 24.9±33.0 individuals per gram of wet material (n = 38. The densities of tardigrades on Hans Glacier reached values of up to 168 ind. cm3, 104 ind. g−1 wet weight, and 275 ind. g−1 dry weight. The densities of tardigrades of the three glaciers in Billefjorden were up to 82 ind. cm2, 326 ind. g−1 wet weight and 624 ind. g−1 dry weight. Surprisingly, although the model included area, depth and elevation as independent variables, it cannot explain Tardigrada density in cryoconite holes. We propose that due to the rapid melting of the glacier surface in the Arctic, the constant flushing of cryoconite sediments, and inter-hole water-sediment mixing, the functioning of these ecosystems is disrupted. We conclude that cryoconite holes are dynamic ecosystems for microinvertebrates in the Arctic.

  10. Shoulder biomechanics

    Energy Technology Data Exchange (ETDEWEB)

    Lugo, Roberto; Kung, Peter; Ma, C. Benjamin [Sports Medicine and Shoulder Service, University of California, San Francisco, 500 Parnassus Avenue, MU 320W-0728 San Francisco, CA 914143 (United States)], E-mail: maben@orthosurg.ucsf.edu

    2008-10-15

    The biomechanics of the glenohumeral joint depend on the interaction of both static and dynamic-stabilizing structures. Static stabilizers include the bony anatomy, negative intra-articular pressure, the glenoid labrum, and the glenohumeral ligaments along with the joint capsule. The dynamic-stabilizing structures include the rotator cuff muscles and the other muscular structures surrounding the shoulder joint. The combined effect of these stabilizers is to support the multiple degrees of motion within the glenohumeral joint. The goal of this article is to review how these structures interact to provide optimal stability and how failure of some of these mechanisms can lead to shoulder joint pathology.

  11. Dinosaur biomechanics

    OpenAIRE

    Alexander, R. McNeill

    2006-01-01

    Biomechanics has made large contributions to dinosaur biology. It has enabled us to estimate both the speeds at which dinosaurs generally moved and the maximum speeds of which they may have been capable. It has told us about the range of postures they could have adopted, for locomotion and for feeding, and about the problems of blood circulation in sauropods with very long necks. It has made it possible to calculate the bite forces of predators such as Tyrannosaurus, and the stresses they imp...

  12. Dinosaur biomechanics.

    Science.gov (United States)

    Alexander, R McNeill

    2006-08-07

    Biomechanics has made large contributions to dinosaur biology. It has enabled us to estimate both the speeds at which dinosaurs generally moved and the maximum speeds of which they may have been capable. It has told us about the range of postures they could have adopted, for locomotion and for feeding, and about the problems of blood circulation in sauropods with very long necks. It has made it possible to calculate the bite forces of predators such as Tyrannosaurus, and the stresses they imposed on its skull; and to work out the remarkable chewing mechanism of hadrosaurs. It has shown us how some dinosaurs may have produced sounds. It has enabled us to estimate the effectiveness of weapons such as the tail spines of Stegosaurus. In recent years, techniques such as computational tomography and finite element analysis, and advances in computer modelling, have brought new opportunities. Biomechanists should, however, be especially cautious in their work on animals known only as fossils. The lack of living specimens and even soft tissues oblige us to make many assumptions. It is important to be aware of the often wide ranges of uncertainty that result.

  13. Biomechanics in Schools.

    Science.gov (United States)

    Vincent, J. F. V.

    1980-01-01

    Examines current usage of the term "biomechanics" and emphasizes the importance of differentiating between structure and material. Describes current prolects in biomechanics and lists four points about the educational significance of the field. (GS)

  14. Research Techniques in Biomechanics.

    Science.gov (United States)

    Ward, Terry

    Biomechanics involves the biological human beings interacting with his/her mechanical environment. Biomechanics research is being done in connection with sport, physical education, and general motor behavior, and concerns mechanics independent of implements. Biomechanics research falls in the following two general categories: (1) that specific…

  15. FUNDAMENTALS OF BIOMECHANICS

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    Duane Knudson

    2007-09-01

    Full Text Available DESCRIPTION This book provides a broad and in-depth theoretical and practical description of the fundamental concepts in understanding biomechanics in the qualitative analysis of human movement. PURPOSE The aim is to bring together up-to-date biomechanical knowledge with expert application knowledge. Extensive referencing for students is also provided. FEATURES This textbook is divided into 12 chapters within four parts, including a lab activities section at the end. The division is as follows: Part 1 Introduction: 1.Introduction to biomechanics of human movement; 2.Fundamentals of biomechanics and qualitative analysis; Part 2 Biological/Structural Bases: 3.Anatomical description and its limitations; 4.Mechanics of the musculoskeletal system; Part 3 Mechanical Bases: 5.Linear and angular kinematics; 6.Linear kinetics; 7.Angular kinetics; 8.Fluid mechanics; Part 4 Application of Biomechanics in Qualitative Analysis :9.Applying biomechanics in physical education; 10.Applying biomechanics in coaching; 11.Applying biomechanics in strength and conditioning; 12.Applying biomechanics in sports medicine and rehabilitation. AUDIENCE This is an important reading for both student and educators in the medicine, sport and exercise-related fields. For the researcher and lecturer it would be a helpful guide to plan and prepare more detailed experimental designs or lecture and/or laboratory classes in exercise and sport biomechanics. ASSESSMENT The text provides a constructive fundamental resource for biomechanics, exercise and sport-related students, teachers and researchers as well as anyone interested in understanding motion. It is also very useful since being clearly written and presenting several ways of examples of the application of biomechanics to help teach and apply biomechanical variables and concepts, including sport-related ones

  16. Biomechanics principles and practices

    CERN Document Server

    Peterson, Donald R

    2014-01-01

    Presents Current Principles and ApplicationsBiomedical engineering is considered to be the most expansive of all the engineering sciences. Its function involves the direct combination of core engineering sciences as well as knowledge of nonengineering disciplines such as biology and medicine. Drawing on material from the biomechanics section of The Biomedical Engineering Handbook, Fourth Edition and utilizing the expert knowledge of respected published scientists in the application and research of biomechanics, Biomechanics: Principles and Practices discusses the latest principles and applicat

  17. Biomechanics of corneal ectasia and biomechanical treatments.

    Science.gov (United States)

    Roberts, Cynthia J; Dupps, William J

    2014-06-01

    Many algorithms exist for the topographic/tomographic detection of corneas at risk for post-refractive surgery ectasia. It is proposed that the reason for the difficulty in finding a universal screening tool based on corneal morphologic features is that curvature, elevation, and pachymetric changes are all secondary signs of keratoconus and post-refractive surgery ectasia and that the primary abnormality is in the biomechanical properties. It is further proposed that the biomechanical modification is focal in nature, rather than a uniform generalized weakening, and that the focal reduction in elastic modulus precipitates a cycle of biomechanical decompensation that is driven by asymmetry in the biomechanical properties. This initiates a repeating cycle of increased strain, stress redistribution, and subsequent focal steepening and thinning. Various interventions are described in terms of how this cycle of biomechanical decompensation is interrupted, such as intrastromal corneal ring segments, which redistribute the corneal stress, and collagen crosslinking, which modifies the basic structural properties. Proprietary or commercial disclosures are listed after the references. Copyright © 2014 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  18. Water bears in the Anthropocene: a comparison of urban and woodland tardigrade (Phylum Tardigrada communities in Southwestern Louisiana, USA

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    Harry A. Meyer

    2013-05-01

    Full Text Available Humans have had such a profound effect on global ecosystems, including biodiversity, that Anthropocene is being increasingly used as a chronological term to mark the period of greatest human impact. No areas show the effect of human impact on the environment more than cities, which often have novel combinations of species in unique communities. Tardigrades (Phylum Tardigrada have often been collected in cities, but studies dedicated to urban tardigrade biodiversity are few, and those comparing urban diversity with nearby rural or natural sites even fewer. In this paper we compare the diversity and abundance of tardigrade species in Lake Charles with a nearby forested nonurban site, Sam Houston Jones State Park (SHJSP. Although tardigrade density did not differ significantly between Lake Charles and SHJSP, species richness and diversity were greater in SHJSP (17 species, H1=3.01 than in Lake Charles (8 species, H1=1.30. All but one species found in Lake Charles also occurred in SHJSP. The number of species found in Lake Charles lies within the range (5-10 found in previous urban surveys. All tardigrade studies comparing urban with nearby nonurban habitats have found lower species richness in cities.

  19. Biomechanically Engineered Athletes.

    Science.gov (United States)

    Perry, Tekla S.

    1991-01-01

    The real-world meeting of electronics, computer monitoring, control systems, and mathematics, introduced in the context of sports, is described. Recent advances in the field of biomechanics and its use in improving athletic performance are discussed. (KR)

  20. Computational modeling in biomechanics

    CERN Document Server

    Mofrad, Mohammad

    2010-01-01

    This book provides a glimpse of the diverse and important roles that modern computational technology is playing in various areas of biomechanics. It includes unique chapters on ab initio quantum mechanical, molecular dynamic and scale coupling methods..

  1. Biomechanics of the brain

    CERN Document Server

    Miller, Karol

    2011-01-01

    With contributions from scientists at major institutions, this book presents an introduction to brain anatomy for engineers and scientists. It provides, for the first time, a comprehensive resource in the field of brain biomechanics.

  2. Biomechanics and tennis.

    Science.gov (United States)

    Elliott, B

    2006-05-01

    Success in tennis requires a mix of player talent, good coaching, appropriate equipment, and an understanding of those aspects of sport science pertinent to the game. This paper outlines the role that biomechanics plays in player development from sport science and sport medicine perspectives. Biomechanics is a key area in player development because all strokes have a fundamental mechanical structure and sports injuries primarily have a mechanical cause.

  3. Evolution of pigment-dispersing factor neuropeptides in Panarthropoda: Insights from Onychophora (velvet worms) and Tardigrada (water bears).

    Science.gov (United States)

    Mayer, Georg; Hering, Lars; Stosch, Juliane M; Stevenson, Paul A; Dircksen, Heinrich

    2015-09-01

    Pigment-dispersing factor (PDF) denotes a conserved family of homologous neuropeptides present in several invertebrate groups, including mollusks, nematodes, insects, and crustaceans (referred to here as pigment-dispersing hormone [PDH]). With regard to their encoding genes (pdf, pdh), insects possess only one, nematodes two, and decapod crustaceans up to three, but their phylogenetic relationship is unknown. To shed light on the origin and diversification of pdf/pdh homologs in Panarthropoda (Onychophora + Tardigrada + Arthropoda) and other molting animals (Ecdysozoa), we analyzed the transcriptomes of five distantly related onychophorans and a representative tardigrade and searched for putative pdf homologs in publically available genomes of other protostomes. This revealed only one pdf homolog in several mollusk and annelid species; two in Onychophora, Priapulida, and Nematoda; and three in Tardigrada. Phylogenetic analyses suggest that the last common ancestor of Panarthropoda possessed two pdf homologs, one of which was lost in the arthropod or arthropod/tardigrade lineage, followed by subsequent duplications of the remaining homolog in some taxa. Immunolocalization of PDF-like peptides in six onychophoran species, by using a broadly reactive antibody that recognizes PDF/PDH peptides in numerous species, revealed an elaborate system of neurons and fibers in their central and peripheral nervous systems. Large varicose projections in the heart suggest that the PDF neuropeptides functioned as both circulating hormones and locally released transmitters in the last common ancestor of Onychophora and Arthropoda. The lack of PDF-like-immunoreactive somata associated with the onychophoran optic ganglion conforms to the hypothesis that onychophoran eyes are homologous to the arthropod median ocelli. © 2015 Wiley Periodicals, Inc.

  4. Dr Dapertutto's biomechanics

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    Stojmenović Dragan

    2015-01-01

    Full Text Available The subject matter of the research is the basic models of Meyerhold's biomechanics, which were used to define its theoretical principles. Professor Meyerhold, the theatrical leader of an eccentric stream, with which he changed the modern understanding of the theatre, established the technique of biomechanics by analysing the calculated type of movement. The analysis determines the answers to the questions: What kind of influence does Taylor's 'scientific management of work' have on defining the principles of Meyerhold's techniques of biomechanics? Which aesthetic models of stage movement were some of the basic subjects of Meyerhold's research? Meyerhold's theatrical work has been researched by a number of theatre theorists. However, how much does his work influence the film medium?.

  5. Gingival Recessions and Biomechanics

    DEFF Research Database (Denmark)

    Laursen, Morten Godtfredsen

    by moving the root back in the alveolus. The tooth movement is accompanied by bone gain and thus increase the success rate for soft tissue augmentation. The choice of biomechanical system influences the treatment outcome. If a standard straight wire appliance is used, a biomechanical dilemma can arise....... The forces applied to bring the tooth back into the alveolar process generate opposite reactive forces, which can direct the adjacent teeth out towards the boundary of the bony envelope. A different force system can be achieved with a segmented appliance: The reaction forces from the root movement...

  6. Mathematical foundations of biomechanics.

    Science.gov (United States)

    Niederer, Peter F

    2010-01-01

    The aim of biomechanics is the analysis of the structure and function of humans, animals, and plants by means of the methods of mechanics. Its foundations are in particular embedded in mathematics, physics, and informatics. Due to the inherent multidisciplinary character deriving from its aim, biomechanics has numerous connections and overlapping areas with biology, biochemistry, physiology, and pathophysiology, along with clinical medicine, so its range is enormously wide. This treatise is mainly meant to serve as an introduction and overview for readers and students who intend to acquire a basic understanding of the mathematical principles and mechanics that constitute the foundation of biomechanics; accordingly, its contents are limited to basic theoretical principles of general validity and long-range significance. Selected examples are included that are representative for the problems treated in biomechanics. Although ultimate mathematical generality is not in the foreground, an attempt is made to derive the theory from basic principles. A concise and systematic formulation is thereby intended with the aim that the reader is provided with a working knowledge. It is assumed that he or she is familiar with the principles of calculus, vector analysis, and linear algebra.

  7. Biomechanical pulping of kenaf

    Science.gov (United States)

    Aziz Ahmed; Masood Akhtar; Gary C. Myers; Gary M. Scott

    1999-01-01

    The objective of this study was to investigate the effect of fungal pretreatment of whole kenaf prior to refining on refiner electrical energy consumption, paper strength, and optical properties. We also explored the suitability of whole kenaf biomechanical pulp for making newsprint in terms of ISO brightness and strength properties. Kenaf was sterilized by autoclaving...

  8. Biomechanics of footwear.

    Science.gov (United States)

    Snijders, C J

    1987-07-01

    This article discusses biomechanical principles that indicate a number of basic design criteria for shoes and the properties of good footwear in terms of normal daily activities at home, at school, and at work. These properties also apply to normal occupational footwear and safety footwear.

  9. Biomechanics of the upper limb

    OpenAIRE

    Łukasz Jaworski; Robert Karpiński; Angelika Dobrowolska

    2016-01-01

    The article presents basics of the human upper limb’s anatomy, including skeletal system, joints and basic division of muscles in the limb. The biomechanics of the upper limb is introduced. The range of performed motions is depicted. The possible applications of anatomy and biomechanics of the upper limb are shown.

  10. Biomechanics in clinical practice.

    Science.gov (United States)

    Deusinger, R H

    1984-12-01

    Evidence from dynamic biomechanical analyses of physical activities has greatly expanded our knowledge about the mechanical bases for human movement function with potential implications for further understanding movement dysfunction. The purpose of this review is to relate these findings to present knowledge about the effect on human joints during movement, the role of muscle action on human skeletal levers during movement, and the application of this information to functional tasks by physical therapy clinicians. Also presented are some thoughts regarding what must be accomplished so that this material can be generalized to clinical practice.

  11. Neuroanatomy of Tardigrada

    DEFF Research Database (Denmark)

    Persson, Dennis Krog

    ventral trunk ganglion. It is clear that the brain of A. doryphorus exhibits a more pronounced partitioning compared to the brain of H. crispae. The first and second brain lobes of A. doryphorus innervate the clavae and cirri of the head. These external structures are strongly reduced in H. crispae...... brain structure, is needed in order to clarify their affiliation to Cycloneuralia or Panarthropoda. Also, deducing the number of segments from which the tardigrade brain and head region originate could be central to understanding the evolution of tardigrades and their related phyla. In this thesis I...... provide a detailed description of the nervous system and brain of the arthrotardigrade Actinarctus doryphorus Schulz, 1935, and the eutardigrade Halobiotus crispae Kristensen, 1982. By combining transmission electron microscopy with confocal laser scanning microscopy and immunocytochemical staining...

  12. Neuroanatomy of Tardigrada

    DEFF Research Database (Denmark)

    Persson, Dennis Krog

    brain structure, is needed in order to clarify their affiliation to Cycloneuralia or Panarthropoda. Also, deducing the number of segments from which the tardigrade brain and head region originate could be central to understanding the evolution of tardigrades and their related phyla. In this thesis I......; however, innervations are present in the cuticle or epidermis in the areas termed temporalia and papilla cephalica, as well as in an area corresponding to the area of the median cirrus. The innervations of these areas suggest a homology between the clavae and cirri of A. doryphorus and the temporalia...

  13. Aeronautical Inspirations in Biomechanics

    Directory of Open Access Journals (Sweden)

    Maroński Ryszard

    2017-03-01

    Full Text Available Introduction. The goal of the paper is to show that some problems formulated in the dynamics of atmospheric flight are very similar to the problems formulated in the biomechanics of motion and medicine. Three problems were compared: minimumheat transfer from the boundary layer to the ballistic missile skin, minimum-time ski descent, and the minimisation of the negative cumulated effect of the drug in cancer chemotherapy. Material and methods. All these problems are solved using the same method originally developed for aerospace systems - the method of Miele (the extremisation method of linear integrals via Green’s theorem. Results. It is shown that the problems arising in different branches of knowledge are very similar in problem formulations, mathematical models, and solution methods used. Conclusions. There are no barriers between different disciplines.

  14. Scale-Independent Biomechanical Optimization

    National Research Council Canada - National Science Library

    Schutte, J. F; Koh, B; Reinbolt, J. A; Haftka, R. T; George, A; Fregly, B. J

    2003-01-01

    ...: the Particle Swarm Optimizer (PSO). They apply this method to the biomechanical system identification problem of finding positions and orientations of joint axes in body segments through the processing of experimental movement data...

  15. Systems biomechanics of the cell

    CERN Document Server

    Maly, Ivan V

    2013-01-01

    Systems Biomechanics of the Cell attempts to outline systems biomechanics of the cell as an emergent and promising discipline. The new field owes conceptually to cell mechanics, organism-level systems biomechanics, and biology of biochemical systems. Its distinct methodology is to elucidate the structure and behavior of the cell by analyzing the unintuitive collective effects of elementary physical forces that interact within the heritable cellular framework. The problematics amenable to this approach includes the variety of cellular activities that involve the form and movement of the cell body and boundary (nucleus, centrosome, microtubules, cortex, and membrane). Among the elementary system effects in the biomechanics of the cell, instability of symmetry, emergent irreversibility, and multiperiodic dissipative motion can be noted. Research results from recent journal articles are placed in this unifying framework. It is suggested that the emergent discipline has the potential to expand the spectrum of ques...

  16. FEBio: finite elements for biomechanics.

    Science.gov (United States)

    Maas, Steve A; Ellis, Benjamin J; Ateshian, Gerard A; Weiss, Jeffrey A

    2012-01-01

    In the field of computational biomechanics, investigators have primarily used commercial software that is neither geared toward biological applications nor sufficiently flexible to follow the latest developments in the field. This lack of a tailored software environment has hampered research progress, as well as dissemination of models and results. To address these issues, we developed the FEBio software suite (http://mrl.sci.utah.edu/software/febio), a nonlinear implicit finite element (FE) framework, designed specifically for analysis in computational solid biomechanics. This paper provides an overview of the theoretical basis of FEBio and its main features. FEBio offers modeling scenarios, constitutive models, and boundary conditions, which are relevant to numerous applications in biomechanics. The open-source FEBio software is written in C++, with particular attention to scalar and parallel performance on modern computer architectures. Software verification is a large part of the development and maintenance of FEBio, and to demonstrate the general approach, the description and results of several problems from the FEBio Verification Suite are presented and compared to analytical solutions or results from other established and verified FE codes. An additional simulation is described that illustrates the application of FEBio to a research problem in biomechanics. Together with the pre- and postprocessing software PREVIEW and POSTVIEW, FEBio provides a tailored solution for research and development in computational biomechanics.

  17. Biomechanics of bird flight.

    Science.gov (United States)

    Tobalske, Bret W

    2007-09-01

    Power output is a unifying theme for bird flight and considerable progress has been accomplished recently in measuring muscular, metabolic and aerodynamic power in birds. The primary flight muscles of birds, the pectoralis and supracoracoideus, are designed for work and power output, with large stress (force per unit cross-sectional area) and strain (relative length change) per contraction. U-shaped curves describe how mechanical power output varies with flight speed, but the specific shapes and characteristic speeds of these curves differ according to morphology and flight style. New measures of induced, profile and parasite power should help to update existing mathematical models of flight. In turn, these improved models may serve to test behavioral and ecological processes. Unlike terrestrial locomotion that is generally characterized by discrete gaits, changes in wing kinematics and aerodynamics across flight speeds are gradual. Take-off flight performance scales with body size, but fully revealing the mechanisms responsible for this pattern awaits new study. Intermittent flight appears to reduce the power cost for flight, as some species flap-glide at slow speeds and flap-bound at fast speeds. It is vital to test the metabolic costs of intermittent flight to understand why some birds use intermittent bounds during slow flight. Maneuvering and stability are critical for flying birds, and design for maneuvering may impinge upon other aspects of flight performance. The tail contributes to lift and drag; it is also integral to maneuvering and stability. Recent studies have revealed that maneuvers are typically initiated during downstroke and involve bilateral asymmetry of force production in the pectoralis. Future study of maneuvering and stability should measure inertial and aerodynamic forces. It is critical for continued progress into the biomechanics of bird flight that experimental designs are developed in an ecological and evolutionary context.

  18. Biomechanics and the wheelchair.

    Science.gov (United States)

    McLaurin, C A; Brubaker, C E

    1991-04-01

    Wheelchair biomechanics involves the study of how a wheelchair user imparts power to the wheels to achieve mobility. Because a wheelchair can coast, power input need not be continuous, but each power strike can be followed by a period of recovery, with the stroking frequency depending on user preferences and the coasting characteristics of the wheelchair. The latter is described in terms of rolling resistance, wind resistance and the slope of the surface. From these three factors the power required to propel the wheelchair is determined, and must be matched by the power output of the user. The efficiency of propulsion is the ratio of this power output to the metabolic cost and is typically in the order of 5% in normal use. The features required in a wheelchair depend upon user characteristics and intended activities. The ideal wheelchair for an individual will have the features that closely match these characteristics and activities. Thus prescription is not just choosing a wheelchair, but choosing the components of the wheelchair that best serve the intended purpose. In this paper, each component is examined for available options and how these options effect the performance of the wheelchair for the individual. The components include wheels, tyres, castors, frames, bearings, materials, construction details, seats, backrests, armrests, foot and legrests, headrests, wheel locks, running brakes, handrims, levers, accessories, adjustments and detachable parts. Each component is considered in relation to performance characteristics including rolling resistance, versatility, weight, comfort, stability, maneouvrability, transfer, stowage, durability and maintenance. Where they exist, wheelchair standards are referred to as a source of information regarding these characteristics.

  19. Biomechanical Perspectives on Concussion in Sport

    Science.gov (United States)

    Rowson, Steven; Bland, Megan L.; Campolettano, Eamon T.; Press, Jaclyn N.; Rowson, Bethany; Smith, Jake A.; Sproule, David W.; Tyson, Abigail M.; Duma, Stefan M.

    2016-01-01

    Concussions can occur in any sport. Often, clinical and biomechanical research efforts are disconnected. This review paper analyzes current concussion issues in sports from a biomechanical perspective and is geared towards Sports Med professionals. Overarching themes of this review include: the biomechanics of the brain during head impact, role of protective equipment, potential population-based differences in concussion tolerance, potential intervention strategies to reduce the incidence of injury, and common biomechanical misconceptions. PMID:27482775

  20. Biomechanical analysis of rollator walking

    DEFF Research Database (Denmark)

    Alkjaer, T; Larsen, Peter K; Pedersen, Gitte

    2006-01-01

    The rollator is a very popular walking aid. However, knowledge about how a rollator affects the walking patterns is limited. Thus, the purpose of the study was to investigate the biomechanical effects of walking with and without a rollator on the walking pattern in healthy subjects.......The rollator is a very popular walking aid. However, knowledge about how a rollator affects the walking patterns is limited. Thus, the purpose of the study was to investigate the biomechanical effects of walking with and without a rollator on the walking pattern in healthy subjects....

  1. Simulations of Biomechanical Phenomena

    Science.gov (United States)

    Gonzalez, Jose Cruz

    Recent studies have published breakthroughs in the application of finite element (FEA) studies in the design and analysis of advanced orthodontics. However, FEA has not captured bone remodeling responses to advanced orthodontics. The results of these simulations report unrealistic displacement around the nasal bridge, which impeded correlation with clinical data. Bone remodeling has been previously documented in FEA and has shown bone response to mechanical stimulus in femur bone models. However, the relationship between mechanical stimulus and bone remodeling has not been reported in orthodontic studies due to the complexity of the skull. In the current study, strain energy is used as the mechanical stimulus to control remodeling, from which density and modulus evolve. Due to the localization of forces in orthodontics, current remodeling algorithms have limited application. In turn, we developed an algorithm that dynamically collects, sorts, and bins stresses in all elements for regional remodeling based on the proximity of the element to the load. The results demonstrate that bone response to orthodontic appliances is different than that of an FEA without bone remodeling, due to load path changes based upon evolution of the bone properties. It was also found that density and moduli proximal to the load application site exhibit faster remodeling than those located remotely. Modeling another biomechanical phenomena, a 3D simulation was created to simulate recent experimental results that discovered a difference in impact mitigation properties of dense-polymer/foam bilayer structure based on the orientation of the dense-polymer with respect to the impact site. The impact energy transmitted varied in time of arrival and amplitude depending on the orientation of the structure (thin layer up or down). By creating a 3D explicit dynamic FEA simulation, it is expected to reduce costly experiments and time consumed in set up, and offer opportunities for optimization for

  2. Clinical applications of biomechanics cinematography.

    Science.gov (United States)

    Woodle, A S

    1986-10-01

    Biomechanics cinematography is the analysis of movement of living organisms through the use of cameras, image projection systems, electronic digitizers, and computers. This article is a comparison of cinematographic systems and details practical uses of the modality in research and education.

  3. The Biomechanics of Cervical Spondylosis

    Directory of Open Access Journals (Sweden)

    Lisa A. Ferrara

    2012-01-01

    Full Text Available Aging is the major risk factor that contributes to the onset of cervical spondylosis. Several acute and chronic symptoms can occur that start with neck pain and may progress into cervical radiculopathy. Eventually, the degenerative cascade causes desiccation of the intervertebral disc resulting in height loss along the ventral margin of the cervical spine. This causes ventral angulation and eventual loss of lordosis, with compression of the neural and vascular structures. The altered posture of the cervical spine will progress into kyphosis and continue if the load balance and lordosis is not restored. The content of this paper will address the physiological and biomechanical pathways leading to cervical spondylosis and the biomechanical principles related to the surgical correction and treatment of kyphotic progression.

  4. Wearable Biomechanical Energy Harvesting Technologies

    Directory of Open Access Journals (Sweden)

    Young-Man Choi

    2017-09-01

    Full Text Available Energy harvesting has been attracting attention as a technology that is capable of replacing or supplementing a battery with the development of various mobile electronics. In environments where stable electrical supply is not possible, energy harvesting technology can guarantee an increased leisure and safety for human beings. Harvesting with several watts of power is essential for directly driving or efficiently charging mobile electronic devices such as laptops or cell phones. In this study, we reviewed energy harvesting technologies that harvest biomechanical energy from human motion such as foot strike, joint motion, and upper limb motion. They are classified based on the typical principle of kinetic energy harvesting: piezoelectric, triboelectric, and electromagnetic energy harvesting. We focused on the wearing position of high-power wearable biomechanical energy harvesters (WBEHs generating watt-level power. In addition, the features and future trends of the watt-level WBEHs are discussed.

  5. The Biomechanics of Cervical Spondylosis

    Science.gov (United States)

    Ferrara, Lisa A.

    2012-01-01

    Aging is the major risk factor that contributes to the onset of cervical spondylosis. Several acute and chronic symptoms can occur that start with neck pain and may progress into cervical radiculopathy. Eventually, the degenerative cascade causes desiccation of the intervertebral disc resulting in height loss along the ventral margin of the cervical spine. This causes ventral angulation and eventual loss of lordosis, with compression of the neural and vascular structures. The altered posture of the cervical spine will progress into kyphosis and continue if the load balance and lordosis is not restored. The content of this paper will address the physiological and biomechanical pathways leading to cervical spondylosis and the biomechanical principles related to the surgical correction and treatment of kyphotic progression. PMID:22400120

  6. Confidence crisis of results in biomechanics research.

    Science.gov (United States)

    Knudson, Duane

    2017-11-01

    Many biomechanics studies have small sample sizes and incorrect statistical analyses, so reporting of inaccurate inferences and inflated magnitude of effects are common in the field. This review examines these issues in biomechanics research and summarises potential solutions from research in other fields to increase the confidence in the experimental effects reported in biomechanics. Authors, reviewers and editors of biomechanics research reports are encouraged to improve sample sizes and the resulting statistical power, improve reporting transparency, improve the rigour of statistical analyses used, and increase the acceptance of replication studies to improve the validity of inferences from data in biomechanics research. The application of sports biomechanics research results would also improve if a larger percentage of unbiased effects and their uncertainty were reported in the literature.

  7. Qualitative biomechanical principles for application in coaching.

    Science.gov (United States)

    Knudson, Duane

    2007-01-01

    Many aspects of human movements in sport can be readily understood by Newtonian rigid-body mechanics. Many of these laws and biomechanical principles, however, are counterintuitive to a lot of people. There are also several problems in the application of biomechanics to sports, so the application of biomechanics in the qualitative analysis of sport skills by many coaches has been limited. Biomechanics scholars have long been interested in developing principles that facilitate the qualitative application of biomechanics to improve movement performance and reduce the risk of injury. This paper summarizes the major North American efforts to establish a set of general biomechanical principles of movement, and illustrates how principles can be used to improve the application of biomechanics in the qualitative analysis of sport technique. A coach helping a player with a tennis serve is presented as an example. The standardization of terminology for biomechanical principles is proposed as an important first step in improving the application ofbiomechanics in sport. There is also a need for international cooperation and research on the effectiveness of applying biomechanical principles in the coaching of sport techniques.

  8. A review of biomechanics of the shoulder and biomechanical concepts of rotator cuff repair

    Directory of Open Access Journals (Sweden)

    Nobuyuki Yamamoto

    2015-01-01

    Full Text Available In this article, we describe the basic knowledge about shoulder biomechanics, which is thought to be useful for surgeons. Some clinical reports have described that the excellent outcome after cuff repair without acromioplasty and a limited acromioplasty might be enough for subacromial decompression. It was biomechanically demonstrated that a 10-mm medial shift of the tendon repair site has a minimum effect on biomechanics. Many biomechanical studies reported that the transosseous equivalent repair was superior to other techniques, although the tendon may lose its inherent elasticity. We herein introduce our recent experiment data and latest information on biomechanics.

  9. Biomechanics of the human uterus.

    Science.gov (United States)

    Myers, Kristin M; Elad, David

    2017-09-01

    The appropriate biomechanical function of the uterus is required for the execution of human reproduction. These functions range from aiding the transport of the embryo to the implantation site, to remodeling its tissue walls to host the placenta, to protecting the fetus during gestation, to contracting forcefully for a safe parturition and postpartum, to remodeling back to its nonpregnant condition to renew the cycle of menstruation. To serve these remarkably diverse functions, the uterus is optimally geared with evolving and contractile muscle and tissue layers that are cued by chemical, hormonal, electrical, and mechanical signals. The relationship between these highly active biological signaling mechanisms and uterine biomechanical function is not completely understood for normal reproductive processes and pathological conditions such as adenomyosis, endometriosis, infertility and preterm labor. Animal studies have illuminated the rich structural function of the uterus, particularly in pregnancy. In humans, medical imaging techniques in ultrasound and magnetic resonance have been combined with computational engineering techniques to characterize the uterus in vivo, and advanced experimental techniques have explored uterine function using ex vivo tissue samples. The collective evidence presented in this review gives an overall perspective on uterine biomechanics related to both its nonpregnant and pregnant function, highlighting open research topics in the field. Additionally, uterine disease and infertility are discussed in the context of tissue injury and repair processes and the role of computational modeling in uncovering etiologies of disease. WIREs Syst Biol Med 2017, 9:e1388. doi: 10.1002/wsbm.1388 For further resources related to this article, please visit the WIREs website. © 2017 Wiley Periodicals, Inc.

  10. Relationships between physical and biomechanical parameters and ...

    African Journals Online (AJOL)

    A proficient golf swing is composed of a sequence of highly complex biomechanical movements and requires precisely timed and coordinated body movements to achieve great distance and accuracy. The aim of the current study was to identify the key physiological and biomechanical variables that relate to golf drive ...

  11. Biomechanical Factors in Tibial Stress Fractures

    Science.gov (United States)

    2004-08-01

    1996. Worthen, L., Hamill, J. Biomechanical issues in ballet : ankle alignment in pointe shoes. 15d, Annual Symposium on Medical Problems of Musicians... Mexico Race Walkers Association, Albuquerque, New Mexico , June, 1987. Biomechanics of fitness walking. American Diabetes Association, St. Louis, Missouri

  12. Biomechanical benefits of symmetrical strengthening of hip ...

    African Journals Online (AJOL)

    There is abundant literature encouraging athletes to engage in concurrent strength training. However, little emphasis is placed on the value of biomechanics with regard to symmetrical strengthening of force-couple relationships. A review of literature reveals 565 biomechanical papers versus 2085 physiological papers ...

  13. Applied Biomechanics in an Instructional Setting

    Science.gov (United States)

    Hudson, Jackie L.

    2006-01-01

    Biomechanics is the science of how people move better, meaning more skillfully and more safely. This article places more emphasis on skill rather than safety, though there are many parallels between them. It shares a few features of the author's paradigm of applied biomechanics and discusses an integrated approach toward a middle school football…

  14. Biomechanical properties of bone allografts

    International Nuclear Information System (INIS)

    Pelker, R.R.; Friedlaender, G.E.; Markham, T.C.

    1983-01-01

    The biomechanical properties of allograft bone can be altered by the methods chosen for its preservation and storage. These effects are minimal with deep-freezing or low-level radiation. Freeze-drying, however, markedly diminishes the torsional and bending strength of bone allografts but does not deleteriously affect the compressive or tensile strength. Irradiation of bone with more than 3.0 megarad or irradiation combined with freeze-drying appears to cause a significant reduction in breaking strength. These factors should be considered when choosing freeze-dried or irradiated allogeneic bone that will be subjected to significant loads following implantation

  15. Problems of Sport Biomechanics and Robotics

    Directory of Open Access Journals (Sweden)

    Wlodzimierz S. Erdmann

    2013-02-01

    Full Text Available This paper presents many common areas of interest of different specialists. There are problems described from sport, biomechanics, sport biomechanics, sport engineering, robotics, biomechanics and robotics, sport biomechanics and robotics. There are many approaches to sport from different sciences and engineering. Robotics is a relatively new area and has had moderate attention from sport specialists. The aim of this paper is to present several areas necessary to develop sport robots based on biomechanics and also to present different types of sport robots: serving balls, helping to provide sports training, substituting humans during training, physically participating in competitions, physically participating in competitions against humans, serving as models of real sport performance, helping organizers of sport events and robot toys. Examples of the application of robots in sports communities are also given.

  16. ES-2 Dummy Biomechanical Responses.

    Science.gov (United States)

    Byrnes, Katie; Abramczyk, Joseph; Berliner, Jeff; Irwin, Annette; Jensen, Jack; Kowsika, Murthy; Mertz, Harold J; Rouhana, Stephen W; Scherer, Risa; Shi, Yibing; Sutterfield, Aleta; Xu, Lan; Tylko, Suzanne; Dalmotas, Dainius

    2002-11-01

    This technical paper presents the results of biomechanical testing conducted on the ES-2 dummy by the Occupant Safety Research Partnership and Transport Canada. The ES-2 is a production dummy, based on the EuroSID-1 dummy, that was modified to further improve testing capabilities as recommended by users of the EuroSID-1 dummy. Biomechanical response data were obtained by completing a series of drop, pendulum, and sled tests that are outlined in the International Organization of Standardization Technical Report 9790 that describes biofidelity requirements for the midsize adult male side impact dummy. A few of the biofidelity tests were conducted on both sides of the dummy to evaluate the symmetry of its responses. Full vehicle crash tests were conducted to verify if the changes in the EuroSID-1, resulting in the ES-2 design, did improve the dummy's testing capability. In addition to the biofidelity testing, the ES-2 dummy repeatability, reproducibility and durability are discussed. Finally, this technical paper will compare the biofidelity ratings of the current adult side impact dummies with the ES-2 dummy, which received an overall dummy biofidelity rating of 4.6.

  17. New records of Mexican Tardigrada Nuevos registros de Tardigrada mexicanos

    Directory of Open Access Journals (Sweden)

    Łukasz Kaczmarek

    2011-12-01

    Full Text Available In 9 moss samples collected from Mexico, 6 tardigrade species, including 4 new records for the country, were found. The new records raise the number of known Mexican water bear species to forty-one. We provide a full list of the known Mexican tardigrade species and discuss some biogeographical and taxonomic issues.En 9 muestras de musgo recolectadas en México, se encontraron 6 especies de tardígrados, incluyendo 4 nuevos registros para el país. Los nuevos registros incrementaron a 41 el número de especies de tardígrados mexicanos conocidos. Se proporciona una lista completa de tardígrados mexicanos conocidos y se discuten algunas cuestiones biogeográficas y taxonómicas.

  18. Biomechanics in Paralympics: Implications for Performance.

    Science.gov (United States)

    Morriën, Floor; Taylor, Matthew J D; Hettinga, Florentina J

    2017-05-01

    To provide an overview of biomechanical studies in Paralympic research and their relevance for performance in Paralympic sports. The search terms paralympic biomechanics, paralympic sport performance, paralympic athlete performance, and paralympic athlete were entered into the electronic database PubMed. Thirty-four studies were found. Biomechanical studies in Paralympics mainly contributed to performance enhancement by technical optimization (n = 32) and/or injury prevention (n = 6). In addition, biomechanics was found to be important in understanding activity limitation caused by various impairments, which is relevant for evidence-based classification in Paralympic sports (n = 6). Distinctions were made between biomechanical studies in sitting (41%), standing (38%), and swimming athletes (21%). In sitting athletes, mostly kinematics and kinetics in wheelchair propulsion were studied, mainly in athletes with spinal-cord injuries. In addition, kinetics and/or kinematics in wheelchair basketball, seated discus throwing, stationary shot-putting, hand-cycling, sit-skiing, and ice sledge hockey received attention. In standing sports, primarily kinematics of athletes with amputations performing jump sports and running and the optimization of prosthetic devices were investigated. No studies were reported on other standing sports. In swimming, mainly kick rate and resistance training were studied. Biomechanical research is important for performance by gaining insight into technical optimization, injury prevention, and evidence-based classification in Paralympic sports. In future studies it is advised to also include physiological and biomechanical measures, allowing the assessment of the capability of the human body, as well as the resulting movement.

  19. Biomechanics-Hot Topics Part II.

    Science.gov (United States)

    Finkemeier, Christopher; Adams, John D; Bernstein, Mitchell; Lee, Mark A; Harvey, Ed; Crist, Brett D

    2018-03-01

    Orthopaedic surgery and biomechanics are intimately partnered topics in medicine. Biomechanical principles are used to design implants and fashion treatment protocols. Although it would seem that biomechanical principles in the design of fixation devices and fracture repair constructs have been already finalized, there are several points of controversy remaining. New technology has raised new questions, while at the same time, we still do not fully understand simple clinical principles such as time of fracture healing depending on the construct used. This review looks at several of these current controversies to better understand what work is needed in fracture care going forward.

  20. Biomechanical aspects of playing surfaces.

    Science.gov (United States)

    Nigg, B M; Yeadon, M R

    1987-01-01

    The purpose of this paper is to discuss some biomechanical aspects of playing surfaces with special focus on (a) surface induced injuries, (b) methodologies used to assess surfaces and (c) findings from various sports. The paper concentrates primarily on questions related to load on the athlete's body. Data from epidemiological studies suggest strongly that the surface is an important factor in the aetiology of injuries. Injury frequencies are reported to be significantly different for different surfaces in several sports. The methodologies used to assess surfaces with respect to load or performance include material tests and tests using experimental subjects. There is only little correlation between the results of these two approaches. Material tests used in many standardized test procedures are not validated which suggests that one should exercise restraint in the interpretation of these results. Point elastic surfaces are widely studied while area elastic surfaces have received little attention to date. Questions of energy losses on sport surfaces have rarely been studied scientifically.

  1. THE CENTER FOR MILITARY BIOMECHANICS RESEARCH

    Data.gov (United States)

    Federal Laboratory Consortium — The Center for Military Biomechanics Research is a 7,500 ft2 dedicated laboratory outfitted with state-of-the-art equipment for 3-D analysis of movement, measurement...

  2. FUNDAMENTA LS OF BIOMECHANIC BIOMEDICAL ENGINERING

    OpenAIRE

    Sriwijaya, Rachmat

    2017-01-01

    Studi tentang biomechanics telah berkembang pesat dari awalnya hanya aplikasi studi mekanika teknik yang sederhana kemudian meluas dengan pelibatan berbagai bidang studi. Dalam bidang biomechanics buku ini sangat membantu mahasiswa ataupun peneliti untuk memahami dasar-dasar mekanika dan dinamika tubuh manusia, yang menjadi bidang kajian penting dalam studi rekayasa biomedik. Buku ini memberikan pengetahuan yang memadai tentang konsep statika, gerak, dinamika, pemodelan, dan aplikasinya dikai...

  3. Lingual biomechanics, case selection and success

    Directory of Open Access Journals (Sweden)

    Sanjay Labh

    2016-01-01

    Full Text Available Deeper understanding of lingual biomechanics is prerequisite for success with lingual appliance. The difference between labial and lingual force system must be understood and kept in mind during treatment planning, especially anchorage planning, and extraction decision-making. As point of application of force changes, it completely changes the force system in all planes. This article describes lingual biomechanics, anchorage planning, diagnostic considerations, treatment planning, and case selection criteria in lingual orthodontics.

  4. Biomechanics of single cortical neurons.

    Science.gov (United States)

    Bernick, Kristin B; Prevost, Thibault P; Suresh, Subra; Socrate, Simona

    2011-03-01

    This study presents experimental results and computational analysis of the large strain dynamic behavior of single neurons in vitro with the objective of formulating a novel quantitative framework for the biomechanics of cortical neurons. Relying on the atomic force microscopy (AFM) technique, novel testing protocols are developed to enable the characterization of neural soma deformability over a range of indentation rates spanning three orders of magnitude, 10, 1, and 0.1 μm s(-1). Modified spherical AFM probes were utilized to compress the cell bodies of neonatal rat cortical neurons in load, unload, reload and relaxation conditions. The cell response showed marked hysteretic features, strong non-linearities, and substantial time/rate dependencies. The rheological data were complemented with geometrical measurements of cell body morphology, i.e. cross-diameter and height estimates. A constitutive model, validated by the present experiments, is proposed to quantify the mechanical behavior of cortical neurons. The model aimed to correlate empirical findings with measurable degrees of (hyper)elastic resilience and viscosity at the cell level. The proposed formulation, predicated upon previous constitutive model developments undertaken at the cortical tissue level, was implemented in a three-dimensional finite element framework. The simulated cell response was calibrated to the experimental measurements under the selected test conditions, providing a novel single cell model that could form the basis for further refinements. Copyright © 2010 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  5. Biomechanics and mechanobiology in functional tissue engineering

    Science.gov (United States)

    Guilak, Farshid; Butler, David L.; Goldstein, Steven A.; Baaijens, Frank P.T.

    2014-01-01

    The field of tissue engineering continues to expand and mature, and several products are now in clinical use, with numerous other preclinical and clinical studies underway. However, specific challenges still remain in the repair or regeneration of tissues that serve a predominantly biomechanical function. Furthermore, it is now clear that mechanobiological interactions between cells and scaffolds can critically influence cell behavior, even in tissues and organs that do not serve an overt biomechanical role. Over the past decade, the field of “functional tissue engineering” has grown as a subfield of tissue engineering to address the challenges and questions on the role of biomechanics and mechanobiology in tissue engineering. Originally posed as a set of principles and guidelines for engineering of load-bearing tissues, functional tissue engineering has grown to encompass several related areas that have proven to have important implications for tissue repair and regeneration. These topics include measurement and modeling of the in vivo biomechanical environment; quantitative analysis of the mechanical properties of native tissues, scaffolds, and repair tissues; development of rationale criteria for the design and assessment of engineered tissues; investigation of the effects biomechanical factors on native and repair tissues, in vivo and in vitro; and development and application of computational models of tissue growth and remodeling. Here we further expand this paradigm and provide examples of the numerous advances in the field over the past decade. Consideration of these principles in the design process will hopefully improve the safety, efficacy, and overall success of engineered tissue replacements. PMID:24818797

  6. SPORT AND EXERCISE BIOMECHANICS (BIOS INSTANT NOTES

    Directory of Open Access Journals (Sweden)

    Paul Grimshaw

    2007-06-01

    Full Text Available DESCRIPTION Instant Notes on Sport and Exercise Biomechanics provides a broad overview of the fundamental concepts in exercise and sport biomechanics. PURPOSE The book aims to provide instant notes on essential information about biomechanics, and is designed to help undergraduate students to grasp the corresponding subjects in physical effort rapidly and easily. AUDIENCE The book provides a useful resource for undergraduate and graduate students as a fundamental reference book. For the researcher and lecturer it would be a starting point to plan and prepare more detailed experimental designs or lecture and/or laboratory classes in the field of exercise and sport biomechanics. It would also be interest to anyone who wonders the concepts like momentum possessed, whole body angular momentum, opposite parallel forces, superman position, parabolic flight path, joint/normal reaction force, etc. FEATURES This textbook is divided into following sections from A to F: kinematics of motion, kinetics of linear motion, kinetics of angular motion, special topics, applications and measurement techniques, respectively. In sub-sections the kinematics of motion are reviewed in detail, outlining the physics of motion. Furthermore, the discussions of mechanical characteristics of motion, the mechanisms of injury, and the analysis of the sport technique provide a source of valuable information for both students and lecturers in appropriate fields. ASSESSMENT This book is an important reading for biomechanics students, teachers and even researchers as well as anyone interested in understanding motion.

  7. 4th International Plant Biomechanics Conference Proceedings (Abstracts)

    Energy Technology Data Exchange (ETDEWEB)

    Frank W. Telewski; Lothar H. Koehler; Frank W. Ewers

    2003-07-20

    The 4th International Plant Biomechanics Conference facilitated an interdisciplinary exchange between scientists, engineers, and educators addressing the major questions encountered in the field of Plant Biomechanics. Subjects covered by the conference include: Evolution; Ecology; Mechanoreception; Cell Walls; Genetic Modification; Applied Biomechanics of Whole Plants, Plant Products, Fibers & Composites; Fluid Dynamics; Wood & Trees; Fracture Mechanics; Xylem Pressure & Water Transport; Modeling; and Introducing Plant Biomechanics in Secondary School Education.

  8. Computational biomechanics for medicine from algorithms to models and applications

    CERN Document Server

    Joldes, Grand; Nielsen, Poul; Doyle, Barry; Miller, Karol

    2017-01-01

    This volume comprises the latest developments in both fundamental science and patient-specific applications, discussing topics such as: cellular mechanics; injury biomechanics; biomechanics of heart and vascular system; medical image analysis; and both patient-specific fluid dynamics and solid mechanics simulations. With contributions from researchers world-wide, the Computational Biomechanics for Medicine series of titles provides an opportunity for specialists in computational biomechanics to present their latest methodologies and advancements.

  9. Sixth Computational Biomechanics for Medicine Workshop

    CERN Document Server

    Nielsen, Poul MF; Miller, Karol; Computational Biomechanics for Medicine : Deformation and Flow

    2012-01-01

    One of the greatest challenges for mechanical engineers is to extend the success of computational mechanics to fields outside traditional engineering, in particular to biology, biomedical sciences, and medicine. This book is an opportunity for computational biomechanics specialists to present and exchange opinions on the opportunities of applying their techniques to computer-integrated medicine. Computational Biomechanics for Medicine: Deformation and Flow collects the papers from the Sixth Computational Biomechanics for Medicine Workshop held in Toronto in conjunction with the Medical Image Computing and Computer Assisted Intervention conference. The topics covered include: medical image analysis, image-guided surgery, surgical simulation, surgical intervention planning, disease prognosis and diagnostics, injury mechanism analysis, implant and prostheses design, and medical robotics.

  10. Multiscale modeling in biomechanics and mechanobiology

    CERN Document Server

    Hwang, Wonmuk; Kuhl, Ellen

    2015-01-01

    Presenting a state-of-the-art overview of theoretical and computational models that link characteristic biomechanical phenomena, this book provides guidelines and examples for creating multiscale models in representative systems and organisms. It develops the reader's understanding of and intuition for multiscale phenomena in biomechanics and mechanobiology, and introduces a mathematical framework and computational techniques paramount to creating predictive multiscale models.   Biomechanics involves the study of the interactions of physical forces with biological systems at all scales – including molecular, cellular, tissue and organ scales. The emerging field of mechanobiology focuses on the way that cells produce and respond to mechanical forces – bridging the science of mechanics with the disciplines of genetics and molecular biology. Linking disparate spatial and temporal scales using computational techniques is emerging as a key concept in investigating some of the complex problems underlying these...

  11. The vertebral biomechanic previous and after kyphoplasty.

    Science.gov (United States)

    Pesce, V; Piazzolla, Andrea; Moretti, L; Carlucci, S; Parato, C; Maxy, P; Moretti, B

    2013-10-01

    The biomechanical understanding of increasing anterior column load with progressing kyphosis leading to subsequent vertebral compression fracture (VCF) established the basic rationale for kyphoplasty. The lumbar spine can support an effort of 500 kg in the axis of the vertebral body, and a bending moment of 20 Nm in flexion. Consequently, if this effort is forward deviated of only 10 cm, the acceptable effort will be reduced to 20 kg so it is important to restore the vertebral anterior wall after a VCF: the authors describe the biomechanical modifications in the spine after kyphoplasty.

  12. Biomechanical, anthropometrical and physical profile of elite ...

    African Journals Online (AJOL)

    Literature indicates that deficiencies of certain parameters such as biomechanics, anthropometry, physical and motor abilities, may influence a netball players susceptibility to injury, as well as the players physical performance during a game. The primary aim of this study was to determine the physical profile of elite netball ...

  13. Biomechanical Remodeling of the Diabetic Gastrointestinal Tract

    DEFF Research Database (Denmark)

    Zhao, Jingbo; Liao, Donghua; Yang, Jian

    2010-01-01

    several years, several studies demonstrated that experimental diabetes induces GI morphological and biomechanical remodeling. Following the development of diabetes, the GI wall becomes thicker and the stiffness of the GI wall increases in a time-dependent manner. It is well known that mechanosensitive...

  14. The Value of Biomechanical Research in Dance.

    Science.gov (United States)

    Ranney, D. A.

    Simple observation of dance movement, while very useful, can lead to misconceptions, about the physical realities of dance movement, that make learning difficult. This gap between reality and understanding can be reduced by the application of biomechanical techniques such as cinematography, electromyography, and force-plate analysis. Biomechanical…

  15. Biomechanical Concepts for the Physical Educator

    Science.gov (United States)

    Strohmeyer, H. Scott

    2004-01-01

    The concepts and principles of biomechanics are familiar to the teacher of physical science as well as to the physical educator. The difference between the two instructors, however, is that one knows the language of science and the other provides an experientially rich environment to support acquisition of these concepts and principles. Use of…

  16. Biomechanical pulping : a mill-scale evaluation

    Science.gov (United States)

    Masood. Akhtar; Gary M. Scott; Ross E. Swaney; Mike J. Lentz; Eric G. Horn; Marguerite S. Sykes; Gary C. Myers

    1999-01-01

    Mechanical pulping process is electrical energy intensive and results in low paper strength. Biomechanical pulping, defined as the fungal treatment of lignocellulosic materials prior to mechanical pulping, has shown at least 30% savings in electrical energy consumption, and significant improvements in paper strength properties compared to the control at a laboratory...

  17. Biomechanical aspects of bone microstructure in vertebrates ...

    Indian Academy of Sciences (India)

    Prakash

    2009-10-29

    Oct 29, 2009 ... Bone is an important tissue in paleontological studies as it is a commonly preserved element in most fossil vertebrates, and can often allow its ... biomechanical studies now tend to use FEA. However, despite its use in .... the cross sectional area of each concentric annular region,. i.e. lamella, increases with ...

  18. The biomechanical interaction between horse and rider

    NARCIS (Netherlands)

    Cocq, de P.

    2012-01-01

    The forces exerted by a rider on a horse have a direct influence on the mechanical load experienced by the horse and consequently on its motion pattern. The aim of this thesis is to explore the biomechanical interaction between rider, saddle and horse in order to get insight in the loading of

  19. Incidence of Bacterial Pathogens following Biomechanical ...

    African Journals Online (AJOL)

    A correlation exists between endodontic microflora in pulpal disease and endodontic treatment failure. This study presents data on the recoverable bacterial pathogens following biomechanical treatment of infected root canals. Standard endodontic procedure were used to access tooth pulp cavity, processed and fluid ...

  20. In vivo biomechanics of cruciate ligament injuries

    NARCIS (Netherlands)

    Van de Velde, S.K.

    2016-01-01

    Measuring biomechanics of the knee with an acceptable degree of accuracy is difficult. When the in vivo knee joint motion is analyzed in all its six degrees-of-freedom without compromising on physiological loading conditions, the task becomes even more challenging. This thesis offers a brief

  1. A Biomechanical Analysis of the Karate Chop.

    Science.gov (United States)

    Cavanagh, Peter R.; Landa, Jean

    Although the sport of karate has been somewhat neglected by scientists, the following two isolated biomechanical studies exist in literature: (1) tracings of a karate chop in two planes were presented, but no data was given concerning the rates of movement of the limb segments, and (2) pre- and postimpact phenomena of five subjects were studied,…

  2. Biomechanics Scholar Citations across Academic Ranks

    Directory of Open Access Journals (Sweden)

    Knudson Duane

    2015-11-01

    Full Text Available Study aim: citations to the publications of a scholar have been used as a measure of the quality or influence of their research record. A world-wide descriptive study of the citations to the publications of biomechanics scholars of various academic ranks was conducted.

  3. Expose Mechanical Engineering Students to Biomechanics Topics

    Science.gov (United States)

    Shen, Hui

    2011-01-01

    To adapt the focus of engineering education to emerging new industries and technologies nationwide and in the local area, a biomechanics module has been developed and incorporated into a mechanical engineering technical elective course to expose mechanical engineering students at ONU (Ohio Northern University) to the biomedical engineering topics.…

  4. Biomechanics of the pelvic floor musculature

    NARCIS (Netherlands)

    Janda, S.

    2006-01-01

    The present thesis was motivated by two main goals. The first research goal of the thesis was to understand the complex biomechanical behaviour of the pelvic floor muscles. The second goal was to study the mechanism of the pelvic organ prolapse (genital prolapse). The pelvic floor in humans is a

  5. Injury incidence and selected biomechanical, postural and ...

    African Journals Online (AJOL)

    The strongest predictors for lower extremity injuries (I>0.3) were uneven hips, pronated feet, tight hamstrings, anatomical leg length differences, gait pronation and a tall stature. It was concluded that certain postural and biomechanical imbalances in the lower extremities could contribute to injury among rugby union players.

  6. Biomechanical analysis of drop and countermovement jumps

    NARCIS (Netherlands)

    Bobbert, M. F.; Mackay, M.T.; Schinkelshoek, D.; Huijing, P. A.; van Ingen Schenau, G. J.

    For 13 subjects the performance of drop jumps from a height of 40 cm (DJ) and of countermovement jumps (CMJ) was analysed and compared. From force plate and cine data biomechanical variables including forces, moments, power output and amount of work done were calculated for hip, knee and ankle

  7. Biomechanical comparison of transoral and transbuccal lateral ...

    African Journals Online (AJOL)

    Objectives: The purpose of this experimental study was to compare the biomechanical behaviors of two different types of osteosynthesis that are used in the treatment of mandibular angle fractures. Materials and Methods: Twenty synthetic polyurethane human mandible replicas, with medullar and cortical portions, were ...

  8. Biomechanics and mechanobiology in functional tissue engineering.

    Science.gov (United States)

    Guilak, Farshid; Butler, David L; Goldstein, Steven A; Baaijens, Frank P T

    2014-06-27

    The field of tissue engineering continues to expand and mature, and several products are now in clinical use, with numerous other preclinical and clinical studies underway. However, specific challenges still remain in the repair or regeneration of tissues that serve a predominantly biomechanical function. Furthermore, it is now clear that mechanobiological interactions between cells and scaffolds can critically influence cell behavior, even in tissues and organs that do not serve an overt biomechanical role. Over the past decade, the field of "functional tissue engineering" has grown as a subfield of tissue engineering to address the challenges and questions on the role of biomechanics and mechanobiology in tissue engineering. Originally posed as a set of principles and guidelines for engineering of load-bearing tissues, functional tissue engineering has grown to encompass several related areas that have proven to have important implications for tissue repair and regeneration. These topics include measurement and modeling of the in vivo biomechanical environment; quantitative analysis of the mechanical properties of native tissues, scaffolds, and repair tissues; development of rationale criteria for the design and assessment of engineered tissues; investigation of the effects biomechanical factors on native and repair tissues, in vivo and in vitro; and development and application of computational models of tissue growth and remodeling. Here we further expand this paradigm and provide examples of the numerous advances in the field over the past decade. Consideration of these principles in the design process will hopefully improve the safety, efficacy, and overall success of engineered tissue replacements. Copyright © 2014 Elsevier Ltd. All rights reserved.

  9. Role of Aquaporin 0 in lens biomechanics

    Energy Technology Data Exchange (ETDEWEB)

    Sindhu Kumari, S.; Gupta, Neha [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); Shiels, Alan [Washington University School of Medicine, St. Louis, MO (United States); FitzGerald, Paul G. [Cell Biology and Human Anatomy, School of Medicine, University of California, Davis, CA (United States); Menon, Anil G. [University of Cincinnati College of Medicine, Cincinnati, OH (United States); Mathias, Richard T. [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); SUNY Eye Institute, NY (United States); Varadaraj, Kulandaiappan, E-mail: kulandaiappan.varadaraj@stonybrook.edu [Physiology and Biophysics, Stony Brook University, Stony Brook, NY (United States); SUNY Eye Institute, NY (United States)

    2015-07-10

    Maintenance of proper biomechanics of the eye lens is important for its structural integrity and for the process of accommodation to focus near and far objects. Several studies have shown that specialized cytoskeletal systems such as the beaded filament (BF) and spectrin-actin networks contribute to mammalian lens biomechanics; mutations or deletion in these proteins alters lens biomechanics. Aquaporin 0 (AQP0), which constitutes ∼45% of the total membrane proteins of lens fiber cells, has been shown to function as a water channel and a structural cell-to-cell adhesion (CTCA) protein. Our recent ex vivo study on AQP0 knockout (AQP0 KO) mouse lenses showed the CTCA function of AQP0 could be crucial for establishing the refractive index gradient. However, biomechanical studies on the role of AQP0 are lacking. The present investigation used wild type (WT), AQP5 KO (AQP5{sup −/−}), AQP0 KO (heterozygous KO: AQP0{sup +/−}; homozygous KO: AQP0{sup −/−}; all in C57BL/6J) and WT-FVB/N mouse lenses to learn more about the role of fiber cell AQPs in lens biomechanics. Electron microscopic images exhibited decreases in lens fiber cell compaction and increases in extracellular space due to deletion of even one allele of AQP0. Biomechanical assay revealed that loss of one or both alleles of AQP0 caused a significant reduction in the compressive load-bearing capacity of the lenses compared to WT lenses. Conversely, loss of AQP5 did not alter the lens load-bearing ability. Compressive load-bearing at the suture area of AQP0{sup +/−} lenses showed easy separation while WT lens suture remained intact. These data from KO mouse lenses in conjunction with previous studies on lens-specific BF proteins (CP49 and filensin) suggest that AQP0 and BF proteins could act co-operatively in establishing normal lens biomechanics. We hypothesize that AQP0, with its prolific expression at the fiber cell membrane, could provide anchorage for cytoskeletal structures like BFs and

  10. Biomechanical research in artistic gymnastics: a review.

    Science.gov (United States)

    Prassas, Spiros; Kwon, Young-Hoo; Sands, William A

    2006-07-01

    Biomechanical research into artistic gymnastics has grown substantially over the years. However, most research is still skill oriented with few tries at generalization. Consequently, our understanding of the principles and bases of the sport, although improved, is still marginal with gaps in knowledge about technique attributes throughout the sport. For that reason, this review begins with an attempt to identify important variables contributing to successful performance. The review is presented in clusters of work in similar apparatuses culminating in Tables offering an 'at a glance' summary of knowledge in each cluster. The last section of the review tries to give some direction to future biomechanical research in gymnastics in issues relating to data collection--two-dimensional or three-dimensional, image size, frame rate--and analysis, such as descriptive or explanatory, simulation and optimization, and statistical issues.

  11. Biomedical Imaging and Computational Modeling in Biomechanics

    CERN Document Server

    Iacoviello, Daniela

    2013-01-01

    This book collects the state-of-art and new trends in image analysis and biomechanics. It covers a wide field of scientific and cultural topics, ranging from remodeling of bone tissue under the mechanical stimulus up to optimizing the performance of sports equipment, through the patient-specific modeling in orthopedics, microtomography and its application in oral and implant research, computational modeling in the field of hip prostheses, image based model development and analysis of the human knee joint, kinematics of the hip joint, micro-scale analysis of compositional and mechanical properties of dentin, automated techniques for cervical cell image analysis, and iomedical imaging and computational modeling in cardiovascular disease.   The book will be of interest to researchers, Ph.D students, and graduate students with multidisciplinary interests related to image analysis and understanding, medical imaging, biomechanics, simulation and modeling, experimental analysis.

  12. Biomechanical study of percutaneous lumbar diskectomy

    International Nuclear Information System (INIS)

    Li Yuan; Huang Xianglong; Shen Tianzhen; Hu Zhou; Hong Shuizong; Mei Haiying

    2003-01-01

    Objective: To investigate the stiffness of lumbar spine after the injury caused by percutaneous diskectomy and evaluate the efficiency of percutaneous lumbar diskectomy by biomechanical study. Methods: Four fresh lumbar specimens were used to analyse load-displacement curves in the intact lumbar spine and vertical disc-injured lumbar spine. The concepts of average flexibility coefficient (f) and standardized average flexibility coefficient (fs) were also introduced. Results: The load-displacement curves showed a good stabilization effect of the intact lumbar spine and disc-injured lumbar spine in flexion, extension, right and left bending. The decrease of anti-rotation also can be detected (P<0.05). Conclusion: In biomechanical study, percutaneous lumbar diskectomy is one of the efficiency methods to treat lumbar diac hernia

  13. Biomechanical considerations in mandibular incisor extraction cases.

    Science.gov (United States)

    Rachala, Madhukar Reddy; Aileni, Kaladhar Reddy; Dasari, Arun Kumar; Sinojiya, Jay

    2015-01-01

    Mandibular incisor extraction can be regarded as a valuable treatment option in certain malocclusions to obtain excellence in orthodontic results in terms of function, aesthetics and stability. This treatment alternative is indicated in clinical situations like mild to moderate class III malocclusion, mild anterior mandibular tooth size excess, periodontally compromised teeth, ectopic eruption of mandibular incisor and minimal openbite tendencies. Unlike in premolar extraction cases, space closure in mandibular incisor extraction cases is unique in which the extraction space will be in the middle of the arch. The end result of space closure in these cases should be well aligned, upright, anterior teeth with parallel roots and the goal can be achieved with the bodily tooth movement through proper application of biomechanics. The purpose of this article is to explain the biomechanics of space closure in mandibular incisor extraction cases.

  14. Biomechanics/risk management (Working Group 2)

    DEFF Research Database (Denmark)

    Sanz, Mariano; Naert, Ignace; Gotfredsen, Klaus

    2009-01-01

    survival and complications of implant supported restorations? * A systematic review on the accuracy and the clinical outcome of computer-guided template based implant dentistry. * What is the impact of systemic bisphosphonates on patients undergoing oral implant therapy? * What is the impact......INTRODUCTION: The remit of this workgroup was to update the existing knowledge base in biomechanical factors, navigation systems and medications that may affect the outcome of implant therapy. MATERIAL AND METHODS: The literature was systematically searched and critically reviewed. Five manuscripts...... were produced in five specific topics identified as areas where innovative approaches have been developed in biomechanical factors, navigation systems and medications that may affect the outcome of implant therapy. RESULTS: The results and conclusions of the review process are presented...

  15. Numerical Simulation of Some Biomechanical Problems

    Czech Academy of Sciences Publication Activity Database

    Nedoma, Jiří; Klézl, Z.; Fousek, J.; Kestřánek, Zdeněk; Stehlík, J.

    2003-01-01

    Roč. 61, 3-6 (2003), s. 283-295 ISSN 0378-4754. [MODELLING 2001. IMACS Conference on Mathematical Modelling and Computational Methods in Mechanics, Physics , Biomechanics and Geodynamics /2./. Pilsen, 19.06.2001-25.06.2001] Institutional research plan: AV0Z1030915 Keywords : non-linear elasticity * contact problems * variational inequality * finite element method * wrist * spine * fracture Subject RIV: BA - General Mathematics Impact factor: 0.558, year: 2003

  16. Analysis of Biomechanical Factors in Bend Running

    OpenAIRE

    Bing Zhang; Xinping You; Feng Li

    2013-01-01

    Sprint running is the demonstration of comprehensive abilities of technology and tactics, under various conditions. However, whether it is just to allocate the tracks for short-distance athletes from different racetracks has been the hot topic. This study analyzes its forces, differences in different tracks and winding influences, in the aspects of sport biomechanics. The results indicate, many disadvantages exist in inner tracks, middle tracks are the best and outer ones are inferior to midd...

  17. [Fundamental biomechanic problems on osteosynthesis (author's transl)].

    Science.gov (United States)

    Labitzke, R

    1976-02-26

    By means of compression plate osteosynthesis, of the lateral tension band and of the treatment with external chucks the main demand for stability of osteosynthesises is derivated: by adjustified, in the resultant axial tension of the metal implantats is to produce only pressure in the entire fracture zone without detrimental osteosynthesis induced excentric powers. The joint biomechanic aspects of the three methods are worked out.

  18. Biomechanical Factors in Planning of Periacetabular Osteotomy

    Directory of Open Access Journals (Sweden)

    Noushin eNiknafs

    2013-12-01

    Full Text Available This study addresses the effects of cartilage thickness distribution and compressive properties in the context of optimal alignment planning for periacetabular osteotomy (PAO. The Biomechanical Guidance System (BGS is a computer-assisted surgical suite assisting surgeon’s in determining the most beneficial new alignment of a patient’s acetabulum. The BGS uses biomechanical analysis of the hip to find this optimal alignment. Articular cartilage is an essential component of this analysis and its physical properties can affect contact pressure outcomes. Patient-specific hip joint models created from CT scans of a cohort of 29 dysplastic subjects were tested with four different cartilage thickness profiles (one uniform and threenonuniform and two sets of compressive characteristics. For each combination of thickness distribution and compressive properties, the optimal alignment of the acetabulum was found; the resultant geometric and biomechanical characterization of the hip were compared among the optimal alignments. There was an average decrease of 49.2 +/- 22.27% in peak contact pressure from the preoperative to the optimal alignment over all patients. We observed an average increase of 19 +/- 7.7 degrees in center-edge angle and an average decrease of 19.5 +/- 8.4 degrees in acetabular index angle from the preoperative case to the optimized plan. The optimal alignment increased the lateral coverage of the femoral head and decreased the obliqueness of the acetabular roof in all patients. These anatomical observations were independent of the choice for either cartilage thickness profile, or compressive properties. While patient-specific acetabular morphology is essential for surgeons in planning PAO, the predicted optimal alignment of the acetabulum was not significantly sensitive to the choice of cartilage thickness distribution over the acetabulum. However, in all groups the biomechanically predicted optimal alignment resulted in decreased

  19. Integrative Structural Biomechanical Concepts of Ankylosing Spondylitis

    OpenAIRE

    Alfonse T. Masi; Kalyani Nair; Brian J. Andonian; Kristina M. Prus; Joseph Kelly; Jose R. Sanchez; Jacqueline Henderson

    2011-01-01

    Ankylosing spondylitis (AS) is not fully explained by inflammatory processes. Clinical, epidemiological, genetic, and course of disease features indicate additional host-related risk processes and predispositions. Collectively, the pattern of predisposition to onset in adolescent and young adult ages, male preponderance, and widely varied severity of AS is unique among rheumatic diseases. However, this pattern could reflect biomechanical and structural differences between the sexes, naturally...

  20. Biomechanics of the pelvic floor musculature

    OpenAIRE

    Janda, S.

    2006-01-01

    The present thesis was motivated by two main goals. The first research goal of the thesis was to understand the complex biomechanical behaviour of the pelvic floor muscles. The second goal was to study the mechanism of the pelvic organ prolapse (genital prolapse). The pelvic floor in humans is a very complex muscular structure. It is largely responsible for supporting both pelvic and abdominal organs and acts synergistically with the striated muscle of the anterior abdominal wall to generate ...

  1. Computational Biomechanics Theoretical Background and BiologicalBiomedical Problems

    CERN Document Server

    Tanaka, Masao; Nakamura, Masanori

    2012-01-01

    Rapid developments have taken place in biological/biomedical measurement and imaging technologies as well as in computer analysis and information technologies. The increase in data obtained with such technologies invites the reader into a virtual world that represents realistic biological tissue or organ structures in digital form and allows for simulation and what is called “in silico medicine.” This volume is the third in a textbook series and covers both the basics of continuum mechanics of biosolids and biofluids and the theoretical core of computational methods for continuum mechanics analyses. Several biomechanics problems are provided for better understanding of computational modeling and analysis. Topics include the mechanics of solid and fluid bodies, fundamental characteristics of biosolids and biofluids, computational methods in biomechanics analysis/simulation, practical problems in orthopedic biomechanics, dental biomechanics, ophthalmic biomechanics, cardiovascular biomechanics, hemodynamics...

  2. Basic biomechanic principles of knee instability.

    Science.gov (United States)

    Zlotnicki, Jason P; Naendrup, Jan-Hendrik; Ferrer, Gerald A; Debski, Richard E

    2016-06-01

    Motion at the knee joint is a complex mechanical phenomenon. Stability is provided by a combination of static and dynamic structures that work in concert to prevent excessive movement or instability that is inherent in various knee injuries. The anterior cruciate ligament (ACL) is a main stabilizer of the knee, providing both translational and rotatory constraint. Despite the high volume of research directed at native ACL function, pathogenesis and surgical reconstruction of this structure, a gold standard for objective quantification of injury and subsequent repair, has not been demonstrated. Furthermore, recent studies have suggested that novel anatomic structures may play a significant role in knee stability. The use of biomechanical principles and testing techniques provides essential objective/quantitative information on the function of bone, ligaments, joint capsule, and other contributing soft tissues in response to various loading conditions. This review discusses the principles of biomechanics in relation to knee stability, with a focus on the objective quantification of knee stability, the individual contributions of specific knee structures to stability, and the most recent technological advances in the biomechanical evaluation of the knee joint.

  3. Morphology and biomechanics of human heart

    Science.gov (United States)

    Chelnokova, Natalia O.; Golyadkina, Anastasiya A.; Kirillova, Irina V.; Polienko, Asel V.; Ivanov, Dmitry V.

    2016-03-01

    Object of study: A study of the biomechanical characteristics of the human heart ventricles was performed. 80 hearts were extracted during autopsy of 80 corpses of adults (40 women and 40 men) aged 31-70 years. The samples were investigated in compliance with the recommendations of the ethics committee. Methods: Tension and compression tests were performed with help of the uniaxial testing machine Instron 5944. Cardiometry was also performed. Results: In this work, techniques for human heart ventricle wall biomechanical properties estimation were developed. Regularities of age and gender variability in deformative and strength properties of the right and left ventricle walls were found. These properties were characterized by a smooth growth of myocardial tissue stiffness and resistivity at a relatively low strain against reduction in their strength and elasticity from 31-40 to 61-70 years. It was found that tissue of the left ventricle at 61-70 years had a lower stretchability and strength compared with tissues of the right ventricle and septum. These data expands understanding of the morphological organization of the heart ventricles, which is very important for the development of personalized medicine. Taking into account individual, age and gender differences of the heart ventricle tissue biomechanical characteristics allows to rationally choosing the type of patching materials during reconstructive operations on heart.

  4. An introduction to biomechanics solids and fluids, analysis and design

    CERN Document Server

    Humphrey, Jay D

    2004-01-01

    Designed to meet the needs of undergraduate students, Introduction to Biomechanics takes the fresh approach of combining the viewpoints of both a well-respected teacher and a successful student. With an eye toward practicality without loss of depth of instruction, this book seeks to explain the fundamental concepts of biomechanics. With the accompanying web site providing models, sample problems, review questions and more, Introduction to Biomechanics provides students with the full range of instructional material for this complex and dynamic field.

  5. Biomechanical Studies and Optical Digitizer Development for Enhanced Orthopedic Footwear

    National Research Council Canada - National Science Library

    Houston, Vern

    2001-01-01

    .... Custom designed and manufactured orthopedic footwear is also an essential component in treatment and rehabilitative care of persons with neuromusculoskeletal foot/ankle pathologies, biomechanical...

  6. The biomechanics of soccer: a review.

    Science.gov (United States)

    Lees, A; Nolan, L

    1998-04-01

    This review considers the biomechanical factors that are relevant to success in the game of soccer. Three broad areas are covered: (1) the technical performance of soccer skills; (2) the equipment used in playing the game; and (3) the causative mechanisms of specific soccer injuries. Kicking is the most widely studied soccer skill. Although there are many types of kick, the variant most widely reported in the literature is the maximum velocity instep kick of a stationary ball. In contrast, several other skills, such as throwing-in and goalkeeping, have received little attention; some, for example passing and trapping the ball, tackling, falling behaviour, jumping, running, sprinting, starting, stopping and changing direction, have not been the subject of any detailed biomechanical investigation. The items of equipment reviewed are boots, the ball, artificial and natural turf surfaces and shin guards. Little of the research conducted by equipment manufacturers is in the public domain; this part of the review therefore concentrates on the mechanical responses of equipment, player-equipment interaction, and the effects of equipment on player performance and protection. Although the equipment has mechanical characteristics that can be reasonably well quantified, the player-equipment interaction is more difficult to establish; this makes its efficacy for performance or protection difficult to predict. Some soccer injuries may be attributable to the equipment used. The soccer boot has a poor protective capability, but careful design can have a minor influence on reducing the severity of ankle inversion injuries. Performance requirements limit the scope for reducing these injuries; alternative methods for providing ankle stability are necessary. Artificial surfaces result in injury profiles different from those on natural turf pitches. There is a tendency for fewer serious injuries, but more minor injuries, on artificial turf than on natural turf pitches. Players adapt to

  7. Modelling biomechanics of bark patterning in grasstrees.

    Science.gov (United States)

    Dale, Holly; Runions, Adam; Hobill, David; Prusinkiewicz, Przemyslaw

    2014-09-01

    Bark patterns are a visually important characteristic of trees, typically attributed to fractures occurring during secondary growth of the trunk and branches. An understanding of bark pattern formation has been hampered by insufficient information regarding the biomechanical properties of bark and the corresponding difficulties in faithfully modelling bark fractures using continuum mechanics. This study focuses on the genus Xanthorrhoea (grasstrees), which have an unusual bark-like structure composed of distinct leaf bases connected by sticky resin. Due to its discrete character, this structure is well suited for computational studies. A dynamic computational model of grasstree development was created. The model captures both the phyllotactic pattern of leaf bases during primary growth and the changes in the trunk's width during secondary growth. A biomechanical representation based on a system of masses connected by springs is used for the surface of the trunk, permitting the emergence of fractures during secondary growth to be simulated. The resulting fracture patterns were analysed statistically and compared with images of real trees. The model reproduces key features of grasstree bark patterns, including their variability, spanning elongated and reticulate forms. The patterns produced by the model have the same statistical character as those seen in real trees. The model was able to support the general hypothesis that the patterns observed in the grasstree bark-like layer may be explained in terms of mechanical fractures driven by secondary growth. Although the generality of the results is limited by the unusual structure of grasstree bark, it supports the hypothesis that bark pattern formation is primarily a biomechanical phenomenon.

  8. Head Impact Biomechanics in Women's College Soccer.

    Science.gov (United States)

    Lynall, Robert C; Clark, Michael D; Grand, Erin E; Stucker, Jaclyn C; Littleton, Ashley C; Aguilar, Alain J; Petschauer, Meredith A; Teel, Elizabeth F; Mihalik, Jason P

    2016-09-01

    There are limited nonlaboratory soccer head impact biomechanics data. This is surprising given soccer's global popularity. Epidemiological data suggest that female college soccer players are at a greater concussion injury risk than their male counterparts. Therefore, the purposes of our study were to quantify head impact frequency and magnitude during women's soccer practices and games in the National Collegiate Athletic Association and to characterize these data across event type, playing position, year on the team, and segment of game (first and second halves). Head impact biomechanics were collected from female college soccer players (n = 22; mean ± SD age = 19.1 ± 0.1 yr, height = 168.0 ± 3.5 cm, mass = 63.7 ± 6.0 kg). We employed a helmetless head impact measurement device (X2 Biosystems xPatch) before each competition and practice across a single season. Peak linear and rotational accelerations were categorized based on impact magnitude and subsequently analyzed using appropriate nonparametric analyses. Overall, women's college soccer players experience approximately seven impacts per 90 min of game play. The overwhelming majority (~90%) of all head impacts were categorized into our mildest linear acceleration impact classification (10g-20g). Interestingly, a higher percentage of practice impacts in the 20g-40g range compared with games (11% vs 7%) was observed. Head impact biomechanics studies have provided valuable insights into understanding collision sports and for informing evidence-based rule and policy changes. These have included changing the football kickoff, ice hockey body checking ages, and head-to-head hits in both sports. Given soccer's global popularity, and the growing public concern for the potential long-term neurological implications of collision and contact sports, studying soccer has the potential to impact many athletes and the sports medicine professionals caring for them.

  9. Biomechanical study of the funnel technique applied in thoracic ...

    African Journals Online (AJOL)

    Background: Funnel technique is a method used for the insertion of screw into thoracic pedicle. Aim: To evaluate the biomechanical characteristics of thoracic pedicle screw placement using the Funnel technique, trying to provide biomechanical basis for clinical application of this technology. Methods: 14 functional spinal ...

  10. Factors Related to Students' Learning of Biomechanics Concepts

    Science.gov (United States)

    Hsieh, ChengTu; Smith, Jeremy D.; Bohne, Michael; Knudson, Duane

    2012-01-01

    The purpose of this study was to replicate and expand a previous study to identify the factors that affect students' learning of biomechanical concepts. Students were recruited from three universities (N = 149) located in the central and western regions of the United States. Data from 142 students completing the Biomechanics Concept Inventory…

  11. Biomechanical effects of trees on soil and regolith: beyond treethrow

    Science.gov (United States)

    Jonathan D. Phillips; Daniel A. Marion

    2006-01-01

    Forest soils are profoundly influenced by the biomechanical as well as the chemical and biological effects of trees. Studies of biomechanical impacts have focused mainly on uprooting (treethrow), but this study shows that at least two other effects are significant: physical displacement of soil by root growth, and infilling of stump rot pits. Rocky soils in the...

  12. The Undergraduate Biomechanics Experience at Iowa State University.

    Science.gov (United States)

    Francis, Peter R.

    This paper discusses the objectives of a program in biomechanics--the analysis of sports skills and movement--and the evolution of the biomechanics program at Iowa State University. The primary objective of such a course is to provide the student with the basic tools necessary for adequate analysis of human movement, with special emphasis upon…

  13. Steven Vogel and His Theory of Comparative Biomechanics

    Indian Academy of Sciences (India)

    IAS Admin

    motivating examples of biological systems. Vogel's books are different. He truly talks about biomechanics or rather comparative bio- mechanics. The book is perfect for teaching biomechan- ics to biology students. It will surely sensitize them to mechanics. But what about engineer- ing students who presumably know mechan ...

  14. Biomechanics, Exercise Physiology, and the 75th Anniversary of RQES

    Science.gov (United States)

    Hamill, Joseph; Haymes, Emily M.

    2005-01-01

    The purpose of this paper is to review the biomechanics and exercise physiology studies published in the Research Quarterly for Exercise and Sport (RQES) over the past 75 years. Studies in biomechanics, a relatively new subdiscipline that evolved from kinesiology, first appeared in the journal about 40 years ago. Exercise physiology studies have…

  15. Biomechanical studies: science (f)or common sense?

    NARCIS (Netherlands)

    Mellema, Jos J.; Doornberg, Job N.; Guitton, Thierry G.; Ring, David; van der Zwan, A. L.; Spoor, A. B.; van Vugt, A. B.; Armstrong, A. D.; Shrivastava, A.; Wahegaonkar, A. L.; Shafritz, A. B.; Adams, J.; Ilyas, A.; Vochteloo, A. J. H.; Castillo, A. P.; Basak, A.; Andreas, P.; Barquet, A.; Kristan, A.; Berner, A.; Ranade, A. B.; Ashish, S.; Terrono, A. L.; Jubel, A.; Frieman, B.; Bamberger, H. B.; van den Bekerom, M. P. J.; Belangero, W. D.; Hearon, B. F.; Boler, J. M.; Walter, F. L.; Boyer, M.; Wills, B. P. D.; Broekhuyse, H.; Buckley, R.; Watkins, B.; Sears, B. W.; Calfee, R. P.; Ekholm, C.; Fernandes, C. H.; Swigart, C.; Cassidy, C.; Wilson, C. J.; Bainbridge, L. C.; Wilson, C.; Jones, C. M.; Cornell, C.; Crist, B. D.; van Deurzen, D. F. P.; Beingessner, D.; Rowland, D. J.; Della Rocca, G. J.; Eygendaal, D.; McKee, D. M.; Verbeek, D. O. F.; Kalainov, D. M.; Polatsch, D.; Barreto, C. J. R.; Merchant, M.; Brilej, D.; Bijlani, N.; Silva, D. M.; Maman, E.; Ibrahim, I. M.; Nyszkiewicz, R.; Henry, P. D. G.; Ruchelsman, D.; Vishwanath, I. M.; Scott, D. F.; Harvey, E.; Grosso, E.; Stojkovska, E.; Pemovska, N. N.; Tolo, E. T.; Schumer, E. D.; Suarez, F.; Frihagen, F.; Lopez-Gonzalez, F.; Rodríguez, F. M.; Caro, G. C. Zambrano; Garnavos, C.; Athwal, G. S.; DeSilva, G.; Dyer, G. S. M.; Babis, G. C.; Gradl, G.; Frykman, G. K.; Gaston, R. G.; Garrigues, G.; Bayne, G. J.; Merrell, G.; Hernandez, G. R.; Gadbled, G.; Campinhos, L. A. B.; Balfour, G. W.; van der Heide, H.; Nancollas, M.; Young, C.; Pess, G. M.; Goost, H.; Alonso, H.; Villamizar, N. N.; Awan, H.; Routman, H. D.; Kimball, H. L.; Hofmeister, E.; McGraw, I.; Erol, K.; Biert, J.; Goslings, J. C.; Di Giovanni, J. F.; Bishop, J.; Abzug, J. M.; Greenberg, J. A.; Ahn, J.; McAuliffe, J.; Fanuele, J. C.; Boretto, J. G.; Choueka, J.; Murachovsky, J.; Ribeiro Filho, J. E. G.; Isaacs, J.; Izzi, J. A.; Kellam, J.; Giuffre, J. L.; Conflitti, J. M.; Wolf, J. M.; Scheer, J. H.; Capo, J. T.; Rubio, J.; Taras, J.; Wint, J.; Wolkenfelt, J.; Kakar, S.; Chivers, K.; Zyto, K.; Keener, J. D.; Eng, K.; Jeray, K.; Lee, K.; Malone, K. J.; Kabir, K.; Kraan, G. A.; Radcliff, K.; Dickson, K.; Poelhekke, L. M. S. J.; Mica, L.; Weiss, L.; Adolfsson, L. E.; Borris, L. C.; Lasanianos, N. G.; Schulte, L. M.; Paz, L.; Felipe, N. E. L.; Verhofstad, N. N.; van de Sande, M. A. J.; Mormino, M.; Richard, M. J.; Bonczar, M.; Hammerberg, E. M.; Menon, M.; Mazzocca, A. D.; Bronkhorst, M. W. G. A.; McKee, M.; Soong, M.; Costanzo, R. M.; Wood, M. M.; Abdel-Ghany, M. I.; Baskies, M.; Behrman, M.; Quell, M.; Kessler, M. W.; Palmer, M. J.; Prayson, M.; Pirpiris, M.; Ragsdell, M. M.; Krijnen, M. R.; Tyllianakis, M.; Grafe, M. W.; Schep, N.; Nelson, E.; Akabudike, N. M.; Shortt, N. L.; Horangic, N. J.; Leung, N. L.; Gummerson, N. W.; Kanakaris, N. K.; Wilson, N.; Calandruccio, J.; Semenkin, O. M.; Omid, R.; Veillette, C. J. H.; Richardson, M.; Ortiz, J. A.; Forigua, J. E.; Brink, P. R. G.; Kloen, P.; van Eerten, P. V.; Prashanth, I.; Althausen, P.; Lygdas, P.; Parnes, N.; Martineau, P. A.; Benhaim, P.; Blazar, P.; Schandelmaier, N. N.; Petrisor, B.; Jebson, P.; Levin, P.; Batson, W. A.; García, F.; Owens, P. W.; Guenter, L.; Haverlag, R.; Peters, R. W.; de Bedout, R.; Shatford, R.; Rowinski, S.; Verhagen, R. A. W.; Babst, R. H.; Hauck, R.; Papandrea, R.; Gilbert, R. S.; Rizzo, M.; Jenkinson, R.; Hutchison, R. L.; Liem, R.; Smith, R. M.; Tashijan, R.; Zura, R. D.; Page, R. S.; Pesantez, R.; Wagenmakers, R.; Abrams, J.; Spruijt, S.; Kennedy, S. A.; Mehta, S.; Beldner, S.; Schmidt, A.; Mitchell, S.; Fischer, S. T.; Checchia, S. L.; Dodds, S.; Nolan, B. M.; Kaplan, S.; Kaar, S. G.; Kronlage, S.; Meylaerts, S. A.; Steinmann, S.; McCabe, S. J.; Streubel, P. N.; Omara, T.; Swiontkowski, M.; Gosens, T.; DeCoster, T.; Taitsman, L.; Baxamusa, T.; Dienstknecht, T.; Kaplan, F. T. D.; Siff, T.; Begue, T.; Higgins, T.; Mittlmeier, T.; Apard, T.; Hughes, T.; Havliček, T.; Wyrick, T.; Rozental, N. N.; Stackhouse, T. G.; Giordano, V.; Varecka, T. F.; Nikolaou, V. S.; Jokhi, V.; Philippe, V.; Wall, C. J.; Walsh, C. J.; Hammert, W. C.; Weil, Y.; Satora, W.; Wright, T.; Zalavras, C.

    2014-01-01

    It is our impression that many biomechanical studies invest substantial resources studying the obvious: that more and larger metal is stronger. The purpose of this study is to evaluate if a subset of biomechanical studies comparing fixation constructs just document common sense. Using a web-based

  16. High resolution extremity CT for biomechanics modeling

    International Nuclear Information System (INIS)

    Ashby, A.E.; Brand, H.; Hollerbach, K.; Logan, C.M.; Martz, H.E.

    1995-01-01

    With the advent of ever more powerful computing and finite element analysis (FEA) capabilities, the bone and joint geometry detail available from either commercial surface definitions or from medical CT scans is inadequate. For dynamic FEA modeling of joints, precise articular contours are necessary to get appropriate contact definition. In this project, a fresh cadaver extremity was suspended in parafin in a lucite cylinder and then scanned with an industrial CT system to generate a high resolution data set for use in biomechanics modeling

  17. High resolution extremity CT for biomechanics modeling

    Energy Technology Data Exchange (ETDEWEB)

    Ashby, A.E.; Brand, H.; Hollerbach, K.; Logan, C.M.; Martz, H.E.

    1995-09-23

    With the advent of ever more powerful computing and finite element analysis (FEA) capabilities, the bone and joint geometry detail available from either commercial surface definitions or from medical CT scans is inadequate. For dynamic FEA modeling of joints, precise articular contours are necessary to get appropriate contact definition. In this project, a fresh cadaver extremity was suspended in parafin in a lucite cylinder and then scanned with an industrial CT system to generate a high resolution data set for use in biomechanics modeling.

  18. Biomechanical factors associated with the development of tibiofemoral knee osteoarthritis

    DEFF Research Database (Denmark)

    van Tunen, Joyce A C; Dell'Isola, Andrea; Juhl, Carsten

    2016-01-01

    INTRODUCTION: Altered biomechanics, increased joint loading and tissue damage, might be related in a vicious cycle within the development of knee osteoarthritis (KOA). We have defined biomechanical factors as joint-related factors that interact with the forces, moments and kinematics in and around...... a synovial joint. Although a number of studies and systematic reviews have been performed to assess the association of various factors with the development of KOA, a comprehensive overview focusing on biomechanical factors that are associated with the development of KOA is not available. The aim...... of this review is (1) to identify biomechanical factors that are associated with (the development of) KOA and (2) to identify the impact of other relevant risk factors on this association. METHODS AND ANALYSIS: Cohort, cross-sectional and case-control studies investigating the association of a biomechanical...

  19. Integrative Structural Biomechanical Concepts of Ankylosing Spondylitis

    Directory of Open Access Journals (Sweden)

    Alfonse T. Masi

    2011-01-01

    Full Text Available Ankylosing spondylitis (AS is not fully explained by inflammatory processes. Clinical, epidemiological, genetic, and course of disease features indicate additional host-related risk processes and predispositions. Collectively, the pattern of predisposition to onset in adolescent and young adult ages, male preponderance, and widely varied severity of AS is unique among rheumatic diseases. However, this pattern could reflect biomechanical and structural differences between the sexes, naturally occurring musculoskeletal changes over life cycles, and a population polymorphism. During juvenile development, the body is more flexible and weaker than during adolescent maturation and young adulthood, when strengthening and stiffening considerably increase. During middle and later ages, the musculoskeletal system again weakens. The novel concept of an innate axial myofascial hypertonicity reflects basic mechanobiological principles in human function, tissue reactivity, and pathology. However, these processes have been little studied and require critical testing. The proposed physical mechanisms likely interact with recognized immunobiological pathways. The structural biomechanical processes and tissue reactions might possibly precede initiation of other AS-related pathways. Research in the combined structural mechanobiology and immunobiology processes promises to improve understanding of the initiation and perpetuation of AS than prevailing concepts. The combined processes might better explain characteristic enthesopathic and inflammatory processes in AS.

  20. Biomechanical metrics of aesthetic perception in dance.

    Science.gov (United States)

    Bronner, Shaw; Shippen, James

    2015-12-01

    The brain may be tuned to evaluate aesthetic perception through perceptual chunking when we observe the grace of the dancer. We modelled biomechanical metrics to explain biological determinants of aesthetic perception in dance. Eighteen expert (EXP) and intermediate (INT) dancers performed développé arabesque in three conditions: (1) slow tempo, (2) slow tempo with relevé, and (3) fast tempo. To compare biomechanical metrics of kinematic data, we calculated intra-excursion variability, principal component analysis (PCA), and dimensionless jerk for the gesture limb. Observers, all trained dancers, viewed motion capture stick figures of the trials and ranked each for aesthetic (1) proficiency and (2) movement smoothness. Statistical analyses included group by condition repeated-measures ANOVA for metric data; Mann-Whitney U rank and Friedman's rank tests for nonparametric rank data; Spearman's rho correlations to compare aesthetic rankings and metrics; and linear regression to examine which metric best quantified observers' aesthetic rankings, p dance movements revealed differences between groups and condition, p brain combines sensory motor elements into integrated units of behaviour. In this representation, the chunk of information which is remembered, and to which the observer reacts, is the elemental mode shape of the motion rather than physical displacements. This suggests that reduction in redundant information to a simplistic dimensionality is related to the experienced observer's aesthetic perception.

  1. Biomechanics of running with rocker shoes.

    Science.gov (United States)

    Sobhani, Sobhan; van den Heuvel, Edwin R; Dekker, Rienk; Postema, Klaas; Kluitenberg, Bas; Bredeweg, Steef W; Hijmans, Juha M

    2017-01-01

    Load reduction is an important consideration in conservative management of tendon overuse injuries such as Achilles tendinopathy. Previous research has shown that the use of rocker shoes can reduce the positive ankle power and plantar flexion moment which might help in unloading the Achilles tendon. Despite this promising implication of rocker shoes, the effects on hip and knee biomechanics remain unclear. Moreover, the effect of wearing rocker shoes on different running strike types is unexplored. The aim of this study was to investigate biomechanics of the ankle, knee and hip joints and the role of strike type on these outcomes. Randomized cross-over study. In this study, 16 female endurance runners underwent three-dimensional gait analysis wearing rocker shoes and standard shoes. We examined work, moments, and angles of the ankle, knee and hip during the stance phase of running. In comparison with standard shoes, running with rocker shoes significantly (pshoes significantly increased the positive work (14%), extension moment peak (6%), and extension moment impulse (12%). These findings indicate that although running with rocker shoes might lower mechanical load on the Achilles tendon, it could increase the risk of overuse injuries of the knee joint. Copyright © 2016 Sports Medicine Australia. Published by Elsevier Ltd. All rights reserved.

  2. Integrative structural biomechanical concepts of ankylosing spondylitis.

    Science.gov (United States)

    Masi, Alfonse T; Nair, Kalyani; Andonian, Brian J; Prus, Kristina M; Kelly, Joseph; Sanchez, Jose R; Henderson, Jacqueline

    2011-01-01

    Ankylosing spondylitis (AS) is not fully explained by inflammatory processes. Clinical, epidemiological, genetic, and course of disease features indicate additional host-related risk processes and predispositions. Collectively, the pattern of predisposition to onset in adolescent and young adult ages, male preponderance, and widely varied severity of AS is unique among rheumatic diseases. However, this pattern could reflect biomechanical and structural differences between the sexes, naturally occurring musculoskeletal changes over life cycles, and a population polymorphism. During juvenile development, the body is more flexible and weaker than during adolescent maturation and young adulthood, when strengthening and stiffening considerably increase. During middle and later ages, the musculoskeletal system again weakens. The novel concept of an innate axial myofascial hypertonicity reflects basic mechanobiological principles in human function, tissue reactivity, and pathology. However, these processes have been little studied and require critical testing. The proposed physical mechanisms likely interact with recognized immunobiological pathways. The structural biomechanical processes and tissue reactions might possibly precede initiation of other AS-related pathways. Research in the combined structural mechanobiology and immunobiology processes promises to improve understanding of the initiation and perpetuation of AS than prevailing concepts. The combined processes might better explain characteristic enthesopathic and inflammatory processes in AS.

  3. How few? Bayesian statistics in injury biomechanics.

    Science.gov (United States)

    Cutcliffe, Hattie C; Schmidt, Allison L; Lucas, Joseph E; Bass, Cameron R

    2012-10-01

    In injury biomechanics, there are currently no general a priori estimates of how few specimens are necessary to obtain sufficiently accurate injury risk curves for a given underlying distribution. Further, several methods are available for constructing these curves, and recent methods include Bayesian survival analysis. This study used statistical simulations to evaluate the fidelity of different injury risk methods using limited sample sizes across four different underlying distributions. Five risk curve techniques were evaluated, including Bayesian techniques. For the Bayesian analyses, various prior distributions were assessed, each incorporating more accurate information. Simulated subject injury and biomechanical input values were randomly sampled from each underlying distribution, and injury status was determined by comparing these values. Injury risk curves were developed for this data using each technique for various small sample sizes; for each, analyses on 2000 simulated data sets were performed. Resulting median predicted risk values and confidence intervals were compared with the underlying distributions. Across conditions, the standard and Bayesian survival analyses better represented the underlying distributions included in this study, especially for extreme (1, 10, and 90%) risk. This study demonstrates that the value of the Bayesian analysis is the use of informed priors. As the mean of the prior approaches the actual value, the sample size necessary for good reproduction of the underlying distribution with small confidence intervals can be as small as 2. This study provides estimates of confidence intervals and number of samples to allow the selection of the most appropriate sample sizes given known information.

  4. Adaptive sports technology and biomechanics: wheelchairs.

    Science.gov (United States)

    Cooper, Rory A; De Luigi, Arthur Jason

    2014-08-01

    Wheelchair sports are an important tool in the rehabilitation of people with severe chronic disabilities and have been a driving force for innovation in technology and practice. In this paper, we will present an overview of the adaptive technology used in Paralympic sports with a special focus on wheeled technology and the impact of design on performance (defined as achieving the greatest level of athletic ability and minimizing the risk of injury). Many advances in manual wheelchairs trace their origins to wheelchair sports. Features of wheelchairs that were used for racing and basketball 25 or more years ago have become integral to the manual wheelchairs that people now use every day; moreover, the current components used on ultralight wheelchairs also have benefitted from technological advances developed for sports wheelchairs. For example, the wheels now used on chairs for daily mobility incorporate many of the components first developed for sports chairs. Also, advances in manufacturing and the availability of aerospace materials have driven current wheelchair design and manufacture. Basic principles of sports wheelchair design are universal across sports and include fit; minimizing weight while maintaining high stiffness; minimizing rolling resistance; and optimizing the sports-specific design of the chair. However, a well-designed and fitted wheelchair is not sufficient for optimal sports performance: the athlete must be well trained, skilled, and use effective biomechanics because wheelchair athletes face some unique biomechanical challenges. Copyright © 2014 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

  5. Artificial intelligence in sports biomechanics: new dawn or false hope?

    Science.gov (United States)

    Bartlett, Roger

    2006-12-15

    This article reviews developments in the use of Artificial Intelligence (AI) in sports biomechanics over the last decade. It outlines possible uses of Expert Systems as diagnostic tools for evaluating faults in sports movements ('techniques') and presents some example knowledge rules for such an expert system. It then compares the analysis of sports techniques, in which Expert Systems have found little place to date, with gait analysis, in which they are routinely used. Consideration is then given to the use of Artificial Neural Networks (ANNs) in sports biomechanics, focusing on Kohonen self-organizing maps, which have been the most widely used in technique analysis, and multi-layer networks, which have been far more widely used in biomechanics in general. Examples of the use of ANNs in sports biomechanics are presented for javelin and discus throwing, shot putting and football kicking. I also present an example of the use of Evolutionary Computation in movement optimization in the soccer throw in, which predicted an optimal technique close to that in the coaching literature. After briefly overviewing the use of AI in both sports science and biomechanics in general, the article concludes with some speculations about future uses of AI in sports biomechanics. Key PointsExpert Systems remain almost unused in sports biomechanics, unlike in the similar discipline of gait analysis.Artificial Neural Networks, particularly Kohonen Maps, have been used, although their full value remains unclear.Other AI applications, including Evolutionary Computation, have received little attention.

  6. Teaching undergraduate biomechanics with Just-in-Time Teaching.

    Science.gov (United States)

    Riskowski, Jody L

    2015-06-01

    Biomechanics education is a vital component of kinesiology, sports medicine, and physical education, as well as for many biomedical engineering and bioengineering undergraduate programmes. Little research exists regarding effective teaching strategies for biomechanics. However, prior work suggests that student learning in undergraduate physics courses has been aided by using the Just-in-Time Teaching (JiTT). As physics understanding plays a role in biomechanics understanding, the purpose of study was to evaluate the use of a JiTT framework in an undergraduate biomechanics course. This two-year action-based research study evaluated three JiTT frameworks: (1) no JiTT; (2) mathematics-based JiTT; and (3) concept-based JiTT. A pre- and post-course assessment of student learning used the biomechanics concept inventory and a biomechanics concept map. A general linear model assessed differences between the course assessments by JiTT framework in order to evaluate learning and teaching effectiveness. The results indicated significantly higher learning gains and better conceptual understanding in a concept-based JiTT course, relative to a mathematics-based JiTT or no JiTT course structure. These results suggest that a course structure involving concept-based questions using a JiTT strategy may be an effective method for engaging undergraduate students and promoting learning in biomechanics courses.

  7. Biomechanical ToolKit: Open-source framework to visualize and process biomechanical data.

    Science.gov (United States)

    Barre, Arnaud; Armand, Stéphane

    2014-04-01

    C3D file format is widely used in the biomechanical field by companies and laboratories to store motion capture systems data. However, few software packages can visualize and modify the integrality of the data in the C3D file. Our objective was to develop an open-source and multi-platform framework to read, write, modify and visualize data from any motion analysis systems using standard (C3D) and proprietary file formats (used by many companies producing motion capture systems). The Biomechanical ToolKit (BTK) was developed to provide cost-effective and efficient tools for the biomechanical community to easily deal with motion analysis data. A large panel of operations is available to read, modify and process data through C++ API, bindings for high-level languages (Matlab, Octave, and Python), and standalone application (Mokka). All these tools are open-source and cross-platform and run on all major operating systems (Windows, Linux, MacOS X). Copyright © 2014 Elsevier Ireland Ltd. All rights reserved.

  8. Biomechanics trends in modeling and simulation

    CERN Document Server

    Ogden, Ray

    2017-01-01

    The book presents a state-of-the-art overview of biomechanical and mechanobiological modeling and simulation of soft biological tissues. Seven well-known scientists working in that particular field discuss topics such as biomolecules, networks and cells as well as failure, multi-scale, agent-based, bio-chemo-mechanical and finite element models appropriate for computational analysis. Applications include arteries, the heart, vascular stents and valve implants as well as adipose, brain, collagenous and engineered tissues. The mechanics of the whole cell and sub-cellular components as well as the extracellular matrix structure and mechanotransduction are described. In particular, the formation and remodeling of stress fibers, cytoskeletal contractility, cell adhesion and the mechanical regulation of fibroblast migration in healing myocardial infarcts are discussed. The essential ingredients of continuum mechanics are provided. Constitutive models of fiber-reinforced materials with an emphasis on arterial walls ...

  9. Physiopathology and biomechanics of hip osteoarthritis

    Directory of Open Access Journals (Sweden)

    M. Cutolo

    2011-09-01

    Full Text Available Several factors seem to play a relevant role in the pathogenesis of hip osteoarthritis. Among these, an altered biomechanic and neuromuscular integrity of the hip joint should be considered. This is a review of the recent international literature concerning the role of loads and strengths acting on the hip joint, in order to better understand the pathogenesis and the physiopathology of the hip osteoarthritis. The study of these factors might be important to prevent the development of the osteoarthritis and might suggest the conservative treatment. In particular, the role of the balance among the muscles working in maintaining the equilibrium of the acting strengths is matter of discussion. The articular and neuromuscular dysfunction might induce an altered load distribution in the hip, particularly on the articular cartilage surface, and seems to favour the development of hip osteoarthritis...

  10. Biomechanics of posterior dynamic stabilization systems.

    Science.gov (United States)

    Erbulut, D U; Zafarparandeh, I; Ozer, A F; Goel, V K

    2013-01-01

    Spinal rigid instrumentations have been used to fuse and stabilize spinal segments as a surgical treatment for various spinal disorders to date. This technology provides immediate stability after surgery until the natural fusion mass develops. At present, rigid fixation is the current gold standard in surgical treatment of chronic back pain spinal disorders. However, such systems have several drawbacks such as higher mechanical stress on the adjacent segment, leading to long-term degenerative changes and hypermobility that often necessitate additional fusion surgery. Dynamic stabilization systems have been suggested to address adjacent segment degeneration, which is considered to be a fusion-associated phenomenon. Dynamic stabilization systems are designed to preserve segmental stability, to keep the treated segment mobile, and to reduce or eliminate degenerative effects on adjacent segments. This paper aimed to describe the biomechanical aspect of dynamic stabilization systems as an alternative treatment to fusion for certain patients.

  11. Biomechanics of Posterior Dynamic Stabilization Systems

    Directory of Open Access Journals (Sweden)

    D. U. Erbulut

    2013-01-01

    Full Text Available Spinal rigid instrumentations have been used to fuse and stabilize spinal segments as a surgical treatment for various spinal disorders to date. This technology provides immediate stability after surgery until the natural fusion mass develops. At present, rigid fixation is the current gold standard in surgical treatment of chronic back pain spinal disorders. However, such systems have several drawbacks such as higher mechanical stress on the adjacent segment, leading to long-term degenerative changes and hypermobility that often necessitate additional fusion surgery. Dynamic stabilization systems have been suggested to address adjacent segment degeneration, which is considered to be a fusion-associated phenomenon. Dynamic stabilization systems are designed to preserve segmental stability, to keep the treated segment mobile, and to reduce or eliminate degenerative effects on adjacent segments. This paper aimed to describe the biomechanical aspect of dynamic stabilization systems as an alternative treatment to fusion for certain patients.

  12. Biomechanical research in dance: a literature review.

    Science.gov (United States)

    Krasnow, Donna; Wilmerding, M Virginia; Stecyk, Shane; Wyon, Matthew; Koutedakis, Yiannis

    2011-03-01

    The authors reviewed the literature, published from 1970 through December 2009, on biomechanical research in dance. To identify articles, the authors used search engines, including PubMed and Web of Science, five previous review articles, the Dance Medicine and Science Bibliography, and reference lists of theses, dissertations, and articles being reviewed. Any dance research articles (English language) involving the use of electromyography, forceplates, motion analysis using photography, cinematography or videography, and/or physics analysis were included. A total of 89 papers, theses/dissertations, and abstracts were identified and reviewed, grouped by the movement concept or specialized movements being studied: alignment (n = 8), plié (8), relevé (8), passé (3), degagé (3), développé (7), rond de jambe (3), grand battement (4), arm movements (1), forward stepping (3), turns (6), elevation work (28), falls (1), and dance-specific motor strategies (6). Several recurring themes emerged from these studies: that elite dancers demonstrate different and superior motor strategies than novices or nondancers; that dancers perform differently when using a barre as opposed to without a barre, both in terms of muscle activation patterns and weight shift strategies; that while skilled dancers tend to be more consistent across multiple trials of a task, considerable variability is seen among participants, even when matched for background, years of training, body type, and other variables; and that dance teachers recommend methods of achieving movement skills that are inconsistent with optimal biomechanical function, as well as inconsistent with strategies employed by elite dancers. Measurement tools and the efficacy of study methodologies are also discussed.

  13. A biomechanical model of mammographic compressions.

    Science.gov (United States)

    Chung, J H; Rajagopal, V; Nielsen, P M F; Nash, M P

    2008-02-01

    A number of biomechanical models have been proposed to improve nonrigid registration techniques for multimodal breast image alignment. A deformable breast model may also be useful for overcoming difficulties in interpreting 2D X-ray projections (mammograms) of 3D volumes (breast tissues). If a deformable model could accurately predict the shape changes that breasts undergo during mammography, then the model could serve to localize suspicious masses (visible in mammograms) in the unloaded state, or in any other deformed state required for further investigations (such as biopsy or other medical imaging modalities). In this paper, we present a validation study that was conducted in order to develop a biomechanical model based on the well-established theory of continuum mechanics (finite elasticity theory with contact mechanics) and demonstrate its use for this application. Experimental studies using gel phantoms were conducted to test the accuracy in predicting mammographic-like deformations. The material properties of the gel phantom were estimated using a nonlinear optimization process, which minimized the errors between the experimental and the model-predicted surface data by adjusting the parameter associated with the neo-Hookean constitutive relation. Two compressions (the equivalent of cranio-caudal and medio-lateral mammograms) were performed on the phantom, and the corresponding deformations were recorded using a MRI scanner. Finite element simulations were performed to mimic the experiments using the estimated material properties with appropriate boundary conditions. The simulation results matched the experimental recordings of the deformed phantom, with a sub-millimeter root-mean-square error for each compression state. Having now validated our finite element model of breast compression, the next stage is to apply the model to clinical images.

  14. Development of a biomechanical energy harvester.

    Science.gov (United States)

    Li, Qingguo; Naing, Veronica; Donelan, J Maxwell

    2009-06-23

    Biomechanical energy harvesting-generating electricity from people during daily activities-is a promising alternative to batteries for powering increasingly sophisticated portable devices. We recently developed a wearable knee-mounted energy harvesting device that generated electricity during human walking. In this methods-focused paper, we explain the physiological principles that guided our design process and present a detailed description of our device design with an emphasis on new analyses. Effectively harvesting energy from walking requires a small lightweight device that efficiently converts intermittent, bi-directional, low speed and high torque mechanical power to electricity, and selectively engages power generation to assist muscles in performing negative mechanical work. To achieve this, our device used a one-way clutch to transmit only knee extension motions, a spur gear transmission to amplify the angular speed, a brushless DC rotary magnetic generator to convert the mechanical power into electrical power, a control system to determine when to open and close the power generation circuit based on measurements of knee angle, and a customized orthopaedic knee brace to distribute the device reaction torque over a large leg surface area. The device selectively engaged power generation towards the end of swing extension, assisting knee flexor muscles by producing substantial flexion torque (6.4 Nm), and efficiently converted the input mechanical power into electricity (54.6%). Consequently, six subjects walking at 1.5 m/s generated 4.8 +/- 0.8 W of electrical power with only a 5.0 +/- 21 W increase in metabolic cost. Biomechanical energy harvesting is capable of generating substantial amounts of electrical power from walking with little additional user effort making future versions of this technology particularly promising for charging portable medical devices.

  15. Development of a biomechanical energy harvester

    Directory of Open Access Journals (Sweden)

    Donelan J Maxwell

    2009-06-01

    Full Text Available Abstract Background Biomechanical energy harvesting–generating electricity from people during daily activities–is a promising alternative to batteries for powering increasingly sophisticated portable devices. We recently developed a wearable knee-mounted energy harvesting device that generated electricity during human walking. In this methods-focused paper, we explain the physiological principles that guided our design process and present a detailed description of our device design with an emphasis on new analyses. Methods Effectively harvesting energy from walking requires a small lightweight device that efficiently converts intermittent, bi-directional, low speed and high torque mechanical power to electricity, and selectively engages power generation to assist muscles in performing negative mechanical work. To achieve this, our device used a one-way clutch to transmit only knee extension motions, a spur gear transmission to amplify the angular speed, a brushless DC rotary magnetic generator to convert the mechanical power into electrical power, a control system to determine when to open and close the power generation circuit based on measurements of knee angle, and a customized orthopaedic knee brace to distribute the device reaction torque over a large leg surface area. Results The device selectively engaged power generation towards the end of swing extension, assisting knee flexor muscles by producing substantial flexion torque (6.4 Nm, and efficiently converted the input mechanical power into electricity (54.6%. Consequently, six subjects walking at 1.5 m/s generated 4.8 ± 0.8 W of electrical power with only a 5.0 ± 21 W increase in metabolic cost. Conclusion Biomechanical energy harvesting is capable of generating substantial amounts of electrical power from walking with little additional user effort making future versions of this technology particularly promising for charging portable medical devices.

  16. WorldSID Prototype Dummy Biomechanical Responses.

    Science.gov (United States)

    Cesari, D; Compigne, S; Scherer, R; Xu, L; Takahashi, N; Page, M; Asakawa, K; Kostyniuk, G; Hautmann, E; Bortenschlager, K; Sakurai, M; Harigae, T

    2001-11-01

    The results of biomechanical testing of the WorldSID prototype dummy are presented in this paper. The WorldSID dummy is a new, advanced Worldwide Side Impact Dummy that has the anthropometry of a mid-sized adult male. The first prototype of this dummy has been evaluated by the WorldSID Task Group against previously established corridors for its critical body regions. The response corridors are defined in the International Organization of Standardization (ISO) Technical Report 9790. The prototype is the first version of the WorldSID dummy to be built and tested. This dummy has been subjected to a rigorous program of testing to evaluate, first and foremost its biofidelity, but also its repeatability. Following this initial evaluation, any required modifications will be incorporated into a pre-production version of the WorldSID dummy so that it rates "good" to "excellent" on the ISO dummy biofidelity scale - a rating exceeding that of all current side impact dummies. Also, the overall WorldSID repeatability must not exceed a coefficient of variation of 7% at injury assessment level and this has to be verified for the different body regions. The dummy's head, neck, thorax, abdomen and pelvis were evaluated against the ISO technical report requirements. Testing included drop tests, pendulum impacts, and sled tests. The biofidelity rating of the WorldSID prototype was calculated using the weighted biomechanical test response procedure developed by ISO. The paper presents the results of the testing, which give a very positive indication of the dummy's potential. Based on this evaluation of the dummy biofidelity, the WorldSID prototype dummy exhibits a biofidelity rating of 6.15 that corresponds to an ISO biofidelity classification of "fair". In addition, the dummy shows good repeatability with a global coefficient of variation of 3.30% for the pendulum and rigid sled tests.

  17. Laryngeal biomechanics of the singing voice.

    Science.gov (United States)

    Koufman, J A; Radomski, T A; Joharji, G M; Russell, G B; Pillsbury, D C

    1996-12-01

    By transnasal fiberoptic laryngoscopy, patients with functional voice often demonstrate abnormal laryngeal biomechanics, commonly supraglottic contraction. Appropriately, such conditions are sometimes termed muscle tension dysphonias. Singers working at the limits of their voice may also transiently demonstrate comparable tension patterns. However, the biomechanics of normal singing, particularly for different singing styles, have not been previously well characterized. We used transnasal fiberoptic laryngoscopy to study 100 healthy singers to assess patterns of laryngeal tension during normal singing and to determine whether factors such as sex, occupation, and style of singing influence laryngeal muscle tension. Thirty-nine male and 61 female singers were studied; 48 were professional singers, and 52 were amateurs. Examinations of study subjects performing standardized and nonstandardized singing tasks were recorded on a laser disk and subsequently analyzed in a frame-by-frame fashion by a blinded otolaryngologist. Each vocal task was graded for muscle tension by previously established criteria, and objective muscle tension scores were computed. The muscle tension score was expressed as a percentage of frames for each task with one of the laryngeal muscle tension patterns shown. The lowest muscle tension scores were seen in female professional singers, and the highest muscle tension scores were seen in amateur female singers. Male singers (professional and amateur) had intermediate muscle tension scores. Classical singers had lower muscle tension scores than nonclassical singers, with the lowest muscle tension scores being seen in those singing choral music (41%), art song (47%), and opera (57%), and the highest being seen in those singing jazz/pop (65%), musical theater (74%), bluegrass/country and western (86%), and rock/gospel (94%). Analyzed also were the influences of vocal nodules, prior vocal training, number of performance and practice hours per week

  18. [BIOMECHANICS STUDY ON ACETABULAR POSTERIOR WALL FRACTURE].

    Science.gov (United States)

    Tang, Yang; Hu Xiaopeng; Lu, Xiongwei; Zhang, Yuntong; Zhang, Chuncai; Wang, Panfeng; Zhao, Xue

    2015-08-01

    To study the experimental biomechanics of acetabular posterior wall fractures so as to provide theoretical basis for its clinical treatment. Six formalin-preserved cadaveric pelvises were divided into groups A and B (n=3). The fracture models of superior-posterior wall and inferior-posterior wall of the acetabulum were created on both hips in group A; fractures were fixed with two interfragmentary screws and a locking reconstruction plate. The fracture models of superior-posterior wall of acetabulum were created on both hips in group B; fractures were fixed with two interfragmentary screws and a locking reconstruction plate at one side, and with acetabular tridimensional memory fixation system (ATMFS) at the other side. The biomechanical testing machine was used to load to 1 500 N at 10 mm/min speed for 30 seconds. The displacement of superior and inferior fracture sites was analyzed with the digital image correlation technology. No fracture or internal fixation breakage occurred during loading and measuring; the displacement valuess of the upper and lower fracture lines were below 2 mm (the clinically tolerable maximum value) in 2 groups. In group A, the displacement values of the upper and lower fracture lines at superior-posterior wall fracture site were significantly higher than those at inferior-posterior wall fracture site (P fracture line were significantly higher than those of lower fracture line (P fracture types. In group B, the displacement values of the upper and lower fracture lines at the side fixed with screws and a locking reconstruction plate were similar to the values at the side fixed with ATMFS, all being close to 2 mm; the displacement values of the upper fracture line were significantly higher than those of lower fracture line (P acetabulum is much greater than that of the inferior-posterior wall of acetabulum and they should be discriminated, which might be the reasons of reduction loss, femoral head subluxation, and traumatic arthritis

  19. Keratoconus: A biomechanical perspective on loss of corneal stiffness

    Directory of Open Access Journals (Sweden)

    Abhijit Sinha Roy

    2013-01-01

    Full Text Available Keratoconus (KC is progressive disease of corneal thinning, steepening and collagen degradation. Biomechanics of the cornea is maintained by the intricate collagen network, which is responsible for its unique shape and function. With the disruption of this collagen network, the cornea loses its shape and function, resulting in progressive visual degradation. While KC is essentially a stromal disease, there is evidence that the epithelium undergoes significant thinning similar to the stroma. Several topographical approaches have been developed to detect KC early. However, it is now hypothesized that biomechanical destabilization of the cornea may precede topographic evidence of KC. Biomechanics of KC has been investigated only to a limited extent due to lack of in vivo measurement techniques and/or devices. In this review, we focus on recent work performed to characterize the biomechanical characteristics of KC.

  20. Recent microfluidic devices for studying gamete and embryo biomechanics.

    Science.gov (United States)

    Lai, David; Takayama, Shuichi; Smith, Gary D

    2015-06-25

    The technical challenges of biomechanic research such as single cell analysis at a high monetary cost, labor, and time for just a small number of measurements is a good match to the strengths of microfluidic devices. New scientific discoveries in the fertilization and embryo development process, of which biomechanics is a major subset of interest, is crucial to fuel the continual improvement of clinical practice in assisted reproduction. The following review will highlight some recent microfluidic devices tailored for gamete and embryo biomechanics where biomimicry arises as a major theme of microfluidic device design and function, and the application of fundamental biomechanic principles are used to improve outcomes of cryopreservation. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Soft Tissue Biomechanical Modeling for Computer Assisted Surgery

    CERN Document Server

    2012-01-01

      This volume focuses on the biomechanical modeling of biological tissues in the context of Computer Assisted Surgery (CAS). More specifically, deformable soft tissues are addressed since they are the subject of the most recent developments in this field. The pioneering works on this CAS topic date from the 1980's, with applications in orthopaedics and biomechanical models of bones. More recently, however, biomechanical models of soft tissues have been proposed since most of the human body is made of soft organs that can be deformed by the surgical gesture. Such models are much more complicated to handle since the tissues can be subject to large deformations (non-linear geometrical framework) as well as complex stress/strain relationships (non-linear mechanical framework). Part 1 of the volume presents biomechanical models that have been developed in a CAS context and used during surgery. This is particularly new since most of the soft tissues models already proposed concern Computer Assisted Planning, with ...

  2. Biomechanics Strategies for Space Closure in Deep Overbite

    OpenAIRE

    Harryanto Wijaya; Isnani Jenie; Himawan Halim

    2013-01-01

    Space closure is an interesting aspect of orthodontic treatment related to principles of biomechanics. It should be tailored individually based on patient’s diagnosis and treatment plan. Understanding the space closure biomechanics basis leads to achieve the desired treatment objective. Overbite deepening and losing posterior anchorage are the two most common unwanted side effects in space closure. Conventionally, correction of overbite must be done before space closure resulted in longer tre...

  3. Hand biomechanics in skilled pianists playing a scale in thirds.

    Science.gov (United States)

    Lee, Sang-Hie

    2010-12-01

    Pianists, who attend to the integral relationship of their particular musculoskeletal characteristics to the piano technique at hand, discover an efficient path to technical advancement and, consequently, to injury prevention. Thus, a study of pianist's hand biomechanics in relation to different piano techniques is highly relevant, as hand features may influence various techniques in different ways. This study addressed relationships between pianists' hand biomechanics and the performance of a scale in thirds, as a part of an ongoing series of studies examining relationships between hand biomechanics and performance data of primary techniques. The biomechanics of hand length and width, finger length, hand span, hand and arm weights, and ulnar deviation at the wrist were compared with tempo, articulation, and dynamic voicing (tone balance between two notes of the thirds). Pearson correlation analysis showed a positive association between ulnar deviation and tempo; the other biomechanical features showed no relationships with any of the performance criteria. Qualitative cross-sectional observation of individual profiles showed that experienced pianists perform with a higher degree of synchrony in two-note descent while pianists with organ training background play with a lesser degree of synchrony. All biomechanical features were closely related among one another with one exception: wrist ulnar deviation was not associated with any other biomechanical features; rather, data suggest possible negative associations. This study underscores the importance of wrist mobility in piano skills development. Further research using a complete set of prototype piano techniques and multiple-level pianist-subjects could provide substantive biomechanical information that may be used to develop efficient pedagogy and prevention strategies for playing-related injuries as well as rehabilitation.

  4. ARTIFICIAL INTELLIGENCE IN SPORTS BIOMECHANICS: NEW DAWN OR FALSE HOPE?

    Directory of Open Access Journals (Sweden)

    Roger Bartlett

    2006-12-01

    Full Text Available This article reviews developments in the use of Artificial Intelligence (AI in sports biomechanics over the last decade. It outlines possible uses of Expert Systems as diagnostic tools for evaluating faults in sports movements ('techniques' and presents some example knowledge rules for such an expert system. It then compares the analysis of sports techniques, in which Expert Systems have found little place to date, with gait analysis, in which they are routinely used. Consideration is then given to the use of Artificial Neural Networks (ANNs in sports biomechanics, focusing on Kohonen self-organizing maps, which have been the most widely used in technique analysis, and multi-layer networks, which have been far more widely used in biomechanics in general. Examples of the use of ANNs in sports biomechanics are presented for javelin and discus throwing, shot putting and football kicking. I also present an example of the use of Evolutionary Computation in movement optimization in the soccer throw in, which predicted an optimal technique close to that in the coaching literature. After briefly overviewing the use of AI in both sports science and biomechanics in general, the article concludes with some speculations about future uses of AI in sports biomechanics.

  5. Gait biomechanics in the era of data science.

    Science.gov (United States)

    Ferber, Reed; Osis, Sean T; Hicks, Jennifer L; Delp, Scott L

    2016-12-08

    Data science has transformed fields such as computer vision and economics. The ability of modern data science methods to extract insights from large, complex, heterogeneous, and noisy datasets is beginning to provide a powerful complement to the traditional approaches of experimental motion capture and biomechanical modeling. The purpose of this article is to provide a perspective on how data science methods can be incorporated into our field to advance our understanding of gait biomechanics and improve treatment planning procedures. We provide examples of how data science approaches have been applied to biomechanical data. We then discuss the challenges that remain for effectively using data science approaches in clinical gait analysis and gait biomechanics research, including the need for new tools, better infrastructure and incentives for sharing data, and education across the disciplines of biomechanics and data science. By addressing these challenges, we can revolutionize treatment planning and biomechanics research by capitalizing on the wealth of knowledge gained by gait researchers over the past decades and the vast, but often siloed, data that are collected in clinical and research laboratories around the world. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Cyclomorphosis in Tardigrada: adaptation to environmental constraints

    DEFF Research Database (Denmark)

    Halberg, Kenneth Agerlin; Persson, Dennis; Ramløv, Hans

    2009-01-01

    Tardigrades exhibit a remarkable resilience against environmental extremes. In the present study, we investigate mechanisms of survival and physiological adaptations associated with sub-zero temperatures and severe osmotic stress in two commonly found cyclomorphic stages of the marine eutardigrade...

  7. DYNAMIC MAGNIFICATION OF BIOMECHANICAL SYSTEM MOTION

    Directory of Open Access Journals (Sweden)

    A. E. Pokatilov

    2017-01-01

    Full Text Available Methods for estimation of dynamic magnification pertaining to motion in biomechanics have been developed and approbаted in the paper. It has been ascertained that widely-used characteristics for evaluation of motion influence on mechanisms and machinery such as a dynamic coefficient and acceleration capacity factor become irrelevant while investigating human locomotion under elastic support conditions. The reason is an impossibility to compare human motion in case when there is a contact with elastic and rigid supports because while changing rigidity of the support exercise performing technique is also changing. In this case the technique still depends on a current state of a specific sportsman. Such situation is observed in sports gymnastics. Structure of kinematic and dynamic models for human motion has been investigated in the paper. It has been established that properties of an elastic support are reflected in models within two aspects: in an explicit form, when models have parameters of dynamic deformation for a gymnastic apparatus, and in an implicit form, when we have numerically changed parameters of human motion. The first part can be evaluated quantitatively while making comparison with calculations made in accordance with complete models. For this reason notions of selected and complete models have been introduced in the paper. It has been proposed to specify models for support and models of biomechanical system that represent models pertaining only to human locomotor system. It has been revealed that the selected models of support in kinematics and dynamics have structural difference. Kinematics specifies only parameters of elastic support deformation and dynamics specifies support parameters in an explicit form and additionally in models of human motion in an explicit form as well. Quantitative estimation of a dynamic motion magnification in kinematics and dynamics models has been given while using computing experiment for grand

  8. Functional anatomy and biomechanics of the carpus

    International Nuclear Information System (INIS)

    Schmitt, R.

    2006-01-01

    The wrist is an exceedingly complex structure composed of several joints and a dedicated ligamentous system. Its functional principles allow a wide range of carpal motion and make the wrist remarkably resistant to external stress forces: The proximal carpal row serves as an intercalated link interposed between the static elements of both the forearm and the distal carpal row. Like a flexible placeholder, the proximal row synchronously adapts to the spatial and temporal requirements of the wrist. There are synergistic movement patterns including simultaneous flexion of the proximal row as the wrist is deviated radially and simultaneous extension during ulnar deviation. Together with pronosupination of the radioulnar joints, the combined radial/ulnar inclination and flexion/extension enable spherical, out-of-plane movements of the hand. Carpal function is best explained by the ''model of a ring under tension.'' This review addresses the anatomy and the biomechanics of the wrist and illustrates systematic image analysis by using carpal lines and angles as well as indices of carpal height. (orig.) [de

  9. Physiological and biomechanical aspects of orienteering.

    Science.gov (United States)

    Creagh, U; Reilly, T

    1997-12-01

    Orienteering is an endurance running event which differs from other running sports both in its cognitive element and in the type of terrain encountered. The demands of overcoming this terrain are not manifest in significant differences between orienteers and road runners in somatotype, though elite female orienteers have consistently been shown to have higher levels of adiposity (> 19%) than elite road runners. High aerobic power in orienteers (up to 63 and 76 ml/kg/min in women and men, respectively) is coupled with lower anaerobic performance. While leg strength is generally not high when compared with other athletic specialties, female orienteers have relatively good leg flexion strength. The energy cost of running is greatly increased in rough terrain. Oxygen cost was 26% higher while running in a forest when compared with road running. Biomechanical differences in stride pattern contribute towards this increased demand. Despite the high energy demands during competition, orienteers pace themselves such that their mean heart rate remains within the range of 167 to 172 beats/min, despite large fluctuations. The rough terrain encountered in orienteering results not only in a high energy cost but also in a higher incidence of sport-specific injuries, particularly to the ankle. Minor injuries such as cuts and bruises are common during competition.

  10. Comparative biomechanics: life's physical world (second edition)

    CERN Document Server

    Vogel, Steven

    2013-01-01

    Why do you switch from walking to running at a specific speed? Why do tall trees rarely blow over in high winds? And why does a spore ejected into air at seventy miles per hour travel only a fraction of an inch? Comparative Biomechanics is the first and only textbook that takes a comprehensive look at the mechanical aspects of life--covering animals and plants, structure and movement, and solids and fluids. An ideal entry point into the ways living creatures interact with their immediate physical world, this revised and updated edition examines how the forms and activities of animals and plants reflect the materials available to nature, considers rules for fluid flow and structural design, and explores how organisms contend with environmental forces. Drawing on physics and mechanical engineering, Steven Vogel looks at how animals swim and fly, modes of terrestrial locomotion, organism responses to winds and water currents, circulatory and suspension-feeding systems, and the relationship between size and mech...

  11. Biomechanical origin of the Denonvilliers' fascia.

    Science.gov (United States)

    Bertrand, M M; Alsaid, B; Droupy, S; Benoit, G; Prudhomme, M

    2014-01-01

    Since 1836 and the first description of the recto-genital fascia by Charles Denonvilliers, many anatomists have shown interest in this subject. Recently, pelvic surgeons have in turn shown similar interest, for they consider that perfect knowledge of this anatomical domain is crucial for optimal nerve conservation during surgery. Thanks to new anatomical description techniques, fascia location and relationships with pelvic nerves now appear clearer. To describe and represent Denonvilliers' fascia and its relationships in the female foetus at different stages of gestation and in three-dimensional space (3D). Computer-assisted anatomical dissection technique was used. Serial histological sections were made from four human female foetuses. Sections were treated with conventional staining, as well as with nerve and smooth muscle immunostaining. Finally, the sections were digitalized and reconstructed in 3D. Denonvilliers' fascia was clearly located and visualized in three dimensions. It was present in the female foetus, being distinct from the fascia propria of the rectum. It appeared to be composed of multiple parallel layers situated between the vagina and the rectum. From a lateral view, it had an asymmetrical "Y-shaped" aspect that seemed to play the role of a protective sheet for the neurovascular bundles. This study betters our comprehension of the Denonvilliers' fascia in the female foetus and of its connections with pelvic nerves. It also provides a better understanding of safe planes during pelvic dissection. These findings also suggest a biomechanical theory for embryological origin of the Denonvilliers' fascia.

  12. Biomechanic Factors Associated With Orbital Floor Fractures.

    Science.gov (United States)

    Patel, Sagar; Andrecovich, Christopher; Silverman, Michael; Zhang, Liying; Shkoukani, Mahdii

    2017-07-01

    Orbital floor fractures are commonly seen in clinical practice, yet the etiology underlying the mechanism of fracture is not well understood. Current research focuses on the buckling theory and hydraulic theory, which implicate trauma to the orbital rim and the globe, respectively. To elucidate and define the biomechanical factors involved in an orbital floor fracture. A total of 10 orbits from 5 heads (3 male and 2 female) were used for this study. These came from fresh, unfixed human postmortem cadavers that were each selected so that the cause of death did not interfere with the integrity of orbital walls. Using a drop tower with an accelerometer, we measured impact force on the globe and rim of cadaver heads affixed with strain gauges. The mean impacts for rim and globe trauma were 3.9 J (95% CI, 3.4-4.3 J) and 3.9 J (95% CI, 3.5-4.3 J), respectively. Despite similar impact forces to the globe and rim, strain-gauge data displayed greater mean strain for globe impact (6563 μS) compared with rim impact (3530 μS); however, these data were not statistically significant (95% CI, 3598-8953 μS; P = .94). Our results suggest that trauma directly to the globe predisposes a patient to a more posterior fracture while trauma to the rim demonstrates an anterior predilection. Both the hydraulic and buckling mechanisms of fracture exist and demonstrate similar fracture thresholds. NA.

  13. Patient-specific models of cardiac biomechanics

    Science.gov (United States)

    Krishnamurthy, Adarsh; Villongco, Christopher T.; Chuang, Joyce; Frank, Lawrence R.; Nigam, Vishal; Belezzuoli, Ernest; Stark, Paul; Krummen, David E.; Narayan, Sanjiv; Omens, Jeffrey H.; McCulloch, Andrew D.; Kerckhoffs, Roy C. P.

    2013-07-01

    Patient-specific models of cardiac function have the potential to improve diagnosis and management of heart disease by integrating medical images with heterogeneous clinical measurements subject to constraints imposed by physical first principles and prior experimental knowledge. We describe new methods for creating three-dimensional patient-specific models of ventricular biomechanics in the failing heart. Three-dimensional bi-ventricular geometry is segmented from cardiac CT images at end-diastole from patients with heart failure. Human myofiber and sheet architecture is modeled using eigenvectors computed from diffusion tensor MR images from an isolated, fixed human organ-donor heart and transformed to the patient-specific geometric model using large deformation diffeomorphic mapping. Semi-automated methods were developed for optimizing the passive material properties while simultaneously computing the unloaded reference geometry of the ventricles for stress analysis. Material properties of active cardiac muscle contraction were optimized to match ventricular pressures measured by cardiac catheterization, and parameters of a lumped-parameter closed-loop model of the circulation were estimated with a circulatory adaptation algorithm making use of information derived from echocardiography. These components were then integrated to create a multi-scale model of the patient-specific heart. These methods were tested in five heart failure patients from the San Diego Veteran's Affairs Medical Center who gave informed consent. The simulation results showed good agreement with measured echocardiographic and global functional parameters such as ejection fraction and peak cavity pressures.

  14. Biomechanical comments about Triassic dinosaurs from Brazil

    Directory of Open Access Journals (Sweden)

    Rafael Delcourt

    2012-01-01

    Full Text Available Triassic dinosaurs of Brazil are found in Santa Maria and Caturrita formations, Rio Grande do Sul state, Brazil. There are three species known from the Santa Maria Formation (Staurikosaurus pricei, Saturnalia tupiniquim and Pampadromaeus barberenai, and two from Caturrita Formation (Guaibasaurus candelariensis and Unaysaurus tolentinoi. These dinosaur materials are, for the most part, well preserved and allow for descriptions of musculature and biomechanical studies. The lateral rotation of the Saturnalia femur is corroborated through calculations of muscle moment arms. The enhanced supracetabular crest of Saturnalia, Guaibasaurus, Staurikosaurus, Herrerasaurus ischigualastensis, Efraasia minor and Chormogisaurus novasi suggests that basal dinosaurs may have maintained an inclination of the trunk at least 20º on the horizontal axis. The pectoral girdle articulation of basal sauropodomorphs (Saturnalia and Unaysaurus was established using a new method, the Clavicular Ring, and the scapular blade remains near 60º on the horizontal axis. This is a plesiomorphic condition among sauropodomorphs and is also seen in the articulated plateosauridae Seitaad ruessi. The Brazilian basal dinosaurs were lightweight with a body mass estimated around 18.5 kg for Staurikosaurus, 6.5 kg for Saturnalia, and 17 kg for Guaibasaurus. Pampadromaeus probably weighed 2.5 kg, but measures of its femur are necessary to confirm this hypothesis. The Triassic dinosaurs from Brazil were diversified but shared some functional aspects that were important in an evolutionary context.

  15. An overview on plant cuticle biomechanics.

    Science.gov (United States)

    Domínguez, Eva; Cuartero, Jesús; Heredia, Antonio

    2011-08-01

    Plant biomechanics combines the principles of physics, chemistry and engineering to answer questions about plant growth, development and interaction with the environment. The epidermal-growth-control theory, postulated in 1867 and verified in 2007, states that epidermal cells determine the rate of organ elongation since they are under tension, while inner tissues are under compression. The lipid cuticle layer is deposited on the surface of outer epidermal cell walls and modifies the chemical and mechanical nature of these cell walls. Thus, the plant cuticle plays a key role in plant interaction with the environment and in controlling organ expansion. Rheological analyses indicate that the cuticle is a mostly viscoelastic and strain-hardening material that stiffens the comparatively more elastic epidermal cell walls. Cuticle stiffness can be attributed to polysaccharides and flavonoids present in the cuticle whereas a cutin matrix is mainly responsible for its extensibility. Environmental conditions such as temperature and relative humidity have a plasticizing effect on the mechanical properties of cuticle since they lower cuticle stiffness and strength. The external appearance of agricultural commodities, especially fruits, is of great economic value. Mechanical properties of the cuticle can have a positive or negative effect on disorders like fruit cracking, fungal pathogen penetration and pest infestation. Cuticle rheology has significant variability within a species and thus can be subjected to selection in order to breed cultivars resistant to pests, infestation and disorders. Copyright © 2011 Elsevier Ireland Ltd. All rights reserved.

  16. Adaptive sports technology and biomechanics: prosthetics.

    Science.gov (United States)

    De Luigi, Arthur Jason; Cooper, Rory A

    2014-08-01

    With the technologic advances in medicine and an emphasis on maintaining physical fitness, the population of athletes with impairments is growing. It is incumbent upon health care practitioners to make every effort to inform these individuals of growing and diverse opportunities and to encourage safe exercise and athletic participation through counseling and education. Given the opportunities for participation in sports for persons with a limb deficiency, the demand for new, innovative prosthetic designs is challenging the clinical and technical expertise of the physician and prosthetist. When generating a prosthetic prescription, physicians and prosthetists should consider the needs and preferences of the athlete with limb deficiency, as well as the functional demands of the chosen sporting activity. The intent of this article is to provide information regarding the current advancements in the adaptive sports technology and biomechanics in the field of prosthetics, and to assist clinicians and their patients in facilitating participation in sporting activities. Copyright © 2014 American Academy of Physical Medicine and Rehabilitation. Published by Elsevier Inc. All rights reserved.

  17. Biomechanics of Nested Transforaminal Lumbar Interbody Cages.

    Science.gov (United States)

    Soriano-Baron, Hector; Newcomb, Anna G U S; Malhotra, Devika; de Tranaltes, Kaylee; Martinez-Del-Campo, Eduardo; Reyes, Phillip M; Crawford, Neil R; Theodore, Nicholas; Tumialán, Luis M

    2016-02-01

    Arthrodesis is optimized when the structural graft occupies most of the surface area within a disc space. The transforaminal corridor inherently limits interbody size. To evaluate the biomechanical implications of nested interbody spacers (ie, a second curved cage placed behind a first) to increase disc space coverage in transforaminal approaches. Seven lumbar human cadaveric specimens (L3-S1) underwent nondestructive flexibility and axial compression testing intact and after transforaminal instrumentation at L4-L5. Specimens were tested in 5 conditions: (1) intact, (2) interbody, (3) interbody plus bilateral pedicle screws and rods (PSR), (4) 2 nested interbodies, and (5) 2 nested interbodies plus PSR. Mean range of motion (ROM) with 1 interbody vs 2 nested interbodies, respectively, was: flexion, 101% vs 85%; extension, 97% vs 92%; lateral bending, 127% vs 132%; and axial rotation, 145% vs 154%. One interbody and 2 nested interbodies did not differ significantly by loading mode (P > .10). With PSR, ROM decreased significantly compared with intact, but not between interbody and interbody plus PSR or 2 interbodies plus PSR (P > .80). Mean vertical height during compressive loading (ie, axial compressive stiffness) was significantly different with 2 nested interbodies vs 1 interbody alone (P < .001) (compressive stiffness, 89% of intact vs 67% of intact, respectively). Inserting a second interbody using a transforaminal approach is anatomically feasible and nearly doubles the disc space covered without affecting ROM. Compressive stiffness significantly increased with 2 nested interbodies, and foraminal height increased. Evaluation of the clinical safety and efficacy of nested interbodies is underway.

  18. Biomechanics of the Gastrointestinal Tract in Health and Disease

    DEFF Research Database (Denmark)

    Zhao, Jingbo; Liao, Donghua; Gregersen, Hans

    2010-01-01

    The gastrointestinal (GI) tract is functionally subjected to dimensional changes. Hence, biomechanical properties such as the stress-strain relationships are of particularly importance. These properties vary along the normal GI tract and remodel in response to growth, aging and disease. The biome......The gastrointestinal (GI) tract is functionally subjected to dimensional changes. Hence, biomechanical properties such as the stress-strain relationships are of particularly importance. These properties vary along the normal GI tract and remodel in response to growth, aging and disease....... The biomechanical properties are crucial for GI motor function because peristaltic motion that propels the food through the GI tract is a result of interaction of the passive and active tissue forces and the hydrodynamic forces in the food bolus and remodeling of the mechanical properties reflects the changes...... in the tissue structure that determine a specific motor dysfunction. Therefore, biomechanical data on the GI wall are important to understand the pathogenesis to the GI motor-sensory function and dysfunction. Moreover, biomechanical studies of the GI tract pave the way for further mathematical and computational...

  19. Biomechanics and functionality of hepatocytes in liver cirrhosis.

    Science.gov (United States)

    Sun, Shan; Song, Zhenyuan; Cotler, Scott J; Cho, Michael

    2014-06-27

    Cirrhosis is a life-threatening condition that is generally attributed to overproduction of collagen fibers in the extracellular matrix that mechanically stiffens the liver. Chronic liver injury due to causes including viral hepatitis, inherited and metabolic liver diseases and external factors such as alcohol abuse can result in the development of cirrhosis. Progression of cirrhosis leads to hepatocellular dysfunction. While extensive studies to understand the complexity underlying liver fibrosis have led to potential application of anti-fibrotic drugs, no such FDA-approved drugs are currently available. Additional studies of hepatic fibrogenesis and cirrhosis primarily have focused on the extracellular matrix, while hepatocyte biomechanics has received limited attention. The role of hepatocyte biomechanics in liver cirrhosis remains elusive, and how the cell stiffness is correlated with biological functions of hepatocytes is also unknown. In this study, we demonstrate that the biomechanical properties of hepatocytes are correlated with their functions (e.g., glucose metabolism), and that hepatic dysfunction can be restored through modulation of the cellular biomechanics. Furthermore, our results indicate the hepatocyte functionality appears to be regulated through a crosstalk between the Rho and Akt signaling. These novel findings may lead to biomechanical intervention of hepatocytes and the development of innovative tissue engineering for clinical treatment to target liver cells rather than exclusively focusing on the extracellular matrix alone in liver cirrhosis. © 2013 Published by Elsevier Ltd.

  20. Biomechanics Strategies for Space Closure in Deep Overbite

    Directory of Open Access Journals (Sweden)

    Harryanto Wijaya

    2013-07-01

    Full Text Available Space closure is an interesting aspect of orthodontic treatment related to principles of biomechanics. It should be tailored individually based on patient’s diagnosis and treatment plan. Understanding the space closure biomechanics basis leads to achieve the desired treatment objective. Overbite deepening and losing posterior anchorage are the two most common unwanted side effects in space closure. Conventionally, correction of overbite must be done before space closure resulted in longer treatment. Application of proper space closure biomechanics strategies is necessary to achieve the desired treatment outcome. This cases report aimed to show the space closure biomechanics strategies that effectively control the overbite as well as posterior anchorage in deep overbite patients without increasing treatment time. Two patients who presented with class II division 1 malocclusion were treated with fixed orthodontic appliance. The primary strategies included extraction space closure on segmented arch that employed two-step space closure, namely single canine retraction simultaneously with incisors intrusion followed by enmasse retraction of four incisors by using differential moment concept. These strategies successfully closed the space, corrected deep overbite and controlled posterior anchorage simultaneously so that the treatment time was shortened. Biomechanics strategies that utilized were effective to achieve the desired treatment outcome.

  1. BIOMECHANICAL MODEL OF THE SPRINT START

    Directory of Open Access Journals (Sweden)

    Milan Čoh

    2007-05-01

    Full Text Available The study analysed and identifi ed the major kinematic parameters of the phases of sprint start and block acceleration that infl uence the results of sprint running. The biomechanical measurements and kinematic analysis were performed on the best world’s best sprinters during his preparation for the European Athletics Championship in Geteborg 2006. In this competition Matic Osovnikar won the bronze medal in a 100- metre run set the Slovenian national record with 10.14 s. The kinematic parameters of the sprint start were established on the basis of a 2-D kinematic analysis, using a high-speed camera with a frequency of 200 F/s. The measurements of block acceleration were made by means of the OPTO TRACK technology and an infra-red photo cell system. The athlete performed fi ve, 20m low-start sprints in constant and controlled measurement conditions. The subject of the study was the set position from the point of view of the height of the total body centre of gravity (TBCG, the block time at the front and rear blocks, block velocity, the block face angle, the velocity of the TBCG in the fi rst three metres and the kinematic parameters of block acceleration in the fi rst ten steps. The study showed the following were the key performance factors in the two phases of sprint running: medium start block distance, block velocity, low block face angles, fi rst step length, low vertical rise in the TBCG in the fi rst three metres of block acceleration, contact phase/fl ight phase index in the fi rst ten steps and the optimal ratio between the length and frequency of steps.

  2. Biomechanical Behavior of the Dental Implant Macrodesign.

    Science.gov (United States)

    Lima de Andrade, Camila; Carvalho, Marco Aurélio; Bordin, Dimorvan; da Silva, Wander José; Del Bel Cury, Altair Antoninha; Sotto-Maior, Bruno Salles

    The aim of this study was to evaluate the influence of implant macrodesign when using different types of collar and thread designs on stress/strain distributions in a maxillary bone site. Six groups were obtained from the combination of two collar designs (smooth and microthread) and three thread shapes (square, trapezoidal, and triangular) in external hexagon implants (4 × 10 mm) supporting a single zirconia crown in the maxillary first molar region. A 200-N axial occlusal load was applied to the crown, and measurements were made of the von Mises stress (σ vM ) for the implant, and tensile stress (σ max ), shear stress (τ max ), and strain (ε max ) for the surrounding bone using tridimensional finite element analysis. The main effects of each level of the two factors investigated (collar and thread designs) were evaluated by one-way analysis of variance (ANOVA) at a 5% significance level. Collar design was the main factor of influence on von Mises stress in the implant and stresses/strain in the cortical bone, while thread design was the main factor of influence on stresses in the trabecular bone (P design able to produce more favorable stress/strain distribution was the microthreaded design for the cortical bone. For the trabecular bone, the triangular thread shape had the lowest stresses and strain values among the square and trapezoidal implants. Stress/strain distribution patterns were influenced by collar design in the implant and cortical bone, and by thread design in the trabecular bone. Microthreads and triangular thread-shape designs presented improved biomechanical behavior in posterior maxillary bone when compared with the smooth collar design and trapezoidal and square-shaped threads.

  3. Biomechanics and pathophysiology of flat foot.

    Science.gov (United States)

    Van Boerum, Drew H; Sangeorzan, Bruce J

    2003-09-01

    When the foot works properly it is an amazing, adaptive, powerful aid during walking, running, jumping, and in locomotion up or down hill and over uneven ground. Dysfunction of the foot can often arise from the foot losing its normal structural support, thus altering is shape. An imbalance in the forces that tend to flatten the arch and those that support the arch can lead to loss of the medial longitudinal arch. An increase in the arch-flattening effects of the triceps surae or an increase in the weight of the body will tend to flatten the arch. Weakness of the muscular, ligamentous, or bony arch supporting structures will lead to collapse of the arch. The main factors that contribute to an acquired flat foot deformity are excessive tension in the triceps surae, obesity, PTT dysfunction, or ligamentous laxity in the spring ligament, plantar fascia, or other supporting plantar ligaments. Too little support for the arch or too much arch flattening effect will lead to collapse of the arch. Acquired flat foot most often arises from a combination of too much force flattening the arch in the face of too little support for the arch. Treatment of the adult acquired flat foot is often difficult. The clinician should remember the biomechanics of the normal arch and respond with a treatment that strengthens the supporting structures of the arch or weakens the arch-flattening effects on the arch. After osteotomies or certain hindfoot fusions, the role of the supporting muscles of the arch, in particular the PTT, play less of a role in supporting the arch. Rebalancing the forces that act on the arch can improve function and lessen the chance for further or subsequent development of deformity.

  4. Biomechanical analysis using Kinovea for sports application

    Science.gov (United States)

    Muaza Nor Adnan, Nor; Patar, Mohd Nor Azmi Ab; Lee, Hokyoo; Yamamoto, Shin-Ichiroh; Jong-Young, Lee; Mahmud, Jamaluddin

    2018-04-01

    This paper assesses the reliability of HD VideoCam–Kinovea as an alternative tool in conducting motion analysis and measuring knee relative angle of drop jump movement. The motion capture and analysis procedure were conducted in the Biomechanics Lab, Shibaura Institute of Technology, Omiya Campus, Japan. A healthy subject without any gait disorder (BMI of 28.60 ± 1.40) was recruited. The volunteered subject was asked to per the drop jump movement on preset platform and the motion was simultaneously recorded using an established infrared motion capture system (Hawk–Cortex) and a HD VideoCam in the sagittal plane only. The capture was repeated for 5 times. The outputs (video recordings) from the HD VideoCam were input into Kinovea (an open-source software) and the drop jump pattern was tracked and analysed. These data are compared with the drop jump pattern tracked and analysed earlier using the Hawk–Cortex system. In general, the results obtained (drop jump pattern) using the HD VideoCam–Kinovea are close to the results obtained using the established motion capture system. Basic statistical analyses show that most average variances are less than 10%, thus proving the repeatability of the protocol and the reliability of the results. It can be concluded that the integration of HD VideoCam–Kinovea has the potential to become a reliable motion capture–analysis system. Moreover, it is low cost, portable and easy to use. As a conclusion, the current study and its findings are found useful and has contributed to enhance significant knowledge pertaining to motion capture-analysis, drop jump movement and HD VideoCam–Kinovea integration.

  5. ANALYSIS OF BIOMECHANICAL PARAMETERS IN COLONIC ANASTOMOSIS.

    Science.gov (United States)

    Iwanaga, Tiago Cavalcanti; Aguiar, José Lamartine de Andrade; Martins-Filho, Euclides Dias; Kreimer, Flávio; Silva-Filho, Fernando Luiz; Albuquerque, Amanda Vasconcelos de

    2016-01-01

    The use of measures in colonic anastomoses to prevent dehiscences is of great medical interest. Sugarcane molasses, which has adequate tolerability and compatibility in vivo, has not yet been tested for this purpose. To analyze the biomechanical parameters of colonic suture in rats undergoing colectomy, using sugarcane molasses polysaccharide as tape or gel. 45 Wistar rats (Rattus norvegicus albinus) were randomized into three groups of 15 animals: irrigation of enteric sutures with 0.9% saline solution; application of sugarcane molasses polysaccharide as tape; and sugarcane molasses polysaccharide as gel. The rats underwent colon ressection, with subsequent reanastomosis using polypropylene suture; they were treated according to their respective groups. Five rats from each group were evaluated at different times after the procedure: 30, 90 and 180 days postoperatively. The following variables were evaluated: maximum rupture force, modulus of elasticity and specific deformation of maximum force. The biomechanical variables among the scheduled times and treatment groups were statistically calculated. The characteristics of maximum rupture force and modulus of elasticity of the specimens remained identical, regardless of treatment with saline, polysaccharide gel or tape, and treatment time. However, it was found that the specific deformation of maximum force of the intestinal wall was higher after 180 days in the group treated with sugarcane polysaccharide gel (p=0.09). Compared to control, it was detected greater elasticity of the intestinal wall in mice treated with sugarcane polysaccharide gel, without changing other biomechanical characteristics, regardless of type or time of treatment. A aplicação de produtos em anastomoses colônicas que possam prevenir o surgimento de deiscências são de grande interesse médico. O emprego do polissacarídeo de melaço de cana-de-açúcar (Saccharum officinarum), que possui adequada tolerabilidade e compatibilidade in vivo

  6. Modeling and rational determination of the main biomechanical characteristics in javelin throwing.

    Directory of Open Access Journals (Sweden)

    Adashevskiy V.M.

    2011-06-01

    Full Text Available The possibilities of the use of biomechanical models in training athletes. The approaches in the construction of biomechanical models. A biomechanical model of throwing the javelin. An solution to the problem of dynamic influence on flight range spear absolute initial rate of departure, departure angle, height of release of the spear. The most important biomechanical characteristics of the "athlete-spear. " The possibilities of using individual features of the athlete to achieve better results.

  7. Intestinal morphometric and biomechanical changes during aging in rats

    DEFF Research Database (Denmark)

    Zhao, Jingbo; Gregersen, Hans

    2015-01-01

    Background and aim: Previously we demonstrated pronounced morphometric and biomechanical remodeling in the rat intestine during physiological growth up to 32 weeks of age. The aim of the present study is to study intestinal geometric and biomechanical changes in aging rats. Materials and methods...... in the circumferential direction. In conclusion pronounced morphometric and biomechanical remodeling occurred in the rat intestine during aging. The observed changes likely reflect the changes of the physiological function of the intestine during ageing, similar to other tissues where function, mechanical loading......: Twenty-four male Wistar rats, aged from 6 to 22 months, were used in the study. The body weight and the wet weight per length of duodenal and ileal segments were measured at the termination of experiment. Morphometric data were obtained by measuring the wall thickness and wall cross-sectional area...

  8. Biomechanical analysis technique choreographic movements (for example, "grand battman jete"

    Directory of Open Access Journals (Sweden)

    N.P. Batieieva

    2015-04-01

    Full Text Available Purpose : biomechanical analysis of the execution of choreographic movement "grand battman jete". Material : the study involved students (n = 7 of the department of classical choreography faculty of choreography. Results : biomechanical analysis of choreographic movement "grand battman jete" (classic exercise, obtained kinematic characteristics (path, velocity, acceleration, force of the center of mass (CM bio parts of the body artist (foot, shin, thigh. Built bio kinematic model (phase. The energy characteristics - mechanical work and kinetic energy units legs when performing choreographic movement "grand battman jete". Conclusions : It was found that the ability of an athlete and coach-choreographer analyze the biomechanics of movement has a positive effect on the improvement of choreographic training of qualified athletes in gymnastics (sport, art, figure skating and dance sports.

  9. Computational biomechanics for medicine new approaches and new applications

    CERN Document Server

    Miller, Karol; Wittek, Adam; Nielsen, Poul

    2015-01-01

    The Computational Biomechanics for Medicine titles provide an opportunity for specialists in computational biomechanics to present their latest methodologiesand advancements. Thisvolumecomprises twelve of the newest approaches and applications of computational biomechanics, from researchers in Australia, New Zealand, USA, France, Spain and Switzerland. Some of the interesting topics discussed are:real-time simulations; growth and remodelling of soft tissues; inverse and meshless solutions; medical image analysis; and patient-specific solid mechanics simulations. One of the greatest challenges facing the computational engineering community is to extend the success of computational mechanics to fields outside traditional engineering, in particular to biology, the biomedical sciences, and medicine. We hope the research presented within this book series will contribute to overcoming this grand challenge.

  10. [Air transport biomechanical risk: reduced mobility passengers' handling].

    Science.gov (United States)

    Draicchio, F; Campoli, G; Silvetti, A; Badellino, E; Forzano, F; Ranavolo, A; Iavicoli, S; Campagna, G; Raffaele, G; Gismondi, M

    2012-01-01

    As the airport traffic increases there is a continuous increase of passengers with different motor disabilities. Disabled passenger's assistance causes a biomechanical overload in airport workers. Some disabled passengers are classified by IATA as WCHC (wheel chair in cabin or Charlie). Our study, was performed in one of the most important Italian airport on Charlie passengers (about 10% of all assistances). We identified four critical points: 1) wheelchair and baggage moving (unstable load), 2) inclined ramps with worker's backwards steps and braked wheelchair to prevent passenger tipping or falling, 3) transfer from standard wheelchair to bicycle wheelchair, specifically designed for the aisle; 4.) transfer from bicycle wheelchair to aircraft seat. The last two points required sometimes to lift passengers over the armrest and positioning them on a window side seat, causing a serious increase of biomechanical load. For each critical point we have proposed technical and organizational measures to reduce airport worker's biomechanical risk.

  11. Biomechanics of Wheat/Barley Straw and Corn Stover

    Energy Technology Data Exchange (ETDEWEB)

    Christopher T. Wright; Peter A. Pryfogle; Nathan A. Stevens; Eric D. Steffler; J. Richard Hess; Thomas H. Ulrich

    2005-03-01

    The lack of understanding of the mechanical characteristics of cellulosic feedstocks is a limiting factor in economically collecting and processing crop residues, primarily wheat and barley stems and corn stover. Several testing methods, including compression, tension, and bend have been investigated to increase our understanding of the biomechanical behavior of cellulosic feedstocks. Biomechanical data from these tests can provide required input to numerical models and help advance harvesting, handling, and processing techniques. In addition, integrating the models with the complete data set from this study can identify potential tools for manipulating the biomechanical properties of plant varieties in such a manner as to optimize their physical characteristics to produce higher value biomass and more energy efficient harvesting practices.

  12. Computational biomechanics for medicine imaging, modeling and computing

    CERN Document Server

    Doyle, Barry; Wittek, Adam; Nielsen, Poul; Miller, Karol

    2016-01-01

    The Computational Biomechanics for Medicine titles provide an opportunity for specialists in computational biomechanics to present their latest methodologies and advancements. This volume comprises eighteen of the newest approaches and applications of computational biomechanics, from researchers in Australia, New Zealand, USA, UK, Switzerland, Scotland, France and Russia. Some of the interesting topics discussed are: tailored computational models; traumatic brain injury; soft-tissue mechanics; medical image analysis; and clinically-relevant simulations. One of the greatest challenges facing the computational engineering community is to extend the success of computational mechanics to fields outside traditional engineering, in particular to biology, the biomedical sciences, and medicine. We hope the research presented within this book series will contribute to overcoming this grand challenge.

  13. Biomechanical Profile of Danish Elite and Sub-elite Soccer Goalkeepers

    DEFF Research Database (Denmark)

    Sørensen, Henrik; Thomassen, Martin; Zacho, Morten

    2008-01-01

    The purpose of this study was to define a biomechanical profile of the soccer goalkeeper. We tested whether the skill level of 6 goalkeepers correlated with a number of biomechanical tests. The skill level of each goalkeeper was defined as the league he played in. The biomechanical tests were...

  14. Biomechanically Excited SMD Model of a Walking Pedestrian

    DEFF Research Database (Denmark)

    Zhang, Mengshi; Georgakis, Christos T.; Chen, Jun

    2016-01-01

    of biomechanical forces, was used to model a pedestrian for application in vertical human-structure interaction (HSI). Tests were undertaken in a gait laboratory, where a three-dimensional motion-capture system was used to record a pedestrian's walking motions at various frequencies. The motion-capture system...... produced the pedestrian's center of mass (COM) trajectories from the captured motion markers. The vertical COM trajectory was approximated to be the pedestrian SMD dynamic responses under the excitation of biomechanical forces. SMD model parameters of a pedestrian for a specific walking frequency were...

  15. Biomechanical Response and Behavior of Users under Emergency Buffer Crash

    Directory of Open Access Journals (Sweden)

    R. Miralbes

    2013-01-01

    Full Text Available This paper aims to study the biomechanical effects on elevator users and the injuries sustained should an elevator crash happen. The analysis will focus on buffer impact, signaling that the earlier mentioned buffer is usually located at the bottom of the pit. In order to carry out this analysis, a numerical technique based on finite element method will be used, while elevator users will be simulated by means of automotive dummies. Two crash factors will be studied, namely, location of dummy and fall velocity. The analysis criteria will be damages sustained by the dummy, based on biomechanical index such as HIC, CSI, forces, and accelerations.

  16. The modern biomechanics technology in practice of preparedness athletes.

    Directory of Open Access Journals (Sweden)

    Akhmetov R.F.

    2011-01-01

    Full Text Available The generalized information about directions of application of biomechanics technologies in modern sport is resulted. Some aspects of the use of biomechanics ergogenical tools of the moved delayed action in the system of preparation of athletes-jumpers are considered. Presents the possibility of using training complex «easy leading» for perfection of structure of motive actions of sportsmen, specialized in high jumps. The introduction of a vast arsenal of technical tools in practice the training process open new prospects associated with increased efficiency in the preparation of athletes.

  17. Biomechanical constraints and optimal posture of a human operator

    Energy Technology Data Exchange (ETDEWEB)

    Riffard, V.; Chedmail, P. [Ecole entrale de Nantes-LAN, Nantes Cedex (France)

    1995-12-31

    In complex mechanical systems, an important feature of concurrent engineering is to take into account the operators accessibility for assembly operations and maintenance checking in the earliest phases of assembly design. Accessibility can be viewed from geometric and biomechanical points of view. The first one was described in a previous paper. The object of this paper is to integrate the biomechanical aspects of finding optimal postures of a human operator in an encumbered environment. Research on mechanical modeling of human operators deals with (1) geometric and kinematics models; (2) inertial characterizations; (3) static and muscular efforts; and (4) human-gesture characterization.

  18. Development of esMOCA Biomechanic, Motion Capture Instrumentation for Biomechanics Analysis

    Science.gov (United States)

    Arendra, A.; Akhmad, S.

    2018-01-01

    This study aims to build motion capture instruments using inertial measurement unit sensors to assist in the analysis of biomechanics. Sensors used are accelerometer and gyroscope. Estimation of orientation sensors is done by digital motion processing in each sensor nodes. There are nine sensor nodes attached to the upper limbs. This sensor is connected to the pc via a wireless sensor network. The development of kinematics and inverse dynamamic models of the upper limb is done in simulink simmechanic. The kinematic model receives streaming data of sensor nodes mounted on the limbs. The output of the kinematic model is the pose of each limbs and visualized on display. The dynamic inverse model outputs the reaction force and reaction moment of each joint based on the limb motion input. Model validation in simulink with mathematical model of mechanical analysis showed results that did not differ significantly

  19. Left ventricular biomechanics in professional football players.

    Science.gov (United States)

    von Lueder, T G; Hodt, A; Gjerdalen, G F; Steine, K

    2018-01-01

    Chronic exercise induces adaptive changes of left ventricular (LV) ejection and filling capacities which may be detected by novel speckle-tracking echocardiography (STE) and tissue Doppler imaging (TDI)-based techniques. A total of 103 consecutive male elite Norwegian soccer players and 46 age-matched healthy controls underwent echocardiography at rest. STE was used to assess LV torsional mechanics and LV systolic longitudinal strain (LS). Diastolic function was evaluated by trans-mitral blood flow, mitral annular velocities by TDI, and LV inflow propagation velocity by color M-mode. Despite similar global LS, players displayed lower basal wall and higher apical wall LS values vs controls, resulting in an incremental base-to-apex gradient of LS. Color M-mode and TDI-derived data were similar in both groups. Peak systolic twist rate (TWR) was significantly lower in players (86.4±2.8 vs controls 101.9±5.2 deg/s, P<.01). Diastolic untwisting rate (UTWR) was higher in players (-124.5±4.2 vs -106.9±6.7 deg/s) and peaked earlier during the cardiac cycle (112.7±0.8 vs 117.4±2.4% of systole duration, both P<.05). Untwisting/twisting ratio (-1.48±0.05 vs -1.11±0.08; P<.001) and untwisting performance (=UTR/TW; -9.25±0.34 vs -7.38±0.40 s -1 , P<.01) were increased in players. Augmented diastolic wall strain (DWS), a novel measure of LV compliance in players, was associated with improved myocardial mechanical efficiency. The described myocardial biomechanics may underlie augmented exertional cardiac function in athletes and may have a potential role to characterize athlete's heart by itself or to distinguish it from hypertensive or hypertrophic cardiomyopathy. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  20. Physiological and biomechanical in different swimming intensities

    Directory of Open Access Journals (Sweden)

    Sebastião Iberes Lopes de Melo

    2004-06-01

    Full Text Available The objective of this study was to analyze the physiological and biomechanical responses of swimmers at different swimming intensities. The intentionally selected sample was composed by seven athletes with swimming times for qualifying on the Brazilian Swimming Championship. A series of 8x200 free style swimming at speeds of 80%, 85%, 90%, 95% and 100% of individual maximum effort was used as the task. A film camera of 60 Hz and an Accusport mMol lactimeter were used for data collection. Descriptive statistics, analysis of variance (ANOVA with “post-hoc” Tukey test and Spearman’s correlation were used for statistical analyses to identify the differences between athletes for the variables blood lactate, crawl stroke frequency (FB and dimension (BR at different intensities. The level of significance was set at 0.05. Based on the results, there were significant differences on swimming technique among effort intensities, for both the physiological and mechanical responses, especially at levels above 95% individual maximum effort. The high correlation between blood lactate and crawl stroke frequency and length, and between crawl stroke frequency and length, with the last two correlations being negative, indicated that the proposed series was adequate to analyze physiological and biomechanical response. It was concluded that as the intensity increases, there is a need for mechanical adjustments to enable the athletes to endure different speeds. It was also possible to establish the ideal swimming speed for each energetic zone, providing data for coaches and athletes to train both speed and technique within the specific energetic zones. RESUMO O objetivo deste estudo foi analisar as respostas fisiológicas e biomecânicas de nadadores em diferentes intensidades de nado. A amostra, intencionalmente escolhida, foi composta por sete atletas que possuíam índices de participação em campeonato brasileiro absoluto. Foi utilizada como tarefa de

  1. Biomechanical research on bowed string musicians: a scoping study.

    Science.gov (United States)

    Kelleher, Leila K; Campbell, Kody R; Dickey, James P

    2013-12-01

    Performing arts biomechanics is concerned with quantifying the musculoskeletal demands of artistic tasks. The growing body of related research has prompted this scoping study, solely focused on quantitative research, to summarize the state of the science, identify knowledge gaps, and identify opportunities for future research. To identify, summarize, and categorize quantitative research on the biomechanics of violin, viola, cello, and double bass players, using scoping study methodology. Established scoping study methodology was used to identify and categorize existing research. We identified 74 articles for review. Of these, 34 met our scoping study criteria and were included in this study. Twenty-one of the 34 articles that met the scoping criteria were published since 2000. Investigations using electromyography (16 studies) and kinematics (15 studies) comprise the bulk of the research. Two studies employed force transducers for data collection. Violinists were the most frequently studied musicians (22 studies) and double bass players were the least (1 study). Fewer than half of the studies used solely professional musicians as their subjects (13 studies). This scoping study confirmed that quantitative biomechanical research into bowed string musicians has been performed with increasing frequency and that there are voids in the research, particularly in investigating mechanisms of injury and protective strategies. Currently, arts biomechanics research is largely descriptive in nature. There are few studies that investigate protective strategies, although it is expected that the field will progress to incorporate this type of research.

  2. Steven Vogel and His Theory of Comparative Biomechanics

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 21; Issue 5. Steven Vogel and His Theory of Comparative Biomechanics. Book Review Volume 21 Issue 5 May 2016 pp 467-471. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/021/05/0467-0471. Abstract ...

  3. Quantitative modelling of the biomechanics of the avian syrinx

    DEFF Research Database (Denmark)

    Elemans, Coen P. H.; Larsen, Ole Næsbye; Hoffmann, Marc R.

    2003-01-01

    We review current quantitative models of the biomechanics of bird sound production. A quantitative model of the vocal apparatus was proposed by Fletcher (1988). He represented the syrinx (i.e. the portions of the trachea and bronchi with labia and membranes) as a single membrane. This membrane acts...

  4. The history of biomechanics in total hip arthroplasty

    Directory of Open Access Journals (Sweden)

    Jan Van Houcke

    2017-01-01

    Full Text Available Biomechanics of the hip joint describes how the complex combination of osseous, ligamentous, and muscular structures transfers the weight of the body from the axial skeleton into the appendicular skeleton of the lower limbs. Throughout history, several biomechanical studies based on theoretical mathematics, in vitro, in vivo as well as in silico models have been successfully performed. The insights gained from these studies have improved our understanding of the development of mechanical hip pathologies such as osteoarthritis, hip fractures, and developmental dysplasia of the hip. The main treatment of end-stage degeneration of the hip is total hip arthroplasty (THA. The increasing number of patients undergoing this surgical procedure, as well as their demand for more than just pain relief and leading an active lifestyle, has challenged surgeons and implant manufacturers to deliver higher function as well as longevity with the prosthesis. The science of biomechanics has played and will continue to play a crucial and integral role in achieving these goals. The aim of this article, therefore, is to present to the readers the key concepts in biomechanics of the hip and their application to THA.

  5. Early Specialization in Youth Sport: A Biomechanical Perspective

    Science.gov (United States)

    Mattson, Jeffrey M.; Richards, Jim

    2010-01-01

    This article examines, from a biomechanical perspective, three issues related to early specialization: overuse injuries, the developmental aspects, and the performance aspects. It concludes that "there is no evidence that early specialization causes overuse injuries or hinders growth and maturation." At the same time, early specialization has…

  6. Biomechanical, microvascular, and cellular factors promote muscle and bone regeneration.

    Science.gov (United States)

    Duda, Georg N; Taylor, William R; Winkler, Tobias; Matziolis, Georg; Heller, Markus O; Haas, Norbert P; Perka, Carsten; Schaser, Klaus-D

    2008-04-01

    It is becoming clear that the long-term outcome of complex bone injuries benefits from approaches that selectively target biomechanical, vascular, and cellular pathways. The typically held view of either biological or mechanical aspects of healing is oversimplified and does not correspond to clinical reality. The fundamental mechanisms of soft tissue regeneration most likely hold the key to understanding healing response.

  7. How to Assess the Biomechanical Risk Levels in Beekeeping.

    Science.gov (United States)

    Maina, G; Rossi, F; Baracco, A

    2016-01-01

    Beekeepers are at particular risk of developing work-related musculoskeletal disorders, but many of the studies lack detailed exposure assessment. To evaluate the biomechanical overload exposure in a specific farming activity, a multitasking model has been developed through the characterization of 37 basic operational tasks typical of the beekeeping activity. The Occupational Repetitive Actions (OCRA) Checklist and the National Institute for Occupational Safety and Health (NIOSH) Lifting Index methodologies have been applied to these elementary tasks to evaluate the exposure, and the resulting risk indices have been time-weighted averaged. Finally, an easy access, computer-assisted toolkit has been developed to help the beekeepers in the biomechanical risk assessment process. The risk of biomechanical overload for the upper limbs ranges from acceptable (maintenance and recovery of woody material and honey packaging with dosing machine tasks) to high (distribution of the top supers) risk level. The risk for back injury is always borderline in women and increases with exposure time, whereas it ranges from acceptable to borderline in men. The definition of the biomechanical risk levels allows for planning of corrective actions aimed at preventing and reducing the risk of musculoskeletal disorders through engineering, administrative, and behavioral interventions. The methodology can be used for risk assessment in other mainly manual agricultural activities.

  8. The biomechanical and physiological effect of two dynamic workstations

    NARCIS (Netherlands)

    Botter, J.; Burford, E.M.; Commissaris, D.; Könemann, R.; Mastrigt, S.H.V.; Ellegast, R.P.

    2013-01-01

    The aim of this research paper was to investigate the effect, both biomechanically and physiologically, of two dynamic workstations currently available on the commercial market. The dynamic workstations tested, namely the Treadmill Desk by LifeSpan and the LifeBalance Station by RightAngle, were

  9. Focusing on the Hard parts: A Biomechanics Laboratory Exercise

    Science.gov (United States)

    Fingerut, Jonathan; Orbe, Kristina; Flynn, Daniel; Habdas, Piotr

    2013-01-01

    As part of a biomechanics course aimed at both upper-division Biology and Physics majors, this laboratory exercise introduces students to the ingenious ways in which organisms vary the composition and form of support and defensive structures such as bone and shell to maximize their strength while minimizing the energetic cost needed to produce…

  10. Biomechanics Curriculum: Its Content and Relevance to Movement Sciences

    Science.gov (United States)

    Hamill, Joseph

    2007-01-01

    While the National Association for Sport and Physical Education (NASPE) has outlined a number of learning outcomes for undergraduate biomechanics, there are a number of factors that can influence the curriculum in such courses. These factors create a situation that indeed can influence students and their attitude towards these classes.…

  11. Future of crash dummies and biomechanical mathematical models

    NARCIS (Netherlands)

    Wismans, J.S.H.M.

    2000-01-01

    Thorough knowledge of the characteristics of the human body and its behaviour under extreme loading conditions is essential in order to prevent the serious consequences of road and other accidents. This field of research is called injury or impact biomechanics. In order to study the human body

  12. Biomechanics research in ski jumping, 1991-2006.

    Science.gov (United States)

    Schwameder, Hermann

    2008-01-01

    In this paper, I review biomechanics research in ski jumping with a specific focus on publications presented between 1991 and 2006 on performance enhancement, limiting factors of the take-off, specific training and conditioning, aerodynamics, and safety. The first section presents a brief description of ski jumping phases (in-run, take-off, early flight, stable flight, and landing) regarding the biomechanical and functional fundamentals. The most important and frequently used biomechanical methods in ski jumping (kinematics, ground reaction force analyses, muscle activation patterns, aerodynamics) are summarized in the second section. The third section focuses on ski jumping articles and research findings published after the establishment of the V-technique in 1991, as the introduction of this technique has had a major influence on performance enhancement, ski jumping regulations, and the construction of hill profiles. The final section proposes topics for future research in the biomechanics of ski jumping, including: take-off and early flight and the relative roles of vertical velocity and forward somersaulting angular momentum; optimal jumping patterns utilizing the capabilities of individual athletes; development of kinematic and kinetic feedback systems for hill jumps; comparisons of simulated and hill jumps; effect of equipment modifications on performance and safety enhancement.

  13. Using Clinical Gait Case Studies to Enhance Learning in Biomechanics

    Science.gov (United States)

    Chester, Victoria

    2011-01-01

    Clinical case studies facilitate the development of clinical reasoning strategies through knowledge and integration of the basic sciences. Case studies have been shown to be more effective in developing problem-solving abilities than the traditional lecture format. To enhance the learning experiences of students in biomechanics, clinical case…

  14. Biomechanics of the elbow joint in tennis players.

    NARCIS (Netherlands)

    Eygendaal, D.; Rahussen, F.T.; Diercks, R.L.

    2007-01-01

    Elbow injuries constitute a sizeable percentage of tennis injuries. A basic understanding of biomechanics of tennis and analysis of forces, loads and motions of the elbow during tennis can will improve the understanding of the pathophysiology of these injuries. All different strokes in tennis have a

  15. Assessment and characterization of in situ rotator cuff biomechanics

    Science.gov (United States)

    Trent, Erika A.; Bailey, Lane; Mefleh, Fuad N.; Raikar, Vipul P.; Shanley, Ellen; Thigpen, Charles A.; Dean, Delphine; Kwartowitz, David M.

    2013-03-01

    Rotator cuff disease is a degenerative disorder that is a common, costly, and often debilitating, ranging in severity from partial thickness tear, which may cause pain, to total rupture, leading to loss in function. Currently, clinical diagnosis and determination of disease extent relies primarily on subjective assessment of pain, range of motion, and possibly X-ray or ultrasound images. The final treatment plan however is at the discretion of the clinician, who often bases their decision on personal experiences, and not quantitative standards. The use of ultrasound for the assessment of tissue biomechanics is established, such as in ultrasound elastography, where soft tissue biomechanics are measured. Few studies have investigated the use of ultrasound elastography in the characterization of musculoskeletal biomechanics. To assess tissue biomechanics we have developed a device, which measures the force applied to the underlying musculotendentious tissue while simultaneously obtaining the related ultrasound images. In this work, the musculotendinous region of the infraspinatus of twenty asymptomatic male organized baseball players was examined to access the variability in tissue properties within a single patient and across a normal population. Elastic moduli at percent strains less than 15 were significantly different than those above 15 percent strain within the normal population. No significant difference in tissue properties was demonstrated within a single patient. This analysis demonstrated elastic moduli are variable across individuals and incidence. Therefore threshold elastic moduli will likely be a function of variation in local-tissue moduli as opposed to a specific global value.

  16. Steven Vogel and His Theory of Comparative Biomechanics

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 21; Issue 5. Steven Vogel and His Theory of Comparative Biomechanics. Book Review Volume 21 Issue 5 May 2016 pp 467-471. Fulltext. Click here to view fulltext PDF. Permanent link: https://www.ias.ac.in/article/fulltext/reso/021/05/0467-0471. Abstract ...

  17. Corneal Biomechanics in Ectatic Diseases: Refractive Surgery Implications

    Science.gov (United States)

    Ambrósio, Jr, Renato; Correia, Fernando Faria; Lopes, Bernardo; Salomão, Marcella Q.; Luz, Allan; Dawson, Daniel G.; Elsheikh, Ahmed; Vinciguerra, Riccardo; Vinciguerra, Paolo; Roberts, Cynthia J.

    2017-01-01

    Background: Ectasia development occurs due to a chronic corneal biomechanical decompensation or weakness, resulting in stromal thinning and corneal protrusion. This leads to corneal steepening, increase in astigmatism, and irregularity. In corneal refractive surgery, the detection of mild forms of ectasia pre-operatively is essential to avoid post-operative progressive ectasia, which also depends on the impact of the procedure on the cornea. Method: The advent of 3D tomography is proven as a significant advancement to further characterize corneal shape beyond front surface topography, which is still relevant. While screening tests for ectasia had been limited to corneal shape (geometry) assessment, clinical biomechanical assessment has been possible since the introduction of the Ocular Response Analyzer (Reichert Ophthalmic Instruments, Buffalo, USA) in 2005 and the Corvis ST (Oculus Optikgeräte GmbH, Wetzlar, Germany) in 2010. Direct clinical biomechanical evaluation is recognized as paramount, especially in detection of mild ectatic cases and characterization of the susceptibility for ectasia progression for any cornea. Conclusions: The purpose of this review is to describe the current state of clinical evaluation of corneal biomechanics, focusing on the most recent advances of commercially available instruments and also on future developments, such as Brillouin microscopy. PMID:28932334

  18. Applied Biomechanics Research for the United States Ski Team.

    Science.gov (United States)

    Dillman, Charles J.

    1982-01-01

    Assisted by a team of physicians and sports scientists, the United States Ski Team has developed its own sports medicine program, the purpose of which is to assist coaches and athletes in controlling and optimizing factors which influence skiing performance. A number of biomechanical research projects which have been undertaken as part of this…

  19. A highly versatile autonomous underwater vehicle with biomechanical propulsion

    NARCIS (Netherlands)

    Simons, D.G.; Bergers, M.M.C.; Henrion, S.; Hulzenga, J.I.J.; Jutte, R.W.; Pas, W.M.G.; Van Schravendijk, M.; Vercruyssen, T.G.A.; Wilken, A.P.

    2009-01-01

    An autonomous underwater vehicle with a biomechanical propulsion system is a possible answer to the demand for small, silent sensor platforms in many fields. The design of Galatea, a bio-mimetic AUV, involves four aspects: hydrodynamic shape, the propulsion, the motion control systems and payload.

  20. Corneal Biomechanical Changes and Tissue Remodeling After SMILE and LASIK.

    Science.gov (United States)

    Shetty, Rohit; Francis, Mathew; Shroff, Rushad; Pahuja, Natasha; Khamar, Pooja; Girrish, Molleti; Nuijts, Rudy M M A; Sinha Roy, Abhijit

    2017-11-01

    To evaluate transient corneal tissue healing and biomechanical changes between laser in situ keratomileusis (LASIK) and small incision lenticule extraction (SMILE) eyes. In each patient, one eye underwent LASIK and the other underwent SMILE. Optical coherence tomography (OCT) and dynamic Scheimpflug imaging (Corvis-ST) was used to assess tissue healing and biomechanics, respectively. Analyses of OCT scans yielded corneal speckle distribution (CSD) and Bowman's roughness index (BRI). Waveform analyses of deformation amplitude yielded corneal stiffness. Further, corneal force versus corneal deformation data helped compare the two procedures. BRI increased and then decreased transiently after both treatments (P < 0.05). However, SMILE eyes had BRI similar to that of their preoperative state compared to LASIK eyes at 6-month follow-up. CSD indicated a marked increase in the number of bright pixels and a decrease in the number of dark pixels after SMILE (1-month follow-up) and LASIK eyes (3-month follow-up), respectively. CSD returned to near preoperative state thereafter, respectively. Corneal stiffness change from preoperative state was similar between LASIK and SMILE eyes. However, deformation at discrete values of corneal force indicated some recovery of biomechanical strength after SMILE, but not in LASIK eyes. BRI and CSD indicated earlier tissue healing in SMILE eyes than in LASIK. CSD results may indicate delayed cell death in LASIK eyes and increased light scatter due to interface fluid in SMILE eyes. Corneal biomechanical strength remodeled better in SMILE. This may indicate some hydration-related recovery.

  1. Biomechanical analysis of titanium fixation plates and screws in ...

    African Journals Online (AJOL)

    2015-08-10

    Aug 10, 2015 ... Materials and Methods: Three different three-dimensional finite element models of the mandible were developed to simulate the biomechanical responses of titanium plates and screws. The fracture lines were fixed with double 4-hole straight, 4-hole square, and 5-hole Y plates with monocortical screws.

  2. Pathobiology of obesity and osteoarthritis: integrating biomechanics and inflammation

    Directory of Open Access Journals (Sweden)

    Rita I. Issa

    2012-05-01

    Full Text Available Obesity is a significant risk factor for developing osteoarthritis in weight-bearing and non-weight-bearing joints. Although the pathogenesis of obesity-associated osteoarthritis is not completely understood, recent studies indicate that pro-inflammatory metabolic factors contribute to an increase in osteoarthritis risk. Adipose tissue, and in particular infrapatellar fat, is a local source of pro-inflammatory mediators that are increased with obesity and have been shown to increase cartilage degradation in cell and tissue culture models. One adipokine in particular, leptin, may be a critical mediator of obesity-associated osteoarthritis via synergistic actions with other inflammatory cytokines. Biomechanical factors may also increase the risk of osteoarthritis by activating cellular inflammation and promoting oxidative stress. However, some types of biomechanical stimulation, such as physiologic cyclic loading, inhibit inflammation and protect against cartilage degradation. A high percentage of obese individuals with knee osteoarthritis are sedentary, suggesting that a lack of physical activity may increase the susceptibility to inflammation. A more comprehensive approach to understanding how obesity alters daily biomechanical exposures within joint tissues may provide new insight into the protective and damaging effects of biomechanical factors on inflammation in osteoarthritis.

  3. Biomechanical effects of pedicle screw fixation on adjacent segments.

    Science.gov (United States)

    Kyaw, Thein Aung; Wang, Zhuo; Sakakibara, Toshihiko; Yoshikawa, Takamasa; Inaba, Tadashi; Kasai, Yuichi

    2014-07-01

    Various biomechanical investigations have attempted to clarify the aetiology of adjacent segment disease (ASD). However, no biomechanical study has examined in detail the deformation behaviour of the adjacent segments when both pure torque and an angular displacement load are applied to the vertebrae along multiple segments. The purpose of this study is to investigate the biomechanical effects of pedicle screw fixation on adjacent segments. Ten cadaveric lumbar spines (L2-L5) of boars were used. Control and fusion models were prepared by disc damage and pedicle screw fixation of each specimen, and then, bending and rotation tests were performed using a six-axis material tester. In the biomechanical tests regulated by an angular displacement load, the range of motion (ROM) of the cranial and caudal adjacent segments in antero-posterior flexion and lateral bending was increased by about 20 % (p fusion surgery as a mechanism to compensate for the ROM lost due to excessive fusion by pedicle screw fixation, so that a large torque may be applied to adjacent segments within a physiologically possible range, and it might gradually lead to a degenerative intervertebral disc or progression of spondylolisthesis in the adjacent segments.

  4. Biomechanical, anthropometric, and psychological determinants of barbell back squat strength.

    Science.gov (United States)

    Vigotsky, Andrew D; Bryanton, Megan A; Nuckols, Greg; Beardsley, Chris; Contreras, Bret; Evans, Jessica; Schoenfeld, Brad J

    2018-02-27

    Previous investigations of strength have only focused on biomechanical or psychological determinants, while ignoring the potential interplay and relative contributions of these variables. The purpose of this study was to investigate the relative contributions of biomechanical, anthropometric, and psychological variables to the prediction of maximum parallel barbell back squat strength. Twenty-one college-aged participants (male = 14; female = 7; age = 23 ± 3 years) reported to the laboratory for two visits. The first visit consisted of anthropometric, psychometric, and parallel barbell back squat one-repetition maximum (1RM) testing. On the second visit, participants performed isometric dynamometry testing for the knee, hip, and spinal extensors in a sticking point position-specific manner. Multiple linear regression and correlations were used to investigate the combined and individual relationships between biomechanical, anthropometric, and psychological variables and squat 1RM. Multiple regression revealed only one statistically predictive determinant: fat free mass normalized to height (standardized estimate ± SE = 0.6 ± 0.3; t(16) = 2.28; p = 0.037). Correlation coefficients for individual variables and squat 1RM ranged from r = -0.79-0.83, with biomechanical, anthropometric, experiential, and sex predictors showing the strongest relationships, and psychological variables displaying the weakest relationships. These data suggest that back squat strength in a heterogeneous population is multifactorial and more related to physical rather than psychological variables.

  5. Biomechanical design considerations for transradial prosthetic interface: A review.

    Science.gov (United States)

    Sang, Yuanjun; Li, Xiang; Luo, Yun

    2016-03-01

    Traditional function and comfort assessment of transradial prostheses pay scant attention to prosthetic interface. With better understanding of the biomechanics of prosthetic interface comes better efficiency and safety for interface design; in this way, amputees are more likely to accept prosthetic usage. This review attempts to provide design and selection criteria of transradial interface for prosthetists and clinicians. Various transradial socket types in the literature were chronologically reviewed. Biomechanical discussion of transradial prosthetic interface design from an engineering point of view was also done. Suspension control, range of motion, stability, as well as comfort and safety of socket designs have been considered in varying degrees in the literature. The human-machine interface design should change from traditional "socket design" to new "interface design." From anatomy and physiology to biomechanics of the transradial residual limb, the force and motion transfer, together with comfort and safety, are the two main aspects in prosthetic interface design. Load distribution and transmission should mainly rely on achieving additional skeletal control through targeted soft tissue relief. Biomechanics of the residual limb soft tissues should be studied to find the relationship between mechanical properties and the comfort and safety of soft tissues. © IMechE 2016.

  6. Stability of the human spine: a biomechanical study

    NARCIS (Netherlands)

    Scholten, P.J.M.; Veldhuizen, A.G.; Grootenboer, H.J.

    1988-01-01

    The influences of curvatures and of physical properties on the mechanical stability of the spine were analysed by means of a three-dimensional, geometrical, nonlinear biomechanical model. According to the model, the initial buckling load decreases with increasing lordotic and kyphotic curvatures.

  7. Steven Vogel and His Theory of Comparative Biomechanics

    Indian Academy of Sciences (India)

    IAS Admin

    Bio-Cyber Physical Systems) or a suffix (e.g.,. Mathematical Biology). The traditional fields of biology and mechanics present a peculiar problem when they are combined together because biomechanics and mechanobiology are both used, the latter being much younger than the former. How is mechanobiology dif-.

  8. Unified Approach to the Biomechanics of Dental Implantology

    Science.gov (United States)

    Grenoble, D. E.; Knoell, A. C.

    1973-01-01

    The human need for safe and effective dental implants is well-recognized. Although many implant designs have been tested and are in use today, a large number have resulted in clinical failure. These failures appear to be due to biomechanical effects, as well as biocompatibility and surgical factors. A unified approach is proposed using multidisciplinary systems technology, for the study of the biomechanical interactions between dental implants and host tissues. The approach progresses from biomechanical modeling and analysis, supported by experimental investigations, through implant design development, clinical verification, and education of the dental practitioner. The result of the biomechanical modeling, analysis, and experimental phases would be the development of scientific design criteria for implants. Implant designs meeting these criteria would be generated, fabricated, and tested in animals. After design acceptance, these implants would be tested in humans, using efficient and safe surgical and restorative procedures. Finally, educational media and instructional courses would be developed for training dental practitioners in the use of the resulting implants.

  9. Biomechanical comparison of osteosynthesis with poly‑L‑lactic acid ...

    African Journals Online (AJOL)

    Background and Aims: The aim of this study was to compare the biomechanical stability of poly‑L‑lactic acid and titanium screws in the fixation of intracapsular condylar fractures, in 10 polyurethane hemimandibles. Materials and Methods: Artificial intracapsular fractures were created with a steel disk and electronic ...

  10. The History of Biomechanics in Total Hip Arthroplasty.

    Science.gov (United States)

    Houcke, Jan Van; Khanduja, Vikas; Pattyn, Christophe; Audenaert, Emmanuel

    2017-01-01

    Biomechanics of the hip joint describes how the complex combination of osseous, ligamentous, and muscular structures transfers the weight of the body from the axial skeleton into the appendicular skeleton of the lower limbs. Throughout history, several biomechanical studies based on theoretical mathematics, in vitro , in vivo as well as in silico models have been successfully performed. The insights gained from these studies have improved our understanding of the development of mechanical hip pathologies such as osteoarthritis, hip fractures, and developmental dysplasia of the hip. The main treatment of end-stage degeneration of the hip is total hip arthroplasty (THA). The increasing number of patients undergoing this surgical procedure, as well as their demand for more than just pain relief and leading an active lifestyle, has challenged surgeons and implant manufacturers to deliver higher function as well as longevity with the prosthesis. The science of biomechanics has played and will continue to play a crucial and integral role in achieving these goals. The aim of this article, therefore, is to present to the readers the key concepts in biomechanics of the hip and their application to THA.

  11. Biomechanics of the Gastrointestinal Tract in Health and Disease

    DEFF Research Database (Denmark)

    Zhao, Jingbo; Liao, Donghua; Gregersen, Hans

    2010-01-01

    The gastrointestinal (GI) tract is functionally subjected to dimensional changes. Hence, biomechanical properties such as the stress-strain relationships are of particularly importance. These properties vary along the normal GI tract and remodel in response to growth, aging and disease. The biome...

  12. Biomechanical Indices for Rupture Risk Estimation in Abdominal Aortic Aneurysms

    NARCIS (Netherlands)

    Leemans, Eva L.; Willems, Tineke P.; van der Laan, Maarten J.; Slump, Cornelis H.; Zeebregts, Clark J.

    2017-01-01

    Purpose: To review the use of biomechanical indices for the estimation of abdominal aortic aneurysm (AAA) rupture risk, emphasizing their potential use in a clinical setting. Methods: A search of the PubMed, Embase, Scopus, and Compendex databases was made up to June 2015 to identify articles

  13. Energetics, Biomechanics, and Performance in Masters' Swimmers: A Systematic Review.

    Science.gov (United States)

    Ferreira, Maria I; Barbosa, Tiago M; Costa, Mário J; Neiva, Henrique P; Marinho, Daniel A

    2016-07-01

    Ferreira, MI, Barbosa, TM, Costa, MJ, Neiva, HP, and Marinho, DA. Energetics, biomechanics, and performance in masters' swimmers: a systematic review. J Strength Cond Res 30(7): 2069-2081, 2016-This study aimed to summarize evidence on masters' swimmers energetics, biomechanics, and performance gathered in selected studies. An expanded search was conducted on 6 databases, conference proceedings, and department files. Fifteen studies were selected for further analysis. A qualitative evaluation of the studies based on the Quality Index (QI) was performed by 2 independent reviewers. The studies were thereafter classified into 3 domains according to the reported data: performance (10 studies), energetics (4 studies), and biomechanics (6 studies). The selected 15 articles included in this review presented low QI scores (mean score, 10.47 points). The biomechanics domain obtained higher QI (11.5 points), followed by energetics and performance (10.6 and 9.9 points, respectively). Stroke frequency (SF) and stroke length (SL) were both influenced by aging, although SF is more affected than SL. Propelling efficiency (ηp) decreased with age. Swimming performance declined with age. The performance declines with age having male swimmers deliver better performances than female counterparts, although this difference tends to be narrow in long-distance events. One single longitudinal study is found in the literature reporting the changes in performance over time. The remaining studies are cross-sectional designs focusing on the energetics and biomechanics. Overall, biomechanics parameters, such as SF, SL, and ηp, tend to decrease with age. This review shows the lack of a solid body of knowledge (reflected in the amount and quality of the articles published) on the changes in biomechanics, energetics, and performance of master swimmers over time. The training programs for this age-group should aim to preserve the energetics as much as possible and, concurrently, improve the

  14. An Anatomic and Biomechanical Comparison of Bankart Repair Configurations.

    Science.gov (United States)

    Judson, Christopher H; Voss, Andreas; Obopilwe, Elifho; Dyrna, Felix; Arciero, Robert A; Shea, Kevin P

    2017-11-01

    Suture anchor repair for anterior shoulder instability can be performed using a number of different repair techniques, but none has been proven superior in terms of anatomic and biomechanical properties. Purpose/Hypothesis: The purpose was to compare the anatomic footprint coverage and biomechanical characteristics of 4 different Bankart repair techniques: (1) single row with simple sutures, (2) single row with horizontal mattress sutures, (3) double row with sutures, and (4) double row with labral tape. The hypotheses were as follows: (1) double-row techniques would improve the footprint coverage and biomechanical properties compared with single-row techniques, (2) horizontal mattress sutures would increase the footprint coverage compared with simple sutures, and (3) repair techniques with labral tape and sutures would not show different biomechanical properties. Controlled laboratory study. Twenty-four fresh-frozen cadaveric specimens were dissected. The native labrum was removed and the footprint marked and measured. Repair for each of the 4 groups was performed, and the uncovered footprint was measured using a 3-dimensional digitizer. The strength of the repair sites was assessed using a servohydraulic testing machine and a digital video system to record load to failure, cyclic displacement, and stiffness. The double-row repair techniques with sutures and labral tape covered 73.4% and 77.0% of the footprint, respectively. These percentages were significantly higher than the footprint coverage achieved by single-row repair techniques using simple sutures (38.1%) and horizontal mattress sutures (32.8%) ( P footprint coverage of the simple suture and horizontal mattress suture groups was not significantly different ( P = .44). There were no significant differences in load to failure, cyclic displacement, or stiffness between the single-row and double-row groups or between the simple suture and horizontal mattress suture techniques. Likewise, there was no

  15. Biomechanics Associated with Patellofemoral Pain and ACL Injuries in Sports.

    Science.gov (United States)

    Weiss, Kaitlyn; Whatman, Chris

    2015-09-01

    Knee injuries are prevalent among a variety of competitive sports and can impact an athlete's ability to continue to participate in their sport or, in the worst case, end an athlete's career. The aim was to evaluate biomechanics associated with both patellofemoral pain syndrome (PFPS) and anterior cruciate ligament (ACL) injuries (in sports involving landing, change in direction, or rapid deceleration) across the three time points frequently reported in the literature: pre-injury, at the time of injury, and following injury. A search of the literature was conducted for research evaluating biomechanics associated with ACL injury and PFPS. The Web of Science, SPORTDiscus, EBSCO, PubMed, and CINAHL databases, to March 2015, were searched, and journal articles focused on ACL injuries and PFPS in sports that met the inclusion criteria were reviewed. The search methodology was created with the intent of extracting case-control, case, and cohort studies of knee injury in athletic populations. The search strategy was restricted to only full-text articles published in English. These articles were included in the review if they met all of the required selection criteria. The following inclusion criteria were used: (1) The study must report lower extremity biomechanics in one of the following settings: (a) a comparison of currently injured and uninjured participants, (b) a prospective study evaluating risk factors for injury, or (c) a study reporting on the injury event itself. (2) The study must include only currently active participants who were similar at baseline (i.e. healthy, high school level basketball players currently in-season) and include biomechanical analysis of either landing, change in direction, or rapid deceleration. (3) The study must include currently injured participants. The studies were graded on the basis of quality, which served as an indication of risk of bias. An adapted version of the 'Strengthening the Reporting of Observational Studies in

  16. Morphological and biomechanical response to eutrophication and hydrodynamic stresses.

    Science.gov (United States)

    Zhu, Guorong; Yuan, Changbo; Di, Guilan; Zhang, Meng; Ni, Leyi; Cao, Te; Fang, Rongting; Wu, Gongguo

    2018-05-01

    Eutrophication and hydrodynamics determine the final distribution patterns of aquatic macrophytes; however, there is limited available knowledge regarding their interactive effects. Morphological and biomechanical responses to eutrophication and hydrodynamic stresses were assessed by sampling five abundant and dominant species, Potamogeton maackianus, P. pectinatus, P. lucens, Ceratophyllum demersum and Myriophyllum spicatum, in three macrophyte beds in Lake Erhai, Yunnan Province, China: one exposed to eutrophication and moderate southeast (SE) wind; one with mesotrophication, but sheltered by the lakeshore, with weak wind disturbance; and one with meso-eutrophication and strong SE wind. The results showed significant interactive effects of eutrophication and hydrodynamics on most biomechanical traits and some morphological traits, suggesting that aquatic macrophytes preferentially undergo biomechanical adjustments to resist the coexisting eutrophication and hydrodynamic stresses. In particular, hydrodynamics increased both the tensile force and tensile strain of P. maackianus under meso-eutrophication and dramatically decreased them in eutrophic areas, suggesting that eutrophication triggers mechanical failure in this species. Additionally, P. pectinatus, C. demersum and M. spicatum showed the lowest and highest values for the biomechanical variables (greater values for M. spicatum) in the most eutrophic and hydrodynamic areas, respectively, implying that increases in hydrodynamics primarily induce mechanical damage in eutrophic species. The plants generally exhibited greater tensile strain in both shallow and deep waters and the greatest tensile force at moderate depths. The stem cross-sectional area, plant height, stem length, internode length, and branch traits were all responsible for determining the biomechanical variables. This study reveals that hydrodynamic changes primarily induce mechanical damage in eutrophic species, whereas eutrophication triggers

  17. Evaluation of a Particle Swarm Algorithm For Biomechanical Optimization

    Science.gov (United States)

    Schutte, Jaco F.; Koh, Byung; Reinbolt, Jeffrey A.; Haftka, Raphael T.; George, Alan D.; Fregly, Benjamin J.

    2006-01-01

    Optimization is frequently employed in biomechanics research to solve system identification problems, predict human movement, or estimate muscle or other internal forces that cannot be measured directly. Unfortunately, biomechanical optimization problems often possess multiple local minima, making it difficult to find the best solution. Furthermore, convergence in gradient-based algorithms can be affected by scaling to account for design variables with different length scales or units. In this study we evaluate a recently-developed version of the particle swarm optimization (PSO) algorithm to address these problems. The algorithm’s global search capabilities were investigated using a suite of difficult analytical test problems, while its scale-independent nature was proven mathematically and verified using a biomechanical test problem. For comparison, all test problems were also solved with three off-the-shelf optimization algorithms—a global genetic algorithm (GA) and multistart gradient-based sequential quadratic programming (SQP) and quasi-Newton (BFGS) algorithms. For the analytical test problems, only the PSO algorithm was successful on the majority of the problems. When compared to previously published results for the same problems, PSO was more robust than a global simulated annealing algorithm but less robust than a different, more complex genetic algorithm. For the biomechanical test problem, only the PSO algorithm was insensitive to design variable scaling, with the GA algorithm being mildly sensitive and the SQP and BFGS algorithms being highly sensitive. The proposed PSO algorithm provides a new off-the-shelf global optimization option for difficult biomechanical problems, especially those utilizing design variables with different length scales or units. PMID:16060353

  18. Computer simulation of human motion in sports biomechanics.

    Science.gov (United States)

    Vaughan, C L

    1984-01-01

    This chapter has covered some important aspects of the computer simulation of human motion in sports biomechanics. First the definition and the advantages and limitations of computer simulation were discussed; second, research on various sporting activities were reviewed. These activities included basic movements, aquatic sports, track and field athletics, winter sports, gymnastics, and striking sports. This list was not exhaustive and certain material has, of necessity, been omitted. However, it was felt that a sufficiently broad and interesting range of activities was chosen to illustrate both the advantages and the pitfalls of simulation. It is almost a decade since Miller [53] wrote a review chapter similar to this one. One might be tempted to say that things have changed radically since then--that computer simulation is now a widely accepted and readily applied research tool in sports biomechanics. This is simply not true, however. Biomechanics researchers still tend to emphasize the descriptive type of study, often unfortunately, when a little theoretical explanation would have been more helpful [29]. What will the next decade bring? Of one thing we can be certain: The power of computers, particularly the readily accessible and portable microcomputer, will expand beyond all recognition. The memory and storage capacities will increase dramatically on the hardware side, and on the software side the trend will be toward "user-friendliness." It is likely that a number of software simulation packages designed specifically for studying human motion [31, 96] will be extensively tested and could gain wide acceptance in the biomechanics research community. Nevertheless, a familiarity with Newtonian and Lagrangian mechanics, optimization theory, and computers in general, as well as practical biomechanical insight, will still be a prerequisite for successful simulation models of human motion. Above all, the biomechanics researcher will still have to bear in mind that

  19. History of spine biomechanics: part I--the pre-Greco-Roman, Greco-Roman, and medieval roots of spine biomechanics.

    Science.gov (United States)

    Naderi, Sait; Andalkar, Niteen; Benzel, Edward C

    2007-02-01

    The roots of spine biomechanics reside in the Antiquity and the Medieval and Renaissance periods. A review of historical treatises reveals detailed information regarding this often historically neglected discipline. Ancient medical, philosophical, and physical documents were reviewed, as they pertained to the historical foundation of spine biomechanics. These included medical case reports and observations of nature and motion by ancient philosophers and scientists. These documents heavily influenced the portion of the scientific literature that we now regard as "spine biomechanics" up through the Renaissance. The focus of Part I of this two-part series is placed on the ancient and medieval biomechanics-related literature and on associated literature that influenced the development of the field of modern spine biomechanics.

  20. [Biomechanics and imaging evaluation on stable structure of pelvis].

    Science.gov (United States)

    Ma, Zhi-Jian; Bai, Li-Ping; Zeng, Xiang-Sen; Ya, Jun; Wang, Qiu-Gen

    2016-12-25

    The treatment of difficulty and prognosis of pelvic fracture are directly related to the pelvic girdle stability. Diagnosis of pelvic fracture is mainly imaging manifestations based on biomechanics of pelvic anatomy. With the progress of biomechanics experiment technology, previousopinion has changed, such as separation of symphysis pubis 2.5 cm could not be seen as distinguishing feature of type I and II for anterior-posterior compression;displacement of sacroilliac joints less than 1 cm could cause loss of vertical stability;lateral extrusion could also cause vertical instability;part description of Young-Burgess classification is not suitable for experiment results;ligament plays an important role in restricting displacement and having proprioceptors;SPECT-CT could improve sensitivity of diagnosis, but could not evaluate stability of pelvic fractures precisely. Copyright© 2016 by the China Journal of Orthopaedics and Traumatology Press.

  1. Hand Posture Prediction Using Neural Networks within a Biomechanical Model

    Directory of Open Access Journals (Sweden)

    Marta C. Mora

    2012-10-01

    Full Text Available This paper proposes the use of artificial neural networks (ANNs in the framework of a biomechanical hand model for grasping. ANNs enhance the model capabilities as they substitute estimated data for the experimental inputs required by the grasping algorithm used. These inputs are the tentative grasping posture and the most open posture during grasping. As a consequence, more realistic grasping postures are predicted by the grasping algorithm, along with the contact information required by the dynamic biomechanical model (contact points and normals. Several neural network architectures are tested and compared in terms of prediction errors, leading to encouraging results. The performance of the overall proposal is also shown through simulation, where a grasping experiment is replicated and compared to the real grasping data collected by a data glove device.

  2. [Preliminary study of biomechanic property on human forethigh skin].

    Science.gov (United States)

    Liu, C; Chen, H

    1997-12-01

    HLC0-I biomechanical living-tissues testing mechanic was adopted for testing the biomechanical property of normal adult forethigh skin. The figures acquired were calculated using one dimension strain energy function and the constitutive equation of mono-way stress and strain was established. The results showed that the relationship between stress and strain could be expressed by the exponential function. The rise of stress was not evident when the strain was lower than 1.2, but the stress rose much sharply when the strain was higher than 1.2. The curves were nonlinear. This suggests that when we sew up a wound or perform skin transplantation, the strain should be lower than 1.2.

  3. Hierarchical multiscale model for biomechanics analysis of microfilament networks

    Science.gov (United States)

    Li, Tong; Gu, Y. T.; Feng, Xi-Qiao; Yarlagadda, Prasad K. D. V.; Oloyede, Adekunle

    2013-05-01

    The mechanisms of force generation and transference via microfilament networks are crucial to the understandings of mechanobiology of cellular processes in living cells. However, there exists an enormous challenge for all-atom physics simulation of real size microfilament networks due to scale limitation of molecular simulation techniques. Following biophysical investigations of constitutive relations between adjacent globular actin monomers on filamentous actin, a hierarchical multiscale model was developed to investigate the biomechanical properties of microfilament networks. This model was validated by previous experimental studies of axial tension and transverse vibration of single F-actin. The biomechanics of microfilament networks can be investigated at the scale of real eukaryotic cell size (10 μm). This multiscale approach provides a powerful modeling tool which can contribute to the understandings of actin-related cellular processes in living cells.

  4. The role of biomechanics in orthopedic and neurological rehabilitation.

    Science.gov (United States)

    Kulig, Kornelia; Burnfield, Judith M

    2008-01-01

    Movement is fundamental to human well-being, function and participation in work and leisure activities. As a result, regaining optimal movement abilities and independence frequently become central foci of rehabilitation programs developed for individuals recovering from serious orthopedic and neurologic injuries. Further, preventing additional injury to the locomotor system becomes essential for effective long-term management of chronic medical conditions such as tendon dysfunction and diabetes. The primary aim of this perspective is to illustrate the role of biomechanics in orthopedics, musculoskeletal and neurological rehabilitation. Specifically, this paper discusses selected examples, ranging from the tissue to whole body biomechanics level, that highlight how scientific evidence from the theoretical and applied sciences have merged to address common and sometimes unique clinical problems.

  5. Biomechanical Properties of Recurrent Laryngeal Nerve in the Piglet

    Science.gov (United States)

    Alexander, Megan J.; Barkmeier-Kraemer, Julie M.; Vande Geest, Jonathan P.

    2016-01-01

    Unilateral vocal fold paralysis (UVP) results from damage to the recurrent laryngeal nerve (RLN). The most common causes of UVP are associated with compromised RLN tissue. The purpose of this research was to investigate the biomechanical properties of piglet RLN and identify differences in these properties along its length and in between the left and right side. Quasi-static uniaxial tensile testing and isotropic constitutive modeling was performed on seven piglet RLNs. Stiffness and other biomechanical parameters were derived from these tests and compared from conducting two different statistical analysis for the between and within nerve comparisons. Results showed higher stiffness values in the left RLN segment than for the right. Descriptive data demonstrated a higher stiffness in RLN segments surrounding the aortic arch, indicating a more protective role of the extracellular matrix in these nerves. This research offers insight regarding the protective function of the RLN connective tissues and structural compromise due to its environment. PMID:20369296

  6. BIOMECHANICAL ANALYSIS OF RUNNING IN THE HIGH JUMP

    Directory of Open Access Journals (Sweden)

    Werlayne Leite

    2013-02-01

    Full Text Available The aim of this paper is to analyze the biomechanics of running at high jump. To this study was realized a bibliographic revision. The running phase is the one which starts when the athlete is set in movement for the jump until the moment that he touches the ground with the takeoff foot in front of the bar, this phase can be divided into two parts: the running in straight line and the running in curve. On the other hand, for better understanding and due to a biomechanical complexity, the running in curve will be divided into three other parts: the three last strides, the two last strides and the last strides. Besides that, we could mention important factors for an efficient approach run: the radius of the curve, the distance and length of the takeoff run.

  7. Biomechanical characteristics of the eccentric Achilles tendon exercise

    DEFF Research Database (Denmark)

    Henriksen, Marius; Aaboe, Jens; Bliddal, Henning

    2009-01-01

    BACKGROUND: Eccentric exercise has been shown to provide good short-term clinical results in the treatment of painful mid-portion chronic Achilles tendinopathies. However, the mechanisms behind the positive effects of eccentric rehabilitation regimes are not known, and research into the biomechan......BACKGROUND: Eccentric exercise has been shown to provide good short-term clinical results in the treatment of painful mid-portion chronic Achilles tendinopathies. However, the mechanisms behind the positive effects of eccentric rehabilitation regimes are not known, and research....... No differences in Achilles tendon loads were found. INTERPRETATION: This descriptive study demonstrates differences in the movement biomechanics between the eccentric and concentric phases of one-legged full weight bearing ankle dorsal and plantar flexion exercises. In particular, the findings imply...

  8. [Bus drivers' biomechanical risk assessment in two different contexts].

    Science.gov (United States)

    Baracco, A; Coggiola, M; Perrelli, F; Banchio, M; Martignone, S; Gullino, A; Romano, C

    2012-01-01

    The application of standardize methods for the biomechanical risk assessment in non-industrial cycled activity is not always possible. A typical case is the public transport sector, where workers complain of suffering for shoulder more than elbow and wrist pains. The Authors present the results of two studies involving two public transport companies and the risk of biomechanical overload of upper limbs for bus and tram drivers. The analysis has been made using three different approaches: focus groups; static analysis by using anthropometric manikins; work sampling technique by monitoring worker's activity and posture at each minute, for two hours and for each binomial vehicle-route, considering P5F e P95M drivers and assessing the perceived efforts thorough the Borg's CR10 Scale. The conclusive results show that the ergonomic analysis managed by multiple non-standardized techniques may reach consistent and repeatable results according to the epidemiological evidences.

  9. Biomechanical bases of rehabilitation of children with cerebral palsy

    Science.gov (United States)

    Davlet'yarova, K. V.; Korshunov, S. D.; Kapilevich, L. V.

    2015-11-01

    Biomechanical analysis and the study results of children's with cerebral palsy (CP) muscles bioelectrical activity while walking on a flat surface are represented. Increased flexion in the hip and shoulder joints and extension in the elbow joint in children with cerebral palsy were observed, with the movement of the lower limbs had less smooth character in comparison with the control group. Herewith, the oscillation amplitude was significantly increased, and the frequency in the m. gastrocnemius and m. lateralis was decreased. It was shown, that the dynamic stereotype of walking in children with cerebral palsy was characterized by excessive involvement of m. gastrocnemius and m.latissimus dorsi in locomotion. Thus, resulting biomechanical and bioelectrical parameters of walking should be considered in the rehabilitation programs development.

  10. [Advances on biomechanics and kinematics of sprain of ankle joint].

    Science.gov (United States)

    Zhao, Yong; Wang, Gang

    2015-04-01

    Ankle sprains are orthopedic clinical common disease, accounting for joint ligament sprain of the first place. If treatment is not timely or appropriate, the joint pain and instability maybe develop, and even bone arthritis maybe develop. The mechanism of injury of ankle joint, anatomical basis has been fully study at present, and the diagnostic problem is very clear. Along with the development of science and technology, biological modeling and three-dimensional finite element, three-dimensional motion capture system,digital technology study, electromyographic signal study were used for the basic research of sprain of ankle. Biomechanical and kinematic study of ankle sprain has received adequate attention, combined with the mechanism research of ankle sprain,and to explore the the biomechanics and kinematics research progress of the sprain of ankle joint.

  11. Prosthetic abutment influences bone biomechanical behavior of immediately loaded implants

    Directory of Open Access Journals (Sweden)

    Germana de Villa CAMARGOS

    2016-01-01

    Full Text Available Abstract This study aimed to evaluate the influence of the type of prosthetic abutment associated to different implant connection on bone biomechanical behavior of immediately and delayed loaded implants. Computed tomography-based finite element models comprising a mandible with a single molar implant were created with different types of prosthetic abutment (UCLA or conical, implant connection (external hexagon, EH or internal hexagon, IH, and occlusal loading (axial or oblique, for both immediately and delayed loaded implants. Analysis of variance at 95%CI was used to evaluate the peak maximum principal stress and strain in bone after applying a 100 N occlusal load. The results showed that the type of prosthetic abutment influences bone stress/strain in only immediately loaded implants. Attachment of conical abutments to IH implants exhibited the best biomechanical behavior, with optimal distribution and dissipation of the load in peri-implant bone.

  12. Overall wrist biomechanics are conserved by phenol-based embalming.

    Science.gov (United States)

    Dickinson, Andrew W L; Casier, Craig B; Sellens, Richard W; Pichora, David R; Ellis, Randy E

    2014-01-01

    Although cadaveric specimens that have been fresh-frozen then thawed are considered the gold standard for biomechanics research, because they most closely represent in vivo tissues, potential problems include a relatively short useful time-span and risk of infection. A recently reported new method of phenol-based "soft" embalming has been found to preserve tissues in a fresh-like state over an extended period of time and simultaneously reduced infection risks. This study presents radio-ulnar deviation end-range data from 4 soft-embalmed and refrigerated human cadaveric forearm specimens over 12 months. All end-range comparisons were found to be statistically equivalent to within a clinically acceptable range of ±5 degrees of radio-ulnar deviation with a 95% con. dence measure of p < 0.01 in every case. These soft-embalmed specimens provide promising results for further use in biomechanical studies.

  13. Systematic evaluation of observational methods assessing biomechanical exposures at work

    DEFF Research Database (Denmark)

    Takala, Esa-Pekka; Irmeli, Pehkonen; Forsman, Mikael

    2009-01-01

      Systematic evaluation of observational methods assessing biomechanical exposures at work   Esa-Pekka Takala 1, Irmeli Pehkonen 1, Mikael Forsman 2, Gert-Åke Hansson 3, Svend Erik Mathiassen 4, W. Patrick Neumann 5, Gisela Sjøgaard 6, Kaj Bo Veiersted 7, Rolf Westgaard 8, Jørgen Winkel 9   1...... University of Science and Technology, Trondheim, 9 University of Gothenburg and National Research Centre for the Working Environment, Copenhagen   The aim of this project was to identify and systematically evaluate observational methods to assess workload on the musculoskeletal system. Searches...... by sorting the methods according to the several items evaluated.   Numerous methods have been developed to assess physical workload (biomechanical exposures) in order to identify hazards leading to musculoskeletal disorders, to monitor the effects of ergonomic changes, and for research. No indvidual method...

  14. Meshless methods in biomechanics bone tissue remodelling analysis

    CERN Document Server

    Belinha, Jorge

    2014-01-01

    This book presents the complete formulation of a new advanced discretization meshless technique: the Natural Neighbour Radial Point Interpolation Method (NNRPIM). In addition, two of the most popular meshless methods, the EFGM and the RPIM, are fully presented. Being a truly meshless method, the major advantages of the NNRPIM over the FEM, and other meshless methods, are the remeshing flexibility and the higher accuracy of the obtained variable field. Using the natural neighbour concept, the NNRPIM permits to determine organically the influence-domain, resembling the cellulae natural behaviour. This innovation permits the analysis of convex boundaries and extremely irregular meshes, which is an advantage in the biomechanical analysis, with no extra computational effort associated.   This volume shows how to extend the NNRPIM to the bone tissue remodelling analysis, expecting to contribute with new numerical tools and strategies in order to permit a more efficient numerical biomechanical analysis.

  15. Giovanni Alfonso Borelli--the father of biomechanics.

    Science.gov (United States)

    Pope, Malcolm H

    2005-10-15

    Giovanni Alfonso Borelli is often described as the father of biomechanics. He was born in Naples in 1608. His De Motu Animalium, published in 1680, extended to biology the rigorous analytical methods developed by Galileo in the field of mechanics. Borelli calculated the forces required for equilibrium in various joints of the human body well before Newton published The Laws of Motion Borelli was the first to understand that the levers of the musculoskeletal system magnify motion rather than force, so that muscles must produce much larger forces than those resisting the motion. Borelli died in Rome on December 31, 1679, but his impressive body of original work helped inspire a great number of future scientists, microscopists, and inventors. The highest honor bestowed by the American Society of Biomechanics is the Giovanni Borelli Award.

  16. Tree Branching: Leonardo da Vinci's Rule versus Biomechanical Models

    Science.gov (United States)

    Minamino, Ryoko; Tateno, Masaki

    2014-01-01

    This study examined Leonardo da Vinci's rule (i.e., the sum of the cross-sectional area of all tree branches above a branching point at any height is equal to the cross-sectional area of the trunk or the branch immediately below the branching point) using simulations based on two biomechanical models: the uniform stress and elastic similarity models. Model calculations of the daughter/mother ratio (i.e., the ratio of the total cross-sectional area of the daughter branches to the cross-sectional area of the mother branch at the branching point) showed that both biomechanical models agreed with da Vinci's rule when the branching angles of daughter branches and the weights of lateral daughter branches were small; however, the models deviated from da Vinci's rule as the weights and/or the branching angles of lateral daughter branches increased. The calculated values of the two models were largely similar but differed in some ways. Field measurements of Fagus crenata and Abies homolepis also fit this trend, wherein models deviated from da Vinci's rule with increasing relative weights of lateral daughter branches. However, this deviation was small for a branching pattern in nature, where empirical measurements were taken under realistic measurement conditions; thus, da Vinci's rule did not critically contradict the biomechanical models in the case of real branching patterns, though the model calculations described the contradiction between da Vinci's rule and the biomechanical models. The field data for Fagus crenata fit the uniform stress model best, indicating that stress uniformity is the key constraint of branch morphology in Fagus crenata rather than elastic similarity or da Vinci's rule. On the other hand, mechanical constraints are not necessarily significant in the morphology of Abies homolepis branches, depending on the number of daughter branches. Rather, these branches were often in agreement with da Vinci's rule. PMID:24714065

  17. Comparing dynamical systems concepts and techniques for biomechanical analysis

    OpenAIRE

    van Emmerik, Richard E.A.; Ducharme, Scott W.; Amado, Avelino C.; Hamill, Joseph

    2016-01-01

    Traditional biomechanical analyses of human movement are generally derived from linear mathematics. While these methods can be useful in many situations, they do not describe behaviors in human systems that are predominately nonlinear. For this reason, nonlinear analysis methods based on a dynamical systems approach have become more prevalent in recent literature. These analysis techniques have provided new insights into how systems (1) maintain pattern stability, (2) transition into new stat...

  18. Biomechanics important to interpret radiographs of the hip

    Energy Technology Data Exchange (ETDEWEB)

    Rosenthal, D.I.; Scott, J.A.

    1983-02-01

    Biomechanic principles have important implications to film interpretation. Angulation of the femoral neck results in four different types of forces: compression on the medial side, tension on the lateral side, shear stress in the center, and torque forces at the neck-shaft angle. The body's response to these forces results in recognicable trabecular patterns which respond in a predictable manner to disease states. Surgical intervention in the form of hip replacement or fracture fixation must reflect these engineering consideration.

  19. Static Friction Unsung Hero of Everyday Introductory Biomechanics

    Science.gov (United States)

    Beverly, Nancy

    2006-12-01

    The ability of static friction to accelerate systems does not usually get the attention it deserves in introductory physics. Everyday human contexts abound in our grasp of objects to move them, in our being moved as passengers, and in our own locomotion. Student laboratory, classroom and homework activities have been developed which enable students to explore the vital role of static friction in various biomechanical contexts. Examples will be demonstrated.

  20. Biomechanical analysis of the camelid cervical intervertebral disc

    Directory of Open Access Journals (Sweden)

    Dean K. Stolworthy

    2015-01-01

    Full Text Available Chronic low back pain (LBP is a prevalent global problem, which is often correlated with degenerative disc disease. The development and use of good, relevant animal models of the spine may improve treatment options for this condition. While no animal model is capable of reproducing the exact biology, anatomy, and biomechanics of the human spine, the quality of a particular animal model increases with the number of shared characteristics that are relevant to the human condition. The purpose of this study was to investigate the camelid (specifically, alpaca and llama cervical spine as a model of the human lumbar spine. Cervical spines were obtained from four alpacas and four llamas and individual segments were used for segmental flexibility/biomechanics and/or morphology/anatomy studies. Qualitative and quantitative data were compared for the alpaca and llama cervical spines, and human lumbar specimens in addition to other published large animal data. Results indicate that a camelid cervical intervertebral disc (IVD closely approximates the human lumbar disc with regard to size, spinal posture, and biomechanical flexibility. Specifically, compared with the human lumbar disc, the alpaca and llama cervical disc size are approximately 62%, 83%, and 75% with regard to area, depth, and width, respectively, and the disc flexibility is approximately 133%, 173%, and 254%, with regard to range of motion (ROM in axial-rotation, flexion-extension, and lateral-bending, respectively. These results, combined with the clinical report of disc degeneration in the llama lower cervical spine, suggest that the camelid cervical spine is potentially well suited for use as an animal model in biomechanical studies of the human lumbar spine.

  1. Biomechanical Analysis of the Jump Shot in Basketball

    OpenAIRE

    Struzik Artur; Pietraszewski Bogdan; Zawadzki Jerzy

    2014-01-01

    Basketball players usually score points during the game using the jump shot. For this reason, the jump shot is considered to be the most important element of technique in basketball and requires a high level of performance. The aim of this study was to compare the biomechanical characteristics of the lower limbs during a jump shot without the ball and a countermovement jump without an arm swing. The differences between variables provide information about the potential that an athlete can util...

  2. Biomechanical properties of the keratoconic cornea: a review.

    Science.gov (United States)

    Vellara, Hans R; Patel, Dipika V

    2015-01-01

    There has been a recent surge of interest in assessing corneal biomechanical properties due to potential clinical applications, particularly in the early detection of keratoconus (KC). This review discusses the effects of keratoconus on the biomechanical properties of the cornea and the current techniques used to detect these changes both in the laboratory and clinical setting. Specific structural changes occurring in the corneal stroma as part of the disease process can be linked to alterations in the viscous and elastic properties of the cornea in keratoconus. Although there are extensive ex vivo studies using techniques such as extensometry and inflation testing to analyse the biomechanical properties of the normal cornea, few have investigated the keratoconic cornea using the same methods. There are a number of ex vivo studies that confirm the effectiveness of collagen cross-linking in increasing Young's modulus in healthy corneas. Recently, research has focussed on measuring corneal biomechanical parameters in vivo using two commercially available instruments: the Ocular Response Analyser (ORA) and the CorVis ST (CST). Both instruments analyse the dynamic behaviour of the cornea, when temporarily deformed by an air puff; however, the outputs of these instruments are not directly comparable due to differences in the characteristics of the air puff and output parameters. Studies using these instruments have reported significant differences between keratoconic and healthy corneas; however, neither instrument can currently be used in isolation to reliably diagnose keratoconus. Further research analysing the outputs of these instruments may enhance their diagnostic capabilities. © 2014 The Authors. Clinical and Experimental Optometry © 2014 Optometry Australia.

  3. Forward lunge knee biomechanics before and after partial meniscectomy

    DEFF Research Database (Denmark)

    Hall, Michelle; Nielsen, Jonas Høberg; Holsgaard-Larsen, Anders

    2015-01-01

    partial meniscectomy (APM) on knee joint mechanics. The purpose of this study was to evaluate changes in knee joint biomechanics during a forward lunge in patients with a suspected degenerative meniscal tear from before to three months after APM. METHODS: Twenty-two patients (35-55years old...... strenuous tasks following APM, patients used less knee flexion, a strategy that may limit excessive patellar loads during forward lunge in the recently operated leg....

  4. Artificial Intelligence in Sports Biomechanics: New Dawn or False Hope?

    OpenAIRE

    Bartlett, Roger

    2006-01-01

    This article reviews developments in the use of Artificial Intelligence (AI) in sports biomechanics over the last decade. It outlines possible uses of Expert Systems as diagnostic tools for evaluating faults in sports movements ('techniques') and presents some example knowledge rules for such an expert system. It then compares the analysis of sports techniques, in which Expert Systems have found little place to date, with gait analysis, in which they are routinely used. Consideration is then ...

  5. Probabilistic Modeling of Intracranial Pressure Effects on Optic Nerve Biomechanics

    Science.gov (United States)

    Ethier, C. R.; Feola, Andrew J.; Raykin, Julia; Myers, Jerry G.; Nelson, Emily S.; Samuels, Brian C.

    2016-01-01

    Altered intracranial pressure (ICP) is involved/implicated in several ocular conditions: papilledema, glaucoma and Visual Impairment and Intracranial Pressure (VIIP) syndrome. The biomechanical effects of altered ICP on optic nerve head (ONH) tissues in these conditions are uncertain but likely important. We have quantified ICP-induced deformations of ONH tissues, using finite element (FE) and probabilistic modeling (Latin Hypercube Simulations (LHS)) to consider a range of tissue properties and relevant pressures.

  6. Multiscale computer modeling in biomechanics and biomedical engineering

    CERN Document Server

    2013-01-01

    This book reviews the state-of-the-art in multiscale computer modeling, in terms of both accomplishments and challenges. The information in the book is particularly useful for biomedical engineers, medical physicists and researchers in systems biology, mathematical biology, micro-biomechanics and biomaterials who are interested in how to bridge between traditional biomedical engineering work at the organ and tissue scales, and the newer arenas of cellular and molecular bioengineering.

  7. Esophageal morphometric and biomechanical changes during aging in rats

    DEFF Research Database (Denmark)

    Zhao, Jingbo; Gregersen, Hans

    Background The function of the esophagus have obvious changes during the aging, this functional change is important in relation to the concept of “the form follows function”. It is therefore of great interest to study the aging changes of the esophageal biomechanical properties. Aim The aim of th....... The observed changes likely reflect the changes of the physiological function of the esophagus during aging since for other tissues the function dictates the form of the tissue, and remodeling depend on the mechanical loading.......Background The function of the esophagus have obvious changes during the aging, this functional change is important in relation to the concept of “the form follows function”. It is therefore of great interest to study the aging changes of the esophageal biomechanical properties. Aim The aim...... of the present study is to investigate the esophageal geometry and biomechanical changes during aging in rats. Materials and methods Twenty-four male Wistar rats, aged from 6 to 22 months, were used in the study. The body weight and the wet weight per length of esophageal segment were measured at the termination...

  8. Determining the biomechanics of touch sensation in C. elegans.

    Science.gov (United States)

    Elmi, Muna; Pawar, Vijay M; Shaw, Michael; Wong, David; Zhan, Haoyun; Srinivasan, Mandayam A

    2017-09-26

    The sense of touch is a fundamental mechanism that nearly all organisms use to interact with their surroundings. However, the process of mechanotransduction whereby a mechanical stimulus gives rise to a neuronal response is not well understood. In this paper we present an investigation of the biomechanics of touch using the model organism C. elegans. By developing a custom micromanipulation and force sensing system around a high resolution optical microscope, we measured the spatial deformation of the organism's cuticle and force response to controlled uniaxial indentations. We combined these experimental results with anatomical data to create a multilayer computational biomechanical model of the organism and accurately derive its material properties such as the elastic modulus and poisson's ratio. We demonstrate the utility of this model by combining it with previously published electrophysiological data to provide quantitative insights into different biomechanical states for mechanotransduction, including the first estimate of the sensitivity of an individual mechanoreceptor to an applied stimulus (parameterised as strain energy density). We also interpret empirical behavioural data to estimate the minimum number of mechanoreceptors which must be activated to elicit a behavioural response.

  9. BIOMECHANIC EVALUATION OF CARPENTRY WORKERS IN THE DISTRITO FEDERAL, BRAZIL

    Directory of Open Access Journals (Sweden)

    Nilton Cesar Fiedler

    2010-08-01

    Full Text Available The aim of this study was the biomechanical assessment of carpentry woodworkers, located in Brasília, DF. It was filmed the profile of each worker during the performance of his activities in the carpentry and the forces involved in the work were assessed. The image of each woodworker was congealed to accomplish the measurement of articulation angles. The data were submitted to the software of posture analysis “Winowas” (OWAS Method and to the biomechanic model of posture prognosis and static forces, developed by Michigan University. The OWAS method showed that, for all machines and carpentries assessed, the worst posture occurred when the worker lifted and placed the pieces of wood on the floor and during the feeding in the smoother. The tridimensional biomechanic model registered the worst posture in different phases of the work cycle. In the first one, there were problems in all articulations, except the hips, when placing the pieces on the floor from the smoother. In the second one, there were problems in all articulations, except the elbows and the L5-S1 column disc, by feeding the surface planer. The third one, the ankles were the most injured when feeding the smoother, the surface planer, the circular saw and the band saw. According to the results, the woodworkers should try to eliminate the constant work standing upright, use auxiliary machinery to handle pieces of wood, reduce the load during feeding the machines and improve postures.

  10. The effects of tibiofibularis anterior ligaments on ankle joint biomechanics.

    Science.gov (United States)

    Karakaşlı, Ahmet; Erduran, Mehmet; Baktıroğlu, Lütfü; Büdeyri, Aydın; Yıldız, Didem Venüs; Havıtçıoğlu, Hasan

    2015-03-01

    The aim of this study was to evaluate the biomechanical behavior of anterior inferior tibiofibularis ligament (AITFL) deficient human ankle under axial loading of ankle at stance phase of gait. In order to investigate the contribution of AITFL to ankle stability, an in vitro sequential experimental setup was simulated. The measurement of posterior displacement of distal tibia and anterior displacement of the foot, in neutral position, secondary to axial compression, was performed by two non-contact video extensometers. Eight freshly frozen, anatomically intact, cadaveric human ankle specimens were included and tested. An axial compression test machine was utilized from 0 to 800 Newtonswith a loading speed of 5 mm/min in order to simulate the axial weight-bearing sequence of the ankle at stance phase of human gait. There was a statistically significant difference between anteroposterior displacement values for AITFL-Intact and AITFL-Dissected specimens (p≤0.05). Mean AITFL-Intact and mean AITFL-Dissected ankle anteroposterior displacement was 1.28±0.47 mm and 2.06±0.7 mm, respectively. This study determined some numerical and quantitative data about the biomechanical properties of AITFL in neutral foot position. In the emergency department, diagnosis and treatment of AITFL injury, due to ankle distortion, is important. In AITFL injuries, ankle biomechanics is affected, and ankle instability occurs.

  11. Cell biomechanics and its applications in human disease diagnosis

    Science.gov (United States)

    Nematbakhsh, Yasaman; Lim, Chwee Teck

    2015-04-01

    Certain diseases are known to cause changes in the physical and biomechanical properties of cells. These include cancer, malaria, and sickle cell anemia among others. Typically, such physical property changes can result in several fold increases or decreases in cell stiffness, which are significant and can result in severe pathology and eventual catastrophic breakdown of the bodily functions. While there are developed biochemical and biological assays to detect the onset or presence of diseases, there is always a need to develop more rapid, precise, and sensitive methods to detect and diagnose diseases. Biomechanical property changes can play a significant role in this regard. As such, research into disease biomechanics can not only give us an in-depth knowledge of the mechanisms underlying disease progression, but can also serve as a powerful tool for detection and diagnosis. This article provides some insights into opportunities for how significant changes in cellular mechanical properties during onset or progression of a disease can be utilized as useful means for detection and diagnosis. We will also showcase several technologies that have already been developed to perform such detection and diagnosis.

  12. Personalized biomechanical simulations of orthotic treatment in idiopathic scoliosis.

    Science.gov (United States)

    Périé, Delphine; Aubin, C E; Petit, Y; Labelle, H; Dansereau, J

    2004-02-01

    To analyse patient-specific bracing biomechanics in the treatment of scoliosis. Two complementary computer tools have been developed to quantify the brace action on scoliotic spine from pressure measurements, and to simulate its effect on patient-adapted finite element model. Brace pad forces and brace effect on spine deformities have been reported. However, the brace mechanisms still need to be better understood to obtain more effective treatments. The 3D geometry of the spine and rib cage of three scoliotic adolescents treated by the Boston brace was obtained using a multiview radiographic reconstruction technique. A personalized biomechanical model was constructed for each patient. Pressures generated by the brace on the thorax were measured using pressure sensors. For each zone with a threshold pressure higher than 30 mmHg, a total equivalent force was calculated and applied to the corresponding model nodes. The pressure were generally scattered on the overall torso, with the highest pressures measured on five distinct regions: right thoracic, left lumbar, abdominal, right and left sides of the pelvis. The equivalent forces were of 18-73 N. Differences between simulated deformed shapes and real in-brace geometry of the patients were less than 6 and 9.8 mm for the vertebral positions in the coronal and sagittal planes, and 7.7 degrees for the Cobb angles. The results supported the feasibility of such approach to analyse patient-specific bracing biomechanics, which may be useful in the design of more effective braces.

  13. Musculoskeletal, biomechanical, and physiological gender differences in the US military.

    Science.gov (United States)

    Allison, Katelyn F; Keenan, Karen A; Sell, Timothy C; Abt, John P; Nagai, Takashi; Deluzio, Jennifer; McGrail, Mark; Lephart, Scott M

    2015-01-01

    The repeal of the Direct Ground Combat Assignment Rule has renewed focus on examining performance capabilities of female military personnel and their ability to occupy previously restricted military occupational specialties. Previous research has revealed female Soldiers suffer a greater proportion of musculoskeletal injuries compared to males, including a significantly higher proportion of lower extremity, knee, and overuse injuries. Potential differences may also exist in musculoskeletal, biomechanical, and physiological characteristics between male and female Soldiers requiring implementation of gender-specific training in order to mitigate injury risk and enhance performance. To examine differences in musculoskeletal, biomechanical, and physiological characteristics in male and female Soldiers. A total of 406 101st Airborne Division (Air Assault) Soldiers (348 male; 58 female) participated. Subjects underwent testing for flexibility, isokinetic and isometric strength (percent body weight), single-leg balance, lower body biomechanics during a stop jump and drop landing, body composition, anaerobic power/capacity, and aerobic capacity. Independent t tests assessed between-group comparisons. Women demonstrated significantly greater flexibility (Pphysiological characteristics. Sex-specific interventions may aid in improving such characteristics to optimize physical readiness and decrease the injury risk during gender-neutral training, and decreasing between-sex variability in performance characteristics may result in enhanced overall unit readiness. Identification of sex-specific differences in injury patterns and characteristics should facilitate adjustments in training in order for both sexes to meet the gender-neutral occupational demands for physically demanding military occupational specialties.

  14. In vitro biomechanical modulation--retinal detachment in a box.

    Science.gov (United States)

    Ghosh, Fredrik; Arnér, Karin; Taylor, Linnéa

    2016-03-01

    To illustrate the importance of biomechanical impact on tissue health within the central nervous system (CNS), we herein describe an in vitro model of rhegmatogenous retinal detachment (RRD) in which disruption and restoration of physical tissue support can be studied in isolation. Adult retinal porcine explants were kept in culture for 3 or 12 hours without any tissue support, simulating clinical RRD, after which they were either maintained in this state or reattached to the culture membrane for an additional 48 hours. In vitro detachment resulted in gliosis and severe progressive loss of retinal neurons. In contrast, if the explant was reattached, gliosis and overall cell death was attenuated, ganglion cell death was arrested, and the number of transducin-expressing cone photoreceptors increased. These results support the hypothesis that removal of the elastic retina from its normal physical environment results in degenerative damage, and, if restored, rescues retinal neurons. Our study reinforces the notion of a strong relationship between the biomechanical environment and homeostasis within the retina, which has significant bearing on pathologic events related to RRD, and may also have impact on other regions within the CNS under biomechanical influence.

  15. Citation metrics of excellence in sports biomechanics research.

    Science.gov (United States)

    Knudson, Duane

    2017-11-13

    This study extended research on key citation metrics of winners of two career scholar awards in sports biomechanics. Google Scholar (GS) was searched using Harzing's Publish or Perish software for the 13 most recent winners of the ISBS Geoffrey Dyson Award and the ASB Jim Hay Memorial Award. Returned records were corrected for author, and publications excluded for all but peer-reviewed journal articles, proceedings articles, chapters and books in English. These recent award winners had published about 150 publications that had been cited typically 4,082 and 6,648 times over a 26- and 28-year period before receiving these career awards for sports biomechanics research. Estimated median citations at time of their awards were 2,927 and 4,907 for the Dyson and Hay awards, respectively. Award winners had mean Hirsh indexes of 32-45 and mean h i of 19-28. Their mean g indexes (59-84) and their numerous citation classics (C > 100) indicated that they had many influential publications. The citation metrics of these scholars were outstanding and consistent with recent studies of top scholars in biomechanics and kinesiology/exercise science. Careful searching, cleaning and interpretation of several scholar-level citation metrics may provide useful confirmatory evidence for evaluations of awards committees.

  16. Optical spectroscopic characterization of human meniscus biomechanical properties

    Science.gov (United States)

    Ala-Myllymäki, Juho; Danso, Elvis K.; Honkanen, Juuso T. J.; Korhonen, Rami K.; Töyräs, Juha; Afara, Isaac O.

    2017-12-01

    This study investigates the capacity of optical spectroscopy in the visible (VIS) and near-infrared (NIR) spectral ranges for estimating the biomechanical properties of human meniscus. Seventy-two samples obtained from the anterior, central, and posterior locations of the medial and lateral menisci of 12 human cadaver joints were used. The samples were subjected to mechanical indentation, then traditional biomechanical parameters (equilibrium and dynamic moduli) were calculated. In addition, strain-dependent fibril network modulus and permeability strain-dependency coefficient were determined via finite-element modeling. Subsequently, absorption spectra were acquired from each location in the VIS (400 to 750 nm) and NIR (750 to 1100 nm) spectral ranges. Partial least squares regression, combined with spectral preprocessing and transformation, was then used to investigate the relationship between the biomechanical properties and spectral response. The NIR spectral region was observed to be optimal for model development (83.0%≤R2≤90.8%). The percentage error of the models are: Eeq (7.1%), Edyn (9.6%), Eɛ (8.4%), and Mk (8.9%). Thus, we conclude that optical spectroscopy in the NIR range is a potential method for rapid and nondestructive evaluation of human meniscus functional integrity and health in real time during arthroscopic surgery.

  17. Biomechanical Characteristics and Determinants of Instep Soccer Kick

    Science.gov (United States)

    Kellis, Eleftherios; Katis, Athanasios

    2007-01-01

    Good kicking technique is an important aspect of a soccer player. Therefore, understanding the biomechanics of soccer kicking is particularly important for guiding and monitoring the training process. The purpose of this review was to examine latest research findings on biomechanics of soccer kick performance and identify weaknesses of present research which deserve further attention in the future. Being a multiarticular movement, soccer kick is characterised by a proximal-to-distal motion of the lower limb segments of the kicking leg. Angular velocity is maximized first by the thigh, then by the shank and finally by the foot. This is accomplished by segmental and joint movements in multiple planes. During backswing, the thigh decelerates mainly due to a motion-dependent moment from the shank and, to a lesser extent, by activation of hip muscles. In turn, forward acceleration of the shank is accomplished through knee extensor moment as well as a motion-dependent moment from the thigh. The final speed, path and spin of the ball largely depend on the quality of foot-ball contact. Powerful kicks are achieved through a high foot velocity and coefficient of restitution. Preliminary data indicate that accurate kicks are achieved through slower kicking motion and ball speed values. Key pointsSoccer kick is achieved through segmental and joint rotations in multiple planes and via the proximal-to-distal sequence of segmental angular velocities until ball impact. The quality of ball - foot impact and the mechanical behavior of the foot are also important determinants of the final speed, path and spin of the ball.Ball speed values during the maximum instep kick range from 18 to 35 msec-1 depending on various factors, such as skill level, age, approach angle and limb dominance.The main bulk of biomechanics research examined the biomechanics of powerful kicks, mostly under laboratory conditions. A powerful kick is characterized by the achievement of maximal ball speed. However

  18. Weightbath hydrotraction treatment: application, biomechanics, and clinical effects

    Directory of Open Access Journals (Sweden)

    Márta Kurutz

    2010-04-01

    Full Text Available Márta Kurutz1, Tamás Bender21Department of Structural Mechanics, Budapest University of Technology and Economics, Hungary; 2Department of Physical Medicine, Polyclinic and Hospital of the Hospitaller Brothers of St. John of God, Budapest, Medical University of Szeged, HungaryBackground and purpose: Weightbath hydrotraction treatment (WHT is a simple noninvasive effective method of hydro- or balneotherapy to stretch the spine or lower limbs, applied successfully in hospitals and health resort sanitaria in Hungary for more than fifty years. This study aims to introduce WHT with its biomechanical and clinical effects. History, development, equipment, modes of application, biomechanics, spinal traction forces and elongations, indications and contraindications of WHT are precented.Subjects and methods: The calculation of traction forces acting along the spinal column during the treatment is described together with the mode of suspension and the position of extra weight loads applied. The biomechanics of the treatment are completed by in vivo measured elongations of lumbar segments using a special underwater ultrasound measuring method. The clinical effects, indications, and contraindications of the treatment are also presented.Results: In the underwater cervical suspension of a human body, approximately 25 N stretching load occurs in the cervical spine, and about 11 N occurs in the lumbar spine. By applying extra weights, the above tensile forces along the spinal column can be increased. Thus, the traction effect can be controlled by applying such loads during the treatment. Elongations of segments L3–L4, L4–L5, and L5–S1 were measured during the usual WHT of patients suspended cervically in water for 20 minutes, loaded by 20–20 N lead weights on the ankles. The mean initial elastic elongations of spinal segments were about 0.8 mm for patients aged under 40 years, 0.5 mm between 40–60 years, and 0.2 mm for patients over 60 years. The mean

  19. Biomechanical Analysis of a Filiform Mechanosensory Hair Socket of Crickets.

    Science.gov (United States)

    Joshi, Kanishka; Mian, Ahsan; Miller, John

    2016-08-01

    Filiform mechanosensory hairs of crickets are of great interest to engineers because of the hairs' highly sensitive response to low-velocity air-currents. In this study, we analyze the biomechanical properties of filiform hairs of the cercal sensory system of a common house cricket. The cercal sensory system consists of two antennalike appendages called cerci that are situated at the rear of the cricket's abdomen. Each cercus is covered with 500-750 flow sensitive filiform mechanosensory hairs. Each hair is embedded in a complex viscoelastic socket that acts as a spring and dashpot system and guides the movement of the hair. When a hair deflects due to the drag force induced on its length by a moving air-current, the spiking activity of the neuron that innervates the hair changes and the combined spiking activity of all hairs is extracted by the cercal sensory system. Filiform hairs have been experimentally studied by researchers, though the basis for the hairs' biomechanical characteristics is not fully understood. The socket structure has not been analyzed experimentally or theoretically from a mechanical standpoint, and the characterization that exists is mathematical in nature and only provides a very rudimentary approximation of the socket's spring nature. This study aims to understand and physically characterize the socket's behavior and interaction with the filiform hair by examining hypotheses about the hair and socket biomechanics. A three-dimensional computer-aided design (CAD) model was first created using confocal microscopy images of the hair and socket structure of the cricket, and then finite-element analyses (FEAs) based on the physical conditions that the insect experiences were simulated. The results show that the socket can act like a spring; however, it has two-tier rotational spring constants during pre- and postcontacts of iris and hair bulge due to its constitutive nonstandard geometric shapes.

  20. Clinical evaluation of a biomechanical guidance system for periacetabular osteotomy.

    Science.gov (United States)

    Murphy, Ryan J; Armiger, Robert S; Lepistö, Jyri; Armand, Mehran

    2016-03-30

    Populations suffering from developmental dysplasia of the hip typically have reduced femoral coverage and experience joint pain while walking. Periacetabular osteotomy (PAO) is one surgical solution that realigns the acetabular fragment. This challenging surgery has a steep learning curve. Existing navigation systems for computer-assisted PAO neither track the released fragment nor offer the means to assess fragment location. An intraoperative workstation--the biomechanical guidance system (BGS)--developed for PAO incorporates intraoperative fragment tracking and acetabular characterization through radiographic angles and joint biomechanics. In this paper, we investigate the accuracy and effectiveness of the BGS for bone fragment tracking and acetabular characterization in clinical settings as compared to conventional techniques and postoperative assessments. We also report the issues encountered and our remedies when using the BGS in the clinical setting. Eleven consecutive patients (aged 22-48, mean 34, years) underwent 12 PAO surgeries (one bilateral surgery) where the BGS collected information on acetabular positioning. These measurements were compared with postoperative CT data and manual measurements made intraoperatively. No complications were reported during surgery, with surgical time-95-210 (mean 175) minutes-comparable to reported data for the conventional approach. The BGS-measured acetabular positioning showed strong agreement with postoperative CT measurements (-0.3-9.2, mean 3.7, degrees), whereas larger differences occurred between the surgeon's intraoperative manual measurements and postoperative CT measurements (-2.8-21.3, mean 10.5, degrees). The BGS successfully tracked the acetabular fragment in a clinical environment without introducing complications to the surgical workflow. Accurate 3D positioning of the acetabulum may provide more information intraoperatively (e.g., anatomical angles and biomechanics) without adversely impacting the surgery

  1. Head impacts during high school football: a biomechanical assessment.

    Science.gov (United States)

    Broglio, Steven P; Sosnoff, Jacob J; Shin, SungHoon; He, Xuming; Alcaraz, Christopher; Zimmerman, Jerrad

    2009-01-01

    Little is known about the impact biomechanics sustained by players during interscholastic football. To characterize the location and magnitude of impacts sustained by players during an interscholastic football season. Observational design. On the field. High school varsity football team (n = 35; age = 16.85 +/- 0.75 years, height = 183.49 +/- 5.31 cm, mass = 89.42 +/- 12.88 kg). Biomechanical variables (linear acceleration, rotational acceleration, jerk, force, impulse, and impact duration) related to head impacts were categorized by session type, player position, and helmet impact location. Differences in grouping variables were found for each impact descriptor. Impacts occurred more frequently and with greater intensity during games. Linear acceleration was greatest in defensive linemen and offensive skill players and when the impact occurred at the top of the helmet. The largest rotational acceleration occurred in defensive linemen and with impacts to the front of the helmet. Impacts with the highest-magnitude jerk, force, and impulse and shortest duration occurred in the offensive skill, defensive line, offensive line, and defensive skill players, respectively. Top-of-the-helmet impacts yielded the greatest magnitude for the same variables. We are the first to provide a biomechanical characterization of head impacts in an interscholastic football team across a season of play. The intensity of game play manifested with more frequent and intense impacts. The highest-magnitude variables were distributed across all player groups, but impacts to the top of the helmet yielded the highest values. These high school football athletes appeared to sustain greater accelerations after impact than their older counterparts did. How this finding relates to concussion occurrence has yet to be elucidated.

  2. Dietary water affects human skin hydration and biomechanics

    Directory of Open Access Journals (Sweden)

    Palma L

    2015-08-01

    Full Text Available Lídia Palma,1 Liliana Tavares Marques,1 Julia Bujan,2,3 Luís Monteiro Rodrigues1,4 1CBIOS – Research Center for Health Science and Technologies, Universidade Lusófona, Campo Grande, Lisboa, Portugal; 2Department of Medicine and Medical Specialities, Universidad de Alcalá de Henares, Madrid, Spain; 3CIBER-BBN, Madrid, España, Spain; 4Department of Pharmacological Sciences, School of Pharmacy, Universidade de Lisboa, Lisboa, Portugal Abstract: It is generally assumed that dietary water might be beneficial for the health, especially in dermatological (age preventing terms. The present study was designed to quantify the impact of dietary water on major indicators of skin physiology. A total of 49 healthy females (mean 24.5±4.3 years were selected and characterized in terms of their dietary daily habits, especially focused in water consumption, by a Food Frequency Questionnaire. This allowed two groups to be set – Group 1 consuming less than 3,200 mL/day (n=38, and Group 2 consuming more than 3,200 mL/day (n=11. Approximately 2 L of water were added to the daily diet of Group 2 individuals for 1 month to quantify the impact of this surplus in their skin physiology. Measurements involving epidermal superficial and deep hydration, transepidermal water loss, and several biomechanical descriptors were taken at day 0 (T0, 15 (T1, and 30 (T2 in several anatomical sites (face, upper limb, and leg. This stress test (2 L/day for 30 days significantly modified superficial and deep skin hydration, especially in Group 1. The same impact was registered with the most relevant biomechanical descriptors. Thus, in this study, it is clear that higher water inputs in regular diet might positively impact normal skin physiology, in particular in those individuals with lower daily water consumptions. Keywords: dietary water, water consume, skin hydration, TEWL, skin biomechanics

  3. Biomechanics of the spine. Part I: Spinal stability

    International Nuclear Information System (INIS)

    Izzo, Roberto; Guarnieri, Gianluigi; Guglielmi, Giuseppe; Muto, Mario

    2013-01-01

    Biomechanics, the application of mechanical principles to living organisms, helps us to understand how all the bony and soft spinal components contribute individually and together to ensure spinal stability, and how traumas, tumours and degenerative disorders exert destabilizing effects. Spine stability is the basic requirement to protect nervous structures and prevent the early mechanical deterioration of spinal components. The literature reports a number of biomechanical and clinical definitions of spinal stability, but a consensus definition is lacking. Any vertebra in each spinal motion segment, the smallest functional unit of the spine, can perform various combinations of the main and coupled movements during which a number of bony and soft restraints maintain spine stability. Bones, disks and ligaments contribute by playing a structural role and by acting as transducers through their mechanoreceptors. Mechanoreceptors send proprioceptive impulses to the central nervous system which coordinates muscle tone, movement and reflexes. Damage to any spinal structure gives rise to some degree of instability. Instability is classically considered as a global increase in the movements associated with the occurrence of back and/or nerve root pain. The assessment of spinal instability remains a major challenge for diagnostic imaging experts. Knowledge of biomechanics is essential in view of the increasing involvement of radiologists and neuroradiologists in spinal interventional procedures and the ongoing development of new techniques and devices. Bioengineers and surgeons are currently focusing on mobile stabilization systems. These systems represent a new frontier in the treatment of painful degenerative spine and aim to neutralize noxious forces, restore the normal function of spinal segments and protect the adjacent segments. This review discusses the current concepts of spine stability

  4. Biomechanical analysis of reduction malarplasty with L-shaped osteotomy.

    Science.gov (United States)

    Qiu, Shuang; Gui, Lai; Wang, Meng; Chen, Ying; Niu, Feng; Liu, Jianfeng; Liu, Wei; Zhang, Yankun

    2012-05-01

    Reduction malarplasty with L-shaped osteotomy is widely used for surgical correction of prominent zygoma and bilateral zygomatic asymmetry. One of the keys to this surgery is the formation of the greenstick fracture on the root of the zygomatic arch. However, the greenstick fracture cannot be seen directly both in the postoperative x-ray films and three-dimensional computed tomography images, and it is unknown how the greenstick fracture forms biomechanically. So it is of great concern to both the doctors and patients whether the greenstick fracture can really take place on the root of the zygomatic arch. This study focused on the biomechanism and deformation effects of the surgery by using the method of finite element (FE) analysis. Computed tomography data of 2 patients with prominent malar complex were obtained for three-dimensional reconstruction. The FE models of the zygomatic complex with L-shaped osteotomy were established by using Mimics via thresholding, segmentation techniques, and material properties assignment with gray value conversion. Then simulations including the boundary conditions and the forces of the surgery were performed in ABAQUS. The FE models have fine quality; the first one contains 63,053 units and 100,995 nodes, and the other one contains 70,238 units and 136,219 nodes. Under the loading of pressures, the zygoma and the zygomatic arch inward have deformation displacement. Maximum stress concentration was found just at the root of the zygomatic arch. A appropriate zygomatic pressure will generate a stress concentration to form the greenstick on the root of the zygomatic arch. This study can help surgeons understand and conduct the reduction malarplasty with L-shaped osteotomy from a biomechanical insight.

  5. The role of the fibula in varus and valgus deformity of the tibia: a biomechanical study

    NARCIS (Netherlands)

    Stufkens, S. A.; van Bergen, C. J.; Blankevoort, L.; van Dijk, C. N.; Hintermann, B.; Knupp, M.

    2011-01-01

    It has been suggested that a supramalleolar osteotomy can return the load distribution in the ankle joint to normal. However, due to the lack of biomechanical data, this supposition remains empirical. The purpose of this biomechanical study was to determine the effect of simulated supramalleolar

  6. Training for Women's Basketball: A Biomechanical Emphasis for Preventing Anterior Cruciate Ligament Injury.

    Science.gov (United States)

    Pettitt, Robert W.; Bryson, Erin R.

    2002-01-01

    Summarizes proposed variables linked with higher incidences of anterior cruciate ligament tears in females and the biomechanical aspects of the lower extremity during the performance of common basketball skills, focusing on gender differences in knee joint stability and neuromuscular control, biomechanical aspects of lower extremity skills in…

  7. A comparative biomechanical analysis of term fetal membranes in human and domestic species

    Science.gov (United States)

    The purpose of this study was to biomechanically characterize and compare human, porcine, equine, and ovine fetal membranes. Noncontact metrology was used for topographic analyses. Uniaxial tensile testing was performed to resolve specific biomechanical values. Puncture force and radial stresses we...

  8. How Can Sport Biomechanics Contribute to the Advance of World Record and Best Athletic Performance?

    Science.gov (United States)

    Li, Li

    2012-01-01

    Modern history has evidence that sport biomechanics provide valuable contribution in the pursuit of "faster, higher, and stronger." In this article, the contribution of sport biomechanics to the Olympic Games has been divided into three different categories: improve the physical capacity of the athletes, develop innovative techniques in…

  9. Diagnostic Assessment of Preparedness of Level One Sports Science Students for Biomechanics Modules

    Science.gov (United States)

    Dixon, Sharon J.

    2005-01-01

    The primary objective of this study was to investigate the use of a diagnostic test to assess the preparedness of level one students for a sports biomechanics module. During their first week at university, a cohort of 108 students completed a diagnostic test at the end of their first lecture in sports biomechanics, with no prior notice. Upon…

  10. Finite element analysis of biomechanical effects of total ankle arthroplasty on the foot

    Directory of Open Access Journals (Sweden)

    Yan Wang

    2018-01-01

    The translational potential of this article: Biomechanical variations resulted from total ankle arthroplasty may contribute to negative postoperative outcomes. The exploration of the biomechanical performance in this study might benefit the surgeons in the determination of surgical protocols to avoid complications. The analysis of the performance of the ankle prosthesis could enhance the knowledge of prosthetic design.

  11. Bladder biomechanics and the use of scaffolds for regenerative medicine in the urinary bladder

    DEFF Research Database (Denmark)

    Ajalloueian, Fatemeh; Lemon, Greg; Hilborn, Jöns

    2018-01-01

    in vitro and in vivo, including in the treatment of clinical conditions. The biomechanical properties of the native bladder can be investigated using a range of mechanical tests for standardized assessments, as well as mathematical and computational bladder biomechanics. Despite a large body of research...

  12. Poor relation between biomechanical and clinical studies for the proximal femoral locking compression plate

    DEFF Research Database (Denmark)

    Viberg, Bjarke; Voergård Rasmussen, Katrine Marie; Overgaard, Søren

    2017-01-01

    Background and purpose — The proximal femur locking compression plate (PF-LCP) is a new concept in the treatment of hip fractures. When releasing new implants onto the market, biomechanical studies are conducted to evaluate performance of the implant. We investigated the relation between biomecha......Background and purpose — The proximal femur locking compression plate (PF-LCP) is a new concept in the treatment of hip fractures. When releasing new implants onto the market, biomechanical studies are conducted to evaluate performance of the implant. We investigated the relation between...... biomechanical and clinical studies on PF-LCP. Methods — A systematic literature search of relevant biomechanical and clinical studies was conducted in PubMed on December 1, 2015. 7 biomechanical studies and 15 clinical studies were included. Results — Even though the biomechanical studies showed equivalent...... or higher failure loads for femoral neck fracture, the clinical results were far worse, with a 37% complication rate. There were no biomechanical studies on pertrochanteric fractures. Biomechanical studies on subtrochanteric fractures showed that PF-LCP had a lower failure load than with proximal femoral...

  13. Challenge-Based Instruction: The VaNTH Biomechanics Learning Modules

    Science.gov (United States)

    Barr, Ronald E.; Pandy, Marcus G.; Petrosino, Anthony J.; Roselli, Robert J.; Brophy, Sean; Freeman, Robert A.

    2007-01-01

    This paper presents the methodology and results of teaching an entire engineering course using challenge-based instruction. The challenges consisted of eight biomechanics multimedia learning modules developed by the authors as part of a broader NSF educational coalition. The biomechanics modules were presented in an undergraduate mechanical…

  14. [The biomechanics of screws, cerclage wire and cerclage cable].

    Science.gov (United States)

    Schröder, C; Woiczinski, M; Utzschneider, S; Kraxenberger, M; Weber, P; Jansson, V

    2013-05-01

    In contrast to fracture fixation, when performing an osteotomy the surgeon is able to plan preoperatively. The resulting fixation and compression of the bone fragments are the most important points. A stable osteosynthesis should prevent dislocation of bone fragments and improve bone healing. Beside plates, cerclages can be used for tension band or diaphysis bone fixation. Moreover, cortical or cancellous screws can be used for osteotomy fixation. This work describes biomechanical principles for fixation after an osteotomy with cerclages and cortical or cancellous screws. It also summarizes the materials and geometries used, as well as their influence on the stability of the osteosynthesis.

  15. Analysis of Biomechanical Structure and Passing Techniques in Basketball

    OpenAIRE

    Ricardo E. Izzo; Luca Russo

    2011-01-01

    The basketball is a complex sport, which these days has become increasingly linked to its’ psychophysical aspects rather than to the technical ones. Therefore, it is important to make a through study of the passing techniques from the point of view of the type of the pass and its’ biomechanics. From the point of view of the type of the used passes, the most used is the two-handed chest pass with a frequency of 39.9%. This is followed, in terms of frequency, by one-handed passes – the baseball...

  16. Radiological features and biomechanical patterns in Perthes disease

    International Nuclear Information System (INIS)

    Choo, B.S.; Hogg, A.D.C.; Burwell, R.G.; Moulton, A.; Worthington, B.S.

    1990-01-01

    This paper examines the relationship between radiologic features and biomechanical patterns in Perthes disease as shown in finite element models. A two-dimensional finite element model of a child's hip that allowed for movement at the joint line was loaded to simulate normal heel strike. The finite element method is a computer-based technique of mathematical modeling that permits calculation of the magnitude and direction of stresses, deformation, and dynamic behavior of continuous structures. In the normal hip model, maximum compressive stresses occur superolaterally and inferomedially in the femoral head, corresponding to the radiographic features of flattening and increased tear drop distance, attributable to cartilage thickening, seen in Perthes disease

  17. Material parameter identification and inverse problems in soft tissue biomechanics

    CERN Document Server

    Evans, Sam

    2017-01-01

    The articles in this book review hybrid experimental-computational methods applied to soft tissues which have been developed by worldwide specialists in the field. People developing computational models of soft tissues and organs will find solutions for calibrating the material parameters of their models; people performing tests on soft tissues will learn what to extract from the data and how to use these data for their models and people worried about the complexity of the biomechanical behavior of soft tissues will find relevant approaches to address this complexity.

  18. Age–Related Perspectives on the Biomechanics of Traumatic Injury

    OpenAIRE

    Pezzutti, Silvia

    2017-01-01

    Finite element models have the potential to accurately represent the pediatric body, both from the anatomical and topological point of view. They can describe changes in size and shape as well as changes in the biomechanical properties. Starting from the PIPER human body model, whose baseline represents the anatomy of a 6 years old child, a family of five models between the age of 2 and 6 was created with the purpose of investigating how the body reacts to a traumatic impact. To create these ...

  19. [Biomechanical view of the histology of the TMJ].

    Science.gov (United States)

    Carano, A; Carano, M

    1991-01-01

    Several reasons could explain the confusion and controversy that reign over every aspect of temporomandibular joint dysfunction. The discord includes not only diagnosis and treatment of the dysfunction, but even involves the anatomy and the histology of the TMJ. Different data in the literature indicate the major role of the biomechanical influences on the histology of the temporomandibular joint and on the adaptability of its structures. On the basis of these concepts, the histology of the TMJ has been revisited and a new functional interpretation of the microscopic morphology of the condyle, disc and periarticular connective tissue has been described.

  20. Biomechanical Analysis of Treadmill Locomotion on the International Space Station

    Science.gov (United States)

    De Witt, J. K.; Fincke, R. S.; Guilliams, M. E.; Ploutz-Snyder, L. L.

    2011-01-01

    Treadmill locomotion exercise is an important aspect of ISS exercise countermeasures. It is widely believed that an optimized treadmill exercise protocol could offer benefits to cardiovascular and bone health. If training heart rate is high enough, treadmill exercise is expected to lead to improvements in aerobic fitness. If impact or bone loading forces are high enough, treadmill exercise may be expected to contribute to improved bone outcomes. Ground-based research suggests that joint loads increase with increased running speed. However, it is unknown if increases in locomotion speed results in similar increases in joint loads in microgravity. Although data exist regarding the biomechanics of running and walking in microgravity, a majority were collected during parabolic flight or during investigations utilizing a microgravity analog. The Second Generation Treadmill (T2) has been in use on the International Space Station (ISS) and records the ground reaction forces (GRF) produced by crewmembers during exercise. Biomechanical analyses will aid in understanding potential differences in typical gait motion and allow for modeling of the human body to determine joint and muscle forces during exercise. By understanding these mechanisms, more appropriate exercise prescriptions can be developed that address deficiencies. The objective of this evaluation is to collect biomechanical data from crewmembers during treadmill exercise prior to and during flight. The goal is to determine if locomotive biomechanics differ between normal and microgravity environments and to determine how combinations of subject load and speed influence joint loading during in-flight treadmill exercise. Further, the data will be used to characterize any differences in specific bone and muscle loading during locomotion in these two gravitational conditions. This project maps to the HRP Integrated Research Plan risks including Risk of Bone Fracture (Gap B15), Risk of Early Onset Osteoporosis Due to

  1. An aetiological study on spondylolysis from a biomechanical aspect.

    Science.gov (United States)

    Ichikawa, N.; Ohara, Y.; Morishita, T.; Taniguichi, Y.; Koshikawa, A.; Matsukura, N.

    1982-01-01

    The authors report clinical studies on lumbar disorders (clinical symptoms, X-ray findings) in athletes in various sports. The sport items were divided into three groups according to the main dynamic load applied to the lumbar region. As a result, over 60% of the athletes suffered from "lumbago", and among them spondylolysis reached the high rate of 27%. Arising from these clinical observations, we performed biomechanical laboratory analyses on human cadaver material, axial compression and rotational bending. Our results suggest that the incidence of spondylolysis depends upon the extent and direction of the loads. Images Fig. 4 Fig. 5 Fig. 8 Fig. 9 Fig. 10 PMID:7139222

  2. BIOMECHANICAL CHARACTERISTICS AND DETERMINANTS OF INSTEP SOCCER KICK

    Directory of Open Access Journals (Sweden)

    Eleftherios Kellis

    2007-06-01

    Full Text Available Good kicking technique is an important aspect of a soccer player. Therefore, understanding the biomechanics of soccer kicking is particularly important for guiding and monitoring the training process. The purpose of this review was to examine latest research findings on biomechanics of soccer kick performance and identify weaknesses of present research which deserve further attention in the future. Being a multiarticular movement, soccer kick is characterised by a proximal-to-distal motion of the lower limb segments of the kicking leg. Angular velocity is maximized first by the thigh, then by the shank and finally by the foot. This is accomplished by segmental and joint movements in multiple planes. During backswing, the thigh decelerates mainly due to a motion-dependent moment from the shank and, to a lesser extent, by activation of hip muscles. In turn, forward acceleration of the shank is accomplished through knee extensor moment as well as a motion-dependent moment from the thigh. The final speed, path and spin of the ball largely depend on the quality of foot-ball contact. Powerful kicks are achieved through a high foot velocity and coefficient of restitution. Preliminary data indicate that accurate kicks are achieved through slower kicking motion and ball speed values

  3. Biomechanical factors influencing the performance of elite Alpine ski racers.

    Science.gov (United States)

    Hébert-Losier, Kim; Supej, Matej; Holmberg, Hans-Christer

    2014-04-01

    Alpine ski racing is a popular international winter sport that is complex and challenging from physical, technical, and tactical perspectives. Despite the vast amount of scientific literature focusing on this sport, including topical reviews on physiology, ski-snow friction, and injuries, no review has yet addressed the biomechanics of elite alpine ski racers and which factors influence performance. In World Cup events, winning margins are often mere fractions of a second and biomechanics may well be a determining factor in podium place finishes. The aim of this paper was to systematically review the scientific literature to identify the biomechanical factors that influence the performance of elite alpine ski racers, with an emphasis on slalom, giant slalom, super-G, and downhill events. Four electronic databases were searched using relevant medical subject headings and key words, with an additional manual search of reference lists, relevant journals, and key authors in the field. Articles were included if they addressed human biomechanics, elite alpine skiing, and performance. Only original research articles published in peer-reviewed journals and in the English language were reviewed. Articles that focused on skiing disciplines other than the four of primary interest were excluded (e.g., mogul, ski-cross and freestyle skiing). The articles subsequently included for review were quality assessed using a modified version of a validated quality assessment checklist. Data on the study population, design, location, and findings relating biomechanics to performance in alpine ski racers were extracted from each article using a standard data extraction form. A total of 12 articles met the inclusion criteria, were reviewed, and scored an average of 69 ± 13% (range 40-89%) upon quality assessment. Five of the studies focused on giant slalom, four on slalom, and three on downhill disciplines, although these latter three articles were also relevant to super-G events

  4. Biomechanical determinants of elite rowing technique and performance.

    Science.gov (United States)

    Buckeridge, E M; Bull, A M J; McGregor, A H

    2015-04-01

    In rowing, the parameters of injury, performance, and technique are all interrelated and in dynamic equilibrium. Whilst rowing requires extreme physical strength and endurance, a high level of skill and technique is essential to enable an effective transfer of power through the rowing sequence. This study aimed to determine discrete aspects of rowing technique, which strongly influence foot force production and asymmetries at the foot-stretchers, as these are biomechanical parameters often associated with performance and injury risk. Twenty elite female rowers performed an incremental rowing test on an instrumented rowing ergometer, which measured force at the handle and foot-stretchers, while three-dimensional kinematic recordings of the ankle, knee, hip, and lumbar-pelvic joints were made. Multiple regression analyses identified hip kinematics as a key predictor of foot force output (R(2)  = 0.48), whereas knee and lumbar-pelvic kinematics were the main determinants in optimizing the horizontal foot force component (R(2)  = .41). Bilateral asymmetries of the foot-stretchers were also seen to significantly influence lumbar-pelvic kinematics (R(2)  = 0.43) and pelvic twisting (R(2)  = 0.32) during the rowing stroke. These results provide biomechanical evidence toward aspects of technique that can be modified to optimize force output and performance, which can be of direct benefit to coaches and athletes. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  5. Analysis of Biomechanical Structure and Passing Techniques in Basketball

    Directory of Open Access Journals (Sweden)

    Ricardo E. Izzo

    2011-06-01

    Full Text Available The basketball is a complex sport, which these days has become increasingly linked to its’ psychophysical aspects rather than to the technical ones. Therefore, it is important to make a through study of the passing techniques from the point of view of the type of the pass and its’ biomechanics. From the point of view of the type of the used passes, the most used is the two-handed chest pass with a frequency of 39.9%. This is followed, in terms of frequency, by one-handed passes – the baseball, with 20.9 % – and by the two-handed over the head pass, with 18.2 %, and finally, one- or two-handed indirect passes (bounces, with 11.2 % and 9.8 %. Considering the most used pass in basketball, from the biomechanical point of view, the muscles involved in the correct movement consider all the muscles of the upper extremity, adding also the shoulder muscles as well as the body fixators (abdominals, hip flexors, knee extensors, and dorsal flexors of the foot. The technical and conditional analysis considers the throwing speed, the throw height and the air resistance. In conclusion, the aim of this study is to give some guidelines to improve the mechanical execution of the movements in training, without neglecting the importance of the harmony of the movements themselves.

  6. Can biomechanical variables predict improvement in crouch gait?

    Science.gov (United States)

    Hicks, Jennifer L.; Delp, Scott L.; Schwartz, Michael H.

    2011-01-01

    Many patients respond positively to treatments for crouch gait, yet surgical outcomes are inconsistent and unpredictable. In this study, we developed a multivariable regression model to determine if biomechanical variables and other subject characteristics measured during a physical exam and gait analysis can predict which subjects with crouch gait will demonstrate improved knee kinematics on a follow-up gait analysis. We formulated the model and tested its performance by retrospectively analyzing 353 limbs of subjects who walked with crouch gait. The regression model was able to predict which subjects would demonstrate ‘improved’ and ‘unimproved’ knee kinematics with over 70% accuracy, and was able to explain approximately 49% of the variance in subjects’ change in knee flexion between gait analyses. We found that improvement in stance phase knee flexion was positively associated with three variables that were drawn from knowledge about the biomechanical contributors to crouch gait: i) adequate hamstrings lengths and velocities, possibly achieved via hamstrings lengthening surgery, ii) normal tibial torsion, possibly achieved via tibial derotation osteotomy, and iii) sufficient muscle strength. PMID:21616666

  7. Development of a biomechanical guidance system for periacetabular osteotomy.

    Science.gov (United States)

    Murphy, Ryan J; Armiger, Robert S; Lepistö, Jyri; Mears, Simon C; Taylor, Russell H; Armand, Mehran

    2015-04-01

    This paper presents and validates a computer-navigated system for performing periacetabular osteotomy (PAO) to treat developmental dysplasia of the hip. The main motivation of the biomechanical guidance system (BGS) is to plan and track the osteotomy fragment in real time during PAO while simplifying the procedure for less-experienced surgeons. The BGS aims at developing a platform for comparing biomechanical states of the joint with the current gold standard geometric assessment of anatomical angles. The purpose of this study was to (1) determine the accuracy with which the BGS tracks the hip joint through repositioning and (2) identify improvements to the workflow. Nineteen cadaveric validation studies quantified system accuracy, verified system application, and helped to refine surgical protocol. In two surgeries, navigation and registration accuracy were computed by affixing fiducials to two cadavers prior to surgery. All scenarios compared anatomical angle measurements and joint positioning as measured intraoperatively to postoperatively. In the two cases with fiducials, computed fragment transformations deviated from measured fiducial transformations by 1.4 and 1.8 mm in translation and 1.0° and 2.2° in rotation, respectively. The additional seventeen surgeries showed strong agreement between intraoperative and postoperative anatomical angles, helped to refine the surgical protocol, and demonstrated system robustness. Estimated accuracy with BGS appeared acceptable for future surgical applications. Several major system requirements were identified and addressed, improving the BGS and making it feasible for clinical studies.

  8. Feeding biomechanics of the cownose ray, Rhinoptera bonasus, over ontogeny.

    Science.gov (United States)

    Kolmann, Matthew A; Huber, Daniel R; Motta, Philip J; Grubbs, R Dean

    2015-09-01

    Growth affects the performance of structure, so the pattern of growth must influence the role of a structure and an organism. Because animal performance is linked to morphological specialization, ontogenetic change in size may influence an organism's biological role. High bite force generation is presumably selected for in durophagous taxa. Therefore, these animals provide an excellent study system for investigating biomechanical consequences of growth on performance. An ontogenetic series of 27 cownose rays (Rhinoptera bonasus) were dissected in order to develop a biomechanical model of the feeding mechanism, which was then compared with bite forces measured from live rays. Mechanical advantage of the feeding apparatus was generally conserved throughout ontogeny, while an increase in the mass and cross-sectional area of the jaw adductors resulted in allometric gains in bite force generation. Of primary importance to forceful biting in this taxon is the use of a fibrocartilaginous tendon associated with the insertion of the primary jaw adductor division. This tendon may serve to redirect muscle forces anteriorly, transmitting them within the plane of biting. Measured bite forces obtained through electrostimulation of the jaw adductors in live rays were higher than predicted, possibly due to differences in specific tension of actual batoid muscle and that used in the model. Mass-specific bite forces in these rays are the highest recorded for elasmobranchs. Cownose rays exemplify a species that, through allometric growth of bite performance and morphological novelties, have expanded their ecological performance over ontogeny. © 2015 Anatomical Society.

  9. The volleyball athlete's shoulder: biomechanical adaptations and injury associations.

    Science.gov (United States)

    Challoumas, Dimitrios; Stavrou, Antonio; Dimitrakakis, Georgios

    2017-06-01

    In volleyball, the dominant shoulder of the athlete undergoes biomechanical and morphological adaptations; however, definitive conclusions about their exact nature, aetiology, purpose and associations with shoulder injury have not been reached. We present a systematic review of the existing literature describing biomechanical adaptations in the dominant shoulders of volleyball players and factors that may predispose to shoulder pain/injury. A thorough literature search via Medline, EMBASE and SCOPUS was conducted for original studies of volleyball players and 15 eligible articles were identified. Assessment of study quality was performed using the STROBE statement. The reviewed literature supports the existence of a glenohumeral internal rotation deficit (GIRD) and a possible (and less pronounced) external rotation gain in the dominant vs. the non-dominant shoulder of volleyball athletes. Unlike other overhead sports, the GIRD in volleyball athletes appears to be anatomical as a response to the repetitive overhead movements and not to be associated with shoulder pain/injury. Additionally, the dominant shoulder exhibits muscular imbalance, which appears to be a significant risk factor for shoulder pain. Strengthening of the external rotators should be used alongside shoulder stretching and joint mobilisations, core strengthening and optimisation of spike technique as part of injury management and prevention programmes.

  10. The passive biomechanics of human pelvic collecting lymphatic vessels.

    Directory of Open Access Journals (Sweden)

    Dimitrios Athanasiou

    Full Text Available The lymphatic system has a major significance in the metastatic pathways in women's cancers. Lymphatic pumping depends on both extrinsic and intrinsic mechanisms, and the mechanical behavior of lymphatic vessels regulates the function of the system. However, data on the mechanical properties and function of human lymphatics are lacking. Our aim is to characterize, for the first time, the passive biomechanical behavior of human collecting lymphatic vessels removed at pelvic lymph node dissection during primary debulking surgeries for epithelial ovarian cancer. Isolated vessels were cannulated and then pressurized at varying levels of applied axial stretch in a calcium-free Krebs buffer. Pressurized vessels were then imaged using multi-photon microscopy for collagen-elastin structural composition and fiber orientation. Both pressure-diameter and force-elongation responses were highly nonlinear, and axial stretching of the vessel served to decrease diameter at constant pressure. Pressure-diameter behavior for the human vessels is very similar to data from rat mesenteric vessels, though the human vessels were approximately 10× larger than those from rats. Multiphoton microscopy revealed the vessels to be composed of an inner layer of elastin with an outer layer of aligned collagen fibers. This is the first study that successfully described the passive biomechanical response and composition of human lymphatic vessels in patients with ovarian cancer. Future work should expand on this knowledge base with investigations of vessels from other anatomical locations, contractile behavior, and the implications on metastatic cell transport.

  11. The influence of shoe aging on children running biomechanics.

    Science.gov (United States)

    Herbaut, Alexis; Chavet, Pascale; Roux, Maxime; Guéguen, Nils; Barbier, Franck; Simoneau-Buessinger, Emilie

    2017-07-01

    Athletic children are prone to overuse injuries, especially at the heel and knee. Since footwear is an extrinsic factor of lower limb injury risk, the aim of this study was to assess the influence of shoe aging on children running biomechanics. Fourteen children active in sports participated in a laboratory biomechanical evaluation. A new pair of shoes was provided to each participant at an inclusion visit. Four months later, the participants performed a running task and their kinematics and kinetics were assessed both with their used shoes and with a new pair of shoes identical to the first. Furthermore, mechanical cushioning properties of shoes were evaluated before and after in-vivo aging. After 4months of use, the sole stiffness increased by 16% and the energy loss capacity decreased by 18% (preaction force (+23%, p=0.016), suggesting higher compressive forces under the heel and placing children at risk to experience impact-related injuries. Nevertheless, the decreased peak ankle and knee power absorption in used shoes (-11%, p=0.010 and -12%, p=0.029, respectively) suggests a lower ankle and knee joints loading during the absorption phase that may be beneficial regarding stretch-related injuries. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Application of acoustic microscopy to assessment of cardiovascular biomechanics

    Science.gov (United States)

    Saijo, Yoshifumi; Sasaki, Hidehiko; Nitta, Shin-ichi; Tanaka, Motonao; Joergensen, Claus S.; Falk, Erling

    2002-11-01

    Acoustic microscopy provides information on physical and mechanical properties of biological tissues, while optical microscopy with various staining techniques provides chemical properties. The biomechanics of tissues is especially important in cardiovascular system because its pathophysiology is closely related with mechanical stresses such as blood pressure or blood flow. A scanning acoustic microscope (SAM) system with tone-burst ultrasound in the frequency range of 100-200 MHz has been developed, and attenuation and sound speed of tissues have been measured. In human coronary arteries, attenuation and sound speed were high in calcification and collagen, while both values were low in smooth muscle and lipid. Another SAM system with 800-MHz-1.3-GHz ultrasound was applied for aortas of Apo-E deficient mouse, which is known to develop atherosclerosis. Attenuation of ultrasound was significantly higher in type 1 collagen compared to type 3 collagen. Recently, a new type FFT-SAM using a single-pulse, broadband frequency range ultrasound (20-150 MHz) has been developed. Cardiac allograft was observed by FFT-SAM and the acoustic properties were able to grade allograft rejection. SAM provides very useful information for assessing cardiovascular biomechanics and for understanding normal and abnormal images of clinical ultrasound.

  13. A dynamic biomechanical evaluation of lifting maximum acceptable loads.

    Science.gov (United States)

    Freivalds, A; Chaffin, D B; Garg, A; Lee, K S

    1984-01-01

    A biomechanical evaluation of the job-related stresses imposed upon a worker is a potential means of reducing the high incidence rates of manual material handling injuries in industry. A biomechanical model consisting of seven rigid links joined at six articulations has been developed for this purpose. Using data from cinematographic analysis of lifting motions the model calculates: (1) body position from articulation angles, (2) angular velocities and accelerations, (3) inertial moments and forces, and (4) reactive moments and forces at each articulation, including the L5/S1 joint. Results indicated effects of the common task variables. Larger load and box sizes increased the rise times and peak values of both vertical ground reaction forces and predicted L5/S1 compressive forces. However, boxes with handles resulted in higher L5/S1 compressive forces than for boxes without handles. Also, in lifting the larger boxes the subjects did not sufficiently compensate with reduced box weights in order to maintain uniform L5/S1 compressive forces. Smoothed and rectified EMG of erector spinae muscles correlated significantly with L5/S1 compressive forces, while predicted and measured vertical ground reaction forces also correlated significantly, indicating the validity of the model as a tool for predicting job physical stresses.

  14. Biomechanical parameters of gait among transtibial amputees: a review

    Directory of Open Access Journals (Sweden)

    Alex Sandra Oliveira de Cerqueira Soares

    Full Text Available Rehabilitation for lower-limb amputees needs to focus on restoration of daily functions and independent locomotion. As gait is reestablished, reorganization of the motor pattern takes place in order to optimize the functions of the locomotor system. Biomechanics is a field of study that enables understanding of this reorganization. From such knowledge, appropriate strategies for recovering the autonomy of the means of locomotion can be established. Thus, this paper had the aim of reviewing the current status of the biomechanics of locomotion among unilateral transtibial amputees. To achieve this aim, papers written in English or Portuguese and published up to 2005 were selected from the Cochrane Library, PubMed, Scientific Electronic Library Online (SciELO, Literatura Latino-Americana e do Caribe em Ciências da Saúde (Lilacs and Dedalus databases. In cases of transtibial amputation, the absence of plantar flexors negatively affects locomotion. Increased absorption and energy generation by the muscles that control the hip joint of the amputated leg can be considered to be the main compensatory strategy developed by unilateral transtibial amputees during gait. Factors associated with the characteristics of the amputation, prosthesis and experimental protocol used directly influence the results.

  15. Biomechanics of high-grade spondylolisthesis with and without reduction.

    Science.gov (United States)

    Wang, Wenhai; Aubin, Carl-Eric; Cahill, Patrick; Baran, George; Arnoux, Pierre-Jean; Parent, Stefan; Labelle, Hubert

    2016-04-01

    The clinical advantages of reducing spondylolisthesis over fusion in situ have several intuitive reasons such as restore the spinal column into a more anatomic relationship and alignment. However, there is only little evidence in the literature supporting the theoretical advantages of reduction, and its effect on spinopelvic alignment remains poorly defined. In this study, a comprehensive finite element model was developed to analyze the biomechanics of the spine after spinal fusion at L5-S1 in both types of high-grade spondylolisthesis (balanced and unbalanced pelvis). The relevant clinical indices (i.e. spondylolisthesis grade and Dubousset lumbosacral angle), the displacement of L4-L5, pressure within the annulus and nucleus, and stress at L4-L5 were evaluated and compared. The model can well predict the changes of the important clinical indices during the surgery. For a balanced pelvis, the reduction has a minimal effect on the biomechanical conditions at the adjacent level during postsurgical activities. In the unbalanced case, reduction induced larger deformation in the lumbosacral region and a higher stress concentration at adjacent level. Whether such a stress concentration can lead to long-term disc degeneration is not known. The results provide additional information for the clinician considering reduction of high-grade spondylolisthesis.

  16. Medial malleolar fractures: a biomechanical study of fixation techniques.

    Science.gov (United States)

    Fowler, T Ty; Pugh, Kevin J; Litsky, Alan S; Taylor, Benjamin C; French, Bruce G

    2011-08-08

    Fracture fixation of the medial malleolus in rotationally unstable ankle fractures typically results in healing with current fixation methods. However, when failure occurs, pullout of the screws from tension, compression, and rotational forces is predictable. We sought to biomechanically test a relatively new technique of bicortical screw fixation for medial malleoli fractures. Also, the AO group recommends tension-band fixation of small avulsion type fractures of the medial malleolus that are unacceptable for screw fixation. A well-documented complication of this technique is prominent symptomatic implants and secondary surgery for implant removal. Replacing stainless steel 18-gauge wire with FiberWire suture could theoretically decrease symptomatic implants. Therefore, a second goal was to biomechanically compare these 2 tension-band constructs. Using a tibial Sawbones model, 2 bicortical screws were compared with 2 unicortical cancellous screws on a servohydraulic test frame in offset axial, transverse, and tension loading. Second, tension-band fixation using stainless steel wire was compared with FiberWire under tensile loads. Bicortical screw fixation was statistically the stiffest construct under tension loading conditions compared to unicortical screw fixation and tension-band techniques with FiberWire or stainless steel wire. In fact, unicortical screw fixation had only 10% of the stiffness as demonstrated in the bicortical technique. In a direct comparison, tension-band fixation using stainless steel wire was statistically stiffer than the FiberWire construct. Copyright 2011, SLACK Incorporated.

  17. Elbow joint biomechanics for preclinical evaluation of total elbow prostheses.

    Science.gov (United States)

    Kincaid, Brian L; An, Kai-Nan

    2013-09-27

    Total elbow arthroplasty is a clinically successful procedure, yet long-term implant survival rates have historically lagged behind those reported for total hips and knees. Clinical complications associated with implant wear, osteolysis, stem loosening and device fracture have been implicated as reasons for limited long-term survivorship. Unfortunately, there is little published information on the biomechanics and method(s) for preclinical evaluation of total elbow prostheses that could provide insight into the mechanisms of failure. Additionally, there are no consensus testing standards or summaries of loading profiles of the humero-ulnar joint associated with a range of activities of daily living. Such data would facilitate the standardized preclinical assessment of total elbow devices such is commonplace for other large joints. The objective of the work here is therefore to provide a comprehensive review of elbow joint biomechanics as it relates to preclinical evaluation of total elbow implants. This summary includes a review of elbow joint forces, kinematics, the types and frequency of humero-ulnar joint motions associated with activities of daily living and clinical outcomes, as well as proposing a methodology for deriving humero-ulnar joint reaction force magnitudes and vector orientations as a function of a known mass/force at the hand. From these data, a scalable, bi-axial loading profile is proposed as a foundation for the development of clinically relevant, laboratory simulations for assessment of total elbow prostheses performance. © 2013 Elsevier Ltd. All rights reserved.

  18. A biomechanical comparison of successful and unsuccessful power clean attempts.

    Science.gov (United States)

    Kipp, Kristof; Meinerz, Carolyn

    2017-06-01

    Although the power clean is an almost ubiquitous exercise in the strength and conditioning setting, relatively little is known about the biomechanics of successful and unsuccessful power clean lift attempts. The purpose of this study was to determine biomechanical differences between successful and unsuccessful power clean lift attempts in male collegiate athletes. Fifteen male lacrosse players (Age: 20.1 ± 1.2; Height: 1.78 ± 0.07 m; Body mass: 80.4 ± 8.1 kg; Relative one-repetition maximum power clean: 1.25 ± 0.13 kg/kg) were videotaped during a lifting session that required the completion of maximal effort power cleans to establish a one-repetition maximum. The position of the barbell was digitised and used to calculate the displacement, velocity, acceleration, and acceleration vector of the barbell. The results revealed that unsuccessful attempts were characterised by differences during the second pull phase. Unsuccessful lifts exhibited greater peak forward barbell displacement, lower backward barbell velocities, and lower resultant acceleration angles during the second pull. Strength and conditioning coaches should therefore emphasise limited forward motion of the barbell during the second pull and instruct athletes to generate a more backward-directed force during the second pull in order to lift greater loads during testing and subsequent lifting sessions.

  19. Esophageal morphometric and biomechanical changes during aging in rats.

    Science.gov (United States)

    Zhao, J; Gregersen, H

    2015-11-01

    Human studies have demonstrated aging-related changes in esophagus which may contribute to the increased rate of gastro-esophageal reflux in elderly. The aim of this study was to investigate esophageal morphometric and biomechanical remodeling in aging rats to obtain detailed information about aging-related changes. Twenty-four male Wistar rats, aged from 6 to 22 months, were studied. Morphometric data were obtained by measuring the wall thickness and cross-sectional area. The esophageal diameter and length were obtained from digitized images of the segments at preselected luminal pressure levels and at no-load and zero-stress states. Circumferential and longitudinal stresses (force per area) and strains (deformation) were computed from the length, diameter and pressure data, and from the zero-stress state geometry. The esophageal parameters such as the weight per unit length, the wall thickness and the wall cross-sectional area increased slightly from 6 to 22 months (p aging (p aging. The stress-strain data showed that the esophageal wall became stiffer circumferentially and longitudinally during aging (p change after 12 months. A pronounced morphometric and biomechanical remodeling occurred in the rat esophagus during aging. © 2015 John Wiley & Sons Ltd.

  20. Weightbath hydrotraction treatment: application, biomechanics, and clinical effects.

    Science.gov (United States)

    Kurutz, Márta; Bender, Tamás

    2010-04-07

    Weightbath hydrotraction treatment (WHT) is a simple noninvasive effective method of hydro- or balneotherapy to stretch the spine or lower limbs, applied successfully in hospitals and health resort sanitaria in Hungary for more than fifty years. This study aims to introduce WHT with its biomechanical and clinical effects. History, development, equipment, modes of application, biomechanics, spinal traction forces and elongations, indications and contraindications of WHT are precented. The calculation of traction forces acting along the spinal column during the treatment is described together with the mode of suspension and the position of extra weight loads applied. The biomechanics of the treatment are completed by in vivo measured elongations of lumbar segments using a special underwater ultrasound measuring method. The clinical effects, indications, and contraindications of the treatment are also presented. In the underwater cervical suspension of a human body, approximately 25 N stretching load occurs in the cervical spine, and about 11 N occurs in the lumbar spine. By applying extra weights, the above tensile forces along the spinal column can be increased. Thus, the traction effect can be controlled by applying such loads during the treatment. Elongations of segments L3-L4, L4-L5, and L5-S1 were measured during the usual WHT of patients suspended cervically in water for 20 minutes, loaded by 20-20 N lead weights on the ankles. The mean initial elastic elongations of spinal segments were about 0.8 mm for patients aged under 40 years, 0.5 mm between 40-60 years, and 0.2 mm for patients over 60 years. The mean final viscoelastic elongations were 1.5 mm, 1.2 mm, and 0.6 mm for the same age classes, respectively. No significant difference was found between the sexes regarding age-dependence in tension. WHT for discopathy showed significant improvement of clinical parameters, which was still evident three months later, as demonstrated by using a controlled pilot

  1. Physiologic strains in the lumbar spinal ligaments. An in vitro biomechanical study 1981 Volvo Award in Biomechanics.

    Science.gov (United States)

    Panjabi, M M; Goel, V K; Takata, K

    1982-01-01

    For understanding of the mechanical causes of low-back pain, knowledge of the biomechanics of the various spinal elements is essential. In this in vitro biomechanical study, in situ behavior of spinal ligaments of the L3-4 and L4-5 functional spinal units during physiologic activities was studied in a three-stage procedure. First, 72 load-displacement curves were obtained to determine the three-dimensional flexibility characteristics of the spinal units. Second, three-dimensional morphometric measurements were made of all the spinal ligament attachment points. Finally, a mathematical model was constructed to combine the flexibility and morphometric data and compute the ligament length changes and strains as functions of various spinal movements. In flexion movement, the interspinous and supra-spinous ligaments were found to be subjected to the highest strains, followed by the capsular ligaments and the ligamentum flavum. During extension, it is the anterior longitudinal ligament that has the maximum strain. In lateral bending, the contralateral transverse ligaments carried the highest strains, while the interspinous and supraspinous ligaments were relatively unstrained. In rotation, the capsular ligaments were by far the most strained ligaments.

  2. Arch index and running biomechanics in children aged 10-14 years.

    Science.gov (United States)

    Hollander, Karsten; Stebbins, Julie; Albertsen, Inke Marie; Hamacher, Daniel; Babin, Kornelia; Hacke, Claudia; Zech, Astrid

    2018-03-01

    While altered foot arch characteristics (high or low) are frequently assumed to influence lower limb biomechanics and are suspected to be a contributing factor for injuries, the association between arch characteristics and lower limb running biomechanics in children is unclear. Therefore, the aim of this study was to investigate the relationship between a dynamically measured arch index and running biomechanics in healthy children. One hundred and one children aged 10-14 years were included in this study and underwent a biomechanical investigation. Plantar distribution (Novel, Emed) was used to determine the dynamic arch index and 3D motion capture (Vicon) to measure running biomechanics. Linear mixed models were established to determine the association between dynamic arch index and foot strike patterns, running kinematics, kinetics and temporal-spatial outcomes. No association was found between dynamic arch index and rate of rearfoot strikes (p = 0.072). Of all secondary outcomes, only the foot progression angle was associated with the dynamic arch index (p = 0.032) with greater external rotation in lower arched children. Overall, we found only few associations between arch characteristics and running biomechanics in children. However, altered foot arch characteristics are of clinical interest. Future studies should focus on detailed foot biomechanics and include clinically diagnosed high and low arched children. Copyright © 2018 Elsevier B.V. All rights reserved.

  3. Biomechanical Properties of the Cornea Measured With the Dynamic Scheimpflug Analyzer in Young Healthy Adults.

    Science.gov (United States)

    Lee, Hun; Kang, David Sung Yong; Ha, Byoung Jin; Choi, Jin Young; Kim, Eung Kweon; Seo, Kyoung Yul; Kim, Ha Yan; Kim, Tae-Im

    2017-01-01

    To investigate the biomechanical properties of the cornea using the dynamic Scheimpflug analyzer in young healthy adults. This prospective cross-sectional population study included 944 eyes of 472 participants aged 20 to 40 years. Participants underwent ophthalmic investigations, including evaluation of biomechanical properties of the cornea using the dynamic Scheimpflug analyzer, manifest refraction, and measurements of keratometric values by autokeratometry, intraocular pressure (IOP) by noncontact tonometer, central corneal thickness (CCT) by ultrasound, and white-to-white distance by Scheimpflug tomography. Statistical analyses included determination of the reference interval with a bootstrapping method, linear quantile mixed-effects model, and Spearman correlation analysis between the corneal biomechanical parameters and other variables (age, manifest refraction spherical equivalent, CCT, IOP, white-to-white, and keratometric values). The 90% CIs of all corneal biomechanical parameters demonstrated that the ranges of the 90% CIs for the reference data were almost identical with and without bootstrapping. Quantile regression to determine the fifth, 50th, and 95th percentiles of each corneal biomechanical parameter supported the findings from the nonparametric method with the 90% CIs. Correlation analysis showed significant correlations between the parameters and variables, but there was a relatively high Spearman correlation coefficient in the case of the correlations with the CCT and IOP. Using data from a large population of young healthy adults, we developed a database of normal values for multiple corneal biomechanical parameters obtained from the dynamic Scheimpflug analyzer. We conclude that the biomechanical properties of the cornea are influenced by the CCT and IOP.

  4. Biomechanical Analysis of an Expandable Lumbar Interbody Spacer.

    Science.gov (United States)

    Soriano-Baron, Hector; Newcomb, Anna G U S; Malhotra, Devika; Palma, Atilio E; Martinez-Del-Campo, Eduardo; Crawford, Neil R; Theodore, Nicholas; Kelly, Brian P; Kaibara, Taro

    2018-03-13

    Recently developed expandable interbody spacers are widely accepted in spinal surgery; however, the resulting biomechanical effects of their use have not yet been fully studied. We analyzed the biomechanical effects of an expandable polyetheretherketone interbody spacer inserted through a bilateral posterior approach with and without different modalities of posterior augmentation. Biomechanical nondestructive flexibility testing was performed in 7 human cadaveric lumbar (L2-L5) specimens followed by axial compressive loading. Each specimen was tested under 6 conditions: 1) intact, 2) bilateral L3-L4 cortical screw/rod (CSR) alone, 3) WaveD alone, 4) WaveD + CSR, 5) WaveD + bilateral L3-L4 pedicle screw/rod (PSR), and 6) WaveD + CSR/PSR, where CSR/PSR was a hybrid construct comprising bilateral cortical-level L3 and pedicle-level L4 screws interconnected by rods. The range of motion (ROM) with the interbody spacer alone decreased significantly compared with the intact condition during flexion-extension (P = 0.02) but not during lateral bending or axial rotation (P ≥ 0.19). The addition of CSR or PSR to the interbody spacer alone condition significantly decreased the ROM compared with the interbody spacer alone (P ≤ 0.002); and WaveD + CSR, WaveD + PSR, and WaveD + CSR/PSR (hybrid) (P ≥ 0.29) did not differ. The axial compressive stiffness (resistance to change in foraminal height during compressive loading) with the interbody spacer alone did not differ from the intact condition (P = 0.96), whereas WaveD + posterior instrumentation significantly increased compressive stiffness compared with the intact condition and the interbody spacer alone (P ≤ 0.001). The WaveD alone significantly reduced ROM during flexion-extension while maintaining the axial compressive stiffness. CSR, PSR, and CSR/PSR hybrid constructs were all effective in augmenting the expandable interbody spacer system and improving its stability. Copyright © 2018 Elsevier Inc. All

  5. Biomechanics of the Optic Nerve Sheath in VIIP Syndrome

    Science.gov (United States)

    Ethier, C. Ross; Raykin, Julia; Gleason, Rudy; Mulugeta, Lealem; Myers, Jerry; Nelson, Emily; Samuels, Brian C.

    2014-01-01

    Long-duration space flight carries the risk of developing Visual Impairment and Intracranial Pressure (VIIP) syndrome, a spectrum of ophthalmic changes including posterior globe flattening, choroidal folds, distension of the optic nerve sheath (ONS), optic nerve kinking and potentially permanent degradation of visual function. The slow onset of VIIP, its chronic nature, and certain clinical features strongly suggest that biomechanical factors acting on the ONS play a role in VIIP. Here we measure several relevant ONS properties needed to model VIIP biomechanics. The ONS (meninges) of fresh porcine eyes (n7) was reflected, the nerve proper was truncated near the sclera, and the meninges were repositioned to create a hollow cylinder of meningeal connective tissue attached to the posterior sclera. The distal end was cannulated, sealed, and pressure clamped (mimicking cerebrospinal fluid [CSF] pressure), while the eye was also cannulated for independent control of intraocular pressure (IOP). The meninges were inflated (CSF pressure cycling 7-50 mmHg) while ONS outer diameter was imaged. In another set of experiments (n4), fluid permeation rate across the meninges was recorded by observing the drainage of an elevated fluid reservoir (30 mmHg) connected to the meninges. The ONS showed behavior typical of soft tissues: viscoelasticity, with hysteresis in early preconditioning cycles and repeatable behavior after 4 cycles, and nonlinear stiffening, particularly at CSF pressures 15 mmHg (Figure). Tangent moduli measured from the loading curve were 372 101, 1199 358, and 2050 379 kPa (mean SEM) at CSF pressures of 7, 15 and 30 mmHg, respectively. Flow rate measurements through the intact meninges at 30mmHg gave a permeability of 1.34 0.46 lmincm2mmHg (mean SEM). The ONS is a tough, strain-stiffening connective tissue that is surprisingly permeable. The latter observation suggests that there could be significant CSF drainage through the ONS into the orbit, likely important

  6. The biomechanics of solids and fluids: the physics of life

    Science.gov (United States)

    Alexander, David E.

    2016-09-01

    Biomechanics borrows and extends engineering techniques to study the mechanical properties of organisms and their environments. Like physicists and engineers, biomechanics researchers tend to specialize on either fluids or solids (but some do both). For solid materials, the stress-strain curve reveals such useful information as various moduli, ultimate strength, extensibility, and work of fracture. Few biological materials are linearly elastic so modified elastic moduli are defined. Although biological materials tend to be less stiff than engineered materials, biomaterials tend to be tougher due to their anisotropy and high extensibility. Biological beams are usually hollow cylinders; particularly in plants, beams and columns tend to have high twist-to-bend ratios. Air and water are the dominant biological fluids. Fluids generate both viscous and pressure drag (normalized as drag coefficients) and the Reynolds number (Re) gives their relative importance. The no-slip conditions leads to velocity gradients (‘boundary layers’) on surfaces and parabolic flow profiles in tubes. Rather than rigidly resisting drag in external flows, many plants and sessile animals reconfigure to reduce drag as speed increases. Living in velocity gradients can be beneficial for attachment but challenging for capturing particulate food. Lift produced by airfoils and hydrofoils is used to produce thrust by all flying animals and many swimming ones, and is usually optimal at higher Re. At low Re, most swimmers use drag-based mechanisms. A few swimmers use jetting for rapid escape despite its energetic inefficiency. At low Re, suspension feeding depends on mechanisms other than direct sieving because thick boundary layers reduce effective porosity. Most biomaterials exhibit a combination of solid and fluid properties, i.e., viscoelasticity. Even rigid biomaterials exhibit creep over many days, whereas pliant biomaterials may exhibit creep over hours or minutes. Instead of rigid materials

  7. Reduction of Biomechanical and Welding Fume Exposures in Stud Welding.

    Science.gov (United States)

    Fethke, Nathan B; Peters, Thomas M; Leonard, Stephanie; Metwali, Mahmoud; Mudunkotuwa, Imali A

    2016-04-01

    The welding of shear stud connectors to structural steel in construction requires a prolonged stooped posture that exposes ironworkers to biomechanical and welding fume hazards. In this study, biomechanical and welding fume exposures during stud welding using conventional methods were compared to exposures associated with use of a prototype system that allowed participants to weld from an upright position. The effect of base material (i.e. bare structural beam versus galvanized decking) on welding fume concentration (particle number and mass), particle size distribution, and particle composition was also explored. Thirty participants completed a series of stud welding simulations in a local apprenticeship training facility. Use of the upright system was associated with substantial reductions in trunk inclination and the activity levels of several muscle groups. Inhalable mass concentrations of welding fume (averaged over ~18 min) when using conventional methods were high (18.2 mg m(-3) for bare beam; 65.7 mg m(-3) for through deck), with estimated mass concentrations of iron (7.8 mg m(-3) for bare beam; 15.8 mg m(-3) for through deck), zinc (0.2 mg m(-3) for bare beam; 15.8 mg m(-3) for through deck), and manganese (0.9 mg m(-3) for bare beam; 1.5 mg m(-3) for through deck) often exceeding the American Conference of Governmental Industrial Hygienists Threshold Limit Values (TLVs). Number and mass concentrations were substantially reduced when using the upright system, although the total inhalable mass concentration remained above the TLV when welding through decking. The average diameters of the welding fume particles for both bare beam (31±17 nm) through deck conditions (34±34 nm) and the chemical composition of the particles indicated the presence of metallic nanoparticles. Stud welding exposes ironworkers to potentially high levels of biomechanical loading (primarily to the low back) and welding fume. The upright system used in this study improved exposure

  8. No effects of functional exercise therapy on walking biomechanics in patients with knee osteoarthritis

    DEFF Research Database (Denmark)

    Henriksen, Marius; Klokker, Louise; Bartholdy, Cecilie

    2016-01-01

    AIM: To assess the effects of a functional and individualised exercise programme on gait biomechanics during walking in people with knee OA. METHODS: Sixty participants were randomised to 12 weeks of facility-based functional and individualised neuromuscular exercise therapy (ET), 3 sessions per...... limited confidence in the findings due to multiple statistical tests and lack of biomechanical logics. Therefore we conclude that a 12-week supervised individualised neuromuscular exercise programme has no effects on gait biomechanics. Future studies should focus on exercise programmes specifically...

  9. Physiological, biochemical, anthropometric, and biomechanical influences on exercise economy in humans

    DEFF Research Database (Denmark)

    Lundby, C; Montero, D; Gehrig, S

    2017-01-01

    Interindividual variation in running and cycling exercise economy (EE) remains unexplained although studied for more than a century. This study is the first to comprehensively evaluate the importance of biochemical, structural, physiological, anthropometric, and biomechanical influences on running...... were correlated (R2=.94; Pexercise, the biomechanical influence on EE would be small because of the fixed...... movement pattern. Differences in cycling and running exercise protocols, for example, related to biomechanics, play however only a secondary role in determining EE. There was no evidence for an impact of structural or functional skeletal muscle variables on EE. Body weight was the main determinant of EE...

  10. The forearm complex: anatomy, biomechanics and clinical considerations.

    Science.gov (United States)

    LaStayo, Paul C; Lee, Michael J

    2006-01-01

    The forearm complex is comprised of the proximal radioulnar joint, middle radioulnar joint/interosseous membrane, and the distal radioulnar joint. These three areas function in a coordinated manner to rotate the hand in space and allow performance of functional tasks. If a structure or structures in one of these three areas is disrupted, this can adversely affect the function at any of the other two remaining areas. Surgical intervention focuses on restoring anatomical alignment to preserve the function of the forearm complex. Rehabilitation is guided by the relationships between the three areas of the forearm complex and the awareness of clinical signs, symptoms, and complications. The purposes of this paper are to 1) describe the anatomy and biomechanical function of the forearm complex and 2) discuss clinical correlates pertaining to select forearm injuries (excluding peripheral nerve injuries) that may affect forearm function.

  11. Biomechanical aspects of sports-related head injuries.

    Science.gov (United States)

    Park, Min S; Levy, Michael L

    2008-02-01

    With the increased conditioning, size, and speed of professional athletes and the increase in individuals engaging in sports and recreational activities, there is potential for rising numbers of traumatic brain injuries in sports. Fortunately, parallel strides in basic research technology and improvements in computer and video technology have created a new era of discovery in the study of the biomechanical aspects of sports-related head injuries. Although prevention will always be the most important factor in reducing the incidence of sports-related traumatic brain injuries, ongoing studies will lead to the development of newer protective equipment, improved recognition and management of concussions on the field of play, and modification of rules and guidelines to make these activities safer and more enjoyable.

  12. SURFACE ELECTROMYOGRAPHY IN BIOMECHANICS: APPLICATIONS AND SIGNAL ANALYSIS ASPECTS

    Directory of Open Access Journals (Sweden)

    DEAK GRAłIELA-FLAVIA

    2009-12-01

    Full Text Available Surface electromyography (SEMG is a technique for detecting and recording the electrical activity of the muscles using surface electrodes. The EMG signal is used in biomechanics mainly as an indicator of the initiation of muscle activation, as an indicator of the force produced by a contracting muscle, and as an index ofthe fatigue occurring within a muscle. EMG, used as a method of investigation, can tell us if the muscle is active or not, if the muscle is more or less active, when it is on or off, how much active is it, and finally, if it fatigues.The purpose of this article is to discuss some specific EMG signal analysis aspects with emphasis on comparison type analysis and frequency fatigue analysis.

  13. Biomechanics acetabular dysplasia in hip: Tridimensional Computerized Tomography

    International Nuclear Information System (INIS)

    Sanchez Mesa, Pedro Antonio; Arbelaez Arbelaez, William Rafael

    2003-01-01

    Due to the not precise evaluation of the residual acetabular dysplasia we believe that is very important to have objective parameters for an adequate diagnosis and surgical planning. This observational, descriptive study, for validation of a diagnostic test, including patients from the military central hospital and the San Pedro Claver Clinic ISS Bogota who have been exposed to biomechanics imagenologic analysis in TC 3D between February November of the 2002; 9 months, 80 patients, 148 hips; 56 women (71 lefts, 37 rights) and 24 men (22 lefts, 18 rights); age range 19-50 years; based on objective measures: depth acetabular, lateral and anterior extrusion femoral head percentage, center edge, anterior deficit wall, sharp angle, acetabular anteversion, unoccupied medial acetabulum percentage and center rotation asymmetry made on normal general population's hips. The results were compared with patients that present residual acetabular dysplasia finding more precise parameters of the deformity

  14. Modeling of the condyle elements within a biomechanical knee model

    DEFF Research Database (Denmark)

    Ribeiro, Ana; Rasmussen, John; Flores, Paulo

    2012-01-01

    the two femoral condyles, and points, representing the tibial plateau and the menisci. These elements are closely fitted to the actual knee geometry. This task is undertaken by considering a parameter optimization process to replicate experimental data published in the literature, namely that by Lafortune...... and anatomic properties of the real bones. The biomechanical model characterization is developed under the framework of multibody systems methodologies using Cartesian coordinates. The type of approach used in the proposed knee model is the joint surface contact conditions between ellipsoids, representing...... for this fact is the elastic component of the secondary motions created by the combination of joint forces and soft tissue deformations. The proposed knee model is, therefore, used to investigate whether this observed behavior can be explained by reasonable elastic deformations of the points representing...

  15. Numerical research of biomechanical system with SMA prosthesis

    Directory of Open Access Journals (Sweden)

    Mitura Andrzej

    2018-01-01

    Full Text Available In this paper the modelling of special biomechanical mechanism and application of shape memory materials are presented. The model of the human middle ear is made as multibody system. The basic 3dof ear model of the healthy middle ear is modified to represent the damaged ear. A damaged of the ossicular chainis taken into account by adding gap in visco-elastic joints. In addition, an attempt of the ossicles chain reconstruction through prosthesis made of shape memory alloy is presented. Moreover, a new description of the hysteresis sub-loop which characterise prosthesis material is proposed. Finally, dynamic responses of healthy, damaged and reconstructed models of the middle ear are compared by quality index.

  16. A simple filter circuit for denoising biomechanical impact signals.

    Science.gov (United States)

    Subramaniam, Suba R; Georgakis, Apostolos

    2009-01-01

    We present a simple scheme for denoising non-stationary biomechanical signals with the aim of accurately estimating their second derivative (acceleration). The method is based on filtering in fractional Fourier domains using well-known low-pass filters in a way that amounts to a time-varying cut-off threshold. The resulting algorithm is linear and its design is facilitated by the relationship between the fractional Fourier transform and joint time-frequency representations. The implemented filter circuit employs only three low-order filters while its efficiency is further supported by the low computational complexity of the fractional Fourier transform. The results demonstrate that the proposed method can denoise the signals effectively and is more robust against noise as compared to conventional low-pass filters.

  17. Poroviscoelastic modeling of liver biomechanical response in unconfined compression.

    Science.gov (United States)

    Raghunathan, Smitha; Evans, Douglas; Sparks, Jessica L

    2010-05-01

    Mechanistic modeling approaches are important for understanding how fluid and solid components of the liver interact during impact trauma. This study uses poroviscoelasticity (PVE) theory to simulate liver biomechanical response in unconfined compression stress relaxation experiments, for variable ramp strain rates ranging from 0.001 to 0.1 s(-1). Specimens included 17 ex vivo porcine liver samples tested in a humidified temperature-controlled chamber. Liver response was modeled using ABAQUS, and best-fit parameters were determined using non-linear least-squares algorithms. The PVE model was able to capture the behavior of porcine liver in unconfined compression, with regression analyses for the ramp phase demonstrating high correlation between model and experiment (R(2) > 0.993, slope > 0.833, p dummies, and improved vehicle safety.

  18. Biomechanical performances of trees in the phase of active reorientation

    Directory of Open Access Journals (Sweden)

    Jana Dlouhá

    2008-01-01

    Full Text Available The purpose of the present paper was to investigate the accumulation of growth stresses in a cross section of a tree in active reorientation process and its biomechanical performances i.e. up-righting efficiency and stem flexibility. Effect of two factors was analysed in details: occurrence of juvenile wood and viscoelasticity of wood tissues. In a phase of active reorientation, wood tissues close to the pith are submitted to significant levels of compressive stresses. Production of juvenile wood in earlier stage of a tree life seems to increase the stem flexibility during active reorientation for both softwoods as well as hardwoods. Concerning the viscoelasticity of wood tissues, only minor effect has been observed in softwoods while an important positive impact has been pointed out in hardwoods. Set of simulations with increasing level of maturation strains in reaction tissues indicated possible trade-off between the stem flexibility and the up-righting efficiency.

  19. Biomechanical considerations in intramedullary fixation of lower-extremity fracture.

    Science.gov (United States)

    Inhofe, P D

    1992-08-01

    Since Gerhard Kuntscher's first cloverleaf design was introduced in the early 1940s, intramedullary nail geometry has become increasingly complex. Many design changes have been introduced, and these have had profound effects upon the mechanical performance of intramedullary devices, making them more versatile. The subset of long-bone fractures amenable to intramedullary fixation is expanding, largely because of these advancements in nail design. Selection of the appropriate nail and bone-nail construct for each fracture configuration requires a knowledge of basic biomechanical principles behind nail design and the implant-host interface. Appropriate clinical application of this knowledge not only ensures the best possible intramedullary fixation of long-bone fractures, but it also aids in avoiding some of the complications that may occur.

  20. Computer Models in Biomechanics From Nano to Macro

    CERN Document Server

    Kuhl, Ellen

    2013-01-01

    This book contains a collection of papers that were presented at the IUTAM Symposium on “Computer Models in Biomechanics: From Nano to Macro” held at Stanford University, California, USA, from August 29 to September 2, 2011. It contains state-of-the-art papers on: - Protein and Cell Mechanics: coarse-grained model for unfolded proteins, collagen-proteoglycan structural interactions in the cornea, simulations of cell behavior on substrates - Muscle Mechanics: modeling approaches for Ca2+–regulated smooth muscle contraction, smooth muscle modeling using continuum thermodynamical frameworks, cross-bridge model describing the mechanoenergetics of actomyosin interaction, multiscale skeletal muscle modeling - Cardiovascular Mechanics: multiscale modeling of arterial adaptations by incorporating molecular mechanisms, cardiovascular tissue damage, dissection properties of aortic aneurysms, intracranial aneurysms, electromechanics of the heart, hemodynamic alterations associated with arterial remodeling followin...

  1. Assessment of spring cranioplasty biomechanics in sagittal craniosynostosis patients.

    Science.gov (United States)

    Borghi, Alessandro; Schievano, Silvia; Rodriguez Florez, Naiara; McNicholas, Roisin; Rodgers, Will; Ponniah, Allan; James, Greg; Hayward, Richard; Dunaway, David; Jeelani, N U Owase

    2017-11-01

    OBJECTIVE Scaphocephaly secondary to sagittal craniosynostosis has been treated in recent years with spring-assisted cranioplasty, an innovative approach that leverages the use of metallic spring distractors to reshape the patient skull. In this study, a population of patients who had undergone spring cranioplasty for the correction of scaphocephaly at the Great Ormond Street Hospital for Children was retrospectively analyzed to systematically assess spring biomechanical performance and kinematics in relation to spring model, patient age, and outcomes over time. METHODS Data from 60 patients (49 males, mean age at surgery 5.2 ± 0.9 months) who had received 2 springs for the treatment of isolated sagittal craniosynostosis were analyzed. The opening distance of the springs at the time of insertion and removal was retrieved from the surgical notes and, during the implantation period, from planar radiographs obtained at 1 day postoperatively and at the 3-week follow-up. The force exerted by the spring to the patient skull at each time point was derived after mechanical testing of each spring model-3 devices with the same geometry but different wire thicknesses. Changes in the cephalic index between preoperatively and the 3-week follow-up were recorded. RESULTS Stiffer springs were implanted in older patients (p springs were used (p spring models, however, the devices all plateaued. Indeed, regardless of patient age or spring model, after 10 days from insertion, all the devices were open. CONCLUSIONS Results in this study provide biomechanical insights into spring-assisted cranioplasty and could help to improve spring design and follow-up strategy in the future.

  2. Structural and biomechanical basis of mitochondrial movement in eukaryotic cells

    Directory of Open Access Journals (Sweden)

    Wu M

    2013-10-01

    Full Text Available Min Wu,1 Aruna Kalyanasundaram,2 Jie Zhu1 1Laboratory of Biomechanics and Engineering, Institute of Biophysics, College of Science, Northwest A&F University, Yangling, Shaanxi, People's Republic of China; 2College of Pharmacology, University of Illinois at Chicago, Chicago, IL, USA Abstract: Mitochondria serve as energy-producing organelles in eukaryotic cells. In addition to providing the energy supply for cells, the mitochondria are also involved in other processes, such as proliferation, differentiation, information transfer, and apoptosis, and play an important role in regulation of cell growth and the cell cycle. In order to achieve these functions, the mitochondria need to move to the corresponding location. Therefore, mitochondrial movement has a crucial role in normal physiologic activity, and any mitochondrial movement disorder will cause irreparable damage to the organism. For example, recent studies have shown that abnormal movement of the mitochondria is likely to be the reason for Charcot–Marie–Tooth disease, amyotrophic lateral sclerosis, Alzheimer's disease, Huntington's disease, Parkinson's disease, and schizophrenia. So, in the cell, especially in the particular polarized cell, the appropriate distribution of mitochondria is crucial to the function and survival of the cell. Mitochondrial movement is mainly associated with the cytoskeleton and related proteins. However, those components play different roles according to cell type. In this paper, we summarize the structural basis of mitochondrial movement, including microtubules, actin filaments, motor proteins, and adaptin, and review studies of the biomechanical mechanisms of mitochondrial movement in different types of cells. Keywords: mitochondrial movement, microtubules, actin filaments, motor proteins, adaptin

  3. Evaluation of a laboratory model of human head impact biomechanics.

    Science.gov (United States)

    Hernandez, Fidel; Shull, Peter B; Camarillo, David B

    2015-09-18

    This work describes methodology for evaluating laboratory models of head impact biomechanics. Using this methodology, we investigated: how closely does twin-wire drop testing model head rotation in American football impacts? Head rotation is believed to cause mild traumatic brain injury (mTBI) but helmet safety standards only model head translations believed to cause severe TBI. It is unknown whether laboratory head impact models in safety standards, like twin-wire drop testing, reproduce six degree-of-freedom (6DOF) head impact biomechanics that may cause mTBI. We compared 6DOF measurements of 421 American football head impacts to twin-wire drop tests at impact sites and velocities weighted to represent typical field exposure. The highest rotational velocities produced by drop testing were the 74th percentile of non-injury field impacts. For a given translational acceleration level, drop testing underestimated field rotational acceleration by 46% and rotational velocity by 72%. Primary rotational acceleration frequencies were much larger in drop tests (~100 Hz) than field impacts (~10 Hz). Drop testing was physically unable to produce acceleration directions common in field impacts. Initial conditions of a single field impact were highly resolved in stereo high-speed video and reconstructed in a drop test. Reconstruction results reflected aggregate trends of lower amplitude rotational velocity and higher frequency rotational acceleration in drop testing, apparently due to twin-wire constraints and the absence of a neck. These results suggest twin-wire drop testing is limited in modeling head rotation during impact, and motivate continued evaluation of head impact models to ensure helmets are tested under conditions that may cause mTBI. Copyright © 2015 Elsevier Ltd. All rights reserved.

  4. Longitudinal modeling in sports: young swimmers' performance and biomechanics profile.

    Science.gov (United States)

    Morais, Jorge E; Marques, Mário C; Marinho, Daniel A; Silva, António J; Barbosa, Tiago M

    2014-10-01

    New theories about dynamical systems highlight the multi-factorial interplay between determinant factors to achieve higher sports performances, including in swimming. Longitudinal research does provide useful information on the sportsmen's changes and how training help him to excel. These questions may be addressed in one single procedure such as latent growth modeling. The aim of the study was to model a latent growth curve of young swimmers' performance and biomechanics over a season. Fourteen boys (12.33 ± 0.65 years-old) and 16 girls (11.15 ± 0.55 years-old) were evaluated. Performance, stroke frequency, speed fluctuation, arm's propelling efficiency, active drag, active drag coefficient and power to overcome drag were collected in four different moments of the season. Latent growth curve modeling was computed to understand the longitudinal variation of performance (endogenous variables) over the season according to the biomechanics (exogenous variables). Latent growth curve modeling showed a high inter- and intra-subject variability in the performance growth. Gender had a significant effect at the baseline and during the performance growth. In each evaluation moment, different variables had a meaningful effect on performance (M1: Da, β = -0.62; M2: Da, β = -0.53; M3: η(p), β = 0.59; M4: SF, β = -0.57; all P < .001). The models' goodness-of-fit was 1.40 ⩽ χ(2)/df ⩽ 3.74 (good-reasonable). Latent modeling is a comprehensive way to gather insight about young swimmers' performance over time. Different variables were the main responsible for the performance improvement. A gender gap, intra- and inter-subject variability was verified. Copyright © 2014 Elsevier B.V. All rights reserved.

  5. Evaluating Glucocorticoid Administration on Biomechanical Properties of Rats’ Tibial Diaphysis

    Science.gov (United States)

    Freidouni, Mohammadjavad; Nejati, Hossein; Salimi, Maryam; Bayat, Mohammad; Amini, Abdollah; Noruzian, Mohsen; Asgharie, Mohammad Ali; Rezaian, Milad

    2015-01-01

    Background: Osteoporosis is a disease, which causes bone loss and fractures. Although glucocorticoids effectively suppress inflammation, their chronic use is accompanied by bone loss with a tendency toward secondary osteoporosis. Objectives: This study took into consideration the importance of cortical bone in the entire bone's mechanical competence. Hence, the aim of this study was to assess the effects of different protocols of glucocorticoid administration on the biomechanical properties of tibial bone diaphysis in rats compared to control and low-level laser-treated rats. Materials and Methods: This experimental study was conducted at Shahid Beheshti University of Medical Sciences, Tehran, Iran. We used systematic random sampling to divide 40 adult male rats into 8 groups with 5 rats in each group. Groups were as follows: 1) control, 2) dexamethasone (7 mg/week), 3) dexamethasone (0.7 mg/week), 4) methylprednisolone (7 mg/kg/week), 5) methylprednisolone (5 mg/kg twice weekly), 6) dexamethasone (7 mg/kg three times per week), 7) dexamethasone (0.7 mg/kg thrice per week), and 8) low-level laser-treated rats. The study periods were 4-7 weeks. At the end of the treatment periods, we examined the mechanical properties of tibial bone diaphysis. Data were analyzed by statistical analyses. Results: Glucocorticoid-treated rats showed weight loss and considerable mortality (21%). The biomechanical properties (maximum force) of glucocorticoid-treated rats in groups 4 (62 ± 2.9), 6 (63 ± 5.1), and 7 (60 ± 5.3) were comparable with the control (46 ± 1.5) and low-level laser-treated (57 ± 3.2) rats. Conclusions: In contrast to the findings in humans and certain other species, glucocorticoid administration caused anabolic effect on the cortical bone of tibia diaphysis bone in rats. PMID:26019900

  6. Corneal biomechanics in asymmetrical normal-tension glaucoma

    Directory of Open Access Journals (Sweden)

    Helmy H

    2016-03-01

    Full Text Available Hazem Helmy,1 Mahmoud Leila,2 Ahmed Atef Zaki3 1Department of Glaucoma and Optic Nerve Diseases, 2Retina Department, 3Corneal Diseases Department, Research Institute of Ophthalmology, Cairo, Egypt Purpose: We aimed to assess corneal biomechanics using the ocular response analyzer in patients with normal-tension glaucoma (NTG, and to evaluate the relationship between corneal biomechanics and visual field loss. Methods: This was a prospective observational case series including patients with bilateral asymmetric NTG. For all patients, corneal hysteresis (CH, corneal resistance factor (CRF, CH - CRF difference, and central corneal thickness values were matched against the mean deviation (MD of the visual field and the cup/disc ratio. For paired-eye comparison in each patient, both eyes were categorized into a better-eyes group and a worse-eyes group according to lower and higher corneal-compensated intraocular pressure readings, respectively. Statistical analysis was carried out with the independent-samples Student’s t-test, and the level of statistical significance was set at 0.05. Correlation was assessed using Pearson’s correlation coefficient. Results: The study included 240 eyes of 120 patients. CH was inversely proportional to the MD in the visual field (P=0.01. CRF in both eyes was inversely proportional to the MD of the visual field (P=0.01. CH - CRF difference was directly proportional to the MD of the visual field (P=0.01. For paired-eye comparison, lower corneal-compensated intraocular pressure was associated with higher CH, higher CRF, smaller cup/disc ratio, and less deterioration of MD of visual field. Conclusion: CH, CRF, and CH - CRF are more powerful predictors of NTG progression than central corneal thickness. Keywords: corneal-compensated intraocular pressure, corneal hysteresis, corneal resistance factor

  7. Interactive coordinated multiple-view visualization of biomechanical motion data.

    Science.gov (United States)

    Keefe, Daniel F; Ewert, Marcus; Ribarsky, William; Chang, Remco

    2009-01-01

    We present an interactive framework for exploring space-time and form-function relationships in experimentally collected high-resolution biomechanical data sets. These data describe complex 3D motions (e.g. chewing, walking, flying) performed by animals and humans and captured via high-speed imaging technologies, such as biplane fluoroscopy. In analyzing these 3D biomechanical motions, interactive 3D visualizations are important, in particular, for supporting spatial analysis. However, as researchers in information visualization have pointed out, 2D visualizations can also be effective tools for multi-dimensional data analysis, especially for identifying trends over time. Our approach, therefore, combines techniques from both 3D and 2D visualizations. Specifically, it utilizes a multi-view visualization strategy including a small multiples view of motion sequences, a parallel coordinates view, and detailed 3D inspection views. The resulting framework follows an overview first, zoom and filter, then details-on-demand style of analysis, and it explicitly targets a limitation of current tools, namely, supporting analysis and comparison at the level of a collection of motions rather than sequential analysis of a single or small number of motions. Scientific motion collections appropriate for this style of analysis exist in clinical work in orthopedics and physical rehabilitation, in the study of functional morphology within evolutionary biology, and in other contexts. An application is described based on a collaboration with evolutionary biologists studying the mechanics of chewing motions in pigs. Interactive exploration of data describing a collection of more than one hundred experimentally captured pig chewing cycles is described.

  8. Biomechanical Implications of Training Volume and Intensity in Aging Runners.

    Science.gov (United States)

    Paquette, Max R; Devita, Paul; Williams, D S Blaise

    2018-03-01

    Running speed is slower in middle-age compared with younger runners due to reduced ankle but not hip and knee kinetic output. Running-specific training helps attenuate age-related declines in measures of endurance, muscle strength, and gait speed. Considering the adaptability of the human body in response to imposed stresses, maintaining training volume and intensity may play a role in modifying running biomechanics in middle-age runners. To compare running biomechanics between young and middle-age runners when controlling for the confounding effects of training volume and intensity. Fifteen middle-age runners, 15 young runners with similar training volume as the middle-age group and, 15 young runners with similar preferred training paces (i.e., intensity) as the middle-age runners participated in the study. Lower-limb joint kinetics were calculated from kinematic and ground reaction force data during overground running at a submaximal speed and compared among groups. Middle-age runners ran with similar peak ankle power compared with volume-matched younger runners although peak plantarflexor moment was 10.5% lower in the middle age group (P = 0.046; Cohen d = 0.78). Middle-age runners ran with similar ankle plantarflexor moment and joint power compared with training pace-matched young runners. As expected, no age-related differences were observed in hip and knee kinetics when training volume or pace were matched between age groups. These results suggest that training pace may be more effective in attenuating age-related declines in plantarflexor kinetics in middle-age runners. From these findings, we propose the hypothesis that both training volume and training pace may play a role in maintaining plantarflexor kinetics but that training pace may have a greater impact on ankle plantarflexor kinetics in middle-age runners.

  9. Topographic and biomechanical evaluation of cornea in patients with acromegaly.

    Science.gov (United States)

    Altinkaynak, Hasan; Duru, Necati; Ersoy, Reyhan; Kalkan Akcay, Emine; Ugurlu, Nagihan; Cagil, Nurullah; Cakir, Bekir

    2015-01-01

    The aim of this study was to compare topographic and biomechanical properties of corneas in patients with acromegaly with those of healthy individuals. Thirty-five patients with acromegaly (study group) and 35 healthy individuals (control group) were enrolled in this prospective study. Topographic measurements, including central corneal thickness (CCT), mean keratometry (K) value, K1, K2, surface asymmetry index, corneal volume (CV), and anterior chamber depth in the right eye of each participant were obtained using a Scheimpflug camera with a Placido disc topographer (Sirius; Costruzione Strumenti Oftalmici). Corneal hysteresis (CH), corneal resistance factor (CRF), corneal-compensated intraocular pressure (IOP), and Goldmann-corelated intraocular pressure (IOPg) were measured using Reichert Ocular Response Analyzer (Reichert Ophthalmic Instruments). Mean CCT, CV, CH, CRF, and IOPg values were higher in acromegalic eyes (549.3 ± 30.2 μm, 59.1 ± 3.1 μm, 11.3 ± 1.2 mm Hg, 11.3 ± 1.2 mm Hg, and 17.5 ± 2.9 mm Hg, respectively) than in healthy eyes (531.4 ± 33.6 μm, 57.4 ± 2.7 μm, 10.4 ± 1.2 mm Hg, 10.2 ± 1.6 mm Hg, and 14.8 ± 3.1 mm Hg, respectively; CCT, P = 0.042; CV, P = 0.032; CH, P = 0.044; CRF, P = 0.035; IOPg, P < 0.001). CCT, CV, CH, CRF, IOPg, and IOP with Goldmann applanation tonometry were significantly higher in acromegalic eyes. These corneal topographic and biomechanical properties, disease duration, and disease status should be considered when planning corneal refractive surgery and determining accurate intraocular pressure in patients with acromegaly.

  10. Biomechanical abdominal wall model applied to hernia repair.

    Science.gov (United States)

    Lyons, M; Mohan, H; Winter, D C; Simms, C K

    2015-01-01

    Most surgical innovations require extensive preclinical testing before employment in the operative environment. There is currently no way to develop and test innovations for abdominal wall surgery that is cheap, repeatable and easy to use. In hernia repair, the required mesh overlap relative to defect size is not established. The aims of this study were to develop a biomechanical model of the abdominal wall based on in vivo pressure measurements, and to apply this to study mesh overlap in hernia repair. An observational study of intra-abdominal pressure (IAP) levels throughout abdominal surgery was conducted to identify the peak perioperative IAP in vivo. This was then applied in the development of a surrogate abdominal wall model. An in vitro study of mesh overlap for various defect sizes was then conducted using this clinically relevant surrogate abdomen model. The mean peak perioperative IAP recorded in the clinical study was 1740 Pa, and occurred during awakening from anaesthesia. This was reproduced in the surrogate abdomen model, which was also able to replicate incisional hernia formation. Using this model, the mesh overlap necessary to prevent hernia formation up to 20 kPa was found, independent of anatomical variations, to be 2 × (defect diameter) + 25 mm. This study demonstrated that a surgically relevant surrogate abdominal wall model is a useful translational tool in the study of hernia repair. Surgical relevance This study examined the mesh overlap requirements for hernia repair, evaluated in a biomechanical model of the abdomen. Currently, mesh size is selected based on empirical evidence and may underpredict the requirement for large meshes. The study proposes a relationship between the defect size and mesh size to select the appropriate mesh size. Following further trials and investigations, this could be used in clinical practice to reduce the incidence of hernia recurrence. © 2015 BJS Society Ltd. Published by John Wiley & Sons Ltd.

  11. Corneal biomechanical features in patients with ankylosing spondylitis.

    Science.gov (United States)

    Cabuk, Kubra Serefoglu; Üstün, Emine Isil; Atalay, Kursat; Kirgiz, Ahmet; Aydin, Rukiye

    2017-01-01

    To evaluate the corneal biomechanical features and central corneal thickness in ankylosing spondylitis patients and to evaluate correlations of these parameters with disease activity. The study included 51 patients diagnosed with ankylosing spondylitis (mean age, 40.80 ± 13.15 years; range, 18-72 years) and 34 age- and sex-matched healthy controls (mean age, 42.00 ± 12.32 years; range, 18-60 years). All underwent a complete ophthalmological and physical examination, including visual acuity testing and biomicroscopic anterior and posterior segment examinations. Corneal hysteresis, corneal resistance factor, Goldmann-correlated intraocular pressure, and corneal compensated intraocular pressure were evaluated with an ocular response analyzer, and the central corneal thickness was measured with Sirius® corneal tomography. The Bath Ankylosing Spondylitis Disease Activity Index, Functional Index, and Metrology Index scores were recorded. In the ankylosing spondylitis patients, the mean disease duration was 7.73 ± 6.05 (range, 1-30) years. There was no statistically significant difference between the patients and controls in the corneal biomechanical features. The Goldmann-correlated intraocular pressure and corneal compensated intraocular pressure both showed positive correlations with age (p=0.003 and p=0.001, res-pectively). There was a negative correlation between corneal hysteresis and disease duration (p=0.002), and between central corneal thickness and the Bath Ankylosing Spondylitis Metrology Index score (p=0.003). This study demonstrated a significant negative correlation between corneal hysteresis and disease duration in ankylosing spondylitis patients. Furthermore, the central corneal thickness value decreased with an increase in Bath Ankylosing Spondylitis Metrology Index score, which may result in an underestimate of intraocular pressure readings and thus an inaccurate risk assessment of glaucoma.

  12. Biomechanical and biochemical outcomes of porcine temporomandibular joint disc deformation.

    Science.gov (United States)

    Matuska, Andrea M; Muller, Stephen; Dolwick, M Franklin; McFetridge, Peter S

    2016-04-01

    The structure-function relationship in the healthy temporomandibular joint (TMJ) disc has been well established, however the changes in dysfunctional joints has yet to be systematically evaluated. Due to the poor understanding of the etiology of temporomandibular disorders (TMDs) this study evaluated naturally occurring degenerative remodeling in aged female porcine temporomandibular joint (TMJ) discs in order to gain insight into the progression and effects on possible treatment strategies of TMDs. Surface and regional biomechanical and biochemical properties of discal tissues were determined in grossly deformed (≥Wilkes Stage 3) and morphologically normal (≤Wilkes Stage 2) TMJ discs. Compared to normal disc structure the deformed discs lacked a smooth biconcave shape and characteristic ECM organization. Reduction in tensile biomechanical integrity and increased compressive stiffness and cellularity was found in deformed discs. Regionally, the posterior and intermediate zones of the disc were most frequently affected along with the inferior surface. The frequency of degeneration observed on the inferior surface of the disc (predominantly posterior), suggests that a disruption in the disc-condyle relationship likely contributes to the progression of joint dysfunction more than the temporodiscal relationship. As such, the inferior joint space may be an important consideration in early clinical diagnosis and treatment of TMDs, as it is overlooked in techniques performed in the upper joint space, including arthroscopy and arthrocentesis. Furthermore, permanent damage to the disc mechanical properties would limit the ability to successfully reposition deformed discs, highlighting the importance of emerging therapies such as tissue engineering. Copyright © 2016 Elsevier Ltd. All rights reserved.

  13. Biomechanical Evaluation of Lumbar Decompression Adjacent to Instrumented Segments.

    Science.gov (United States)

    Grunert, Peter; Reyes, Phillip M; Newcomb, Anna G U S; Towne, Sara B; Kelly, Brian P; Theodore, Nicholas; Härtl, Roger

    2016-12-01

    Multilevel lumbar stenosis, in which 1 level requires stabilization due to spondylolisthesis, is routinely treated with multilevel open laminectomy and fusion. We hypothesized that a minimally invasive (MI) decompression is biomechanically superior to open laminectomy and may allow decompression of the level adjacent the spondylolisthesis without additional fusion. To study the mechanical effect of various decompression procedures adjacent to instrumented segments in cadaver lumbar spines. Conditions tested were (1) L4-L5 instrumentation, (2) L3-L4 MI decompression, (3) addition of partial facetectomy at L3-L4, and (4) addition of laminectomy at L3-L4. Flexibility tests were performed for range of motion (ROM) analysis by applying nonconstraining, pure moment loading during flexion-extension, lateral bending, and axial rotation. Compression flexion tests were performed for motion distribution analysis. After instrumentation, MI decompression increased flexion-extension ROM at L3-L4 by 13% (P = .03) and axial rotation by 23% (P = .003). Partial facetectomy further increased axial rotation by 15% (P = .03). After laminectomy, flexion-extension ROM further increased by 12% (P = .05), a 38% increase from baseline, and axial rotation by 17% (P = .02), a 58% increase from baseline. MI decompression yielded no significant increase in segmental contribution of motion at L3-L4, in contrast to partial facetectomy and laminectomy (<.05). MI tubular decompression is biomechanically superior to open laminectomy adjacent to instrumented segments. These results lend support to the concept that in patients in whom a multilevel MI decompression is performed, the fusion might be limited to the segments with actual instability. MI, minimally invasive.

  14. Environmental and Physiological Factors Affect Football Head Impact Biomechanics.

    Science.gov (United States)

    Mihalik, Jason P; Sumrall, Adam Z; Yeargin, Susan W; Guskiewicz, Kevin M; King, Kevin B; Trulock, Scott C; Shields, Edgar W

    2017-10-01

    Recent anecdotal trends suggest a disproportionate number of head injuries in collegiate football players occur during preseason football camp. In warmer climates, this season also represents the highest risk for heat-related illness among collegiate football players. Because concussion and heat illnesses share many common symptoms, we need 1) to understand if environmental conditions, body temperature, and hydration status affect head impact biomechanics; and 2) to determine if an in-helmet thermistor could provide a valid measure of gastrointestinal temperature. A prospective cohort of 18 Division I college football players (age, 21.1 ± 1.4 yr; height, 187.7 ± 6.6 cm; mass, 114.5 ± 23.4 kg). Data were collected during one control and three experimental sessions. During each session, the Head Impact Telemetry System recorded head impact biomechanics (linear acceleration, rotational acceleration, and severity profile) and in-helmet temperature. A wet bulb globe device recorded environmental conditions, and CorTemp™ Ingestible Core Body Temperature Sensors recorded gastrointestinal temperature. Our findings suggest that linear acceleration (P = 0.57), rotational acceleration (P = 0.16), and Head Impact Technology severity profile (P = 0.33) are not influenced by environmental or physiological conditions. We did not find any single or combination of predictors for impact severity. Rotational acceleration was approaching significance between our early experimental sessions when compared with our control session. More research should be conducted to better understand if rotational accelerations are a component of impact magnitudes that are affected due to changes in environmental conditions, body temperature, and hydration status.

  15. Biomechanical comparison of orthogonal versus parallel double plating systems in intraarticular distal humerus fractures

    Directory of Open Access Journals (Sweden)

    Ata C. Atalar

    2017-01-01

    Conclusion: Our study showed that both plating systems had similar biomechanical stabilities when anatomic plates with distal locking screws were used in intraarticular distal humerus fractures in artificial humerus models.

  16. Visual, keratometric and corneal biomechanical changes after intacs SK implantation for moderate to severe keratoconus

    Directory of Open Access Journals (Sweden)

    Mohammad Ali Zare

    2016-01-01

    Conclusion: Visual, refractive and keratometric indices remarkably improved in a parallel fashion. CRF was inversely associated with CCT. Changes in CRF represent the trend of changes in corneal biomechanics and thickness during the early postoperative months.

  17. Biomechanical analysis of the fixation systems for anterior column and posterior hemi-transverse acetabular fractures

    Directory of Open Access Journals (Sweden)

    Jianyin Lei

    2017-05-01

    Conclusion: Our results suggested that all fixation systems enhance biomechanical stability significantly. Anterior column plate combined with quadrilateral area screws has quite comparable results to double column plates, they were superior to anterior column plate combined with posterior screws.

  18. [Retention and biomechanics of retentive complexes. 3. The Kratochvil school and current retentive complexes].

    Science.gov (United States)

    Enrique Fernández, M; Jacques Grimonster, L

    1989-04-01

    The authors analyse the biomechanical bases of the Kratochvil "retentive complex" and show how they have induced the nowadays north-american propositions (RPI & RPA). They compare them to the european ones (Nally-Martinet).

  19. Effect of estrogen on tendon collagen synthesis, tendon structural characteristics, and biomechanical properties in postmenopausal women

    DEFF Research Database (Denmark)

    Hansen, Mette; Kongsgaard, Mads; Holm, Lars

    2009-01-01

    and fibril characteristics were determined by MRI and transmission electron microscopy, whereas tendon biomechanical properties were measured during isometric maximal voluntary contraction by ultrasound recording. Tendon FSR was markedly higher in ERT users (P

  20. Smooth Muscle Biomechanics and Plasticity: Relevance for Vascular Calibre and Remodelling

    NARCIS (Netherlands)

    Guvenc Tuna, Bilge; Bakker, Erik N. T. P.; VanBavel, Ed

    2012-01-01

    Blood vessel structure and calibre are not static. Rather, vessels remodel continuously in response to their biomechanical environment. Vascular calibre is dictated by the amount, composition and organization of the elastic extracellular matrix. In addition, the amount and organization of

  1. Quantitative Assessment of Dance Therapy Infulence on the Parkinson’s Disease Patients’ Lower Limb Biomechanics

    OpenAIRE

    Donatas Lukšys; Julius Griškevičius

    2017-01-01

    Parkinson’s disease – progressive neurologic disorder that damages a variety of motor function and reduces the quality of life. Patients with PD are subject to various physical therapy exercises, but recently is applied more often the dance – music therapy. This study aims assessing the therapeutic effect of the modified Lindy Hop dance therapy on lower extremity biomechanics. The experimental study was performed using inertial sensors that registered lower extremity biomechanical parameters ...

  2. Two-Segment Foot Model for the Biomechanical Analysis of Squat

    OpenAIRE

    Panero, E.; Gastaldi, L.; Rapp, W.

    2017-01-01

    Squat exercise is acquiring interest in many fields, due to its benefits in improving health and its biomechanical similarities to a wide range of sport motions and the recruitment of many body segments in a single maneuver. Several researches had examined considerable biomechanical aspects of lower limbs during squat, but not without limitations. The main goal of this study focuses on the analysis of the foot contribution during a partial body weight squat, using a two-segment foot model tha...

  3. Head Impacts in Hockey and Youth Football: Biomechanical Response and Helmet Padding Characteristics

    OpenAIRE

    MacAlister, Anna Margaret

    2014-01-01

    The research presented herein is a combination of work done in two distinct subcategories of sport related head injury research. The body of work is aimed at increasing the understanding of head impact biomechanics across a broad spectrum of impact scenarios as well as the ability of helmets to affect head impact biomechanics over time. The first study utilizes in situ testing of controlled impacts of an instrumented head form to more fully characterize head accelerations resulting from impac...

  4. Biomechanical Comparison of Single- and Double-Leg Jump Landings in the Sagittal and Frontal Plane.

    Science.gov (United States)

    Taylor, Jeffrey B; Ford, Kevin R; Nguyen, Anh-Dung; Shultz, Sandra J

    2016-06-01

    Double-leg forward or drop-jump landing activities are typically used to screen for high-risk movement strategies and to determine the success of neuromuscular injury prevention programs. However, research suggests that these tasks that occur primarily in the sagittal plane may not adequately represent the lower extremity biomechanics that occur during unilateral foot contact or non-sagittal plane movements that are characteristic of many multidirectional sports. To examine the extent to which lower extremity biomechanics measured during a jump landing on a double leg (DL) after a sagittal plane (SAG) movement is representative of biomechanics measured during single-leg (SL) or frontal plane (FRONT) jump landing tasks. Controlled laboratory study. Lower extremity biomechanics were measured in 15 recreationally active females (mean age [±SD], 19.4 ± 2.1 years; mean height, 163.3 ± 5.9 cm; mean weight, 61.1 ± 7.1 kg) while performing SAGDL, SAGSL, FRONTDL, and FRONTSL jump landing tasks. Repeated-measures analyses of variance examined differences in lower extremity biomechanics between the 4 tasks, and linear regressions examined the extent to which an individual's biomechanics during SAGDL were representative of their biomechanics during SAGSL, FRONTDL, and FRONTSL. Lower extremity kinematics and kinetics differed by condition, with the SAGDL task generally eliciting greater hip and knee flexion angles and lower hip and knee forces than the other tasks (P plane jump landing tasks used to screen for ACL injury risk and the effectiveness of ACL injury prevention programs may not adequately represent the lower extremity biomechanics that occur during single-leg activities. These results support further investigation of single-leg multidirectional landings to identify high-risk movement strategies in female athletes playing multidirectional sports.

  5. Biomechanical Response in Mandibular Bone due to Mastication Loading on 3-Unit Fixed Partial Dentures

    OpenAIRE

    Field, Clarice; Li, Qing; Li, Wei; Swain, Michael

    2009-01-01

    An understanding of functional responses in oral bone is a crucial component of dental biomechanics. The purpose of this study was to investigate the potential biological remodelling response during mastication on the mandibular pre- and post-insertion of a fixed partial denture (FPD). A series of three-dimensional (3D) finite element analysis (FEA) models were presented pre- and postextraction to determine the biomechanical responses to masticatory loading in the anterior mandible. Equivalen...

  6. Root anatomical phenes predict root penetration ability and biomechanical properties in maize (Zea Mays)

    OpenAIRE

    Chimungu, Joseph G.; Loades, Kenneth W.; Lynch, Jonathan P.

    2015-01-01

    The ability of roots to penetrate hard soil is important for crop productivity but specific root phenes contributing to this ability are poorly understood. Root penetrability and biomechanical properties are likely to vary in the root system dependent on anatomical structure. No information is available to date on the influence of root anatomical phenes on root penetrability and biomechanics. Root penetration ability was evaluated using a wax layer system. Root tensile and bending strength we...

  7. Reprogramming of the Ovarian Tumor Stroma by Activation of a Biomechanical ECM Switch

    Science.gov (United States)

    2016-09-01

    AWARD NUMBER: W81XWH-14-1-0178 TITLE: Reprogramming of the Ovarian Tumor Stroma by Activation of a Biomechanical ECM Switch PRINCIPAL...SUBTITLE 5a. CONTRACT NUMBER Reprogramming of the Ovarian Tumor Stroma by Activation of a Biomechanical ECM Switch 5b. GRANT NUMBER W81XWH-14-1...particular we, have characterized stromal cell infiltration of ovarian tumors and have shown extensive infiltration of tumor associated blood vessels as well

  8. Morphological and biomechanical disparity of crocodile-line archosaurs following the end-Triassic extinction

    Science.gov (United States)

    Stubbs, Thomas L.; Pierce, Stephanie E.; Rayfield, Emily J.; Anderson, Philip S. L.

    2013-01-01

    Mesozoic crurotarsans exhibited diverse morphologies and feeding modes, representing considerable ecological diversity, yet macroevolutionary patterns remain unexplored. Here, we use a unique combination of morphological and biomechanical disparity metrics to quantify the ecological diversity and trophic radiations of Mesozoic crurotarsans, using the mandible as a morpho-functional proxy. We recover three major trends. First, the diverse assemblage of Late Triassic crurotarsans was morphologically and biomechanically disparate, implying high levels of ecological variation; but, following the end-Triassic extinction, disparity declined. Second, the Jurassic radiation of marine thalattosuchians resulted in very low morphological disparity but moderate variation in jaw biomechanics, highlighting a hydrodynamic constraint on mandibular form. Third, during the Cretaceous terrestrial radiations of neosuchians and notosuchians, mandibular morphological variation increased considerably. By the Late Cretaceous, crocodylomorphs evolved a range of morphologies equalling Late Triassic crurotarsans. By contrast, biomechanical disparity in the Cretaceous did not increase, essentially decoupling from morphology. This enigmatic result could be attributed to biomechanical evolution in other anatomical regions (e.g. cranium, dentition or postcranium), possibly releasing the mandible from selective pressures. Overall, our analyses reveal a complex relationship between morphological and biomechanical disparity in Mesozoic crurotarsans that culminated in specialized feeding ecologies and associated lifestyles. PMID:24026826

  9. Changes in Drop-Jump Landing Biomechanics During Prolonged Intermittent Exercise

    Science.gov (United States)

    Schmitz, Randy J.; Cone, John C.; Tritsch, Amanda J.; Pye, Michele L.; Montgomery, Melissa M.; Henson, Robert A.; Shultz, Sandra J.

    2014-01-01

    Background: As injury rates rise in the later stages of sporting activities, a better understanding of lower extremity biomechanics in the later phases of gamelike situations may improve training and injury prevention programs. Hypothesis: Lower extremity biomechanics of a drop-jump task (extracted from a principal components analysis) would reveal factors associated with risk of anterior cruciate ligament injury during a 90-minute individualized intermittent exercise protocol (IEP) and for 1 hour following the IEP. Study Design: Controlled laboratory study. Level of Evidence: Level 4. Methods: Fifty-nine athletes (29 women, 30 men) completed 3 sessions. The first session assessed fitness for an IEP designed to simulate the demands of a soccer match. An experimental session assessed drop-jump biomechanics, after a dynamic warm-up, every 15 minutes during the 90-minute IEP, and for 1 hour following the IEP. A control session with no exercise assessed drop-jump performance at the same intervals. Results: Two biomechanical factors early in the first half (hip flexion at initial contact and hip loading; ankle loading and knee shear force) decreased at the end of the IEP and into the 60-minute recovery period, while a third factor (knee loading) decreased only during the recovery period (P ≤ 0.05). Conclusion: The individualized sport-specific IEP may have more subtle effects on landing biomechanics when compared with short-term, exhaustive fatigue protocols. Clinical Relevance: Potentially injurious landing biomechanics may not occur until the later stages of soccer activity. PMID:24587862

  10. Reinforced fixation of distal fibula fractures in elderly patients; A meta-analysis of biomechanical studies.

    Science.gov (United States)

    Dingemans, Siem A; Lodeizen, Olivia A P; Goslings, J Carel; Schepers, Tim

    2016-07-01

    There is an increasing incidence of fragility fractures of the ankle in the elderly population. The open reduction and internal fixation of these fractures is challenging, due to reduced bone stock quality as a result of osteoporosis. Biomechanical studies have shown contradicting results using reinforced constructions in the fixation of fibular fractures. We therefore performed a meta-analysis of biomechanical studies on reinforced fixation of distal fibular fractures. A literature search was conducted utilizing three online databases considering biomechanical testing of different fixation techniques of distal fibular fractures. A meta-analysis was performed on two biomechanical outcome measures; torsional stiffness and torque to failure. In a total number of 13 studies 8 different reinforcement techniques were identified. Of these studies, six compared locked lateral plating with conventional lateral plating. There were no statistically significant differences between the locking and non-locking lateral plate for torque to failure or torsional stiffness. Locked plating strength was independent from bone mineral density in four studies. An antiglide plate proved to be biomechanically superior compared to a lateral plate in one study and to a locked plate in another. Locked lateral plates are not biomechanically superior to conventional lateral plates. However the strength of locked plating may be independent of bone mineral density and could make this technique more suitable in the fixation of severe osteoporotic fractures. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. A novel breast software phantom for biomechanical modeling of elastography.

    Science.gov (United States)

    Bhatti, Syeda Naema; Sridhar-Keralapura, Mallika

    2012-04-01

    In developing breast imaging technologies, testing is done with phantoms. Physical phantoms are normally used but their size, shape, composition, and detail cannot be modified readily. These difficulties can be avoided by creating a software breast phantom. Researchers have created software breast phantoms using geometric and/or mathematical methods for applications like image fusion. The authors report a 3D software breast phantom that was built using a mechanical design tool, to investigate the biomechanics of elastography using finite element modeling (FEM). The authors propose this phantom as an intermediate assessment tool for elastography simulation; for use after testing with commonly used phantoms and before clinical testing. The authors design the phantom to be flexible in both, the breast geometry and biomechanical parameters, to make it a useful tool for elastography simulation. The authors develop the 3D software phantom using a mechanical design tool based on illustrations of normal breast anatomy. The software phantom does not use geometric primitives or imaging data. The authors discuss how to create this phantom and how to modify it. The authors demonstrate a typical elastography experiment of applying a static stress to the top surface of the breast just above a simulated tumor and calculate normal strains in 3D and in 2D with plane strain approximations with linear solvers. In particular, they investigate contrast transfer efficiency (CTE) by designing a parametric study based on location, shape, and stiffness of simulated tumors. The authors also compare their findings to a commonly used elastography phantom. The 3D breast software phantom is flexible in shape, size, and location of tumors, glandular to fatty content, and the ductal structure. Residual modulus, maps, and profiles, served as a guide to optimize meshing of this geometrically nonlinear phantom for biomechanical modeling of elastography. At best, low residues (around 1-5 KPa) were

  12. USE OF OPEN-SOURCE TECHNOLOGY TO TEACH BIOMECHANICS

    Directory of Open Access Journals (Sweden)

    Ana FARO

    2016-10-01

    Full Text Available The purposes of this study was: (1 develop a different methodology based on open-source technologies to promote quantitative movement analysis of sport skills as a regular tool in the biomechanics classroom, (2 analyze the expertise and development students’ level during the work labs and finally, (3 access the students’ engagement, motivational status and technology expertise performed in sports biomechanics. First we explore movement analysis with Dartfish software. A second software Kinovea 0.8.15 was used to extract variables for the 2D kinematical analysis and the Excel 2010 was used for data mapping and the statistics treatment (p ≤ 0,05. For the gait study results presented as an example, the statistically significant differences from the overcharge increase (+ 40% of body weight were found on step time at 1,80 m/s (p=0,029, on the step leng at 1,25 m/s (p=0,001 and at 1,80 m/s (p=0,003, on the leng gait cycle at 1,25 m/s (p=0,011 and at 1,80 m/s (p=0,002, on the torso angle at 1,80 m/s (p=0,000 and on the hip joint angle motion at 1,25 m/s (p=0,000 and at 1,80 m/s (p=0,012. However, we conclude that overcharge (+ 40% body weight reduce the step time and step lengthy, shorter gait cycle, increase torso frontal flexion (sagittal plane and increase the hip joint flexion, mainly in the swing phase.The advantage of this type of classroom lab work with students, besides of having no costs, is an increase of their motivation, pushing the passing rates from 45% to 77% last year. The ability of understanding theory concepts has an exponential raise as every new concept has immediate application on the practical analysis performed with Kinovea At phase 4 we will establish the validity and reliability of all 3 softwares: Dartfish, Kinovea, and Tracker and compare sports and rehabilitation movements at 30 fps versus 60 fps

  13. [The cell as a gravity-dependent biomechanic system].

    Science.gov (United States)

    Tairbekov, M G

    2000-01-01

    In the period of 1995-1997 experimental and theoretical studies with various biomechanic objects, i.e. individual cells and cell associations, were performed under changed gravity (0.00001-5 g). Experimental investigations were conducted using clinostats and centrifuges to model effects of hypo- and hypergravity, and aboard space vehicles in real microgravity. Cell cultures in vitro including fibroblasts and osteoblasts on a solid glass or plastic substrate served as objects of the studies. Changes in value and direction of the gravity vector were found to modify the morphophysiological characteristics of cells: structural organization (spatial rearrangement of the intracell component, changes in forms, sizes and quantity of cells) and functional activity (alterations in energy expenditure and intensity of intracellular metabolism). The data suggest that there should be mechanisms of gravitational sensitivity in living systems on the cellular level. As was stated, sensitivity of unicellular free-living organisms to gravity is mostly defined by the motor activity determined by the level of general metabolism. Morphological characteristics (form, size and mass) are of secondary importance. Theoretical analysis resulted in correction of one of the principle postulates of gravitational biology stating a direct link between size (mass) and gravitational sensitivity of organism. Described were consistent patterns of growth, development, and behavior of unicellular cultures in gravitational fields. Strengthening of the force of gravity (hypergravity) leads to eventual deceleration of cell growth and diminution of biomass gain. On the other hand, the spaceflight environment (microgravity) stimulates growth mechanisms. In our opinion, behind these gravitational effects are altered levels of energy spent by cells to overcome the force of gravity. Opposite trends were observed in experiments with cell cultures in vitro. During space microgravity, fibroblast cultures on the

  14. Biomechanical investigation of the stabilization principle of the Latarjet procedure.

    Science.gov (United States)

    Wellmann, M; de Ferrari, H; Smith, T; Petersen, W; Siebert, C H; Agneskirchner, J D; Hurschler, C

    2012-03-01

    The purpose of the study was to determine the biomechanical status of the different components of the Latarjet procedure. The anterior capsule reconstruction with the transferred coracoacromial ligament (CAL) and the necessity of an intact subscapularis tendon were of particular interest. We hypothesized that the anterior capsule reconstruction will have a significant effect and that the Latarjet procedure will lose its stabilizing effect if the subscapularis tendon is torn. Stability testing of 12 human shoulder specimens was performed. After testing of the intact joint, a combined anterior glenoid and capsule defect was set arthroscopically. Then the Latarjet procedure was performed using an open approach and tested with and without loading of the conjoint tendons (10 N). Afterwards, the specimens were distributed into two groups and the Latarjet technique was reduced stepwise: dissection of the CAL, dissection of the conjoint tendons (group A); reduction of the coracoid segment, dissection of the subscapularis tendon (group B). Biomechanical testing was performed for each condition in two positions: 60° of glenohumeral abduction with neutral rotation and with 60° of external rotation; each with a passive humerus load of 30 N in the anterior, inferior and anteroinferior direction. The Latarjet technique with load applied to the conjoint tendons significantly reduced translation compared with the defect condition for all tested positions in all directions. In group A, the CAL-dissection led to a significant increase of anterior translation (+5.0 mm, p = 0.003) and inferior translation (+7.3 mm, p = 0.025) in neutral rotation and of anterior translation in 60° of external rotation (+4.4 mm, p = 0.034). In group B, the reduction of the coracoid bone down to the coracoid tip resulted in a significant increase of only the anterior translation in abduction and 60° of external rotation (+4.5 mm, p = 0.05). In contrast, the detachment of the

  15. Biomechanical evaluation of the side-cutting manoeuvre associated with ACL injury in young female handball players

    DEFF Research Database (Denmark)

    Bencke, Jesper; Curtis, Derek; Krogshede, Christina

    2013-01-01

    The purpose of the study was to investigate the biomechanics of the knee and hip joint during handball-specific side-cutting on the dominant and non-dominant leg. Understanding the sports-specific biomechanics may improve prevention measures and post-injury treatment.......The purpose of the study was to investigate the biomechanics of the knee and hip joint during handball-specific side-cutting on the dominant and non-dominant leg. Understanding the sports-specific biomechanics may improve prevention measures and post-injury treatment....

  16. Novel 3D “active” representations of skin biomechanics

    Directory of Open Access Journals (Sweden)

    Henrique Silva

    2016-12-01

    Full Text Available Skin exhibits unique biomechanical properties that enable unrestricted body movements without tearing. Several devices have been used to quantify skin mechanical properties, but techniques, in general, do not concern this multidirectional capacity, only allowing measurements in a few angles. CutiScan® is a new device that quantifies skin elasticity over 360°. It uses a suction method to induce skin deformation and a video camera to quantify its displacement. This work aims to assess these properties through the analysis of 3D time-angle-height of displacement representations. 20 female subjects (37.0 ± 18.7 years old were enrolled in this study after informed consent, grouped by age in group 1 (22.0 ± 1.3 years old, and group 2 (52.0 ± 13.7 years old. The in vivo mechanical profile of each volunteer was assessed in the forehead, forearm and in the leg. Significantly higher surface area and volume under the curve values were found in the forehead of the subjects of group 2. Significant differences were also found between the forehead and forearm and between the forehead and leg among each group. These results suggest that these 3D representations are useful in distinguishing the viscoelastic profile of differently aged subjects and of different skin sites.

  17. Passive aortic counterpulsation: biomechanical rationale and bench validation.

    Science.gov (United States)

    Corazza, Ivan; Bianchini, David; Marcelli, Emanuela; Cercenelli, Laura; Zannoli, Romano

    2014-05-07

    Aortic counterpulsation (IABP) consists in an ECG-controlled forced deflation and inflation of a balloon positioned in the aorta. The device is designed to decrease the ventricular afterload during systole and to increase the coronary driving pressure during diastole. In biomechanical terms, the IABP improves the mechanical matching between the pump and the load, facilitating the transfer of ventricular energy. This paper describes a completely passive aortic counterpulsation solution, with an intra-aortic balloon without a pumping system, designed to improve the mechanical matching between the ventricle and the artery at very low cost and complexity. The only requirement is an external reservoir to amplify the balloon pulsations due to physiologic arterial pressure pulse. Using a cardiovascular simulator and changing the reservoir pressure, a systolic not negligible (7.8ml) gas volume exchange between the intra-aortic balloon and the reservoir was measured. The same cardiovascular simulator was used to demonstrate an increase in stroke volume in three conditions of progressive ventricular failure, by detecting a change in systolic and diastolic arterial pressures and stroke volume (SV). The maximal arterial pressure always decreased and the diastolic pressure increased. The SV increased up to 7.8%, demonstrating an arterial elastance reduction and better ventricular-aortic mechanical matching and energy transfer. Copyright © 2014 Elsevier Ltd. All rights reserved.

  18. Comparing dynamical systems concepts and techniques for biomechanical analysis

    Directory of Open Access Journals (Sweden)

    Richard E.A. van Emmerik

    2016-03-01

    Full Text Available Traditional biomechanical analyses of human movement are generally derived from linear mathematics. While these methods can be useful in many situations, they do not describe behaviors in human systems that are predominately nonlinear. For this reason, nonlinear analysis methods based on a dynamical systems approach have become more prevalent in recent literature. These analysis techniques have provided new insights into how systems (1 maintain pattern stability, (2 transition into new states, and (3 are governed by short- and long-term (fractal correlational processes at different spatio-temporal scales. These different aspects of system dynamics are typically investigated using concepts related to variability, stability, complexity, and adaptability. The purpose of this paper is to compare and contrast these different concepts and demonstrate that, although related, these terms represent fundamentally different aspects of system dynamics. In particular, we argue that variability should not uniformly be equated with stability or complexity of movement. In addition, current dynamic stability measures based on nonlinear analysis methods (such as the finite maximal Lyapunov exponent can reveal local instabilities in movement dynamics, but the degree to which these local instabilities relate to global postural and gait stability and the ability to resist external perturbations remains to be explored. Finally, systematic studies are needed to relate observed reductions in complexity with aging and disease to the adaptive capabilities of the movement system and how complexity changes as a function of different task constraints.

  19. Contractility, differential tension and membrane removal lead zebrafish epiboly biomechanics.

    Science.gov (United States)

    Marsal, Maria; Hernández-Vega, Amayra; Martin-Blanco, Enrique

    2017-07-18

    Precise tissue remodeling during development is essential for shaping embryos and optimal organ function. Epiboly is an early gastrulation event by which the blastoderm expands around the yolk to engulf it. Three different layers are involved in this process, an epithelial layer (the enveloping layer, EVL), the embryo proper, constituted by the deep cells (DCs), and the yolk cell. Although teleost epiboly has been studied for many years, a clear understanding of its mechanics was still missing. Here we present new information on the cellular, molecular and mechanical elements involved in epiboly that, together with some other recent data and upon comparison with previous biomechanical models, lets conclude that the expansion of the epithelia is passive and driven by active cortical contraction and membrane removal in the adjacent layer, the External Yolk Syncytial Layer (E-YSL). The isotropic actomyosin contraction of the E-YSL cortex generates an anisotropic stress pattern and a directional net movement consequence of the differences in the deformation response of the 2 opposites adjacent domains (EVL and the Yolk Cytoplasmic Layer - YCL). Contractility is accompanied by the local formation of membrane folds and its removal by Rab5ab dependent macropinocytosis. The increase in area of the epithelia during the expansion is achieved by cell-shape changes (flattening) responding to spherical geometrical cues. The counterbalance between the geometry of the embryo and forces dissipation among different elements is therefore essential for epiboly global coordination.

  20. Experimental techniques for single cell and single molecule biomechanics

    International Nuclear Information System (INIS)

    Lim, C.T.; Zhou, E.H.; Li, A.; Vedula, S.R.K.; Fu, H.X.

    2006-01-01

    Stresses and strains that act on the human body can arise either from external physical forces or internal physiological environmental conditions. These biophysical interactions can occur not only at the musculoskeletal but also cellular and molecular levels and can determine the health and function of the human body. Here, we seek to investigate the structure-property-function relationship of cells and biomolecules so as to understand their important physiological functions as well as establish possible connections to human diseases. With the recent advancements in cell and molecular biology, biophysics and nanotechnology, several innovative and state-of-the-art experimental techniques and equipment have been developed to probe the structural and mechanical properties of biostructures from the micro- down to picoscale. Some of these experimental techniques include the optical or laser trap method, micropipette aspiration, step-pressure technique, atomic force microscopy and molecular force spectroscopy. In this article, we will review the basic principles and usage of these techniques to conduct single cell and single molecule biomechanics research

  1. Pneumatic Artificial Muscles Based on Biomechanical Characteristics of Human Muscles

    Directory of Open Access Journals (Sweden)

    N. Saga

    2006-01-01

    Full Text Available This article reports the pneumatic artificial muscles based on biomechanical characteristics of human muscles. A wearable device and a rehabilitation robot that assist a human muscle should have characteristics similar to those of human muscle. In addition, since the wearable device and the rehabilitation robot should be light, an actuator with a high power to weight ratio is needed. At present, the McKibben type is widely used as an artificial muscle, but in fact its physical model is highly nonlinear. Therefore, an artificial muscle actuator has been developed in which high-strength carbon fibres have been built into the silicone tube. However, its contraction rate is smaller than the actual biological muscles. On the other hand, if an artificial muscle that contracts axially is installed in a robot as compactly as the robot hand, big installing space is required. Therefore, an artificial muscle with a high contraction rate and a tendon-driven system as a compact actuator were developed, respectively. In this study, we report on the basic structure and basic characteristics of two types of actuators.

  2. Biomechanical differences between left- and right-handed baseball pitchers.

    Science.gov (United States)

    Solomito, Matthew J; Ferreira, Joel V; Nissen, Carl W

    2017-06-01

    Left-handed baseball pitchers are thought to have a number of theoretical advantages compared to right-handed pitchers; however, there is limited scientific research detailing differences in the pitching mechanics of right- and left-handed pitchers. Therefore, this study sought to understand whether any kinematic and kinetic differences existed between right- and left-handed baseball pitchers. A total of 52 collegiate pitchers were included in this study; 26 left-handed pitchers were compared to 26 age-, height-, weight- and ball velocity-matched right-handed pitchers. Demographic information, passive shoulder range of motion and kinematic and kinetic data were obtained for each pitcher participating in the study. Results indicated that left-handed pitchers did not have a glenohumeral internal rotation deficit as compared to right-handed pitchers. Kinematic analysis indicated that elbow flexion, horizontal glenohumeral abduction and wrist coronal plane motion were significantly different between the two study cohorts. It was also noted that left-handed pitchers had increased elbow varus moments. The findings of this study suggest that pitching coaches should be aware that there are biomechanical differences between left- and right-handed pitchers.

  3. Mathematical formulation of biomechanical parameters used in orthodontic treatment

    Science.gov (United States)

    Balakrishna, A.; Vamsi, Ch. Raghu; Rao, V. D. Prasad; Swamy, Ch. Kishore; Kuladeep, B.

    2015-05-01

    Orthodontic Treatment is being widely practiced around the world for teeth straightening and extraction to improve alignment of remaining teeth. Here, forces are applied to correct the position of teeth. The force applied on the teeth isn't calibrated and applied arbitrarily based on the recommendations from scientific research and experience of the orthodontist. The number of settings and the total time required for the completion of treatment also remains arbitrary. So, there is a need for determining the force which is actually acting on the teeth and determining the optimal force required for the treatment of each and every individual case. In this paper a mathematical relation is derived between the force applied on the tooth and tooth displacement by considering a 2nd order non-homogeneous linear differential equation. As the tooth displacement is not a direct function of force applied, Biomechanical parameters like mass of tooth, stiffness and damping coefficient of periodontal ligament & alveolar bone are involved in the differential equation. By solving the equation, tooth displacement thereby, tooth velocity can be obtained for a particular force. On the other hand, based on the dimensions of the model, orthodontist could determine the total tooth displacement required for each setting of the treatment, so that, the total displacement is covered. The orthodontist uses the data and applies the required force on to the teeth, based on which the orthodontist can plan his treatment procedure and reduce the number of settings, total treatment time and also increases the success rate of the treatment.

  4. Biomechanical Dynamics of Cranial Sutures during Simulated Impulsive Loading

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    Z. Q. Zhang

    2015-01-01

    Full Text Available Background. Cranial sutures are deformable joints between the bones of the skull, bridged by collagen fibres. They function to hold the bones of the skull together while allowing for mechanical stress transmission and deformation. Objective. The aim of this study is to investigate how cranial suture morphology, suture material property, and the arrangement of sutural collagen fibres influence the dynamic responses of the suture and surrounding bone under impulsive loads. Methods. An idealized bone-suture-bone complex was analyzed using a two-dimensional finite element model. A uniform impulsive loading was applied to the complex. Outcome variables of von Mises stress and strain energy were evaluated to characterize the sutures’ biomechanical behavior. Results. Parametric studies revealed that the suture strain energy and the patterns of Mises stress in both the suture and surrounding bone were strongly dependent on the suture morphologies. Conclusions. It was concluded that the higher order hierarchical suture morphology, lower suture elastic modulus, and the better collagen fiber orientation must benefit the stress attenuation and energy absorption.

  5. Biomechanical analysis of the jump shot in basketball.

    Science.gov (United States)

    Struzik, Artur; Pietraszewski, Bogdan; Zawadzki, Jerzy

    2014-09-29

    Basketball players usually score points during the game using the jump shot. For this reason, the jump shot is considered to be the most important element of technique in basketball and requires a high level of performance. The aim of this study was to compare the biomechanical characteristics of the lower limbs during a jump shot without the ball and a countermovement jump without an arm swing. The differences between variables provide information about the potential that an athlete can utilise during a game when performing a jump shot. The study was conducted among 20 second-league basketball players by means of a Kistler force plate and the BTS SMART system for motion analysis. The variables measured included the take-off time, mean power, peak power, relative mean power, jump height, maximum landing force and calculated impact ratio. Surprisingly, more advantageous variables were found for the jump shot. This finding suggests a very high performance level in the jump shot in the studied group and a maximum utilisation of their motor abilities. Both types of jumps were characterised by high mean and peak power values and average heights. The high forces at landing, which result in considerable impact ratios, may have prompted the studied group to land softly. Use of the countermovement jump without an arm swing is recommended to assess and predict the progression of player's jumping ability.

  6. Biomechanical behaviour in vitro of the spine and lumbosacral junction.

    Science.gov (United States)

    Barthes, X; Walter, B; Zeller, R; Dubousset, J F

    1999-01-01

    Six fresh human specimens extending from the 9th thoracic vertebra (T9) to the pelvis were used to study the biomechanical behaviour of the long lumbopelvic segments, including mobility of the sacrum. The loads were applied at T9 using pure couples up to 5 Nm. The displacements were measured by an optoelectronic method (VICON 140). Stress-displacement curves were obtained for the three angular components of the vertebra studied according to the plane of the principal stresses and of the two other planes corresponding to the coupled mobilities. Mobility decreased from T9 to the sacrum. There was mobility of the sacrum in relation to the pelvis in flexion, with a mean of 1.28 degrees (0.5 to 2.8 degrees); 3 sacrums showed a mobility of the order of one degree for torsional stresses. There was no sacral mobility during stresses in lateral flexion. The use of this experimental protocol with low mechanical stresses should allow the evaluation of long osteosyntheses extending to the sacrum.

  7. Patients’ follow-up using biomechanical analysis of rehabilitation exercises

    Directory of Open Access Journals (Sweden)

    Bruno Bonnechère

    2017-03-01

    Full Text Available Thanks to the evolution of game controllers video games are becoming more and more popular in physical rehabilitation. The integration of serious games in rehabilitation has been tested for various pathologies. Parallel to this clinical research, a lot of studies have been done in order to validate the use of these game controllers for simple biomechanical evaluation. Currently, it is thus possible to record the motions performed by the patients during serious gaming exercises for later analysis. Therefore, data collected during the exercises could be used for monitoring the evolution of the patients during long term rehabilitation. Before using the parameters extracted from the games to assess patients’ evolution two important aspects must be verified: the reproducibility of measurement and a possible effect of learning of the task to be performed. Ten healthy adults played 9 sessions of specific games developed for rehabilitation over a 3-weeks period. Nineteen healthy children played 2 sessions to study the influence of age. Different parameters were extracted from the games: time, range of motion, reaching area. Results of this study indicates that it is possible to follow the evolution of the patients during the rehabilitation process. The majority of the learning effect occurred during the very first session. Therefore, in order to allow proper regular monitoring, the results of this first session should not be included in the follow-up of the patient.

  8. Older Runners Retain Youthful Running Economy despite Biomechanical Differences.

    Science.gov (United States)

    Beck, Owen N; Kipp, Shalaya; Roby, Jaclyn M; Grabowski, Alena M; Kram, Rodger; Ortega, Justus D

    2016-04-01

    Sixty-five years of age typically marks the onset of impaired walking economy. However, running economy has not been assessed beyond the age of 65 yr. Furthermore, a critical determinant of running economy is the spring-like storage and return of elastic energy from the leg during stance, which is related to leg stiffness. Therefore, we investigated whether runners older than 65 yr retain youthful running economy and/or leg stiffness across running speeds. Fifteen young and 15 older runners ran on a force-instrumented treadmill at 2.01, 2.46, and 2.91 m·s(-1). We measured their rates of metabolic energy consumption (i.e., metabolic power), ground reaction forces, and stride kinematics. There were only small differences in running economy between young and older runners across the range of speeds. Statistically, the older runners consumed 2% to 9% less metabolic energy than the young runners across speeds (P = 0.012). Also, the leg stiffness of older runners was 10% to 20% lower than that of young runners across the range of speeds (P = 0.002), and in contrast to the younger runners, the leg stiffness of older runners decreased with speed (P economy despite biomechanical differences. It may be that vigorous exercise, such as running, prevents the age related deterioration of muscular efficiency and, therefore, may make everyday activities easier.

  9. The pulley system of the thumb: anatomic and biomechanical study.

    Science.gov (United States)

    Bayat, Ardeshir; Shaaban, Hassan; Giakas, Giannis; Lees, Vivien C

    2002-07-01

    To examine the precise conformation of the annular and oblique pulleys of the thumb flexor sheath, anatomic dissections were undertaken on 14 hands. In all specimens a distinct pulley was found between the A1 and oblique pulleys. This is named the variable annular pulley or Av pulley. There appear to be 3 discrete forms of this pulley designated type I to III. The biomechanical study was done on 8 limbs by using linear strain transduction techniques. The analysis showed that the strain in the oblique pulley was greater in extension than in flexion of the thumb. This statement remains true even after division of either the A1 or Av pulley and after section of both pulleys. The oblique pulley does not prevent bowstringing of the flexor pollicis longus when A1 and Av pulleys have been sectioned. These studies challenge current concepts of both the anatomy and mechanics of the thumb pulley system with implications for clinical procedures such as trigger thumb release and pulley reconstruction.

  10. Biomechanics of running indicates endothermy in bipedal dinosaurs.

    Science.gov (United States)

    Pontzer, Herman; Allen, Vivian; Hutchinson, John R

    2009-11-11

    One of the great unresolved controversies in paleobiology is whether extinct dinosaurs were endothermic, ectothermic, or some combination thereof, and when endothermy first evolved in the lineage leading to birds. Although it is well established that high, sustained growth rates and, presumably, high activity levels are ancestral for dinosaurs and pterosaurs (clade Ornithodira), other independent lines of evidence for high metabolic rates, locomotor costs, or endothermy are needed. For example, some studies have suggested that, because large dinosaurs may have been homeothermic due to their size alone and could have had heat loss problems, ectothermy would be a more plausible metabolic strategy for such animals. Here we describe two new biomechanical approaches for reconstructing the metabolic rate of 14 extinct bipedal dinosauriforms during walking and running. These methods, well validated for extant animals, indicate that during walking and slow running the metabolic rate of at least the larger extinct dinosaurs exceeded the maximum aerobic capabilities of modern ectotherms, falling instead within the range of modern birds and mammals. Estimated metabolic rates for smaller dinosaurs are more ambiguous, but generally approach or exceed the ectotherm boundary. Our results support the hypothesis that endothermy was widespread in at least larger non-avian dinosaurs. It was plausibly ancestral for all dinosauriforms (perhaps Ornithodira), but this is perhaps more strongly indicated by high growth rates than by locomotor costs. The polarity of the evolution of endothermy indicates that rapid growth, insulation, erect postures, and perhaps aerobic power predated advanced "avian" lung structure and high locomotor costs.

  11. Why do woodpeckers resist head impact injury: a biomechanical investigation.

    Directory of Open Access Journals (Sweden)

    Lizhen Wang

    Full Text Available Head injury is a leading cause of morbidity and death in both industrialized and developing countries. It is estimated that brain injuries account for 15% of the burden of fatalities and disabilities, and represent the leading cause of death in young adults. Brain injury may be caused by an impact or a sudden change in the linear and/or angular velocity of the head. However, the woodpecker does not experience any head injury at the high speed of 6-7 m/s with a deceleration of 1000 g when it drums a tree trunk. It is still not known how woodpeckers protect their brain from impact injury. In order to investigate this, two synchronous high-speed video systems were used to observe the pecking process, and the force sensor was used to measure the peck force. The mechanical properties and macro/micro morphological structure in woodpecker's head were investigated using a mechanical testing system and micro-CT scanning. Finite element (FE models of the woodpecker's head were established to study the dynamic intracranial responses. The result showed that macro/micro morphology of cranial bone and beak can be recognized as a major contributor to non-impact-injuries. This biomechanical analysis makes it possible to visualize events during woodpecker pecking and may inspire new approaches to prevention and treatment of human head injury.

  12. Biomechanical behavior of the tibiofibular frame in nonunion.

    Science.gov (United States)

    Gunzburg, R; Boulvin, S; Bourgeois, R; Wagner, J

    1991-01-01

    In this paper an in vitro investigation of the biomechanical behavior of the tibiofibular frame in nonunion using electrical extensometry is presented. The intact and untreated nonunited frames are studied as well as three surgical treatments classically used in nonunion: the plating technique, the onlay graft technique and the external fixation according to Ilizarov. The monopodal position with extended knee is considered, and particular attention is paid to the different muscle insertions. The results for the plating and onlay grafting techniques resemble those for the intact frame, whereas the Ilizarov external fixator increases the overall rigidity of the frame. In the untreated nonunited tibiofibular frame, an inversion of the tension and compression areas at the level of the tibia was found. We hypothesize that this phenomenon could be one of the mechanical factors leading to nonunion. Indeed, cyclic stresses in the fracture callus might prevent bony fusion, for the areas healing under compression stresses must become tension areas once the tibia is healed and vice versa.

  13. Physical Activity and Obesity: Biomechanical and Physiological Key Concepts

    Directory of Open Access Journals (Sweden)

    Julie Nantel

    2011-01-01

    Full Text Available Overweight (OW and obesity (OB are often associated with low levels of physical activity. Physical activity is recommended to reduce excess body weight, prevent body weight regain, and decrease the subsequent risks of developing metabolic and orthopedic conditions. However, the impact of OW and OB on motor function and daily living activities must be taken into account. OW and OB are associated with musculoskeletal structure changes, decreased mobility, modification of the gait pattern, and changes in the absolute and relative energy expenditures for a given activity. While changes in the gait pattern have been reported at the ankle, knee, and hip, modifications at the knee level might be the most challenging for articular integrity. This review of the literature combines concepts and aims to provide insights into the prescription of physical activity for this population. Topics covered include the repercussions of OW and OB on biomechanical and physiological responses associated with the musculoskeletal system and daily physical activity. Special attention is given to the effect of OW and OB in youth during postural (standing and various locomotor (walking, running, and cycling activities.

  14. Biomechanical Analysis of the Jump Shot in Basketball

    Directory of Open Access Journals (Sweden)

    Struzik Artur

    2014-10-01

    Full Text Available Basketball players usually score points during the game using the jump shot. For this reason, the jump shot is considered to be the most important element of technique in basketball and requires a high level of performance. The aim of this study was to compare the biomechanical characteristics of the lower limbs during a jump shot without the ball and a countermovement jump without an arm swing. The differences between variables provide information about the potential that an athlete can utilise during a game when performing a jump shot. The study was conducted among 20 second-league basketball players by means of a Kistler force plate and the BTS SMART system for motion analysis. The variables measured included the take-off time, mean power, peak power, relative mean power, jump height, maximum landing force and calculated impact ratio. Surprisingly, more advantageous variables were found for the jump shot. This finding suggests a very high performance level in the jump shot in the studied group and a maximum utilisation of their motor abilities. Both types of jumps were characterised by high mean and peak power values and average heights. The high forces at landing, which result in considerable impact ratios, may have prompted the studied group to land softly. Use of the countermovement jump without an arm swing is recommended to assess and predict the progression of player’s jumping ability

  15. Biomechanical indicators of key elements of sports equipment gymnastic exercises

    Directory of Open Access Journals (Sweden)

    Potop V.A.

    2013-09-01

    Full Text Available The aim of this study is to analyze the biomechanical performance of the kinematic and dynamic structures of key elements of sports techniques of basic exercises performed gymnasts aged 12 - 14 years to the vaulting and on the bars of different heights, on the basis of the method of postural orientation movements. The study involved 11 gymnasts doing exercises on the vaulting and 9 gymnasts - on the boards of various heights. It is shown that the method of video - computer analysis of the type Yurchenko vault and dismount from the bars of varying heights, in conjunction with the method of postural orientation movements possible to isolate and identify the node elements. The indicators characterizing the node elements of sports equipment movements gymnasts in the phase structure of the vault and dismount from the bars of different heights have specific features and characteristics. Learned node elements sports equipment is the basis for the measurement, analysis and evaluation of the kinematic and dynamic structures and other types of exercises all-around gymnastics.

  16. Harmful cleats of football boots: a biomechanical evaluation.

    Science.gov (United States)

    Bentley, J A; Ramanathan, A K; Arnold, G P; Wang, W; Abboud, R J

    2011-09-01

    Football players wear boots of varying cleat designs with some preferring the bladed cleats while others opting for the conventional studded cleats. The current study compares biomechanically the boots with differing cleat designs and their effect on feet, if any. Twenty-nine healthy male volunteers were recruited from amateur football teams. They were asked to perform three trials each of two activities: a straight run and a run cutting at a 60° angle wearing bladed and studded Adidas®-F series boots on artificial turf. Plantar pressure values were recorded using the Pedar®-X in-shoe pressure measuring device. Peak pressure and pressure-time integral were analysed over 11 clinically relevant areas under the foot. While the in-shoe pressure and pressure-time integral were higher under the medial half of the foot with studded boots, they were higher under the lateral half of the foot with the bladed design. The studded boots can be considered safer as the pressure distribution across the foot and the pattern of centre of pressure progression mimicked the normal motif, whereas the bladed boots could potentially be deemed relatively more harmful due to the unnatural increased loading under the lateral half of the foot, predisposing the foot to injuries. Copyright © 2010 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

  17. Shape memory alloys: metallurgy, biocompatibility, and biomechanics for neurosurgical applications.

    Science.gov (United States)

    Hoh, Daniel J; Hoh, Brian L; Amar, Arun P; Wang, Michael Y

    2009-05-01

    SHAPE MEMORY ALLOYS possess distinct dynamic properties with particular applications in neurosurgery. Because of their unique physical characteristics, these materials are finding increasing application where resiliency, conformation, and actuation are needed. Nitinol, the most frequently manufactured shape memory alloy, responds to thermal and mechanical stimuli with remarkable mechanical properties such as shape memory effect, super-elasticity, and high damping capacity. Nitinol has found particular use in the biomedical community because of its excellent fatigue resistance and biocompatibility, with special interest in neurosurgical applications. The properties of nitinol and its diffusionless phase transformations contribute to these unique mechanical capabilities. The features of nitinol, particularly its shape memory effect, super-elasticity, damping capacity, as well as its biocompatibility and biomechanics are discussed herein. Current and future applications of nitinol and other shape memory alloys in endovascular, spinal, and minimally invasive neurosurgery are introduced. An understanding of the metallurgic properties of nitinol provides a foundation for further exploration of its use in neurosurgical implant design.

  18. The Influence of Articular Cartilage Thickness Reduction on Meniscus Biomechanics.

    Science.gov (United States)

    Łuczkiewicz, Piotr; Daszkiewicz, Karol; Chróścielewski, Jacek; Witkowski, Wojciech; Winklewski, Pawel J

    2016-01-01

    Evaluation of the biomechanical interaction between meniscus and cartilage in medial compartment knee osteoarthritis. The finite element method was used to simulate knee joint contact mechanics. Three knee models were created on the basis of knee geometry from the Open Knee project. We reduced the thickness of medial cartilages in the intact knee model by approximately 50% to obtain a medial knee osteoarthritis (OA) model. Two variants of medial knee OA model with congruent and incongruent contact surfaces were analysed to investigate the influence of congruency. A nonlinear static analysis for one compressive load case was performed. The focus of the study was the influence of cartilage degeneration on meniscal extrusion and the values of the contact forces and contact areas. In the model with incongruent contact surfaces, we observed maximal compressive stress on the tibial plateau. In this model, the value of medial meniscus external shift was 95.3% greater, while the contact area between the tibial cartilage and medial meniscus was 50% lower than in the congruent contact surfaces model. After the non-uniform reduction of cartilage thickness, the medial meniscus carried only 48.4% of load in the medial compartment in comparison to 71.2% in the healthy knee model. We have shown that the change in articular cartilage geometry may significantly reduce the role of meniscus in load transmission and the contact area between the meniscus and cartilage. Additionally, medial knee OA may increase the risk of meniscal extrusion in the medial compartment of the knee joint.

  19. Biomechanical Characteristics of Osteoporotic Fracture Healing in Ovariectomized Rats: A Systematic Review.

    Science.gov (United States)

    Chen, Lin; Yang, Long; Yao, Min; Cui, Xue-Jun; Xue, Chun-Chun; Wang, Yong-Jun; Shu, Bing

    2016-01-01

    Biomechanical tests are widely used in animal studies on osteoporotic fracture healing. However, the biomechanical recovery process is still unknown, leading to difficulty in choosing time points for biomechanical tests and in correctly assessing osteoporotic fracture healing. To determine the biomechanical recovery process during osteoporotic fracture healing, studies on osteoporotic femur fracture healing with biomechanical tests in ovariectomized rat (OVX) models were collected from PUBMED, EMBASE, and Chinese databases. Quadratic curves of fracture healing time and maximum load were fitted with data from the analyzed studies. In the fitted curve for normal fractures, the predicted maximum load was 145.56 N, and the fracture healing time was 88.0 d. In the fitted curve for osteoporotic fractures, the predicted maximum load was 122.30 N, and the fracture healing time was 95.2 d. The maximum load of fractured femurs in OVX rats was also lower than that in sham rats at day 84 post-fracture (D84 PF). The fracture healing time was prolonged and maximum load at D84 PF decreased in OVX rats with closed fractures. The maximum load of Wister rats was higher than that of Sprague-Dawley (SD) rats, but the fracture healing time of SD and Wister rats was similar. Osteoporotic fracture healing was delayed in rats that were 12 weeks old at ovariectomy. There was no significant difference in maximum load at D84 PF between rats with an osteoporosis modeling time = 12 weeks. In conclusion, fracture healing was delayed and biomechanical property decreased by osteoporosis. Time points around D95.2 PF should be considered for biomechanical tests of osteoporotic femur fracture healing in OVX rat models. Osteoporotic fracture healing in OVX rats was affected by the fracture type but not by the strain of the rat.

  20. Are Cranial Biomechanical Simulation Data Linked to Known Diets in Extant Taxa? A Method for Applying Diet-Biomechanics Linkage Models to Infer Feeding Capability of Extinct Species

    Science.gov (United States)

    Tseng, Zhijie Jack; Flynn, John J.

    2015-01-01

    Performance of the masticatory system directly influences feeding and survival, so adaptive hypotheses often are proposed to explain craniodental evolution via functional morphology changes. However, the prevalence of “many-to-one” association of cranial forms and functions in vertebrates suggests a complex interplay of ecological and evolutionary histories, resulting in redundant morphology-diet linkages. Here we examine the link between cranial biomechanical properties for taxa with different dietary preferences in crown clade Carnivora, the most diverse clade of carnivorous mammals. We test whether hypercarnivores and generalists can be distinguished based on cranial mechanical simulation models, and how such diet-biomechanics linkages relate to morphology. Comparative finite element and geometric morphometrics analyses document that predicted bite force is positively allometric relative to skull strain energy; this is achieved in part by increased stiffness in larger skull models and shape changes that resist deformation and displacement. Size-standardized strain energy levels do not reflect feeding preferences; instead, caniform models have higher strain energy than feliform models. This caniform-feliform split is reinforced by a sensitivity analysis using published models for six additional taxa. Nevertheless, combined bite force-strain energy curves distinguish hypercarnivorous versus generalist feeders. These findings indicate that the link between cranial biomechanical properties and carnivoran feeding preference can be clearly defined and characterized, despite phylogenetic and allometric effects. Application of this diet-biomechanics linkage model to an analysis of an extinct stem carnivoramorphan and an outgroup creodont species provides biomechanical evidence for the evolution of taxa into distinct hypercarnivorous and generalist feeding styles prior to the appearance of crown carnivoran clades with similar feeding preferences. PMID:25923776

  1. [A biomechanic study on the relapse after sagittal split and oblique osteotomy of Ramus].

    Science.gov (United States)

    Li, Wei; Song, Yufeng; Wang, Dazhang

    2004-02-01

    The relapse after orthognathic surgery was frequently reported in recent years. But up to now researches concerning bio-mechanic mechanism of relapse are rare. The purpose of this study, by imitating the operation on monkeys, was to examine the biomechanical properties and histological characteristics after operation in order to investigate the mechanism of the relapse after orthognathic surgery. 20 rhesus monkeys divided into two groups were subjected to bilateral sagittal split and oblique osteotomy, respectively. The broken strength, stress and strain of the operated sites were examined with the use of biomechanical methods, and the healing scab was observed using histological method and SEM at 3, 6, 12, 24 weeks after operation. The results obtained demonstrated that bone healing and biomechanical properties reached certain level after 6 to 12 weeks' recovery in both operation groups; the biomechanical properties and histological characteristics recovered faster in sagittal split group than in oblique osteotomy group. Histological examination also demonstrated similar results. From the data above it is suggested that the higher relapse rate in sagittal split may more closely related to the mechanical effect different from the scab healing, although 8 weeks' fixation may meet the requirement of clinical treatment, accessory fixation method should be adopted after the removal of inter-maxilla fixation.

  2. Static and dynamic biomechanical properties of the regenerating rabbit Achilles tendon.

    Science.gov (United States)

    Nagasawa, Koji; Noguchi, Masahiko; Ikoma, Kazuya; Kubo, Toshikazu

    2008-07-01

    Since tendons show viscoelastic behavior, dynamic viscoelastic properties should be assessed in addition to static biomechanical properties. We evaluated differences between static and dynamic biomechanical properties of the regenerating rabbit Achilles tendon following tenotomy. At 3, 6, or 12 weeks after right Achilles tenotomy, the right (regenerating) and left (control) tendons were collected with the calcaneus from 49 rabbits. A unidirectional failure test and a dynamic viscoelastic test were conducted. Tensile strength and Young's modulus (static biomechanical properties) in the regenerating group at Week 6 were significantly greater than at Week 3, while at Week 12, these were significantly greater than at Week 6. However, even at Week 12, both parameters were less than in the control group. The value of tan delta represents dynamic viscoelasticity, a smaller tan delta indicates greater elasticity. tan delta for the regenerating group was significantly greater than for the control group at Week 3, but regenerating and control groups did not significantly differ at Week 6. No marked change was seen from Weeks 6 to 12 in the regenerating group, and no significant difference in tan delta was evident between the regenerating and control groups at Week 12. Dynamic biomechanical properties of regenerating rabbit Achilles tendons may improve more rapidly than static biomechanical properties. Ability to tolerate dynamic movement in the healing Achilles tendon may improve more rapidly than ability to withstand static stresses.

  3. Biomechanics-based in silico medicine: the manifesto of a new science.

    Science.gov (United States)

    Viceconti, Marco

    2015-01-21

    In this perspective article we discuss the role of contemporary biomechanics in the light of recent applications such as the development of the so-called Virtual Physiological Human technologies for physiology-based in silico medicine. In order to build Virtual Physiological Human (VPH) models, computer models that capture and integrate the complex systemic dynamics of living organisms across radically different space-time scales, we need to re-formulate a vast body of existing biology and physiology knowledge so that it is formulated as a quantitative hypothesis, which can be expressed in mathematical terms. Once the predictive accuracy of these models is confirmed against controlled experiments and against clinical observations, we will have VPH model that can reliably predict certain quantitative changes in health status of a given patient, but also, more important, we will have a theory, in the true meaning this word has in the scientific method. In this scenario, biomechanics plays a very important role, biomechanics is one of the few areas of life sciences where we attempt to build full mechanistic explanations based on quantitative observations, in other words, we investigate living organisms like physical systems. This is in our opinion a Copernican revolution, around which the scope of biomechanics should be re-defined. Thus, we propose a new definition for our research domain "Biomechanics is the study of living organisms as mechanistic systems". Copyright © 2014 Elsevier Ltd. All rights reserved.

  4. Analysis of occupational stress in a high fashion clothing factory with upper limb biomechanical overload.

    Science.gov (United States)

    Forcella, Laura; Bonfiglioli, Roberta; Cutilli, Piero; Siciliano, Eugenio; Di Donato, Angela; Di Nicola, Marta; Antonucci, Andrea; Di Giampaolo, Luca; Boscolo, Paolo; Violante, Francesco Saverio

    2012-07-01

    To study job stress and upper limb biomechanical overload due to repetitive and forceful manual activities in a factory producing high fashion clothing. A total of 518 workers (433 women and 85 men) were investigated to determine anxiety, occupational stress (using the Italian version of the Karasek Job Content Questionnaire) and perception of symptoms (using the Italian version of the Somatization scale of Symptom Checklist SCL-90). Biomechanical overload was analyzed using the OCRA Check list. Biomechanical assessment did not reveal high-risk jobs, except for cutting. Although the perception of anxiety and job insecurity was within the normal range, all the workers showed a high level of job strain (correlated with the perception of symptoms) due to very low decision latitude. Occupational stress resulted partially in line with biomechanical risk factors; however, the perception of low decision latitude seems to play a major role in determining job strain. Interactions between physical and psychological factors cannot be demonstrated. Anyway, simultaneous long-term monitoring of occupational stress features and biomechanical overload could guide workplace interventions aimed at reducing the risk of adverse health effects.

  5. Analysis of Big Data in Gait Biomechanics: Current Trends and Future Directions.

    Science.gov (United States)

    Phinyomark, Angkoon; Petri, Giovanni; Ibáñez-Marcelo, Esther; Osis, Sean T; Ferber, Reed

    2018-01-01

    The increasing amount of data in biomechanics research has greatly increased the importance of developing advanced multivariate analysis and machine learning techniques, which are better able to handle "big data". Consequently, advances in data science methods will expand the knowledge for testing new hypotheses about biomechanical risk factors associated with walking and running gait-related musculoskeletal injury. This paper begins with a brief introduction to an automated three-dimensional (3D) biomechanical gait data collection system: 3D GAIT, followed by how the studies in the field of gait biomechanics fit the quantities in the 5 V's definition of big data: volume, velocity, variety, veracity, and value. Next, we provide a review of recent research and development in multivariate and machine learning methods-based gait analysis that can be applied to big data analytics. These modern biomechanical gait analysis methods include several main modules such as initial input features, dimensionality reduction (feature selection and extraction), and learning algorithms (classification and clustering). Finally, a promising big data exploration tool called "topological data analysis" and directions for future research are outlined and discussed.

  6. Gait biomechanics and hip muscular strength in patients with patellofemoral osteoarthritis.

    Science.gov (United States)

    Pohl, Michael B; Patel, Chirag; Wiley, J Preston; Ferber, Reed

    2013-03-01

    A significant number of patients with patellofemoral osteoarthritis (PFOA) have described a history of patellofemoral pain syndrome (PFPS). This leads to speculation that the underpinning mechanical causes of PFPS and PFOA may be similar. Although alterations in gait biomechanics and hip strength have been reported in PFPS, this relationship has not yet been explored in PFOA. Therefore the purpose of this study was compare gait biomechanics and hip muscular strength between PFOA patients and a healthy control group. Fifteen patients with symptomatic, radiographic PFOA and 15 controls participated. All patients underwent a walking gait analysis and maximal hip strength testing. Biomechanical variables of interest included the peak angular values of contra-lateral pelvic drop, hip adduction and hip internal rotation during the stance phase. Hip abduction and external rotation strength were assessed using maximal voluntary isometric contractions. The PFOA group demonstrated significantly lower hip abduction strength compared to controls but no difference in hip external rotation strength. There were no statistical differences between the PFOA and control groups for contra-lateral pelvic drop, hip adduction and hip internal rotation angles during walking. Despite patients with PFOA exhibiting weaker hip abductor muscle strength compared to their healthy counterparts they did not demonstrate alterations in pelvis or hip biomechanics during gait. These preliminary data suggests that weaker hip abductor strength does not result in biomechanical alterations during gait in this population. Copyright © 2012 Elsevier B.V. All rights reserved.

  7. Effects of Taping and Orthoses on Foot Biomechanics in Adults with Flat-Arched Feet.

    Science.gov (United States)

    Bishop, Christopher; Arnold, John B; May, Thomas

    2016-04-01

    There is a paucity of evidence on the biomechanical effects of foot taping and foot orthoses in realistic conditions. This study aimed to determine the immediate effect and relationships between changes in multisegment foot biomechanics with foot taping and customized foot orthoses in adults with flat-arched feet. Multisegment foot biomechanics were measured in 18 adults with flat-arched feet (age 25.1 ± 2.8 yr; height 1.73 ± .13 m, body mass 70.3 ± 15.7 kg) during walking in four conditions in random order: neutral athletic shoe, neutral shoe with tape (low-Dye method and modified method) and neutral shoe with customized foot orthoses. In-shoe foot biomechanics were compared between conditions using a purpose developed foot model with three-dimensional kinematic analysis and inverse dynamics. Foot orthoses significantly delayed peak eversion compared to the neutral shoe (44% stance vs 39%, P = 0.002). Deformation across the midfoot and medial longitudinal arch was reduced with both the low-Dye taping (2.4°, P foot orthoses (R2 = 0.08-0.52, P = 0.006 to Foot orthoses more effectively altered timing of hindfoot motion whereas taping was superior in supporting the midfoot and medial longitudinal arch. The biomechanical response to taping was significantly related to the subsequent change observed with the use of foot orthoses.

  8. Spinal biomechanical properties are significantly altered with a novel embalming method.

    Science.gov (United States)

    Holewijn, Roderick M; Faraj, Sayf S A; Kingma, Idsart; van Royen, Barend J; de Kleuver, Marinus; van der Veen, Albert J

    2017-04-11

    In vitro tests on the biomechanical properties of human spines are often performed using fresh frozen specimens. However, this carries the risk of pathogen transfer from specimen to the worker and the specimens can only be used for a limited amount of time. Human spinal specimens embalmed with formaldehyde carry an almost absent risk of transfer of pathogens and can be stored and used for a long time, but the tissue properties are strongly affected making this method inapplicable for biomechanical testing. In this study, a new embalming technique called Fix for Life (F4L), which claims to preserve the tissue properties, was tested. The range of motion (ROM) and stiffness of six fresh human spinal specimens was measured using a spinal motion simulator before and after F4L embalming. After F4L embalming, spinal stiffness increased in flexion-extension by 230%, in lateral bending by 284% and in axial rotation by 271%. ROM decreased by 46% in flexion-extension, 56% in lateral bending and 54% in axial rotation. In conclusion, based on this study, F4L does not maintain physiological spinal biomechanical properties, and we propose that this method should not be used for biomechanical studies. Nevertheless, the method may be an alternative to formaldehyde fixation in situations such as training and education because the effect on spinal biomechanics is less detrimental than formaldehyde and tissue color is maintained. Copyright © 2017 Elsevier Ltd. All rights reserved.

  9. Limno-terrestrial Tardigrada of the Nearctic Realm

    Directory of Open Access Journals (Sweden)

    Juliana G. HINTON

    2007-09-01

    Full Text Available We examined all available records of limno-terrestrial tardigrade distribution in the Nearctic realm (Greenland, Canada, Alaska, the continental United States of America, and northern Mexico, both to compare this fauna with other realms and to investigate distribution within North America. We included only those records in which tardigrades had been identified to species. Of 204 Nearctic limno-terrestrial tardigrade species, 38 were cosmopolitan, while 55 were unique to the Nearctic realm. The Nearctic tardigrade fauna is most similar to the Palearctic, with 135 species in common, 39 of which have not been reported elsewhere. The Nearctic realm shares 82 species with the Neotropical realm, only 10 which are not also Palearctic. These data are consistent with the geological history of the three realms, and indicate a distinction between Laurasian and Gondwanan tardigrade faunas. Although little is known about limno-terrestrial tardigrade distribution in much of North America, there are several excellent regional or local surveys. Many species are distributed widely throughout the continent, but 30.0% of Nearctic species have been reported from a single site. Cluster analysis of the fauna of 11 Nearctic regions shows that the Arctic and sub-Arctic fauna constitute a regional fauna distinct from the rest of the continent. Ecological analysis is hampered by inconsistent reporting of tardigrade substrate, though available data suggest little substrate specificity in terrestrial tardigrades. Most species are found in both mosses and lichens. Many are also present in soil and leaf litter, but few are found only in these substrates.

  10. Biomechanics of the Treadmill Locomotion on the International Space Station

    Science.gov (United States)

    DeWitt, John; Cromwell, R. L.; Ploutz-Snyder, L. L.

    2014-01-01

    Exercise prescriptions completed by International Space Station (ISS) crewmembers are typically based upon evidence obtained during ground-based investigations, with the assumption that the results of long-term training in weightlessness will be similar to that attained in normal gravity. Coupled with this supposition are the assumptions that exercise motions and external loading are also similar between gravitational environments. Normal control of locomotion is dependent upon learning patterns of muscular activation and requires continual monitoring of internal and external sensory input [1]. Internal sensory input includes signals that may be dependent on or independent of gravity. Bernstein hypothesized that movement strategy planning and execution must include the consideration of segmental weights and inertia [2]. Studies of arm movements in microgravity showed that individuals tend to make errors but that compensation strategies result in adaptations, suggesting that control mechanisms must include peripheral information [3-5]. To date, however, there have been no studies examining a gross motor activity such as running in weightlessness other than using microgravity analogs [6-8]. The objective of this evaluation was to collect biomechanical data from crewmembers during treadmill exercise before and during flight. The goal was to determine locomotive biomechanics similarities and differences between normal and weightless environments. The data will be used to optimize future exercise prescriptions. This project addresses the Critical Path Roadmap risks 1 (Accelerated Bone Loss and Fracture Risk) and 11 (Reduced Muscle Mass, Strength, and Endurance). Data were collected from 7 crewmembers before flight and during their ISS missions. Before launch, crewmembers performed a single data collection session at the NASA Johnson Space Center. Three-dimensional motion capture data were collected for 30 s at speeds ranging from 1.5 to 9.5 mph in 0.5 mph increments

  11. Human feeding biomechanics: performance, variation, and functional constraints

    Science.gov (United States)

    Dechow, Paul C.; Wang, Qian; Gharpure, Poorva H.; Baab, Karen L.; Smith, Amanda L.; Weber, Gerhard W.; Grosse, Ian R.; Ross, Callum F.; Richmond, Brian G.; Wright, Barth W.; Byron, Craig; Wroe, Stephen; Strait, David S.

    2016-01-01

    The evolution of the modern human (Homo sapiens) cranium is characterized by a reduction in the size of the feeding system, including reductions in the size of the facial skeleton, postcanine teeth, and the muscles involved in biting and chewing. The conventional view hypothesizes that gracilization of the human feeding system is related to a shift toward eating foods that were less mechanically challenging to consume and/or foods that were processed using tools before being ingested. This hypothesis predicts that human feeding systems should not be well-configured to produce forceful bites and that the cranium should be structurally weak. An alternate hypothesis, based on the observation that humans have mechanically efficient jaw adductors, states that the modern human face is adapted to generate and withstand high biting forces. We used finite element analysis (FEA) to test two opposing mechanical hypotheses: that compared to our closest living relative, chimpanzees (Pan troglodytes), the modern human craniofacial skeleton is (1) less well configured, or (2) better configured to generate and withstand high magnitude bite forces. We considered intraspecific variation in our examination of human feeding biomechanics by examining a sample of geographically diverse crania that differed notably in shape. We found that our biomechanical models of human crania had broadly similar mechanical behavior despite their shape variation and were, on average, less structurally stiff than the crania of chimpanzees during unilateral biting when loaded with physiologically-scaled muscle loads. Our results also show that modern humans are efficient producers of bite force, consistent with previous analyses. However, highly tensile reaction forces were generated at the working (biting) side jaw joint during unilateral molar bites in which the chewing muscles were recruited with bilateral symmetry. In life, such a configuration would have increased the risk of joint dislocation and

  12. Peculiarities of Simulation of Biomechanical and Biological Systems

    Directory of Open Access Journals (Sweden)

    А. О. Лопатьєв

    2017-06-01

    Full Text Available The objective is to combine the methods and principles of biomechanics and continuum mechanics in order to pose and solve problems that have practical application in extreme conditions. Materials & methods: the movement of blood through large vessels was studied on the basis of the Euler and Navier-Stokes equations. Analysis of the cardiovascular system was used for the examination of the functional state of the athlete. The initial experimentally measured heart rate (HR was determined by the Polar RC800 cardiac monitor. The resulting time series is analyzed using the software package Kubios HRV. Results: the article proposes to consider a model describing human body as a discrete-continuous system. Using the Euler equation, a mathematical model of the movement of blood through large vessels is considered. A mathematical model of the process of pulse wave propagation in blood vessels is given. We found and interpreted  hidden periodicities relative to the numerical series occurring during analysis of biological and heart rhythms of athletes during training and competitive activities. Conclusions: the use of methods and principles of continuum mechanics makes it possible to pose and solve the problems of mathematical physics for practical purposes. These include the movement of blood through large vessels, the issue of heat protection, and so on. The heart rate changes during the day and has a fluctuating character with certain periods. Periods of heart rate depend on the activity of a person and the time of day. Moreover, the heart rate tends to increase the amplitude and depend significantly on person’s workload.

  13. Biomechanics of fall arrest using the upper extremity: age differences.

    Science.gov (United States)

    Kim, Kyu-Jung; Ashton-Miller, James A

    2003-05-01

    This study tried to isolate critical biomechanical factors in fall arrests using the upper extremity during simulated forward falls. This study also attempted to find the differences in those factors between young and old age groups. The role of the upper extremity is not well defined despite its primary usage as a local shock absorber during fall impact. Comparative study in which two age groups underwent motion analysis.Methods. Ten healthy older males (mean age, 66.4 years) and 10 young males (mean age, 24.1 years) volunteered to perform self-initiated and cable-released falls at selected falling distances, while the joint motion and impact forces at the hand were recorded. Significant age differences were demonstrated in joint kinematics and impact force parameters at close distances. Excessive reflexive responses of the upper extremity in cable-released falls for the older adults resulted in 10-15 times higher peak impact forces and 2-3 times shorter body braking time than in self-initiated falls. Pre-impact activities of the upper extremity predispose the post-impact response during fall arrests. Suppressing excessive pre-impact reflexive activation of the arms could efficiently decrease the risk of fall-related injuries, which calls for securing sufficient arm movement time. Any fall prevention strategy that can increase arm movement time would be effective against injuries of the upper extremity during falling in the older adults. The findings will help to understand underlying mechanisms of fall arrest using the upper extremity for prevention of fall-related fractures.

  14. Gait biomechanics following lower extremity trauma: Amputation vs. reconstruction.

    Science.gov (United States)

    Russell Esposito, Elizabeth; Stinner, Daniel J; Fergason, John R; Wilken, Jason M

    2017-05-01

    Surgical advances have substantially improved outcomes for individuals sustaining traumatic lower extremity injury. Injuries once requiring lower limb amputation are now routinely managed with limb reconstruction surgery. However, comparisons of functional outcomes between the procedures are inconclusive. To compare gait biomechanics after lower limb reconstruction and transtibial amputation. Twenty-four individuals with unilateral lower limb reconstruction wearing a custom ankle-foot orthosis (Intrepid Dynamic Exoskeletal Orthosis), 24 with unilateral, transtibial amputation, and 24 able-bodied control subjects underwent gait analysis at a standardized Froude speed based on leg length. Lower extremity joint angles, moments, and powers, and ground reaction forces were analyzed on the affected limb of patients and right limb of able-bodied individuals. ANOVA with Tukeys post-hoc tests determined differences among groups and post-hoc paired t-tests with Bonferroni-Holm corrections determined differences between limbs. The ankle, knee, and hip exhibited significant kinematic differences between amputated, reconstructed and able-bodied limbs. The reconstruction group exhibited less ankle power and range of motion while the amputee group exhibited lower knee flexor and extensor moments and power generation. Gait deficiencies were more pronounced at the ankle following limb reconstruction with orthosis use and at the knee following transtibial amputation with prosthesis use. Although both groups in the cohorts tested can replicate many key aspects of normative gait mechanics, some deficiencies still persist. These results add to the growing body of literature comparing amputation and limb reconstruction and provide information to inform the patient on functional expectations should either procedure be considered. Copyright © 2017. Published by Elsevier B.V.

  15. Biomechanical analysis of distal biceps tendon repair methods.

    Science.gov (United States)

    Henry, Jon; Feinblatt, Jeff; Kaeding, Christopher C; Latshaw, James; Litsky, Alan; Sibel, Roman; Stephens, Julie A; Jones, Grant L

    2007-11-01

    The 1-incision and 2-incision techniques are commonly used methods to repair a distal biceps rupture, and they differ in the location of reinsertion of tendon into bone. The native distal biceps brachii tendon inserts on the posterior-ulnar aspect of the bicipital tuberosity, which functions as a cam, increasing the tendon's moment arm during its principal action of forearm supination. Repair of the distal biceps tendon to the anterior aspect of the tuberosity compromises forearm supination due to absence of the bicipital tuberosity's cam effect. Controlled laboratory study. Eleven matched pairs of fresh-frozen cadaveric upper extremities were prepared for repair of the distal biceps tendon using either anterior or posterior reattachment with transosseous suture fixation. Specimens were tested on a materials testing machine with intact distal biceps insertion and after repair. A load cell at the distal radial-ulnar joint measured resultant elbow flexion and forearm supination torque produced by 100-N force applied to the proximal aspect of the tendon. Although there was a trend (P= .104) toward loss of supination torque with the anterior reconstruction method, no significant differences in torque (0.80 vs 0.89 N.m) or flexion force (11.87 vs 12.07 N) were found between the anterior and posterior reconstruction techniques. There is no statistically significant difference in flexion force or supination torque between the anterior and posterior reconstruction techniques. This study supports existing limited clinical data suggesting no functional differences exist between 2 common repair methods. Further biomechanical and clinical investigations directly comparing the results of distal biceps tendon repairs made to the anterior aspect versus the posterior aspect of the tuberosity are necessary to definitely determine if differences exist in resultant elbow flexion and forearm supination functions.

  16. Biomechanics of running indicates endothermy in bipedal dinosaurs.

    Directory of Open Access Journals (Sweden)

    Herman Pontzer

    Full Text Available BACKGROUND: One of the great unresolved controversies in paleobiology is whether extinct dinosaurs were endothermic, ectothermic, or some combination thereof, and when endothermy first evolved in the lineage leading to birds. Although it is well established that high, sustained growth rates and, presumably, high activity levels are ancestral for dinosaurs and pterosaurs (clade Ornithodira, other independent lines of evidence for high metabolic rates, locomotor costs, or endothermy are needed. For example, some studies have suggested that, because large dinosaurs may have been homeothermic due to their size alone and could have had heat loss problems, ectothermy would be a more plausible metabolic strategy for such animals. METHODOLOGY/PRINCIPAL FINDINGS: Here we describe two new biomechanical approaches for reconstructing the metabolic rate of 14 extinct bipedal dinosauriforms during walking and running. These methods, well validated for extant animals, indicate that during walking and slow running the metabolic rate of at least the larger extinct dinosaurs exceeded the maximum aerobic capabilities of modern ectotherms, falling instead within the range of modern birds and mammals. Estimated metabolic rates for smaller dinosaurs are more ambiguous, but generally approach or exceed the ectotherm boundary. CONCLUSIONS/SIGNIFICANCE: Our results support the hypothesis that endothermy was widespread in at least larger non-avian dinosaurs. It was plausibly ancestral for all dinosauriforms (perhaps Ornithodira, but this is perhaps more strongly indicated by high growth rates than by locomotor costs. The polarity of the evolution of endothermy indicates that rapid growth, insulation, erect postures, and perhaps aerobic power predated advanced "avian" lung structure and high locomotor costs.

  17. Biomechanical based image registration for head and neck radiation treatment

    Science.gov (United States)

    Al-Mayah, Adil; Moseley, Joanne; Hunter, Shannon; Velec, Mike; Chau, Lily; Breen, Stephen; Brock, Kristy

    2010-02-01

    Deformable image registration of four head and neck cancer patients was conducted using biomechanical based model. Patient specific 3D finite element models have been developed using CT and cone beam CT image data of the planning and a radiation treatment session. The model consists of seven vertebrae (C1 to C7), mandible, larynx, left and right parotid glands, tumor and body. Different combinations of boundary conditions are applied in the model in order to find the configuration with a minimum registration error. Each vertebra in the planning session is individually aligned with its correspondence in the treatment session. Rigid alignment is used for each individual vertebra and to the mandible since deformation is not expected in the bones. In addition, the effect of morphological differences in external body between the two image sessions is investigated. The accuracy of the registration is evaluated using the tumor, and left and right parotid glands by comparing the calculated Dice similarity index of these structures following deformation in relation to their true surface defined in the image of the second session. The registration improves when the vertebrae and mandible are aligned in the two sessions with the highest Dice index of 0.86+/-0.08, 0.84+/-0.11, and 0.89+/-0.04 for the tumor, left and right parotid glands, respectively. The accuracy of the center of mass location of tumor and parotid glands is also improved by deformable image registration where the error in the tumor and parotid glands decreases from 4.0+/-1.1, 3.4+/-1.5, and 3.8+/-0.9 mm using rigid registration to 2.3+/-1.0, 2.5+/-0.8 and 2.0+/-0.9 mm in the deformable image registration when alignment of vertebrae and mandible is conducted in addition to the surface projection of the body.

  18. Do cells contribute to tendon and ligament biomechanics?

    Directory of Open Access Journals (Sweden)

    Niels Hammer

    Full Text Available Acellular scaffolds are increasingly used for the surgical repair of tendon injury and ligament tears. Despite this increased use, very little data exist directly comparing acellular scaffolds and their native counterparts. Such a comparison would help establish the effectiveness of the acellularization procedure of human tissues. Furthermore, such a comparison would help estimate the influence of cells in ligament and tendon stability and give insight into the effects of acellularization on collagen.Eighteen human iliotibial tract samples were obtained from nine body donors. Nine samples were acellularized with sodium dodecyl sulphate (SDS, while nine counterparts from the same donors remained in the native condition. The ends of all samples were plastinated to minimize material slippage. Their water content was adjusted to 69%, using the osmotic stress technique to exclude water content-related alterations of the mechanical properties. Uniaxial tensile testing was performed to obtain the elastic modulus, ultimate stress and maximum strain. The effectiveness of the acellularization procedure was histologically verified by means of a DNA assay.The histology samples showed a complete removal of the cells, an extensive, yet incomplete removal of the DNA content and alterations to the extracellular collagen. Tensile properties of the tract samples such as elastic modulus and ultimate stress were unaffected by acellularization with the exception of maximum strain.The data indicate that cells influence the mechanical properties of ligaments and tendons in vitro to a negligible extent. Moreover, acellularization with SDS alters material properties to a minor extent, indicating that this method provides a biomechanical match in ligament and tendon reconstruction. However, the given protocol insufficiently removes DNA. This may increase the potential for transplant rejection when acellular tract scaffolds are used in soft tissue repair. Further research

  19. The biomechanics of race walking: literature overview and new insights.

    Science.gov (United States)

    Pavei, Gaspare; Cazzola, Dario; La Torre, Antonio; Minetti, Alberto E

    2014-01-01

    This review aims to provide both researchers and coaches with a comprehensive overview of race walking biomechanics and to point out new viable route for future analyses. The examined literature has been divided into three categories according to the method of analysis: kinematics, ground reaction forces and joint power/efficiency. From an overall view, race walking athletes seem to adhere to the 'straightened knee' rule, but at race speed they do not observe the 'no-flight time' rule. The coach-oriented analysis highlights that stride length (SL) is more important than stride frequency (SF) for increasing speed and it is mainly obtained by ankle and hip joint power. Moreover, kinematic differences (SF, SL and flight time) between male and female athletes were shown. Also, we found that the maximal speed prediction according to dynamic similarity theory with walking (Froude number) is not applicable as the 3D trajectory of the body centre of mass does not follow an arc of circumference as in walking. The analysed literature shows some shortcomings: (1) the data collection is often unreliable because of the mixture of gender and performance level and (2) the analysis has sometimes been performed on a limited number of strides and speeds. These limitations lead to a scattered and incomplete gait description and a biased application of the results. The research strategy adopted so far is promising but further rigorous analyses need to be approached to obtain a fully comprehensive picture of race walking and to provide coaches with consistent results and reference values.

  20. Biomechanics of milk extraction during breast-feeding.

    Science.gov (United States)

    Elad, David; Kozlovsky, Pavel; Blum, Omry; Laine, Andrew F; Po, Ming Jack; Botzer, Eyal; Dollberg, Shaul; Zelicovich, Mabel; Ben Sira, Liat

    2014-04-08

    How do infants extract milk during breast-feeding? We have resolved a century-long scientific controversy, whether it is sucking of the milk by subatmospheric pressure or mouthing of the nipple-areola complex to induce a peristaltic-like extraction mechanism. Breast-feeding is a dynamic process, which requires coupling between periodic motions of the infant's jaws, undulation of the tongue, and the breast milk ejection reflex. The physical mechanisms executed by the infant have been intriguing topics. We used an objective and dynamic analysis of ultrasound (US) movie clips acquired during breast-feeding to explore the tongue dynamic characteristics. Then, we developed a new 3D biophysical model of the breast and lactiferous tubes that enables the mimicking of dynamic characteristics observed in US imaging during breast-feeding, and thereby, exploration of the biomechanical aspects of breast-feeding. We have shown, for the first time to our knowledge, that latch-on to draw the nipple-areola complex into the infant mouth, as well as milk extraction during breast-feeding, require development of time-varying subatmospheric pressures within the infant's oral cavity. Analysis of the US movies clearly demonstrated that tongue motility during breast-feeding was fairly periodic. The anterior tongue, which is wedged between the nipple-areola complex and the lower lips, moves as a rigid body with the cycling motion of the mandible, while the posterior section of the tongue undulates in a pattern similar to a propagating peristaltic wave, which is essential for swallowing.

  1. Deriving injury risk curves using survival analysis from biomechanical experiments.

    Science.gov (United States)

    Yoganandan, Narayan; Banerjee, Anjishnu; Hsu, Fang-Chi; Bass, Cameron R; Voo, Liming; Pintar, Frank A; Gayzik, F Scott

    2016-10-03

    Injury risk curves from biomechanical experimental data analysis are used in automotive studies to improve crashworthiness and advance occupant safety. Metrics such as acceleration and deflection coupled with outcomes such as fractures and anatomical disruptions from impact tests are used in simple binary regression models. As an improvement, the International Standards Organization suggested a different approach. It was based on survival analysis. While probability curves for side-impact-induced thorax and abdominal injuries and frontal impact-induced foot-ankle-leg injuries are developed using this approach, deficiencies are apparent. The objective of this study is to present an improved, robust and generalizable methodology in an attempt to resolve these issues. It includes: (a) statistical identification of the most appropriate independent variable (metric) from a pool of candidate metrics, measured and or derived during experimentation and analysis processes, based on the highest area under the receiver operator curve, (b) quantitative determination of the most optimal probability distribution based on the lowest Akaike information criterion, (c) supplementing the qualitative/visual inspection method for comparing the selected distribution with a non-parametric distribution with objective measures, (d) identification of overly influential observations using different methods, and (e) estimation of confidence intervals using techniques more appropriate to the underlying survival statistical model. These clear and quantified details can be easily implemented with commercial/open source packages. They can be used in retrospective analysis and prospective design of experiments, and in applications to different loading scenarios such as underbody blast events. The feasibility of the methodology is demonstrated using post mortem human subject experiments and 24 metrics associated with thoracic/abdominal injuries in side-impacts. Published by Elsevier Ltd.

  2. Biomechanics of Concussion: The Importance of Neck Tension

    Science.gov (United States)

    Jadischke, Ronald

    Linear and angular velocity and acceleration of the head are typically correlated to concussion. Despite improvements in helmet performance to reduce accelerations, a corresponding reduction in the incidence of concussion has not occurred (National Football League [NFL] 1996-present). There is compelling research that forces on and deformation to the brain stem are related to concussion. The brain stem is the center of control for respiration, blood pressure and heart rate and is the root of most cranial nerves. Injury to the brain stem is consistent with most symptoms of concussion reported in the National Football League and the National Hockey League, such as headaches, neck pain, dizziness, and blurred vision. In the Hybrid III anthropomorphic test device (ATD), the upper neck load cell is in close proximity to the human brain stem. This study found that the additional mass of a football helmet onto the Hybrid III headform increases the upper neck forces and moments in response to helmet-to-helmet impact and helmet-to-chest impacts. A new laboratory impactor device was constructed to simulate collisions using two moving Hybrid III ATDs. The impactor was used to recreate on-field collisions (n = 20) in American football while measuring head, neck and upper torso kinematics. A strong correlation between upper neck forces, upper neck power and the estimated strains and strain rates along the axis of the upper cervical spinal cord and brain stem and concussion was found. These biomechanical responses should be added to head kinematic responses for a more comprehensive evaluation of concussion.

  3. Biomechanical comparison of open and arthroscopic Latarjet procedures.

    Science.gov (United States)

    Schulze-Borges, Johanna; Agneskirchner, Jens D; Bobrowitsch, Evgenij; Patzer, Thilo; Struck, Melena; Smith, Tomas; Wellmann, Mathias

    2013-04-01

    To biomechanically compare the effectiveness of the standard open and arthroscopic techniques of the Latarjet procedure to address a critical anterior glenoid defect in combination with a capsular insufficiency. Translation testing of 12 human cadaveric shoulder specimens was performed in a robot-assisted setup under 3 different conditions: (1) intact/vented shoulder joint, (2) combined anterior glenoid bone and capsular defect, and (3) open and arthroscopic Latarjet procedures. Testing was performed for each condition in 2 test positions: 60° of glenohumeral abduction with neutral rotation (ABD position) and 60° of abduction and external rotation (ABER position). Each position was tested with a passive humerus load of 30 N in the anterior, inferior, and anteroinferior directions. Translational movement of the humeral head was evaluated with and without the application of a 10-N load to the conjoint tendon (CJT). In the ABD position, translations after the open Latarjet procedure significantly differed from the arthroscopic technique in the anterior and anteroinferior directions when testing was performed with loading of the CJTs (CJT loading). Without CJT loading, the open Latarjet technique showed significantly lower translations in the anterior, inferior (P = .004), and anteroinferior (P = .001) testing directions in the ABD position. In the ABER position, the arthroscopic procedure showed no significant difference compared with the standard open procedure. We found a superior stabilization effect of the open Latarjet technique in the ABD position. The difference is ascribed to the anterior capsular repair, which was performed within the open technique and omitted during the arthroscopic procedure. The reduction of translation in a pure abduction position of the arm is more effectively performed with a conventional open Latarjet technique that includes a capsular repair. In combined ABER position, there was no difference found between the open and

  4. N.A. Bernstein, the founder of modern biomechanics

    Directory of Open Access Journals (Sweden)

    Vazha M. Devishvili

    2015-12-01

    Full Text Available The paper deals with three major periods of scientific work of Nikolai Alexandrovich Bernstein, the outstanding Russian scientist, the founder the motor activity theory of human and animal. In 2016 is the 120th anniversary of Bernstein´s birth. The first period of his scientific activity, from 1922 when Bernstein started his research at the Central Institute of Labour Protection until the middle of the 30s of the 20th century. By this time, he formulated and published the basic principles and ideas of the annular motion control and sensor correction movements of varying complexity and various performance. The second period ends with the fundamental scientific work «On the Construction of Movements» awarded by the USSR State Prize in 1948. The book sums up Bernstein´s more than twenty years of research in the field of biomechanics and physiology of movement. The paper briefly describes the main assumptions of the three chapters of the book. The first chapter «Movements» reveals the evolutionary ideas about the origin of motor function and shaped the principle of the equation of building movements. The second chapter describes five levels with different functionality in varying degrees involved in the implementation of motor actions. The third chapter of the «Development and Decay» deals with the general laws of occurrence and levels of building movements being signs of confirming the level structure of motion in pathology and standards. In 1950-60-ies of the 20th century Bernstein greatly expanded representation of the functional content and neural substrate levels of building movements, detailed the stages and phases of shaping and improvement of motor skills. The author shows the importance of scientific achievements of N.A. Bernstein for modern research in the psychophysiology of movements.

  5. Identification of biomechanical properties in vivo in human uterine cervix.

    Science.gov (United States)

    Liao, Donghua; Hee, Lene; Sandager, Puk; Uldbjerg, Niels; Gregersen, Hans

    2014-11-01

    The course and outcome of pregnancy is closely correlated to change of biomechanical properties of the uterine cervix. The aim of this study was to build a non-linear, fiber reinforced mechanical model of the cervix for estimation of mechanical characteristics of the cervix in early- and term-pregnant women based on recordings of in vivo pressure and diameter by means of the Functional Luminal Imaging Probe (FLIP) technology. Five early- and six term-pregnant women were examined with a FLIP probe. The bag on the probe was inserted into the cervical canal for concomitant measurement of diameters at 16 serial locations along the canal and the bag pressure. The bag was inflated to a maximum volume of 50 ml. A three-fiber-families model including isotropic elastin-dominated matrix and anisotropic collagen was introduced to describe the mechanical behavior of the cervical canal. The unknown geometric and mechanical parameters were calculated on the basis of the mid-cervical diameters and the intraluminal pressures during the inflation. The wall thickness in the unloaded state (zero pressure applied) and mechanical properties of the matrix material (c) and collagens (c1, c2) were estimated with good fits of the calculated intraluminal pressures to the FLIP recordings during the cervical canal distension. No significant difference in the wall thickness was found between the early- and term-pregnant women (10.3 ± 0.8mm vs. 11.7 ± 2.2mm, p=0.30). The cervical matrix material and the collagen in the early-pregnant women were much stiffer than that in the term-pregnant women (pcervix wall were remodeled during pregnancy. The mechanical model can be applied to other tubular visceral organs where concomitant measures of pressure and diameter can be obtained for better understanding diseases and their evolution or treatment. Copyright © 2014 Elsevier Ltd. All rights reserved.

  6. Classification of deadlift biomechanics with wearable inertial measurement units.

    Science.gov (United States)

    O'Reilly, Martin A; Whelan, Darragh F; Ward, Tomas E; Delahunt, Eamonn; Caulfield, Brian M

    2017-06-14

    The deadlift is a compound full-body exercise that is fundamental in resistance training, rehabilitation programs and powerlifting competitions. Accurate quantification of deadlift biomechanics is important to reduce the risk of injury and ensure training and rehabilitation goals are achieved. This study sought to develop and evaluate deadlift exercise technique classification systems utilising Inertial Measurement Units (IMUs), recording at 51.2Hz, worn on the lumbar spine, both thighs and both shanks. It also sought to compare classification quality when these IMUs are worn in combination and in isolation. Two datasets of IMU deadlift data were collected. Eighty participants first completed deadlifts with acceptable technique and 5 distinct, deliberately induced deviations from acceptable form. Fifty-five members of this group also completed a fatiguing protocol (3-Repition Maximum test) to enable the collection of natural deadlift deviations. For both datasets, universal and personalised random-forests classifiers were developed and evaluated. Personalised classifiers outperformed universal classifiers in accuracy, sensitivity and specificity in the binary classification of acceptable or aberrant technique and in the multi-label classification of specific deadlift deviations. Whilst recent research has favoured universal classifiers due to the reduced overhead in setting them up for new system users, this work demonstrates that such techniques may not be appropriate for classifying deadlift technique due to the poor accuracy achieved. However, personalised classifiers perform very well in assessing deadlift technique, even when using data derived from a single lumbar-worn IMU to detect specific naturally occurring technique mistakes. Copyright © 2017 Elsevier Ltd. All rights reserved.

  7. Heterogeneous meshing and biomechanical modeling of human spine.

    Science.gov (United States)

    Teo, J C M; Chui, C K; Wang, Z L; Ong, S H; Yan, C H; Wang, S C; Wong, H K; Teoh, S H

    2007-03-01

    We aim to develop a patient-specific biomechanical model of human spine for the purpose of surgical training and planning. In this paper, we describe the development of a finite-element model of the spine from the VHD Male Data. The finite-element spine model comprises volumetric elements suitable for deformation and other finite-element analysis using ABAQUS. The mesh generation solution accepts segmented radiological slices as input, and outputs three-dimensional (3D) volumetric finite element meshes that are ABAQUS compliant. The proposed mesh generation method first uses a grid plane to divide the contours of the anatomical boundaries and its inclusions into discrete meshes. A grid frame is then built to connect the grid planes between any two adjacent planes using a novel scheme. The meshes produced consist of brick elements in the interior of the contours and with tetrahedral and wedge elements at the boundaries. The nodal points are classified according to their materials and hence, elements can be assigned different properties. The resultant spine model comprises a detailed model of the 7 cervical vertebrae, 12 thoracic vertebrae, 5 lumbar vertebrae, and S1. Each of the vertebrae and intervertebral disc has between 1200 and 6000 elements, and approximately 1200 elements, respectively. The accuracy of the resultant VHD finite element spine model was good based on visual comparison of volume-rendered images of the original CT data, and has been used in a computational analysis involving needle insertion and static deformation. We also compared the mesh generated using our method against two automatically generated models; one consists of purely tetrahedral elements and the other hexahedral elements.

  8. Biomechanical simulation of thorax deformation using finite element approach.

    Science.gov (United States)

    Zhang, Guangzhi; Chen, Xian; Ohgi, Junji; Miura, Toshiro; Nakamoto, Akira; Matsumura, Chikanori; Sugiura, Seiryo; Hisada, Toshiaki

    2016-02-06

    The biomechanical simulation of the human respiratory system is expected to be a useful tool for the diagnosis and treatment of respiratory diseases. Because the deformation of the thorax significantly influences airflow in the lungs, we focused on simulating the thorax deformation by introducing contraction of the intercostal muscles and diaphragm, which are the main muscles responsible for the thorax deformation during breathing. We constructed a finite element model of the thorax, including the rib cage, intercostal muscles, and diaphragm. To reproduce the muscle contractions, we introduced the Hill-type transversely isotropic hyperelastic continuum skeletal muscle model, which allows the intercostal muscles and diaphragm to contract along the direction of the fibres with clinically measurable muscle activation and active force-length relationship. The anatomical fibre orientations of the intercostal muscles and diaphragm were introduced. Thorax deformation consists of movements of the ribs and diaphragm. By activating muscles, we were able to reproduce the pump-handle and bucket-handle motions for the ribs and the clinically observed motion for the diaphragm. In order to confirm the effectiveness of this approach, we simulated the thorax deformation during normal quiet breathing and compared the results with four-dimensional computed tomography (4D-CT) images for verification. Thorax deformation can be simulated by modelling the respiratory muscles according to continuum mechanics and by introducing muscle contractions. The reproduction of representative motions of the ribs and diaphragm and the comparison of the thorax deformations during normal quiet breathing with 4D-CT images demonstrated the effectiveness of the proposed approach. This work may provide a platform for establishing a computational mechanics model of the human respiratory system.

  9. Research and Teaching: Assessing the Effect of Problem-Based Learning on Undergraduate Student Learning in Biomechanics

    Science.gov (United States)

    Mandeville, David; Stoner, Mark

    2015-01-01

    The aim of this study was to assess the effect of using the problem-based learning (PBL) teaching strategy on student academic achievement and secondary learning outcomes when compared with the traditional lecture (TL) for an undergraduate Biomechanics course. Successive undergraduate Biomechanics courses--a TL cohort and a PBL cohort--were…

  10. Assessing the Impact of Clothing and Individual Equipment (CIE) on Soldier Physical, Biomechanical, and Cognitive Performance Part 1: Test Methodology

    Science.gov (United States)

    2018-02-01

    March: Post-Dynamic Marksmanship End of Day Questionnaires Note: indicates cognitive tasks indicates biomechanical measures indicates physiological ...during ACSM’S resource manual for exercise testing and prescription Human Movement Science, 31(2), Proceedings of the 2016 American Biomechanics...Society Scandinavian Journal of Rehabilitation Medicine, 2, Human factors evaluation of a prototype load-carrying system Technical memorandum: CAN-LEAP

  11. A Novel Fixation System for Acetabular Quadrilateral Plate Fracture: A Comparative Biomechanical Study

    Directory of Open Access Journals (Sweden)

    Guo-Chun Zha

    2015-01-01

    Full Text Available This study aims to assess the biomechanical properties of a novel fixation system (named AFRIF and to compare it with other five different fixation techniques for quadrilateral plate fractures. This in vitro biomechanical experiment has shown that the multidirectional titanium fixation (MTF and pelvic brim long screws fixation (PBSF provided the strongest fixation for quadrilateral plate fracture; the better biomechanical performance of the AFRIF compared with the T-shaped plate fixation (TPF, L-shaped plate fixation (LPF, and H-shaped plate fixation (HPF; AFRIF gives reasonable stability of treatment for quadrilateral plate fracture and may offer a better solution for comminuted quadrilateral plate fractures or free floating medial wall fracture and be reliable in preventing protrusion of femoral head.

  12. Biomechanical analysis of double poling in elite cross-country skiers.

    Science.gov (United States)

    Holmberg, Hans-Christer; Lindinger, Stefan; Stöggl, Thomas; Eitzlmair, Erich; Müller, Erich

    2005-05-01

    To further the understanding of double poling (DP) through biomechanical analysis of upper and lower body movements during DP in cross-country (XC) skiing at racing speed. Eleven elite XC skiers performed DP at 85% of their maximal DP velocity (V85%) during roller skiing at 1 degrees inclination on a treadmill. Pole and plantar ground reaction forces, joint angles (elbow, hip, knee, and ankle), cycle characteristics, and electromyography (EMG) of upper and lower body muscles were analyzed. 1) Pole force pattern with initial impact force peak and the following active force peak (PPF) correlated to V85%, (r = 0.66, P biomechanical aspects. Future research should further investigate the relationship between biomechanical and physiological variables and elaborate training models to improve DP performance.

  13. [The use of open source software in graphic anatomic reconstructions and in biomechanic simulations].

    Science.gov (United States)

    Ciobanu, O

    2009-01-01

    The objective of this study was to obtain three-dimensional (3D) images and to perform biomechanical simulations starting from DICOM images obtained by computed tomography (CT). Open source software were used to prepare digitized 2D images of tissue sections and to create 3D reconstruction from the segmented structures. Finally, 3D images were used in open source software in order to perform biomechanic simulations. This study demonstrates the applicability and feasibility of open source software developed in our days for the 3D reconstruction and biomechanic simulation. The use of open source software may improve the efficiency of investments in imaging technologies and in CAD/CAM technologies for implants and prosthesis fabrication which need expensive specialized software.

  14. 3-d finite element model development for biomechanics: a software demonstration

    Energy Technology Data Exchange (ETDEWEB)

    Hollerbach, K.; Hollister, A.M.; Ashby, E.

    1997-03-01

    Finite element analysis is becoming an increasingly important part of biomechanics and orthopedic research, as computational resources become more powerful, and data handling algorithms become more sophisticated. Until recently, tools with sufficient power did not exist or were not accessible to adequately model complicated, three-dimensional, nonlinear biomechanical systems. In the past, finite element analyses in biomechanics have often been limited to two-dimensional approaches, linear analyses, or simulations of single tissue types. Today, we have the resources to model fully three-dimensional, nonlinear, multi-tissue, and even multi-joint systems. The authors will present the process of developing these kinds of finite element models, using human hand and knee examples, and will demonstrate their software tools.

  15. Conceptual framework on the application of biomechanical measurement methods in driving behavior study

    Science.gov (United States)

    Sanjaya, Kadek Heri; Sya'bana, Yukhi Mustaqim Kusuma

    2017-01-01

    Research on eco-friendly vehicle development in Indonesia has largely neglected ergonomic study, despite the fact that traffic accidents have resulted in greater economic cost than fuel subsidy. We have performed a biomechanical experiment on human locomotion earlier. In this article, we describe the importance of implementing the biomechanical measurement methods in transportation ergonomic study. The instruments such as electromyogram (EMG), load cell, pressure sensor, and motion analysis methods as well as cross-correlation function analysis were explained, then the possibility of their application in driving behavior study is described. We describe the potentials and challenges of the biomechanical methods concerning the future vehicle development. The methods provide greater advantages in objective and accurate measurement not only in human task performance but also its correlation with vehicle performance.

  16. Mandibular Angle Fractures: A Clinical and Biomechanical Comparison-the Works of Ellis and Haug.

    Science.gov (United States)

    Haug, Richard H; Serafin, Bethany L

    2008-11-01

    In a series of articles spanning 8 years, Ed Ellis reviewed the clinical results of the treatment of 478 mandibular angle fractures managed by eight different techniques. During a series of benchtop investigations employing polyurethane synthetic mandible replicas, Rich Haug investigated the biomechanical behavior of approximately 15 different techniques designed to reconstruct mandibular angle fractures. This article reviews these two series of investigations in an attempt to gain insight into the biomechanical and biological factors that affect the successful reconstruction of mandibular angle fractures. It appears that the current techniques used to reconstruct mandibular angle fractures are sound from the standpoint of biomechanics within a range of forces encountered during clinical function. It also appears that an unsuccessful reconstruction is based on a biological result of a behavioral issue such as noncompliance, substance abuse, and/or nutritional or immune compromise.

  17. Innovative approaches to cell biomechanics from cell migration to on-chip manipulation

    CERN Document Server

    Okeyo, Kennedy Omondi; Adachi, Taiji

    2015-01-01

    This book covers topics on mechanosensing, mechanotransduction, and actin cytoskeletal dynamics in cell motility. It will contribute to a better understanding of how cells functionally adapt to their mechanical environment as well as highlighting fundamental concepts for designing material niches for cell manipulation. With topics from multidisciplinary fields of the life sciences, medicine, and engineering, the book is the first of its kind, providing comprehensive, integrated coverage of innovative approaches to cell biomechanics. It provides a valuable resource for seniors and graduate students studying cell biomechanics, and is also suitable for researchers interested in the application of methods and strategies in connection with the innovative approaches discussed. Each section of the book has been supplemented with concrete examples and illustrations to facilitate understanding even for readers unfamiliar with cell biomechanics.

  18. Paralympic sport: an emerging area for research and consultancy in sports biomechanics.

    Science.gov (United States)

    Keogh, Justin W L

    2011-09-01

    The Paralympic Games are the pinnacle of sport for many athletes with a disability. The overall purpose of this paper is to highlight the role that the field of sports biomechanics specifically (and sports science in general) may play in improving performance in various summer Paralympic sports through research and consultancy. To achieve this broad aim, this review provides some history and background on the Summer Paralympic Games, discusses the eligibility and classification rules, describes the potential for the constraints-led approach of dynamical systems theory to inform practice and research in this area, and reviews selected studies examining the biomechanics of the primary forms of Paralympic locomotion. Some recommendations on how sports biomechanics can help facilitate improvements in Paralympic athletic performance through applied research and consultancy are provided, along with commentary on what may be some of the most important issues addressing Paralympic sport.

  19. Interactions of regenerative, inflammatory and biomechanical signals on bone morphogenetic protein-2 in periodontal ligament cells.

    Science.gov (United States)

    Nokhbehsaim, M; Deschner, B; Winter, J; Bourauel, C; Rath, B; Jäger, A; Jepsen, S; Deschner, J

    2011-06-01

    Regeneration of periodontal tissues by EMD remains a major challenge because a number of modifying factors are as yet unknown. The effects of EMD seem to be mediated, at least in part, by bone morphogenetic protein-2 (BMP-2). This in vitro study was performed to examine whether the effects of EMD on BMP-2 activity are modulated by inflammatory and/or biomechanical signals.   Periodontal ligament cells were seeded on BioFlex(®) plates and exposed to EMD under normal, inflammatory or biomechanical loading conditions for 1 and 6 d. In order to mimic proinflammatory or biomechanical loading conditions in vitro, cells were stimulated with interleukin-1β (IL-1β), which is increased at inflamed periodontal sites, and cyclic tensile strain of various magnitudes, respectively. The synthesis of BMP-2, its receptors (BMPR-1A, BMPR-1B and BMPR-2) and its inhibitors (follistatin, matrix gla protein and noggin) were analyzed using real-time RT-PCR and ELISA. In EMD-treated cells, BMP-2 synthesis was increased significantly at 1 d. EMD also induced the expression of all BMP receptors, and of the BMP inhibitors follistatin and noggin. In general, IL-1β and biomechanical loading neither down-regulated BMP-2 nor up-regulated BMP inhibitors in EMD-stimulated cells. However, IL-1β and biomechanical loading, when applied for a longer time period, caused a down-regulation of EMD-induced BMP receptors. EMD induces not only BMP-2, but also its receptors and inhibitors, in PDL cells. IL-1β and biomechanical forces may counteract the beneficial effects of EMD on BMP-2 activity via the down-regulation of BMP receptors. © 2011 John Wiley & Sons A/S.

  20. Consequences of biomechanically constrained tasks in the design and interpretation of synergy analyses.

    Science.gov (United States)

    Steele, Katherine M; Tresch, Matthew C; Perreault, Eric J

    2015-04-01

    Matrix factorization algorithms are commonly used to analyze muscle activity and provide insight into neuromuscular control. These algorithms identify low-dimensional subspaces, commonly referred to as synergies, which can describe variation in muscle activity during a task. Synergies are often interpreted as reflecting underlying neural control; however, it is unclear how these analyses are influenced by biomechanical and task constraints, which can also lead to low-dimensional patterns of muscle activation. The aim of this study was to evaluate whether commonly used algorithms and experimental methods can accurately identify synergy-based control strategies. This was accomplished by evaluating synergies from five common matrix factorization algorithms using muscle activations calculated from 1) a biomechanically constrained task using a musculoskeletal model and 2) without task constraints using random synergy activations. Algorithm performance was assessed by calculating the similarity between estimated synergies and those imposed during the simulations; similarities ranged from 0 (random chance) to 1 (perfect similarity). Although some of the algorithms could accurately estimate specified synergies without biomechanical or task constraints (similarity >0.7), with these constraints the similarity of estimated synergies decreased significantly (0.3-0.4). The ability of these algorithms to accurately identify synergies was negatively impacted by correlation of synergy activations, which are increased when substantial biomechanical or task constraints are present. Increased variability in synergy activations, which can be captured using robust experimental paradigms that include natural variability in motor activation patterns, improved identification accuracy but did not completely overcome effects of biomechanical and task constraints. These results demonstrate that a biomechanically constrained task can reduce the accuracy of estimated synergies and highlight

  1. Surgical fixation of midshaft clavicle fractures: A systematic review of biomechanical studies.

    Science.gov (United States)

    Hulsmans, Martijn H; van Heijl, Mark; Houwert, Roderick M; Burger, Bart J; Verleisdonk, Egbert Jan M; Veeger, Dirk Jan; van der Meijden, Olivier A

    2018-02-21

    Surgical treatment of displaced midshaft clavicle fractures requires a decision between plate fixation and intramedullary (IM) fixation. Numerous studies report on the biomechanical properties of various repair constructs. The goal of this systematic review was to provide an overview of studies describing the biomechanical properties of the most commonly used surgical fixations of midshaft clavicle fractures. Additionally, we aimed to translate these biomechanical results into clinically relevant conclusions. A computer-aided search of the EMBASE and PudMed/MEDLINE databases was conducted. Studies included for review compared biomechanical properties of plate fixation with IM fixation and superiorly positioned plates with anteroinferiorly positioned plates for midshaft clavicle fractures. Fifteen studies were eligible for inclusion. Plate fixation seemed to form a more robust construct than IM fixation in terms of stiffness and failure loading. The remaining clavicle was stronger after removal of the IM device than after removal of the plate. Superior plating of transverse fractures generally seemed to provide greater stiffness and strength during bending loads than anteroinferior plating did. The absence of cortical alignment in wedge and comminuted fractures directly influenced the fixation stability for both IM fixation and plate fixation, regardless of location. Each type of fracture fixation has biomechanical advantages and disadvantages. However, exact thresholds of stiffness for inducing healing and failure strength to withstand refractures are unknown. The clinical relevance of the biomechanical studies may be arguable. Since none of the studies investigate the effect of tissue adaptation over time they should be interpreted with caution. Copyright © 2018 Elsevier Ltd. All rights reserved.

  2. A method to investigate the biomechanical alterations in Perthes’ disease by hip joint contact modeling

    DEFF Research Database (Denmark)

    Salmingo, Remel A.; Skytte, Tina Lercke; Traberg, Marie Sand

    2017-01-01

    Perthes’ disease is a destructive hip joint disorder characterized by malformation of the femoral head in young children. While the morphological changes have been widely studied, the biomechanical effects of these changes still need to be further elucidated. The objective of this study was to de...... is required to test the strength of the proposed method as a pre-surgery planning tool....... for the preoperative planning to obtain stress relief for the highly stressed areas in the malformed hip. This single-patient study demonstrated that the biomechanical alterations in Perthes’ disease can be evaluated individually by patient-specific finite element contact modeling using MRI. A multi-patient study...

  3. Sport-specific biomechanics of spinal injuries in aesthetic athletes (dancers, gymnasts, and figure skaters).

    Science.gov (United States)

    d'Hemecourt, Pierre A; Luke, Anthony

    2012-07-01

    Young aesthetic athletes require special understanding of the athletic biomechanical demands peculiar to each sport. The performance of these activities may impart specific biomechanical stresses and subsequent injury patterns. The clinician must understand these aspects as well as the spinal changes that occur with growth when many of these injuries often occur. Further, athletes, parents, coaches, and healthcare providers must be sensitive to the overall aspects of the athlete, including nutrition, overtraining, adequate recovery, proper technique, and limiting repetition of difficult maneuvers to minimize injuries.

  4. Modeling the links between young swimmers' performance: energetic and biomechanic profiles.

    Science.gov (United States)

    Barbosa, Tiago M; Costa, Mário; Marinho, Daniel A; Coelho, Joel; Moreira, Marc; Silva, António J

    2010-08-01

    The aim was to develop a path-flow analysis model for young swimmers' performance based on biomechanical and energetic parameters, using structural equation modeling. Thirty-eight male young swimmers served as subjects. Performance was assessed by the 200-m freestyle event. For biomechanical assessment the stroke length, the stroke frequency and the swimming velocity were analyzed. Energetics assessment included the critical velocity, the stroke index and the propulsive efficiency. The confirmatory model explained 79% of swimming performance after deleting the stroke index-performance path, which was nonsignificant (SRMR = 0.06). As a conclusion, the model is appropriate to explain performance in young swimmers.

  5. Fluid-structure interaction-based biomechanical perception model for tactile sensing.

    Directory of Open Access Journals (Sweden)

    Zheng Wang

    Full Text Available The reproduced tactile sensation of haptic interfaces usually selectively reproduces a certain object attribute, such as the object's material reflected by vibration and its surface shape by a pneumatic nozzle array. Tactile biomechanics investigates the relation between responses to an external load stimulus and tactile perception and guides the design of haptic interface devices via a tactile mechanism. Focusing on the pneumatic haptic interface, we established a fluid-structure interaction-based biomechanical model of responses to static and dynamic loads and conducted numerical simulation and experiments. This model provides a theoretical basis for designing haptic interfaces and reproducing tactile textures.

  6. The influence of Meyerhold's biomechanics on 20th century theatre: The principle of equivalence

    OpenAIRE

    Prpa-Fink Marijana

    2015-01-01

    Meyerhold's biomechanics (Mejerhol'd Ë. V.), as an acting technique in preparation for a role and performance in front of the audience, originated in the 1920s. It represents a genuine way of work, as it derived from Meyerhold's authentic personality. The need to research the importance and influence of Meyerhold's biomechanics on the 20th century theatre stems from the importance of the opus that Vsevolod Emilevich Meyerhold produced, as well as from the assumption that the output of the 20t...

  7. Computational biomechanics for medicine fundamental science and patient-specific applications

    CERN Document Server

    Miller, Karol; Wittek, Adam; Nielsen, Poul

    2014-01-01

    One of the greatest challenges facing the computational engineering community is to extend the success of computational mechanics to fields outside traditional engineering, in particular to biology, the biomedical sciences, and medicine. The Computational Biomechanics for Medicine titles provide an opportunity for specialists in computational biomechanics to present their latest methodologies and advancements. This latest installment comprises nine of the latest developments in both fundamental science and patient-specific applications, from researchers in Australia, New Zealand, USA, UK, France, Ireland, and China. Some of the interesting topics discussed are: cellular mechanics; tumor growth and modeling; medical image analysis; and both patient-specific fluid dynamics and solid mechanics simulations.

  8. Quantitative Assessment of Dance Therapy Infulence on the Parkinson’s Disease Patients’ Lower Limb Biomechanics

    Directory of Open Access Journals (Sweden)

    Donatas Lukšys

    2017-01-01

    Full Text Available Parkinson’s disease – progressive neurologic disorder that damages a variety of motor function and reduces the quality of life. Patients with PD are subject to various physical therapy exercises, but recently is applied more often the dance – music therapy. This study aims assessing the therapeutic effect of the modified Lindy Hop dance therapy on lower extremity biomechanics. The experimental study was performed using inertial sensors that registered lower extremity biomechanical parameters during gait. Several spatio-temporal parameters of lower limb were calculated and were found statistically significant between groups, which allows quantifying the influence of dance therapy.

  9. Anatomy and Biomechanics of the Finger Proximal Interphalangeal Joint.

    Science.gov (United States)

    Pang, Eric Quan; Yao, Jeffrey

    2018-05-01

    A complete understanding of the normal anatomy and biomechanics of the proximal interphalangeal joint is critical when treating pathology of the joint as well as in the design of new reconstructive treatments. The osseous anatomy dictates the principles of motion at the proximal interphalangeal joint. Subsequently, the joint is stabilized throughout its motion by the surrounding proximal collateral ligament, accessory collateral ligament, and volar plate. The goal of this article is to review the normal anatomy and biomechanics of the proximal interphalangeal joint and its associated structures, most importantly the proper collateral ligament, accessory collateral ligament, and volar plate. Copyright © 2017 Elsevier Inc. All rights reserved.

  10. Biomechanical Effects of Bonding Pericervical Dentin in Maxillary Premolars.

    Science.gov (United States)

    Huynh, Nghia; Li, Fang-Chi; Friedman, Shimon; Kishen, Anil

    2018-02-16

    Pericervical dentin (PCD) loss may increase root fracture propensity in root-filled teeth. This study evaluated the impacts of bonding PCD with composite resin (CR) on radicular microstrain distribution and load at failure of root-filled maxillary premolars. Ten single-canal maxillary premolars decoronated 2 mm coronal to the cementoenamel junction (CEJ) had canals enlarged with ProTaper Universal instruments (Dentsply Tulsa Dental Specialties, Tulsa, OK) to F3. They were root filled with gutta-percha (GP) to the CEJ and restored with Cavit (3M Deutschland GmbH, Neuss, Germany) (GP group, n = 5) or 6 mm apical to the CEJ and restored with bonded CR to simulate bonding of PCD (bonded PCD group, n = 5). Digital moiré interferometry was used to evaluate pre- and postoperative whole-field microstrain distribution in the root dentin under physiologically relevant loads (10-50 N). Another 30 premolars, similarly treated as groups 1 and 2 or left untreated as controls (n = 10/group), were subjected to cyclic loads (1.2 million cycles, 45 N, 4 Hz) followed by uniaxial compressive load to failure. Mechanical data were analyzed with 1-way analysis of variance and the post hoc Tukey test at a 5% level of significance. Microstrain distribution showed bending and compressive patterns at the coronal and apical root dentin, respectively. In the GP group, microstrain distribution was unaltered. In the bonded-PCD group, different microstrain distribution suggested stiffening at the PCD. The load at failure did not differ significantly for the GP, bonded PCD, and control groups (P > .05). CR bonding of PCD might impact the biomechanical responses in maxillary premolar roots at low-level continuous loads. The effect of this impact on root fracture loads when subjected to cyclic load warrants further investigation. Copyright © 2018 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

  11. Biomechanical Analysis of the Swim-Start: A Review

    Directory of Open Access Journals (Sweden)

    Julien Vantorre, Didier Chollet, Ludovic Seifert

    2014-06-01

    Full Text Available This review updates the swim-start state of the art from a biomechanical standpoint. We review the contribution of the swim-start to overall swimming performance, the effects of various swim-start strategies, and skill effects across the range of swim-start strategies identified in the literature. The main objective is to determine the techniques to focus on in swimming training in the contemporary context of the sport. The phases leading to key temporal events of the swim-start, like water entry, require adaptations to the swimmer’s chosen technique over the course of a performance; we thus define the swim-start as the moment when preparation for take-off begins to the moment when the swimming pattern begins. A secondary objective is to determine the role of adaptive variability as it emerges during the swim-start. Variability is contextualized as having a functional role and operating across multiple levels of analysis: inter-subject (expert versus non-expert, inter-trial or intra-subject (through repetitions of the same movement, and inter-preference (preferred versus non-preferred technique. Regarding skill effects, we assume that swim-start expertise is distinct from swim stroke expertise. Highly skilled swim-starts are distinguished in terms of several factors: reaction time from the start signal to the impulse on the block, including the control and regulation of foot force and foot orientation during take-off; appropriate amount of glide time before leg kicking commences; effective transition from leg kicking to break-out of full swimming with arm stroking; overall maximal leg and arm propulsion and minimal water resistance; and minimized energy expenditure through streamlined body position. Swimmers who are less expert at the swim-start spend more time in this phase and would benefit from training designed to reduce: (i the time between reaction to the start signal and impulse on the block, and (ii the time in transition (i

  12. Setscrew distal locking for intramedullary nails: a biomechanical study.

    Science.gov (United States)

    Köse, N; Günal, I; Wang, X; Athanasiou, K A; Agrawal, C M; Mabrey, J D

    2000-08-01

    This biomechanical study was undertaken to examine the effectiveness of setscrew distal locking in a static intramedullary (IM) femoral nail on the stability of fixation of femoral shaft fractures. Fifteen fresh-frozen cadeveric femora were randomly separated into three groups of five bones and transversely sectioned immediately distal to the isthmus. After the insertion of the large-diameter nails, distal locking was obtained by conventional method in the first group. In the second group, set-screw design was used in which two transverse screws penetrated only the lateral cortex of the femur and compressed the nail in the intramedullary canal. No distal locking was used in the third group. All instrumented femurs were mounted on a servohydraulic testing machine and tested in both rotations (20 degrees) and axial compression (amplitude: 1,000 Newton). Loading-versus-displacement data, acquired at a ten-Hertz sampling rate, were calibrated and used to calculate maximum torque, stiffness, and energy capacity to failure. Maximum displacement and axial stiffness also were determined. Mean maximum torque at 10 degrees for each group were 15.3+/-4.8 newton-meters for the interlocking group, 8.5 +/-1.2 newton-meters for the setscrew group, and 3.6+/-2.7 newton-meters for the nonlocked femora. At 20 degrees of rotational displacement, the torque measured 37.4+/-2.6 newton-meters; 15.0+/-4.0 newton-meters; and 5.3+/-3.1 newton-meters, respectively (p 0.05). The setscrew design provided 87 percent of the torsional rigidity of the interlocking group. In the axial compression test, mean maximum shortening was 1.1+/-0.3 millimeters in the interlocking group and 1.4+/-0.6 millimeters in the setscrew group (p > 0.05). The mean stiffness on longitudinal compression provided by the interlocking screws and the setscrews was 918 and 860 newton-meters per millimeter, respectively. The distal setscrew design provides adequate distal fixation of intramedullary nail for patients in the

  13. Biomechanics of the classic metaphyseal lesion: finite element analysis

    Energy Technology Data Exchange (ETDEWEB)

    Tsai, Andy; Kleinman, Paul K. [Boston Children' s Hospital, Department of Radiology, Harvard Medical School, Boston, MA (United States); Coats, Brittany [University of Utah, Department of Mechanical Engineering, Salt Lake City, UT (United States)

    2017-11-15

    The classic metaphyseal lesion (CML) is strongly associated with infant abuse, but the biomechanics responsible for this injury have not been rigorously studied. Radiologic and CT-pathological correlates show that the distal tibial CML always involves the cortex near the subperiosteal bone collar, with variable extension of the fracture into the medullary cavity. Therefore, it is reasonable to assume that the primary site of bone failure is cortical, rather than intramedullary. This study focuses on the strain patterns generated from finite element modeling to identify loading scenarios and regions of the cortex that are susceptible to bone failure. A geometric model was constructed from a normal 3-month-old infant's distal tibia and fibula. The model's boundary conditions were set to mimic forceful manipulation of the ankle with eight load modalities (tension, compression, internal rotation, external rotation, dorsiflexion, plantar flexion, valgus bending and varus bending). For all modalities except internal and external rotation, simulations showed increased cortical strains near the subperiosteal bone collar. Tension generated the largest magnitude of cortical strain (24%) that was uniformly distributed near the subperiosteal bone collar. Compression generated the same distribution of strain but to a lesser magnitude overall (15%). Dorsiflexion and plantar flexion generated high (22%) and moderate (14%) localized cortical strains, respectively, near the subperiosteal bone collar. Lower cortical strains resulted from valgus bending, varus bending, internal rotation and external rotation (8-10%). The highest valgus and varus bending cortical strains occurred medially. These simulations suggest that the likelihood of the initial cortical bone failure of the CML is higher along the margin of the subperiosteal bone collar when the ankle is under tension, compression, valgus bending, varus bending, dorsiflexion and plantar flexion, but not under internal

  14. Failure modes and materials design for biomechanical layer structures

    Science.gov (United States)

    Deng, Yan

    Ceramic materials are finding increasing usage in the area of biomechanical replacements---dental crowns, hip and bone implants, etc.---where strength, wear resistance, biocompatibility, chemical durability and even aesthetics are critical issues. Aesthetic ceramic crowns have been widely used in dentistry to replace damaged or missing teeth. However, the failure rates of ceramic crowns, especially all-ceramic crowns, can be 1%˜6% per year, which is not satisfactory to patients. The materials limitations and underlying fracture mechanisms of these prostheses are not well understood. In this thesis, fundamental fracture and damage mechanisms in model dental bilayer and trilayer structures are studied. Principle failure modes are identified from in situ experimentation and confirmed by fracture mechanics analysis. In bilayer structures of ceramic/polycarbonate (representative of ceramic crown/dentin structure), three major damage sources are identified: (i) top-surface cone cracks or (ii) quasiplasticity, dominating in thick ceramic bilayers; (iii) bottom-surface radial cracks, dominating in thin ceramic bilayers. Critical load P for each damage mode are measured in six dental ceramics: Y-TZP zirconia, glass-infiltrated zirconia and alumina (InCeram), glass-ceramic (Empress II), Porcelain (Mark II and Empress) bonded to polymer substrates, as a function of ceramic thickness d in the range of 100 mum to 10 mm. P is found independent of d for mode (i) and (ii), but has a d 2 relations for mode (iii)---bottom surface radial cracking. In trilayer structures of glass/core-ceramic/polycarbonate (representing veneer porcelain/core/dentin structures), three inner fracture origins are identified: radial cracks from the bottom surface in the (i) first and (ii) second layers; and (iii) quasiplasticity in core-ceramic layer. The role of relative veneer/core thickness, d1/d 2 and materials properties is investigated for three core materials with different modulus (114--270GPa

  15. Anatomical and biomechanical investigations of the iliotibial tract.

    Science.gov (United States)

    Birnbaum, K; Siebert, C H; Pandorf, T; Schopphoff, E; Prescher, A; Niethard, F U

    2004-12-01

    Divergent descriptions of the anatomic location and biomechanical function of the iliotibial tract (IT) can be found in the literature. This study attempted to obtain exact data regarding the anatomic course and material characteristics including the biomechanical properties of this structure. The following were its aims: (1) anatomical investigations of the IT; (2) mechanical properties of the IT; (3) femoral head centralizing force of the IT and subligamentous forces in the height of the greater trochanter in different joint positions by using a custom-made measuring prosthesis and a subligamentous positioned sensor; (4) construction of a finite element model of the proximal femur including the IT and measuring the femoral neck angle under variation. The hip joints and IT in a total of 18 unfixed corpses were evaluated. We studied the anatomic relationship to surrounding structures, as well as the material properties with the help of tensile strength testing utilizing an uniaxial apparatus. During the test, a load-displacement curve was registered, documenting the maximum load and deformation of the IT. To measure the subligamentous pressure at the height of the greater trochanter, a custom-made sensor with a power-recording instrument was constructed. Furthermore, an altered hip prosthesis with a pressure gauge at the height of the femoral neck was used to measure the forces which are directed at the acetabulum. The investigations were done in neutral-0 position and ab/adduction of the hip joint of the unfixed corpse. In addition, we varied the femoral neck angle between 115 degrees and 155 degrees in 5 degrees steps. To confirm the subligamentous forces, we did the same measurements intraoperatively at the height of the greater trochanter before and after hip joint replacement in 12 patients. We constructed a finite element model of the proximal femur and considering the IT. The acquisition of the data was done at physiological (128 degrees), varus (115 degrees

  16. Biomechanical analysis of reducing sacroiliac joint shear load by optimization of pelvic muscle and ligament forces

    NARCIS (Netherlands)

    J.J.M. Pel (Johan); C.W. Spoor (Cornelis); A.L. Pool-Goudzwaard (Annelies); G.A. Hoek van Dijke; C.J. Snijders (Chris)

    2008-01-01

    textabstractEffective stabilization of the sacroiliac joints (SIJ) is essential, since spinal loading is transferred via the SIJ to the coxal bones, and further to the legs. We performed a biomechanical analysis of SIJ stability in terms of reduced SIJ shear force in standing posture using a

  17. Insufficient lumbopelvic stability: a clinical, anatomical and biomechanics approach to low back pain

    NARCIS (Netherlands)

    Pool-Goudzwaard, A.L.; Vleeming, A; Stoeckart, R.; Snijders, C.; Mens, Jan M A

    1998-01-01

    A clinical, anatomical and biomechanical model is introduced based on the concept that under postural load specific ligament and muscle forces are necessary to intrinsically stabilize the pelvis. Since load transfer from spine to pelvis passes through the sacroiliac (SI) joints, effective

  18. Regulatory effects of inflammatory and biomechanical signals on regenerative periodontal healing.

    Science.gov (United States)

    Deschner, James; Nokhbehsaim, Marjan

    2013-01-01

    Periodontitis is a chronic inflammatory disease associated with loss of periodontal attachment, collagen, and alveolar bone. Regeneration of periodontal tissues can be supported by the local application of enamel matrix derivative (EMD). However, periodontal regeneration remains a major and often unpredictable challenge as the result of a number of unknown factors. The authors' in vitro studies revealed that EMD stimulated the wound fill rate, proliferation, and adhesion of periodontal ligament (PDL) cells. However, in the presence of an inflammatory environment or biomechanical loading, the beneficial effects of EMD decreased significantly. EMD also stimulated the synthesis of growth factors and collagen, as well as calcium deposition, in PDL cell cultures. These beneficial effects of EMD on PDL cells were also significantly diminished by inflammation and biomechanical forces, respectively. The findings suggest that critical PDL cell functions pertinent to periodontal regeneration are reduced in an inflammatory environment and under biomechanical loading. Therefore, effective anti-infectious and anti-inflammatory periodontal treatment before the application of EMD may be critical to ensure the full regenerative capacity of the PDL tissue. Furthermore, occlusal loading of EMD-treated teeth, at least immediately following surgery, should be minimized to obtain optimal regenerative healing results. A better understanding of the interactions of growth factors and biomechanical signals will result in more powerful regenerative therapeutic strategies.

  19. A biomechanical model for the analysis of the cervical spine in static postures

    NARCIS (Netherlands)

    C.J. Snijders (Chris); G.A. Hoek van Dijke; E.R. Roosch (E.)

    1991-01-01

    textabstractTo gain a better understanding of the forces working on the cervical spine, a spatial biomechanical computer model was developed. The first part of our research was concerned with the development of a kinematic model to establish the axes of rotation and the mutual position of the head

  20. Biomechanical approaches to identify and quantify injury mechanisms and risk factors in women's artistic gymnastics.

    Science.gov (United States)

    Bradshaw, Elizabeth J; Hume, Patria A

    2012-09-01

    Targeted injury prevention strategies, based on biomechanical analyses, have the potential to help reduce the incidence and severity of gymnastics injuries. This review outlines the potential benefits of biomechanics research to contribute to injury prevention strategies for women's artistic gymnastics by identification of mechanisms of injury and quantification of the effects of injury risk factors. One hundred and twenty-three articles were retained for review after searching electronic databases using key words, including 'gymnastic', 'biomech*', and 'inj*', and delimiting by language and relevance to the paper aim. Impact load can be measured biomechanically by the use of instrumented equipment (e.g. beatboard), instrumentation on the gymnast (accelerometers), or by landings on force plates. We need further information on injury mechanisms and risk factors in gymnastics and practical methods of monitoring training loads. We have not yet shown, beyond a theoretical approach, how biomechanical analysis of gymnastics can help reduce injury risk through injury prevention interventions. Given the high magnitude of impact load, both acute and accumulative, coaches should monitor impact loads per training session, taking into consideration training quality and quantity such as the control of rotation and the height from which the landings are executed.

  1. Biomechanical comparison of rotational activities between anterior cruciate ligament- and posterior cruciate ligament-reconstructed patients.

    Science.gov (United States)

    Lim, Bee Oh; Shin, Han Sol; Lee, Yong Seuk

    2015-04-01

    The purpose of this study was to compare the early functional recovery using biomechanical properties between anterior cruciate ligament (ACL)- and posterior cruciate ligament (PCL)-reconstructed patients and to determine the biomechanical deficit of PCL-reconstructed patients compared to ACL-reconstructed patients. A motion analysis system was used to measure and calculate kinematic and kinetic data for 10 patients who underwent PCL-reconstructed patients [experimental group (group 1)], 10 ACL-reconstructed patients (group 2), and 10 healthy subjects (group 3) during 45°, 90°, 135°, and 180° cutting and turn running tasks. Groups 1 and 2 were assessed at 3 (return to daily activity) and 6 months (return to light sports) postoperatively. At 3 months postoperatively, compared to groups 2 and 3, group 1 showed a decrease in knee flexion angle, extension moment, valgus moment, external rotational moment, ground reaction force, and increased hamstring-quadriceps ratio. At 6 months postoperatively, results from group 1 resembled those of groups 2 and 3 over time. Patients who underwent PCL reconstruction showed some biomechanical deficits in performance of activities requiring rotation, compared to those who underwent ACL reconstruction. Therefore, the modification of a rehabilitation programme for patients who underwent PCL reconstruction would be necessary for improvement of the biomechanical properties during performance of dynamic activities. Case-control study, Level III.

  2. Biomechanical comparison of lumbar spine with or without spina bifida occulta. A finite element analysis.

    Science.gov (United States)

    Sairyo, K; Goel, V K; Vadapalli, S; Vishnubhotla, S L; Biyani, A; Ebraheim, N; Terai, T; Sakai, T

    2006-07-01

    Biomechanical study using finite element model (FEM) of lumbar spine. Very high coincidence of spina bifida occulta (SBO) has been reported more than in 60% of lumbar spondylolysis. The altered biomechanics due to SBO is one considerable factor for this coincidence. Thus, in this study, the biomechanical changes in the lumbar spine due to the presence of SBO were evaluated. United States of America (USA). An experimentally validated three-dimensional nonlinear FEM of the intact ligamentous L3-S1 segment was used and modified to simulate two kinds of SBO at L5. One model had SBO with no change in the length of the spinous process and the other had a small dysplastic spinous process. Von Mises stresses at pars interarticularis were analyzed in the six degrees of lumbar motion with 400 N axial compression, which simulates the standing position. The range of motion at L4/5 and L5/S1 were also calculated. It was observed that the stresses in all the models were similar, and there was no change in the highest stress value when compared to the intact model. The range of motion was also similar in all the models. The lumbar kinematics of SBO was thus shown to be similar to the intact model. SBO does not alter lumbar biomechanics with respect to stress and range of motion. The high coincidence of spondylolysis in spines with SBO may not be due to the mechanical factors.

  3. A knee-mounted biomechanical energy harvester with enhanced efficiency and safety

    Science.gov (United States)

    Chen, Chao; Chau, Li Yin; Liao, Wei-Hsin

    2017-06-01

    Energy harvesting is becoming a major limiting issue for many portable devices. When undertaking any activity, the human body generates a significant amount of biomechanical energy, which can be collected by means of a portable energy harvester. This energy provides a method of powering portable devices such as prosthetic limbs. In this paper, a knee-mounted energy harvester with enhanced efficiency and safety is proposed and developed to convert mechanical energy into electricity during human motion. This device can change the bi-directional knee input into uni-directional rotation for an electromagnetic generator using a specially designed transmission system. Without the constraint of induced impact on the human body, this device can harvest biomechanical energy from both knee flexion and extension, improving the harvesting efficiency over previous single-direction energy harvesters. It can also provide protection from device malfunction, and increase the safety of current biomechanical energy harvesters. A highly compact and light prototype is developed taking into account human kinematics. The biomechanical energy harvesting system is also modeled and analyzed. The prototype is tested under different conditions including walking, running and climbing stairs, to evaluate the energy harvesting performance and effect on the human gait. The experimental results show that the prototype can harvest an average power of 3.6 W at 1.5 m s-1 walking speed, which is promising for portable electronic devices.

  4. Stability of the unlinked Latitude total elbow prosthesis: A biomechanical in vitro analysis.

    NARCIS (Netherlands)

    Wagener, M.L.; Vos, M.J. de; Hendriks, J.C.M.; Eygendaal, D.; Verdonschot, N.J.J.

    2013-01-01

    BACKGROUND: The purpose of this study is to assess the valgus and varus laxity of the unlinked version of the Latitude total elbow prosthesis and the effects of radial head preservation or replacement. METHODS: Biomechanical analysis of the valgus and varus laxity of the unlinked Latitude was

  5. Stability of the unlinked Latitude total elbow prosthesis: A biomechanical in vitro analysis

    NARCIS (Netherlands)

    Wagener, Marc L.; de Vos, Maarten J.; Hendriks, Jan C.M.; Eygendaal, Denise; Verdonschot, Nicolaas Jacobus Joseph

    2013-01-01

    Background The purpose of this study is to assess the valgus and varus laxity of the unlinked version of the Latitude total elbow prosthesis and the effects of radial head preservation or replacement. Methods Biomechanical analysis of the valgus and varus laxity of the unlinked Latitude was

  6. Comparsion of biomechanical modeling of register transitions and voice instabilities with excised larynx experiments

    Czech Academy of Sciences Publication Activity Database

    Tokuda, I.; Horáček, Jaromír; Švec, J.; Herzel, H.

    2007-01-01

    Roč. 122, č. 1 (2007), s. 519-531 ISSN 0001-4966 R&D Projects: GA AV ČR IAA2076401 Institutional research plan: CEZ:AV0Z20760514 Keywords : biomechanics of voice * self-oscillations * numerical simulations Subject RIV: BI - Acoustics Impact factor: 1.587, year: 2007

  7. Biomechanical pulping with Phlebiopsis gigantea reduced energy consumption and increased paper strength : [summary

    Science.gov (United States)

    Chad J. Behrendt; Robert A. Blanchette; Masood. Akhtar; Scott. Enebak; Sara. Iverson; Diane. Williams

    2000-01-01

    Biomechanical pulping of whole logs pretreated with Phlebiopsis gigantea was investigated in several studies using loblolly and red pine. Results from these studies showed P. gigantea was able to colonize 90 to 100% of the freshly cut logs after 8 weeks, with little variation between replicate treatments. Up to a 59% decrease in resinous wood extractives was observed...

  8. Selected Sports Bras: A Biomechanical Analysis of Breast Motion While Jogging.

    Science.gov (United States)

    Lorentzen, Deana; Lawson, LaJean

    1987-01-01

    Eight sports bras were compared and evaluated to determine the amount of biomechanical support they provide for small-, medium-, and large-breasted women (N=59) while jogging. Findings showed that the Exercise Sports Top and the Lady Duke bras allowed the least amount of breast movement. (Author/CB)

  9. Variability of Structural and Biomechanical Parameters of Pelophylax Esculentus (Amphibia, Anura Limb Bones

    Directory of Open Access Journals (Sweden)

    Broshko Ye. O.

    2014-07-01

    Full Text Available Variability of Structural and Biomechanical Prameters of Pelophylax esculentus (Amphibia, Anura Limb Bones. Broshko Ye. O. — Structural and biomechanical parameters of Edible Frog, Pelophylax esculentus (Linnaeus, 1758, limb bones, namely, mass, linear dimensions, parameters of the shaft’s cross-sectional shape (cross-sectional area, moments of inertia, radiuses of inertia were investigated. Some coefficients were also estimated: diameters ratio (df/ds, cross-sectional index (ik, principal moments of inertia ratio (Imax/Imin.. Coefficients of variation of linear dimensions (11.9-20.0 % anrelative bone mass (22-35 % were established. Moments of inertia of various bones are more variable (CV = 41.67-56.35 % in relation to radii of inertia (CV = 9.68-14.67 %. Shaft’s cross-sectional shape is invariable in all cases. However, there is high individual variability of structural and biomechanical parameters of P. esculentus limb bones. Variability of parameters was limited by the certain range. We suggest the presence of stable norm in bone structure. Stylopodium bones have the primary biomechanical function among the elements of limb skeleton, because their parameters most clearly responsive to changes in body mass.

  10. Drop jumping. I. The influence of jumping technique on the biomechanics of jumping

    NARCIS (Netherlands)

    Bobbert, M F; Huijing, P A; van Ingen Schenau, G J

    In the literature, drop jumping is advocated as an effective exercise for athletes who prepare themselves for explosive activities. When executing drop jumps, different jumping techniques can be used. In this study, the influence of jumping technique on the biomechanics of jumping is investigated.

  11. The Challenge of Change for Physical Education in the 1980's: A Biomechanical Viewpoint.

    Science.gov (United States)

    Hay, James G.

    The shifting emphasis in the field of physical education from exercise physiology to motor learning to biomechanics over the past several decades presents a challenge for shaping the future of physical education. The primary challenges involve matching the supply of graduates to the demand for their services, developing a sound philosophy relative…

  12. Biomechanical and Psychological Analysis of High School, Intercollegiate, and Elite Long-Distance Runners

    Science.gov (United States)

    Solorio, Claribel; Hickey, Ann

    2015-01-01

    It is undeniable that efficiency and mentality are crucial to achieving optimal athletic performance during competition. However, development of psychological skills is often neglected, particularly in lower levels of competition. The purpose of this study was to analyze and compare the biomechanical efficiency and psychological skills use among…

  13. Physiological, biochemical, anthropometric, and biomechanical influences on exercise economy in humans.

    Science.gov (United States)

    Lundby, C; Montero, D; Gehrig, S; Andersson Hall, U; Kaiser, P; Boushel, R; Meinild Lundby, A-K; Kirk, N; Valdivieso, P; Flück, M; Secher, N H; Edin, F; Hein, T; Madsen, K

    2017-12-01

    Interindividual variation in running and cycling exercise economy (EE) remains unexplained although studied for more than a century. This study is the first to comprehensively evaluate the importance of biochemical, structural, physiological, anthropometric, and biomechanical influences on running and cycling EE within a single study. In 22 healthy males (VO 2 max range 45.5-72.1 mL·min -1 ·kg -1 ), no factor related to skeletal muscle structure (% slow-twitch fiber content, number of capillaries per fiber), mitochondrial properties (volume density, oxidative capacity, or mitochondrial efficiency), or protein content (UCP3 and MFN2 expression) explained variation in cycling and running EE among subjects. In contrast, biomechanical variables related to vertical displacement correlated well with running EE, but were not significant when taking body weight into account. Thus, running EE and body weight were correlated (R 2 =.94; Pbiomechanical determinants of running EE, we contrasted individual running and cycling EE considering that during cycle ergometer exercise, the biomechanical influence on EE would be small because of the fixed movement pattern. Differences in cycling and running exercise protocols, for example, related to biomechanics, play however only a secondary role in determining EE. There was no evidence for an impact of structural or functional skeletal muscle variables on EE. Body weight was the main determinant of EE explaining 94% of variance in running EE, although more than 50% of the variability of cycling EE remains unexplained. © 2017 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  14. Biomechanics in the Postsecondary Population: Are We Taking Our Best Shot?

    Science.gov (United States)

    Strohmeyer, H. Scott

    2005-01-01

    The program description for the All-Academy Symposium in Chicago contained the phrase, "Traditionally, NASPE has focused on promoting physical activity for K-12 students." While this may be an appropriate reflection of many of the academies, biomechanics research is abundantly filled with data representing postsecondary young adults, and…

  15. First Reported Cases of Biomechanically Adaptive Bone Modeling in Non-Avian Dinosaurs.

    Science.gov (United States)

    Cubo, Jorge; Woodward, Holly; Wolff, Ewan; Horner, John R

    2015-01-01

    Predator confrontation or predator evasion frequently produces bone fractures in potential prey in the wild. Although there are reports of healed bone injuries and pathologies in non-avian dinosaurs, no previously published instances of biomechanically adaptive bone modeling exist. Two tibiae from an ontogenetic sample of fifty specimens of the herbivorous dinosaur Maiasaura peeblesorum (Ornithopoda: Hadrosaurinae) exhibit exostoses. We show that these outgrowths are cases of biomechanically adaptive periosteal bone modeling resulting from overstrain on the tibia after a fibula fracture. Histological and biomechanical results are congruent with predictions derived from this hypothesis. Histologically, the outgrowths are constituted by radial fibrolamellar periosteal bone tissue formed at very high growth rates, as expected in a process of rapid strain equilibration response. These outgrowths show greater compactness at the periphery, where tensile and compressive biomechanical constraints are higher. Moreover, these outgrowths increase the maximum bending strength in the direction of the stresses derived from locomotion. They are located on the antero-lateral side of the tibia, as expected in a presumably bipedal one year old individual, and in the posterior position of the tibia, as expected in a presumably quadrupedal individual at least four years of age. These results reinforce myological evidence suggesting that Maiasaura underwent an ontogenetic shift from the primitive ornithischian bipedal condition when young to a derived quadrupedal posture when older.

  16. First Reported Cases of Biomechanically Adaptive Bone Modeling in Non-Avian Dinosaurs.

    Directory of Open Access Journals (Sweden)

    Jorge Cubo

    Full Text Available Predator confrontation or predator evasion frequently produces bone fractures in potential prey in the wild. Although there are reports of healed bone injuries and pathologies in non-avian dinosaurs, no previously published instances of biomechanically adaptive bone modeling exist. Two tibiae from an ontogenetic sample of fifty specimens of the herbivorous dinosaur Maiasaura peeblesorum (Ornithopoda: Hadrosaurinae exhibit exostoses. We show that these outgrowths are cases of biomechanically adaptive periosteal bone modeling resulting from overstrain on the tibia after a fibula fracture. Histological and biomechanical results are congruent with predictions derived from this hypothesis. Histologically, the outgrowths are constituted by radial fibrolamellar periosteal bone tissue formed at very high growth rates, as expected in a process of rapid strain equilibration response. These outgrowths show greater compactness at the periphery, where tensile and compressive biomechanical constraints are higher. Moreover, these outgrowths increase the maximum bending strength in the direction of the stresses derived from locomotion. They are located on the antero-lateral side of the tibia, as expected in a presumably bipedal one year old individual, and in the posterior position of the tibia, as expected in a presumably quadrupedal individual at least four years of age. These results reinforce myological evidence suggesting that Maiasaura underwent an ontogenetic shift from the primitive ornithischian bipedal condition when young to a derived quadrupedal posture when older.

  17. The influence of Meyerhold's biomechanics on 20th century theatre: The principle of equivalence

    Directory of Open Access Journals (Sweden)

    Prpa-Fink Marijana

    2015-01-01

    Full Text Available Meyerhold's biomechanics (Mejerhol'd Ë. V., as an acting technique in preparation for a role and performance in front of the audience, originated in the 1920s. It represents a genuine way of work, as it derived from Meyerhold's authentic personality. The need to research the importance and influence of Meyerhold's biomechanics on the 20th century theatre stems from the importance of the opus that Vsevolod Emilevich Meyerhold produced, as well as from the assumption that the output of the 20th century directors Jerzy Grotowski, Eugenio Barba and Peter Brook was largely founded on the principles of biomechanics, which Meyerhold had based his work on with theatrical actors for years. The principle of equivalence is one of the principles in the book A Dictionary of Theatre Anthropology: The Secret Art of the Performer by Eugenio Barba and Nicola Savarese. It provides help with the interpretation of the influence that Meyerhold's biomechanics had on the 20th century theatre and the authors such as Grotowski, Barba and Brook.

  18. Biomechanical, psychosocial and individual risk factors predicting low back functional impairment among furniture distribution employees.

    Science.gov (United States)

    Ferguson, Sue A; Allread, W Gary; Burr, Deborah L; Heaney, Catherine; Marras, William S

    2012-02-01

    Biomechanical, psychosocial and individual risk factors for low back disorder have been studied extensively however few researchers have examined all three risk factors. The objective of this was to develop a low back disorder risk model in furniture distribution workers using biomechanical, psychosocial and individual risk factors. This was a prospective study with a six month follow-up time. There were 454 subjects at 9 furniture distribution facilities enrolled in the study. Biomechanical exposure was evaluated using the American Conference of Governmental Industrial Hygienists (2001) lifting threshold limit values for low back injury risk. Psychosocial and individual risk factors were evaluated via questionnaires. Low back health functional status was measured using the lumbar motion monitor. Low back disorder cases were defined as a loss of low back functional performance of -0.14 or more. There were 92 cases of meaningful loss in low back functional performance and 185 non cases. A multivariate logistic regression model included baseline functional performance probability, facility, perceived workload, intermediated reach distance number of exertions above threshold limit values, job tenure manual material handling, and age combined to provide a model sensitivity of 68.5% and specificity of 71.9%. The results of this study indicate which biomechanical, individual and psychosocial risk factors are important as well as how much of each risk factor is too much resulting in increased risk of low back disorder among furniture distribution workers. Copyright © 2011 Elsevier Ltd. All rights reserved.

  19. Calcium requirements of growing rats based on bone mass, structure, or biomechanical strength are similar

    Science.gov (United States)

    Although calcium (Ca) supplementation increases bone density, the increase is small and the impact on bone strength and fracture risk is uncertain. To investigate if bone mass, morphology, and biomechanical properties are affected by deficient to copious dietary Ca concentrations, the long bones (ti...

  20. The Relationship between Running Economy and Biomechanical Variables in Distance Runners

    Science.gov (United States)

    Tartaruga, Marcus Peikriszwili; Brisswalter, Jeanick; Peyre-Tartaruga, Leonardo Alexandre; Avila, Aluisio Otavio Vargas; Alberton, Cristine Lima; Coertjens, Marcelo; Cadore, Eduardo Lusa; Tiggemann, Carlos Leandro; Silva, Eduardo Marczwski; Kruel, Luiz Fernando Martins

    2012-01-01

    In this study, we analyzed the relationship between running economy (RE) and biomechanical parameters in a group running at the same relative intensity and same absolute velocity. Sixteen homogeneous male long-distance runners performed a test to determine RE at 4.4 m.s[superscript -1], corresponding to 11.1% below velocity at the ventilatory…

  1. Quantitative methods for reconstructing tissue biomechanical properties in optical coherence elastography: a comparison study

    Science.gov (United States)

    Han, Zhaolong; Li, Jiasong; Singh, Manmohan; Wu, Chen; Liu, Chih-hao; Wang, Shang; Idugboe, Rita; Raghunathan, Raksha; Sudheendran, Narendran; Aglyamov, Salavat R.; Twa, Michael D.; Larin, Kirill V.

    2015-01-01

    We present a systematic analysis of the accuracy of five different methods for extracting the biomechanical properties of soft samples using optical coherence elastography (OCE). OCE is an emerging noninvasive technique, which allows assessing biomechanical properties of tissues with a micrometer spatial resolution. However, in order to accurately extract biomechanical properties from OCE measurements, application of proper mechanical model is required. In this study, we utilize tissue-mimicking phantoms with controlled elastic properties and investigate the feasibilities of four available methods for reconstructing elasticity (Young’s modulus) based on OCE measurements of an air-pulse induced elastic wave. The approaches are based on the shear wave equation (SWE), the surface wave equation (SuWE), Rayleigh-Lamb frequency equation (RLFE), and finite element method (FEM), Elasticity values were compared with uniaxial mechanical testing. The results show that the RLFE and the FEM are more robust in quantitatively assessing elasticity than the other simplified models. This study provides a foundation and reference for reconstructing the biomechanical properties of tissues from OCE data, which is important for the further development of noninvasive elastography methods. PMID:25860076

  2. Biomechanics of the elbow joint in tennis players and relation to pathology

    NARCIS (Netherlands)

    Eygendaal, Denise; Rahussen, F. T. G.; Diercks, R. L.

    2007-01-01

    Elbow injuries constitute a sizeable percentage of tennis injuries. A basic understanding of biomechanics of tennis and analysis of the forces, loads and motions of the elbow during tennis will improve the understanding of the pathophysiology of these injuries. All different strokes in tennis have a

  3. Keys to an open lock : Subject specific biomechanical modelling of luxations of the human temporomandibular joint

    NARCIS (Netherlands)

    Tuijt, M.

    2017-01-01

    In this thesis, the aims are to: • increase the understanding of the interplay of morphological aspects, such as joint shape and muscle orientation, in open locks of the human temporomandibular joint. • increase the understanding of the biomechanics behind open locks of the temporomandibular joint.

  4. MRI-based biomechanical parameters for carotid artery plaque vulnerability assessment

    NARCIS (Netherlands)

    Speelman, Lambert; Teng, Zhongzhao; Nederveen, Aart J.; van der Lugt, Aad; Gillard, Jonathan H.

    2016-01-01

    Carotid atherosclerotic plaques are a major cause of ischaemic stroke. The biomechanical environment to which the arterial wall and plaque is subjected to plays an important role in the initiation, progression and rupture of carotid plaques. MRI is frequently used to characterize the morphology of a

  5. Polarity effect of microcurrent electrical stimulation on tendon healing: Biomechanical and histopathological studies

    Directory of Open Access Journals (Sweden)

    Amal F. Ahmed

    2012-04-01

    Full Text Available The purpose of the current study was to investigate the effect of microcurrent electrical stimulation (MES applied with different polarity on the biomechanical properties of injured tendons and to correlate results with histopathological studies. Ninety six male white New Zealand rabbits were used in the study. Six rabbits were kept as normal group with intact tendons and the remaining 90 rabbits with their right Achilles tendons tenotomized, sutured and immobilized. After that rabbits were allocated into equal three groups; cathodal, anodal and control. Each group was further subdivided into three subgroups according to the study period; 3, 5 and 8 weeks. There were significant increases of all biomechanical measurements for cathodal and anodal groups than those of control group at all study periods. Furthermore there were significant increases of all biomechanical measurements in the cathodal group more than the anodal group at the 3 week period, while there was significant increase of the anodal group more than the cathodal at 5 and 8 week periods. The histopathological findings supported the biomechanical results. Tendons in cathode group showed better healing picture compared to those of anodal group at third week. While tendons in the anodal group showed better improvement at the 5 and 8 week. MES improved the healing process of tendon and the polarity of MES could be an important factor to be considered in treating tendon injuries.

  6. Biomechanical characterization of an osteoporotic artificial bone model for the distal femur.

    Science.gov (United States)

    Wähnert, Dirk; Hoffmeier, Konrad L; Klos, Kajetan; Stolarczyk, Yves; Fröber, Rosemarie; Hofmann, Gunther O; Mückley, Thomas

    2012-01-01

    The treatment of osteoporotic distal femur fractures is still an unsolved problem of trauma surgery. The poor bone stock often leads to secondary loss of reduction and implant failure. Therefore, the development of new implants and their biomechanical testing is essential. In a previous study, we developed and initially characterized an artificial osteoporotic bone model of the distal femur. This follow-up study was performed to characterize this model in a biomechanical comparison. We investigated two different artificial bones: five foam cortical shell (Sawbones) and 10 custom-made artificial femoral condyles. Additionally, eight human femora were used for comparison. For biomechanical testing, two intramedullary nails (distal femur nail (DFN) and supracondylar nail (SCN)) were cyclically axial loaded in an AO 33 C2 unstable distal femoral fracture model. In our testing, the artificial bone showed a decrease in the axial stiffness of 27% for the SCN and 28% for the DFN compared to the human results. Also the number of cycles for a deformation of 2.5 mm was reduced by 55% (SCN) and 62% (DFN). This decrease was homogenous and caused by the relative high bone mineral density of the human specimen used. The modes of failure showed no difference between the artificial and human bones. Our customized artificial bone provides suitable results. In relation to the human bones classified as mildly osteoporotic, we assume that the biomechanical properties match to serve as an osteoporotic bone. Yet, we suggest to check transferability of the results with human material.

  7. Biomechanical Strain Exacerbates Inflammation on a Progeria-on-a-Chip Model

    NARCIS (Netherlands)

    Ribas, J.; Zhang, Y.S.; Pitrez, P.R.; Leijten, Jeroen Christianus Hermanus; Miscuglio, M.; Rouwkema, Jeroen; Dokmeci, M.R.; Nissan, X.; Ferreira, L.; Khademhosseini, A.

    2017-01-01

    A progeria-on-a-chip model is engineered to recapitulate the biomechanical dynamics of vascular disease and aging. The model shows an exacerbated injury response to strain and is rescued by pharmacological treatments. The progeria-on-a-chip is expected to drive the discovery of new drugs and to

  8. The Growth Form of Croton pullei (Euphorbiaceae) - Functional Morphology and Biomechanics of a Neotropical Liana

    NARCIS (Netherlands)

    Gallenmüller, F.; Müller, U.; Rowe, N.; Speck, T.

    2001-01-01

    Croton pullei (Euphorbiaceae) is a woody climber of the lowland rainforest in French Guyana and Surinam. During ontogeny, a shift from a juvenile free-standing growth phase to an older supported growth phase is observed. The following biomechanical parameters were studied: structural Young's

  9. MR morphology of triangular fibrocartilage complex: correlation with quantitative MR and biomechanical properties

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Won C.; Chang, Eric Y.; Chung, Christine B. [VA San Diego Healthcare System, Radiology Service, San Diego, CA (United States); University of California-San Diego, Department of Radiology, San Diego, CA (United States); Ruangchaijatuporn, Thumanoon [Mahidol University, Department of Diagnostic and Therapeutic Radiology, Faculty of Medicine Ramathibodi Hospital, Rachathewi, Bangkok (Thailand); Biswas, Reni; Du, Jiang; Statum, Sheronda [University of California-San Diego, Department of Radiology, San Diego, CA (United States)

    2016-04-15

    To evaluate pathology of the triangular fibrocartilage complex (TFCC) using high-resolution morphologic magnetic resonance (MR) imaging, and compare with quantitative MR and biomechanical properties. Five cadaveric wrists (22-70 years) were imaged at 3 T using morphologic (proton density weighted spin echo, PD FS, and 3D spoiled gradient echo, 3D SPGR) and quantitative MR sequences to determine T2 and T1rho properties. In eight geographic regions, morphology of TFC disc and laminae were evaluated for pathology and quantitative MR values. Samples were disarticulated and biomechanical indentation testing was performed on the distal surface of the TFC disc. On morphologic PD SE images, TFC disc pathology included degeneration and tears, while that of the laminae included degeneration, degeneration with superimposed tear, mucinous transformation, and globular calcification. Punctate calcifications were highly visible on 3D SPGR images and found only in pathologic regions. Disc pathology occurred more frequently in proximal regions of the disc than distal regions. Quantitative MR values were lowest in normal samples, and generally higher in pathologic regions. Biomechanical testing demonstrated an inverse relationship, with indentation modulus being high in normal regions with low MR values. The laminae studied were mostly pathologic, and additional normal samples are needed to discern quantitative changes. These results show technical feasibility of morphologic MR, quantitative MR, and biomechanical techniques to characterize pathology of the TFCC. Quantitative MRI may be a suitable surrogate marker of soft tissue mechanical properties, and a useful adjunct to conventional morphologic MR techniques. (orig.)

  10. Influence of different sizes of composite femora on the biomechanical behavior of cementless hip prosthesis.

    Science.gov (United States)

    Schmidutz, Florian; Woiczinski, Mathias; Kistler, Manuel; Schröder, Christian; Jansson, Volkmar; Fottner, Andreas

    2017-01-01

    For the biomechanical evaluation of cementless stems different sizes of composite femurs have been used in the literature. However, the impact of different specimen sizes on test results is unknown. To determine the potential effect of femur size the biomechanical properties of a conventional stem (CLS Spotorno) were examined in 3 different sizes (small, medium and large composite Sawbones®). Primary stability was tested under physiologically adapted dynamic loading conditions measuring 3-dimensional micromotions. For the small composite femur the dynamic load needed to be adapted since fractures occurred when reaching 1700N. Additionally, surface strain distribution was recorded before and after implantation to draw conclusions about the tendency for stress shielding. All tested sizes revealed similar micromotions only reaching a significant different level at one measurement point. The highest micromotions were observed at the tip of the stems exceeding the limit for osseous integration of 150μm. Regarding strain distribution the highest strain reduction after implantation was registered in all sizes at the level of the lesser trochanter. Specimen size seems to be a minor influence factor for biomechanical evaluation of cementless stems. However, the small composite femur is less suitable for biomechanical testing since this size failed under physiological adapted loads. For the CLS Spotorno osseous integration is unlikely at the tip of the stem and the tendency for stress shielding is the highest at the level of the lesser trochanter. Copyright © 2016 Elsevier Ltd. All rights reserved.

  11. Biomechanical and nonfunctional assessment of physical capacity in male ICU survivors

    DEFF Research Database (Denmark)

    Poulsen, Jesper Brøndum; Rose, Martin Høyer; Jensen, Bente Rona

    2013-01-01

    : ICU admission is associated with decreased physical function for years after discharge. The underlying mechanisms responsible for this muscle function impairment are undescribed. The aim of this study was to describe the biomechanical properties of the quadriceps muscle in ICU survivors 12 mont...

  12. Tensile strength comparison between peroneus longus and hamstring tendons: A biomechanical study

    Directory of Open Access Journals (Sweden)

    Rudy

    2017-01-01

    Conclusion: The tensile strength of the peroneus longus tendon, which is similar to that of hamstring, gives information that both have the same biomechanic properties. Peroneus longus should not be used as a first option in ACL reconstruction, but may be used as an alternative donor in cases involving multiple instability that require more tendon donors in the reconstruction.

  13. Prospective Study of the Relation between Landing Biomechanics and Jumper's Knee

    NARCIS (Netherlands)

    der Worp, H van; van der Does, H T D; Brink, M.S.; Zwerver, J.; Hijmans, J.M.

    The literature on the relation between jump biomechanics and jumper's knee indicates that a jump with horizontal displacement poses a threat for developing jumper's knee. Subjects with jumper's knee have been shown to display a stiff landing pattern characterized by a small range of motion. However,

  14. Hip protectors: recommendations for biomechanical testing-an international consensus statement (part I)

    DEFF Research Database (Denmark)

    Robinovitch, S.N.; Evans, S.L.; Minns, J.

    2009-01-01

    Hip protectors represent a promising strategy for preventing fall-related hip fractures. However, clinical trials have yielded conflicting results due, in part, to lack of agreement on techniques for measuring and optimizing the biomechanical performance of hip protectors as a prerequisite to cli...

  15. Stability of the elbow joint: relevant anatomy and clinical implications of in vitro biomechanical studies

    NARCIS (Netherlands)

    de Haan, J.; Schep, N. W. L.; Eygendaal, D.; Kleinrensink, G.-J.; Tuinebreijer, W. E.; den Hartog, D.

    2011-01-01

    The aim of this literature review is to describe the clinical anatomy of the elbow joint based on information from in vitro biomechanical studies. The clinical consequences of this literature review are described and recommendations are given for the treatment of elbow joint dislocation.The PubMed

  16. Biomechanical and morphological remodelings of gastrointestinal tract in STZ-induced diabetic rats

    DEFF Research Database (Denmark)

    Sha, Hong; Zhao, Jingbo; Liu, Gui-Fang

    2012-01-01

    AIM: The aim of the study was to investigate the biomechanical and morphometrical remodeling of gastrointestinal (GI) tract in streptozotocin (STZ) induced diabetic rats. METERIALS AND METHODS: Eighteen SD male rats of diabetic group(DM, a single tail vein injection 40mg/kg of STZ, 9 rats) and no...

  17. Fixation Methods for Calcaneus Fractures: A Systematic Review of Biomechanical Studies Using Cadaver Specimens

    NARCIS (Netherlands)

    Dingemans, Siem A.; Sintenie, Floris W.; de Jong, Vincent M.; Luitse, Jan S. K.; Schepers, Tim

    2018-01-01

    Calcaneal fractures are notoriously difficult to treat and wound complications occur often. However, owing to the rare nature of these fractures, clinical trials on this subject are lacking. Thus, biomechanical studies form a viable source of information on this subject. With our systematic review

  18. The effect of an inclined landing surface on biomechanical variables during a jumping task.

    Science.gov (United States)

    Hagins, Marshall; Pappas, Evangelos; Kremenic, Ian; Orishimo, Karl F; Rundle, Andrew

    2007-11-01

    Professional dancers sustain a high number of injuries. Epidemiological studies have suggested that performing on inclined "raked" stages increases the likelihood of injury. However, no studies have examined if biomechanical differences exist between inclined and flat surfaces during functional tasks, such as landing from a jump. Such differences may provide a biomechanical rationale for differences in injury risk for raked stages. Eight professional dancers performed drop jumps from a 40cm platform on flat and inclined surfaces while forces, lower extremity kinematics, and electromyographic activity were collected in a controlled laboratory environment. Dancers landed on the laterally inclined surface with significantly higher knee valgus (4 degrees ), peak knee flexion (9 degrees ), and medial-lateral ground reaction force (GRF) (13.4% body weight) compared to the flat condition. The posterior GRF was higher in the anterior inclined condition compared to the flat condition. In the anterior inclined condition, subjects landed with 1.4 degrees higher knee valgus, 4 degrees more plantarflexion at initial contact, and 3 degrees less dorsiflexion at the end of landing. Biomechanical variables that have been suggested to contribute to injury in previous studies are increased in the inclined floor conditions. These findings provide a preliminary biomechanical rationale for differences in injury rates found in observational studies of raked stages.

  19. The application of finite element analysis in the skull biomechanics and dentistry.

    Science.gov (United States)

    Prado, Felippe Bevilacqua; Rossi, Ana Cláudia; Freire, Alexandre Rodrigues; Ferreira Caria, Paulo Henrique

    2014-01-01

    Empirical concepts describe the direction of the masticatory stress dissipation in the skull. The scientific evidence of the trajectories and the magnitude of stress dissipation can help in the diagnosis of the masticatory alterations and the planning of oral rehabilitation in the different areas of Dentistry. The Finite Element Analysis (FEA) is a tool that may reproduce complex structures with irregular geometries of natural and artificial tissues of the human body because it uses mathematical functions that enable the understanding of the craniofacial biomechanics. The aim of this study was to review the literature on the advantages and limitations of FEA in the skull biomechanics and Dentistry study. The keywords of the selected original research articles were: Finite element analysis, biomechanics, skull, Dentistry, teeth, and implant. The literature review was performed in the databases, PUBMED, MEDLINE and SCOPUS. The selected books and articles were between the years 1928 and 2010. The FEA is an assessment tool whose application in different areas of the Dentistry has gradually increased over the past 10 years, but its application in the analysis of the skull biomechanics is scarce. The main advantages of the FEA are the realistic mode of approach and the possibility of results being based on analysis of only one model. On the other hand, the main limitation of the FEA studies is the lack of anatomical details in the modeling phase of the craniofacial structures and the lack of information about the material properties.

  20. Animal Galloping and Human Hopping: An Energetics and Biomechanics Laboratory Exercise

    Science.gov (United States)

    Lindstedt, Stan L.; Mineo, Patrick M.; Schaeffer, Paul J.

    2013-01-01

    This laboratory exercise demonstrates fundamental principles of mammalian locomotion. It provides opportunities to interrogate aspects of locomotion from biomechanics to energetics to body size scaling. It has the added benefit of having results with robust signal to noise so that students will have success even if not "meticulous" in…

  1. Stoop or squat: a review of biomechanical studies on lifting technique

    NARCIS (Netherlands)

    van Dieen, J.H.; Hoozemans, J.J.M.; Toussaint, H.M.

    1999-01-01

    Objective. To assess the biomechanical evidence in support of advocating the squat lifting technique as an administrative control to prevent low back pain. Background. Instruction with respect to lifting technique is commonly employed to prevent low back pain. The squat technique is the most widely

  2. Stoop or squat : a review of biomechanical studies on lifting technique

    NARCIS (Netherlands)

    van Dieën, J H; Hoozemans, M J; Toussaint, H M

    1999-01-01

    OBJECTIVE: To assess the biomechanical evidence in support of advocating the squat lifting technique as an administrative control to prevent low back pain. BACKGROUND: Instruction with respect to lifting technique is commonly employed to prevent low back pain. The squat technique is the most widely

  3. A biomechanical evaluation of locked plating for distal fibula fractures in an osteoporotic sawbone model.

    Science.gov (United States)

    Bariteau, Jason T; Fantry, Amanda; Blankenhorn, Brad; Lareau, Craig; Paller, David; Digiovanni, Christopher W

    2014-03-01

    Supination external rotation (SER) injuries are commonly fixed with a one third tubular neutralization plate. This study investigated if a combination locked plate with additional fixation options was biomechanically superior in osteoporotic bone and comminuted fracture models. Using an osteoporotic and a comminuted Sawbones model, SER injuries were fixed with a lag screw for simple oblique fibula fractures, and either a one third tubular neutralization plate or a locking plate. Samples were tested in stiffness, peak torque, displacement at failure, and torsion fatigue. There was no statistically significant difference in biomechanical testing for fractures treated with a lag screw and plate. For comminuted fractures, locked plating demonstrated statistically significant stiffer fixation. A combination locked plate is biomechanically superior to a standard one third tubular plate in comminuted SER ankle fractures. There was no biomechanical superiority between locked and one third tubular plates when the fracture was amenable to a lag screw. Copyright © 2013 European Foot and Ankle Society. Published by Elsevier Ltd. All rights reserved.

  4. Predictors of the Biomechanical Effects of Customized Foot Orthoses in Adults With Flat-Arched Feet.

    Science.gov (United States)

    Arnold, John B; May, Thomas; Bishop, Christopher

    2017-07-21

    To determine the potential presence and characteristics of biomechanical responders to customized foot orthoses during walking in adults with flat-arched feet. Experimental, repeated-measures. University clinic and laboratory. Eighteen symptom-free adults with flat-arched feet. Customized foot orthoses. In-shoe foot biomechanics were measured during walking with and without customized foot orthoses using 3D analysis. Selected kinematic and kinetic variables during baseline walking were compared between subgroups who displayed reductions in calcaneal eversion with foot orthoses to those with no change or increases. Biomechanical responders displayed significantly greater peak calcaneal eversion (+2.2 degrees, P = 0.009). Time to peak calcaneal eversion (-11%, P = 0.006), peak dorsiflexion of the hallux (-6 degrees, P = 0.001), and medial-lateral excursion of the center of pressure during loading response were all reduced in the responder subgroup (-2 mm, P ≤ 0.001). Variables significantly different between subgroups were moderately associated with the response to foot orthoses (canonical correlation = 0.687, effect size = 0.47, P = 0.063). Individuals with increased dynamic foot pronation were more likely to show a favorable biomechanical response to customized foot orthoses, providing preliminary evidence to support the stratified use of foot orthoses to optimize their effectiveness.

  5. Spinal biomechanical properties are significantly altered with a novel embalming method

    NARCIS (Netherlands)

    Holewijn, Roderick M.; Faraj, Sayf S.A.; Kingma, Idsart; van Royen, Barend J.; de Kleuver, Marinus; van der Veen, Albert J.

    2017-01-01

    In vitro tests on the biomechanical properties of human spines are often performed using fresh frozen specimens. However, this carries the risk of pathogen transfer from specimen to the worker and the specimens can only be used for a limited amount of time. Human spinal specimens embalmed with

  6. Spinal biomechanical properties are significantly altered with a novel embalming method.

    NARCIS (Netherlands)

    Holewijn, R.M.; Faraj, S.S.; Kingma, I.; Royen, B.J. van; Kleuver, M. de; Veen, A.J. van der

    2017-01-01

    In vitro tests on the biomechanical properties of human spines are often performed using fresh frozen specimens. However, this carries the risk of pathogen transfer from specimen to the worker and the specimens can only be used for a limited amount of time. Human spinal specimens embalmed with

  7. Computer tomography and calculation of bone biomechanics in cross-sections of long bones

    Czech Academy of Sciences Publication Activity Database

    Sailer, R.; Sládek, Vladimír; Berner, M.; Estl, M.

    Supplement 36, - (2003), s. 182 ISSN 0002-9483. [Annual meeting of the American Association of Physical Anthropologists /72./. 23.04.2003-26.04.2003, Tempe] Institutional research plan: CEZ:AV0Z6093917 Keywords : computer tomography * biomechanical analysis Subject RIV: AC - Archeology, Anthropology , Ethnology

  8. Comparison of the biomechanical tensile and compressive properties of decellularised and natural porcine meniscus.

    Science.gov (United States)

    Abdelgaied, A; Stanley, M; Galfe, M; Berry, H; Ingham, E; Fisher, J

    2015-06-01

    Meniscal repair is widely used as a treatment for meniscus injury. However, where meniscal damage has progressed such that repair is not possible, approaches for partial meniscus replacement are now being developed which have the potential to restore the functional role of the meniscus, in stabilising the knee joint, absorbing and distributing stress during loading, and prevent early degenerative joint disease. One attractive potential solution to the current lack of meniscal replacements is the use of decellularised natural biological scaffolds, derived from xenogeneic tissues, which are produced by treating the native tissue to remove the immunogenic cells. The current study investigated the effect of decellularisation on the biomechanical tensile and compressive (indentation and unconfined) properties of the porcine medial meniscus through an experimental-computational approach. The results showed that decellularised medial porcine meniscus maintained the tensile biomechanical properties of the native meniscus, but had lower tensile initial elastic modulus. In compression, decellularised medial porcine meniscus generally showed lower elastic modulus and higher permeability compared to that of the native meniscus. These changes in the biomechanical properties, which ranged from less than 1% to 40%, may be due to the reduction of glycosaminoglycans (GAG) content during the decellularisation process. The predicted biomechanical properties for the decellularised medial porcine meniscus were within the reported range for the human meniscus, making it an appropriate biological scaffold for consideration as a partial meniscus replacement. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

  9. Combining muscle synergies and biomechanical analysis to assess gait in stroke patients.

    Science.gov (United States)

    Barroso, Filipe O; Torricelli, Diego; Molina-Rueda, Francisco; Alguacil-Diego, Isabel M; Cano-de-la-Cuerda, Roberto; Santos, Cristina; Moreno, Juan C; Miangolarra-Page, Juan C; Pons, José L

    2017-10-03

    The understanding of biomechanical deficits and impaired neural control of gait after stroke is crucial to prescribe effective customized treatments aimed at improving walking function. Instrumented gait analysis has been increasingly integrated into the clinical practice to enhance precision and inter-rater reliability for the assessment of pathological gait. On the other hand, the analysis of muscle synergies has gained relevance as a novel tool to describe the neural control of walking. Since muscle synergies and gait analysis capture different but equally important aspects of walking, we hypothesized that their combination can improve the current clinical tools for the assessment of walking performance. To test this hypothesis, we performed a complete bilateral, lower limb biomechanical and muscle synergies analysis on nine poststroke hemiparetic patients during overground walking. Using stepwise multiple regression, we identified a number of kinematic, kinetic, spatiotemporal and synergy-related features from the paretic and non-paretic side that, combined together, allow to predict impaired walking function better than the Fugl-Meyer Assessment score. These variables were time of peak knee flexion, VAF total values, duration of stance phase, peak of paretic propulsion and range of hip flexion. Since these five variables describe important biomechanical and neural control features underlying walking deficits poststroke, they may be feasible to drive customized rehabilitation therapies aimed to improve walking function. This paper demonstrates the feasibility of combining biomechanical and neural-related measures to assess locomotion performance in neurologically injured individuals. Copyright © 2017 Elsevier Ltd. All rights reserved.

  10. [Biomechanical study on the posterior screw fixation in the lower cervical spine].

    Science.gov (United States)

    Lin, Hua-jie; Xu, Rong-min; Liu, Guan-yi

    2011-06-01

    So far, the fixation in the lower cervical spine through posterior approach technology has commonly been used, besides the lateral screw and pedicle screw techniques, transarticular screw and laminar screw techniques have being paid more attention recently. This article introduced four screw fixation ways in the lower cervical spine through posterior approach and reviewed the recent biomechanics studies of four screw fixation techniques. The biomechanics study includes stabilization, pollout strength, insertion technique, and screw characteristic and so on. Lateral screw and pedicle screw techniques have become an effective internal fixation way for the lower cervical spine instability because of their superior stabilization and higher pollout strength. Transarticular screw fixation has become a new way to fix the lower cervical spine through posterior approach, which has widely surgical indications. Besides, this technique is relatively safe, simple and has achieved favorable curative effect in clinic. Laminar screw fixation technique is rarely used in clinic, but the study of anatomy and biomechanics confirmed that this technique can be applied as a salvage technique in clinic. Above four techniques of the screw fixation in the lower cervical spine through posterior approach have advantages and disadvantages, respectively, and the application in clinic is different. Through the biomechanics study of these techniques will contribute to the development of the techniques of the screw fixation in the lower cervical spine through posterior approach and guide the clinical work effectively.

  11. Combining epidemiology and biomechanics in sports injury prevention research: a new approach for selecting suitable controls.

    Science.gov (United States)

    Finch, Caroline F; Ullah, Shahid; McIntosh, Andrew S

    2011-01-01

    Several important methodological issues need to be considered when designing sports injury case-control studies. Major design goals for case-control studies include the accounting for prior injury risk exposure, and optimal definitions of both cases and suitable controls are needed to ensure this. This article reviews methodological aspects of published sports injury case-control studies, particularly with regard to the selection of controls. It argues for a new approach towards selecting controls for case-control studies that draws on an interface between epidemiological and biomechanical concepts. A review was conducted to identify sport injury case-control studies published in the peer-review literature during 1985-2008. Overall, 32 articles were identified, of which the majority related to upper or lower extremity injuries. Matching considerations were used for control selection in 16 studies. Specific mention of application of biomechanical principles in the selection of appropriate controls was absent from all studies, including those purporting to evaluate the benefits of personal protective equipment to protect against impact injury. This is a problem because it could lead to biased conclusions, as cases and controls are not fully comparable in terms of similar biomechanical impact profiles relating to the injury incident, such as site of the impact on the body. The strength of the conclusions drawn from case-control studies, and the extent to which results can be generalized, is directly influenced by the definition and recruitment of cases and appropriate controls. Future studies should consider the interface between epidemiological and biomechanical concepts when choosing appropriate controls to ensure that proper adjustment of prior exposure to injury risk is made. To provide necessary guidance for the optimal selection of controls in case-control studies of interventions to prevent sports-related impact injury, this review outlines a new case

  12. Neuromuscular and biomechanical characteristics do not vary across the menstrual cycle.

    Science.gov (United States)

    Abt, John P; Sell, Timothy C; Laudner, Kevin G; McCrory, Jean L; Loucks, Tammy L; Berga, Sarah L; Lephart, Scott M

    2007-07-01

    Research examining the menstrual cycle and its relationship to ACL injury has focused on determining the incidence of ACL injury during the different phases of the menstrual cycle and assessing the changes in neuromuscular and biomechanical characteristics between these phases. Conflicting results warrant further investigation to determine if neuromuscular and biomechanical characteristics respond in a similar pattern to the fluctuating estradiol and progesterone. The purpose of this study was to determine if changes in the levels of estradiol and progesterone significantly altered fine motor coordination, postural stability, knee strength, and knee joint kinematics and kinetics between the menses, post-ovulatory, and mid-luteal phases of the menstrual cycle. Ten healthy and physically active females (Age: 21.4 +/- 1.4 years, Height: 1.67 +/- 0.06 m, Mass: 59.9 +/- 7.4 kg), who did not use oral contraceptives, were recruited from the local university population. Single-leg postural stability, fine motor coordination, knee strength, knee biomechanics, and serum estradiol and progesterone were assessed at the menses, post-ovulatory, and mid-luteal phases of the menstrual cycle. Levels of estradiol were significantly higher during the post-ovulatory (P = 0.016) and mid-luteal phases (P hamstring - quadriceps strength ratio at 60 degrees s(-1) (P = 0.748) or 180 degrees s(-1) (P = 0.789), knee flexion excursion (P = 0.6), knee valgus excursion (P = 0.899), peak proximal tibial anterior shear force (P = 0.797), flexion moment at peak proximal tibial anterior shear force (P = 0.698), or valgus moment at peak proximal tibial anterior shear force (P = 0.924). The results of the current study suggest neuromuscular and biomechanical characteristics are not influenced by estradiol and progesterone fluctuations. All neuromuscular and biomechanical characteristics remained invariable between testing sessions despite concentration changes in estradiol and progesterone.

  13. Is There an Economical Running Technique? A Review of Modifiable Biomechanical Factors Affecting Running Economy.

    Science.gov (United States)

    Moore, Isabel S

    2016-06-01

    Running economy (RE) has a strong relationship with running performance, and modifiable running biomechanics are a determining factor of RE. The purposes of this review were to (1) examine the intrinsic and extrinsic modifiable biomechanical factors affecting RE; (2) assess training-induced changes in RE and running biomechanics; (3) evaluate whether an economical running technique can be recommended and; (4) discuss potential areas for future research. Based on current evidence, the intrinsic factors that appeared beneficial for RE were using a preferred stride length range, which allows for stride length deviations up to 3 % shorter than preferred stride length; lower vertical oscillation; greater leg stiffness; low lower limb moment of inertia; less leg extension at toe-off; larger stride angles; alignment of the ground reaction force and leg axis during propulsion; maintaining arm swing; low thigh antagonist-agonist muscular coactivation; and low activation of lower limb muscles during propulsion. Extrinsic factors associated with a better RE were a firm, compliant shoe-surface interaction and being barefoot or wearing lightweight shoes. Several other modifiable biomechanical factors presented inconsistent relationships with RE. Running biomechanics during ground contact appeared to play an important role, specifically those during propulsion. Therefore, this phase has the strongest direct links with RE. Recurring methodological problems exist within the literature, such as cross-comparisons, assessing variables in isolation, and acute to short-term interventions. Therefore, recommending a general economical running technique should be approached with caution. Future work should focus on interdisciplinary longitudinal investigations combining RE, kinematics, kinetics, and neuromuscular and anatomical aspects, as well as applying a synergistic approach to understanding the role of kinetics.

  14. Effect of a laparoscopic instrument with rotatable handle piece on biomechanical stress during laparoscopic procedures.

    Science.gov (United States)

    Steinhilber, Benjamin; Seibt, Robert; Reiff, Florian; Rieger, Monika A; Kraemer, Bernhard; Rothmund, Ralf

    2016-01-01

    To investigate the effect of a pistol grip laparoscopic instrument with a rotatable handle piece (rot-HP) on biomechanical stress and precision as well as a possible interaction between the instrument and working height (WH). Biomechanical stress induced by laparoscopic surgery (LS) is associated with work-related upper limb musculoskeletal disorders in surgeons. Ergonomic handle designs of laparoscopic instruments may reduce the risk of musculoskeletal disorders. Without LS experience, 57 healthy subjects (30 women; 27 men, median age: 26) were observed while performing a laparoscopic exercise. Subjects had to pick up coloured pins and place them into a colour-coded wooden set-up inside a pelvitrainer. The exercise was performed at two WHs using the rot-HP and a standard laparoscopic (fixed) handle piece in randomized sequence. Biomechanical stress was monitored via surface electromyography (sEMG) on fife muscles from the upper limb and shoulder region. Further, the wrist angle (palmar and dorsi flexion) and posture of the dominant upper arm were recorded. Precision was assessed using the number of validly placed pins and process time. sEMG parameters and upper arm postures indicated no differences in biomechanical stress related to either laparoscopic handle piece. The higher WH was associated with higher trapezius and deltoid activity and elevated arm postures (p stress in the shoulder or lower arm muscles. However, wrist angle position may be optimized without affecting precision. Long-term effects of the rot-HP on preventing complaints of the upper extremity should be evaluated. Low WH is recommended to reduce biomechanical stress in the shoulder during laparoscopic surgery.

  15. The importance of assessing corneal biomechanical properties in glaucoma patients care – a review

    Science.gov (United States)

    Dascalescu, Dana; Corbu, Catalina; Vasile, Potop; Iancu, Raluca; Cristea, Miruna; Ionescu, Catalina; Radu Constantin, Ciuluvica; Voinea, Liliana

    2016-01-01

    Purpose: to familiarize the public with the role of corneal biomechanics in glaucoma patient management. Methods: Ocular Response Analyzer (ORA) is the only device that measures in vivo corneal biomechanics. Recent studies regarding “corneal biomechanics and glaucoma” were reviewed and the obtained data were compared in order to present a better understanding of the corneal biomechanical properties involvement in glaucoma care. Results: According to the studies reviewed, in primary open angle glaucoma (POAG) the mean corneal hysteresis (CH) and the corneal resistance factor (CRF) were approximately 2 mmHg lower than in normal eyes. In ocular hypertension (OH), the mean CH was about 1mmHg higher than in POAG patients and 1mmHg lower than in the control group, while the mean CRF was about 2mmHg higher than in POAG and 1mmHg higher than in the control group. Regarding the normal tension glaucoma (NTG), there were studies that showed that the mean CH and CRF were approximately 1mmHg lower than in POAG and studies that showed similar values between the POAG and NTG groups. The mean CH did not differ much between POAG and angle closure glaucoma (ACG), being lower than in normal individuals, while CRF appeared to be higher in the ACG than in normal individuals. Concerning congenital glaucoma (CG), both CH and CRF were about 2mmHg lower than in normal eyes. Conclusions: Corneal biomechanics influenced the IOP measurement and have been proven to be of a great significance in glaucoma patients regardless of the central corneal thickness (CCT). Lower values of CH and CRF could suggest an alteration in the corneal response associated to glaucoma. PMID:29450353

  16. The importance of assessing corneal biomechanical properties in glaucoma patients care - a review.

    Science.gov (United States)

    Dascalescu, Dana; Corbu, Catalina; Vasile, Potop; Iancu, Raluca; Cristea, Miruna; Ionescu, Catalina; Radu Constantin, Ciuluvica; Voinea, Liliana

    2016-01-01

    Purpose: to familiarize the public with the role of corneal biomechanics in glaucoma patient management. Methods: Ocular Response Analyzer (ORA) is the only device that measures in vivo corneal biomechanics. Recent studies regarding "corneal biomechanics and glaucoma" were reviewed and the obtained data were compared in order to present a better understanding of the corneal biomechanical properties involvement in glaucoma care. Results: According to the studies reviewed, in primary open angle glaucoma (POAG) the mean corneal hysteresis (CH) and the corneal resistance factor (CRF) were approximately 2 mmHg lower than in normal eyes. In ocular hypertension (OH), the mean CH was about 1mmHg higher than in POAG patients and 1mmHg lower than in the control group, while the mean CRF was about 2mmHg higher than in POAG and 1mmHg higher than in the control group. Regarding the normal tension glaucoma (NTG), there were studies that showed that the mean CH and CRF were approximately 1mmHg lower than in POAG and studies that showed similar values between the POAG and NTG groups. The mean CH did not differ much between POAG and angle closure glaucoma (ACG), being lower than in normal individuals, while CRF appeared to be higher in the ACG than in normal individuals. Concerning congenital glaucoma (CG), both CH and CRF were about 2mmHg lower than in normal eyes. Conclusions: Corneal biomechanics influenced the IOP measurement and have been proven to be of a great significance in glaucoma patients regardless of the central corneal thickness (CCT). Lower values of CH and CRF could suggest an alteration in the corneal response associated to glaucoma.

  17. Lateral Augmentation Procedures in Anterior Cruciate Ligament Reconstruction: Anatomic, Biomechanical, Imaging, and Clinical Evidence.

    Science.gov (United States)

    Weber, Alexander E; Zuke, William; Mayer, Erik N; Forsythe, Brian; Getgood, Alan; Verma, Nikhil N; Bach, Bernard R; Bedi, Asheesh; Cole, Brian J

    2018-02-01

    There has been an increasing interest in lateral-based soft tissue reconstructive techniques as augments to anterior cruciate ligament reconstruction (ACLR). The objective of these procedures is to minimize anterolateral rotational instability of the knee after surgery. Despite the relatively rapid increase in surgical application of these techniques, many clinical questions remain. To provide a comprehensive update on the current state of these lateral-based augmentation procedures by reviewing the origins of the surgical techniques, the biomechanical data to support their use, and the clinical results to date. Systematic review. A systematic search of the literature was conducted via the Medline, EMBASE, Scopus, SportDiscus, and CINAHL databases. The search was designed to encompass the literature on lateral extra-articular tenodesis (LET) procedures and the anterolateral ligament (ALL) reconstruction. Titles and abstracts were reviewed for relevance and sorted into the following categories: anatomy, biomechanics, imaging/diagnostics, surgical techniques, and clinical outcomes. The search identified 4016 articles. After review for relevance, 31, 53, 27, 35, 45, and 78 articles described the anatomy, biomechanics, imaging/diagnostics, surgical techniques, and clinical outcomes of either LET procedures or the ALL reconstruction, respectively. A multitude of investigations were available, revealing controversy in addition to consensus in several categories. The level of evidence obtained from this search was not adequate for systematic review or meta-analysis; thus, a current concepts review of the anatomy, biomechanics, imaging, surgical techniques, and clinical outcomes was performed. Histologically, the ALL appears to be a distinct structure that can be identified with advanced imaging techniques. Biomechanical evidence suggests that the anterolateral structures of the knee, including the ALL, contribute to minimizing anterolateral rotational instability

  18. Factors influencing corneal biomechanical changes after microincision cataract surgery and standard coaxial phacoemulsification.

    Science.gov (United States)

    Alió, Jorge L; Agdeppa, Ma Cecilia C; Rodríguez-Prats, Jose Luis; Amparo, Francisco; Piñero, David P

    2010-06-01

    To determine the factors affecting corneal biomechanics using biomechanical waveform analysis after microincision cataract surgery (MICS) and standard coaxial phacoemulsification with different incision sizes. Vissum-Instituto Oftalmologico de Alicante, Alicante, Spain. This prospective nonrandomized study comprised eyes with significant cataract that had MICS (sub-1.8 mm incision) or coaxial phacoemulsification (2.75 mm incision). Corneal hysteresis (CH) and the corneal resistance factor (CRF) were measured by biomechanical waveform analysis (Ocular Response Analyzer) preoperatively, immediately postoperatively, and at 1 month. Results were analyzed and compared between groups. In the MICS group (n = 30), there was a significant increase in Goldmann-correlated intraocular pressure (IOP) and corneal-compensated IOP, although CH decreased in the immediate postoperative period (P<.05). At 1 month, all parameters in the MICS group returned to normal. The coaxial group (n = 30) had an increase in Goldmann-correlated IOP and corneal-compensated IOP, both of which were higher than normal at 1 month. Backward multiple regression analysis showed significant correlations between CH and preoperative Goldmann-correlated IOP and preoperative CRF (r(2) = 0.631, P<.05); between age, axial length (AL), and preoperative CRF (r(2) = 0.418, P<.05); and between the change in CH and AL, total incision length, and preoperative CH (r(2) = 0.429, P<.05). Cataract surgery with MICS and coaxial phacoemulsification significantly altered corneal biomechanics. Corneal hysteresis was inversely correlated with Goldmann-correlated IOP; CRF was inversely correlated with age and AL. The MICS technique provided more stable corneal biomechanical properties than standard coaxial phacoemulsification 1 month postoperatively. (c) 2010 ASCRS and ESCRS. Published by Elsevier Inc. All rights reserved.

  19. Anatomic and Biomechanical Comparison of the Classic and Congruent-Arc Techniques of the Latarjet Procedure.

    Science.gov (United States)

    Montgomery, Scott R; Katthagen, J Christoph; Mikula, Jacob D; Marchetti, Daniel Cole; Tahal, Dimitri S; Dornan, Grant J; Dahl, Kimi D; Brady, Alex W; Turnbull, Travis Lee; Millett, Peter J

    2017-05-01

    The Latarjet procedure is commonly performed using either the classic or the congruent-arc technique. Each technique has potential clinical advantages and disadvantages. However, data on the anatomic and biomechanical effects, benefits, and limitations of each technique are limited. Hypothesis/Purpose: To compare the anatomy and biomechanical fixation strength (failure load) between the 2 techniques. It was hypothesized that the classic technique would have superior initial fixation when compared with the congruent-arc technique and that this would be affected by sex and coracoid size. Controlled laboratory study. A biomechanical cadaver study was performed with 20 pairs of male and female shoulders. One of each pair of shoulders was randomly assigned to receive the classic or congruent-arc technique. Coracoid and glenoid anatomic measurements were collected before biomechanical testing. A tensile force was applied through the conjoined tendon to replicate forces experienced by the coracoid graft in the early postoperative period, and the failure load was determined for each specimen. The mean ± SD surface area available for fixation was 263 ± 63 mm 2 in the classic technique compared with 177 ± 63 mm 2 in the congruent-arc group ( P Latarjet procedure provided a greater surface area for healing to the glenoid and superior initial fixation when compared with the congruent-arc technique. The congruent-arc technique allowed restoration of a larger glenoid defect. The classic and congruent-arc techniques of coracoid transfer have anatomic and biomechanical advantages and disadvantages that should be considered when choosing between the 2 techniques.

  20. Anterior lumbar interbody fusion using a barbell-shaped cage: a biomechanical comparison.

    Science.gov (United States)

    Murakami, H; Boden, S D; Hutton, W C

    2001-10-01

    There are drawbacks to using threaded cylindrical cages (e.g., limited area for bone ingrowth and metal precluding radiographic visualization of bone healing). To somewhat offset these drawbacks, a barbell-shaped cage has been designed. The central core of the barbell can be wrapped with collagen sheets infiltrated with bone morphogenetic protein. The obvious theoretical advantages of a barbell cage have to be weighed against potential biomechanical disadvantages. Our purpose was to compare the biomechanical properties of an anterior lumbar interbody reconstruction using 18-mm-diameter threaded cylindrical cages, with a reconstruction using barbell cages (18-mm diameter and 6 mm wide at both cylindrical ends, with a round 4-mm-diameter bar joining the two ends). Twelve cadaveric lumbar motion segments were tested. Three L5-S1 segments received two threaded cylindrical cages, and three L5-S1 segments received two barbell cages. Three L3-L4 segments received one threaded cylindrical cage, and three L3-L4 segments received one barbell cage. A series of biomechanical loading sequences were carried out on each motion segment, and stiffness curves were obtained. After the biomechanical testing, an axial compressive load was applied to the motion segments until failure. They were then radiographed and bisected through the disc, and the subsidence (or penetration) of the cage(s) in the cancellous bone of the vertebral bodies was measured. There was no difference in terms of stiffness between the motion segments with the threaded cylindrical cage(s) inserted and those with the barbell cage(s) inserted (p > 0.15). The average values of subsidence was 0.96 mm for the threaded cylindrical cage group and 0.80 mm for the barbell cage group (difference not significant: p = 0.38). The results suggest that a reconstruction using barbell cages is a biomechanically acceptable alternative to one using threaded cylindrical cages.