WorldWideScience

Sample records for biomechanics

  1. 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.

  2. 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)

  3. 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…

  4. 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

  5. Gingival Recessions and Biomechanics

    DEFF Research Database (Denmark)

    Laursen, Morten Godtfredsen

    Gingival recessions and biomechanics “Tissue is the issue, but bone sets the tone.“ A tooth outside the cortical plate can result in loss of bone and development of a gingival recession. The presentation aims to show biomechanical considerations in relation to movement of teeth with gingival...... 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...

  6. 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..

  7. 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.

  8. Biomechanics of oral mucosa

    Science.gov (United States)

    Chen, Junning; Ahmad, Rohana; Li, Wei; Swain, Michael; Li, Qing

    2015-01-01

    The prevalence of prosthodontic treatment has been well recognized, and the need is continuously increasing with the ageing population. While the oral mucosa plays a critical role in the treatment outcome, the associated biomechanics is not yet fully understood. Using the literature available, this paper provides a critical review on four aspects of mucosal biomechanics, including static, dynamic, volumetric and interactive responses, which are interpreted by its elasticity, viscosity/permeability, apparent Poisson's ratio and friction coefficient, respectively. Both empirical studies and numerical models are analysed and compared to gain anatomical and physiological insights. Furthermore, the clinical applications of such biomechanical knowledge on the mucosa are explored to address some critical concerns, including stimuli for tissue remodelling (interstitial hydrostatic pressure), pressure–pain thresholds, tissue displaceability and residual bone resorption. Through this review, the state of the art in mucosal biomechanics and their clinical implications are discussed for future research interests, including clinical applications, computational modelling, design optimization and prosthetic fabrication. PMID:26224566

  9. 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. PMID:21303323

  10. Biomechanics of Rowing

    Science.gov (United States)

    Hase, Kazunori; Andrews, Brian J.; Zavatsky, Amy B.; Halliday, Suzanne E.

    A new control model for the study of biomechanical simulation of human movement was investigated using rowing as an example. The objectives were to explore biological and mechanical alternatives to optimal control methods. The simulation methods included simple control mechanisms based on proportional and derivative (PD) control, consideration of a simple neural model, introduction of an inverse dynamics system for feedback, and computational adjustment of control parameters by using an evaluative criterion and optimization method. By using simulation, appropriate rowing motions were synthesized. The generated rowing motion was periodic, continuous, and adaptable so that the pattern was stable against the mechanical force and independent of the initial condition. We believe that the simulation model is not only practical as a computational research tool from a biomechanical-engineering viewpoint but also significant from the point of view of fundamental biological theories of movement.

  11. Anthropometry and Biomechanics Facility

    Science.gov (United States)

    Bernal, Yaritza

    2016-01-01

    The Anthropometry and Biomechanics Facility (ABF) is equipped with anthropometric and biomechanical instrumentation and regularly performs population analysis based on analytical and modeling capabilities to test and verify if all eligible crew/passengers can be accommodated, and fitted with a protective suit that enables performance of reach and access tasks. The ABF's unique expertise can aid in identifying potential ergonomic and occupational biomechanical problems with recommended solutions to improve a suited passenger's safety, comfort, and injury protection. My involvement was in the following projects: The ABF is currently trying to define human performance capabilities in the Extravehicular Mobility Unit (EMU) space suit. Subjects are tested in an effort to further understand shoulder and elbow strength performance deficits when suited compared to unsuited. Another ongoing project is to develop a protocol to reliably characterize human health and performance metrics for individuals working inside various extravehicular activity (EVA) suits under realistic spaceflight conditions. This project will provide benchmarking data and protocols to be used in the making of future EVA suit configurations.

  12. Laser Metrology In Biomechanics

    Science.gov (United States)

    Pryputniewicz, Ryszard J.

    1983-12-01

    Modern treatment of sceletal disharmonies and malocclusions utilizes application of external forces. In order to effectively use these therapeutic forces, knowledge of three-dimensional displacements of bones with correlation to biological changes is required. In the past, this problem has been studied in a number of ways using, for example, strain gauges, brittle coatings, photoelasticity, as well as clinical observations and mathematical modeling. Becouse of their inherent limitations, these techniques did not always provide all the information necessary for development of meaningful relationships between the applied force system and the resulting biological remodeling. However, recent advances in the field of la-ser metrology allowed to overcome some of the dificulties found in the earlier methods and permitted development of new techniques for non-invasive measurements of bone motions in three-dimensional space. These laser techniques are particularly useful in biomechanics because they provide for rapid and accurate determination of displacements over the entire surface of the investigate object. In this paper, application of laser techniques for quantitative in-vivo and in-vitro measurements in biomechanics will be discussed and illustrated with representative examples.

  13. Biomechanical conditions of walking

    CERN Document Server

    Fan, Y F; Luo, L P; Li, Z Y; Han, S Y; Lv, C S; Zhang, B

    2015-01-01

    The development of rehabilitation training program for lower limb injury does not usually include gait pattern design. This paper introduced a gait pattern design by using equations (conditions of walking). Following the requirements of reducing force to the injured side to avoid further injury, we developed a lower limb gait pattern to shorten the stride length so as to reduce walking speed, to delay the stance phase of the uninjured side and to reduce step length of the uninjured side. This gait pattern was then verified by the practice of a rehabilitation training of an Achilles tendon rupture patient, whose two-year rehabilitation training (with 24 tests) has proven that this pattern worked as intended. This indicates that rehabilitation training program for lower limb injury can rest on biomechanical conditions of walking based on experimental evidence.

  14. 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...

  15. Biomechanics: basic and applied research

    International Nuclear Information System (INIS)

    This volume presents the state of the art in biomechanics. The most recent achievements of biomechanical research in the fields of orthopaedics, dynamics of the musculoskeletal system, hard and soft tissues, rehabilitation, sports, cardiovascular problems and research methodology have been selected and edited by a distinguished panel of reviewers. The material is such that the volume will serve as a reference for many years for bioengineers, sports scientists, clinicians and clinical researchers in rehabilitation, orthopaedics and cardiovascular surgery

  16. Atraumatic extractions: a biomechanical rationale.

    Science.gov (United States)

    Misch, Carl E; Perez, Helena M

    2008-08-01

    Biomechanical aspects of force have been applied to tooth extraction for centuries. However, the mechanical advantages available to extract the teeth were primarily applied to hold the crown of the tooth, rather than help extract it. An extraction device (Physics Forceps) has been developed to apply a biomechanical rationale to the extraction process of a tooth using a class 1 lever, creep, and shear components of force. PMID:18717405

  17. Judo Biomechanical Optimization

    CERN Document Server

    Sacripanti, Attilio

    2016-01-01

    In this paper, for the first time, there is comprehensively tackling the problem of biomechanical optimization of a sport of situation such as judo. Starting from the optimization of more simple sports, optimization of this kind of complex sports is grounded on a general physics tool such as the analysis of variation. The objective function is divided for static and dynamic situation of Athletes couple, and it is proposed also a sort of dynamic programming problem Strategic Optimization. A dynamic programming problem is an optimization problem in which decisions have to be taken sequentially over several time periods linked in some fashion. A strategy for a dynamic programming problem is just a contingency plan, a plan that specifies what is to be done at each stage as a function of all that has transpired up to that point. It is possible to demonstrate, under some conditions, that a Markovian optimal strategy is an optimal strategy for the dynamic programming problem under examination. At last we try to appr...

  18. Ocular biomechanics study: current state and perspectives

    Directory of Open Access Journals (Sweden)

    S. Yu. Petrov

    2015-03-01

    Full Text Available Despite the fact that the eye represents a challenge for biomechanical research due to its size, over the last two decades, much data on ocular biomechanics were accumulated. Scleral and lamina cribrosa biomechanics contribute to our understanding of myopia and open-angle glaucoma; iris and trabecular meshwork biomechanics to that of angle-closure glaucoma; vitreous biomechanics to that of retinal detachment and ocular drug delivery; corneal biomechanics to that of keratoconus; and lens capsule biomechanics to that of cataract. This paper offers a general overview of recent advances in corneal, scleral, crystalline lens, and lamina cribrosa biomechanics and summarizes the results of experimental and clinical studies. Ocular biomechanics abnormalities affect etiology of many eye diseases. Ocular biomechanics plays an important role in the development of novel diagnostic methods, therapeutic and surgical procedures. Corneal biomechanics impacts etiology and pathogenesis of keratoconus as well as tonometry accuracy and explains corneal refractive surgery effect. Scleral biomechanics is associated with IOP and progressive myopia. Accommodative apparatus (ciliary body and crystalline lens is an important anatomic physiological structure. Recent studies uncovered the causes of agerelated loss of accommodation as a result of lens involution. Optic nerve head abnormalities due to IOP fluctuations are the key factor of glaucomatous neuropathy. They are directly associated with ocular biomechanics as well.

  19. Kinesiology/Biomechanics: Perspectives and Trends.

    Science.gov (United States)

    Atwater, Anne E.

    1980-01-01

    Past and recent developments and future directions in kinesiology and biomechanics are reviewed. Similarities and differences between these two areas are clarified. The areas of kinesiology and biomechanics have distinct unique qualities and should be treated as separate disciplines. (CJ)

  20. 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. PMID:17766290

  1. Problems of Sport Biomechanics and Robotics

    OpenAIRE

    Erdmann, Wlodzimierz S.

    2013-01-01

    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...

  2. 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....

  3. 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. PMID:2946390

  4. Sport and Exercise Biomechanics (Bios Instant Notes)

    OpenAIRE

    Paul Grimshaw; Adrian Lees; Neil Fowler; Adrian Burden

    2007-01-01

    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 resear...

  5. 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.

  6. Biomechanical properties of four dermal substitutes

    Institute of Scientific and Technical Information of China (English)

    ZHANG Guo-an; NING Fang-gang; ZHAO Nan-ming

    2007-01-01

    @@ Many kinds of cell-free dermal substitutes have been developed during the past several years, however,their biomechanical properties, including hysteresis,stress relaxation, creep, and non-linear stress-strain, are still unknown. In this study, we tested these biomechanical characteristics of four dermal substitutes,and compared them with those of fresh human skin (FHS).

  7. 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…

  8. Biomechanics finds practical applications in aerospace research

    Science.gov (United States)

    Yanghe, X.

    1984-10-01

    Biomechanics is a branch of science which studies the mechanical properties of biological parts using the basic principles of mechanics and engineering. Formulas and quantitative calculations are used to analyze and understand physiological phenomena. Problems caused by weightlessness, coronary heart disease, blood circulation, use of medication, and application of biomechanics in aviation rescue are discussed.

  9. Mechatronic support of present robotics and biomechanics

    Czech Academy of Sciences Publication Activity Database

    Ehrenberger, Zdeněk; Kratochvíl, Ctirad; Janíček, P.

    Brno: VUT, 2003 - (Ehrenberger, Z.; Houfek, L.; Kratochvíl, C.), s. 1-2 ISBN 80-21423-12-9. [Mechanotronic, Robotics and biomechanics 2003. Hrotovice (CZ), 24.03.2003-27.03.2003] Institutional research plan: CEZ:AV0Z2076919 Keywords : mechatronics * robotics * biomechanics Subject RIV: JD - Computer Applications, Robotics

  10. 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...... the biomechanical environment of the mechanosensitive nerve endings, therefore, the structure as well as the tension, stress and strain distribution in the GI wall is important for the sensory and motor function. Biomechanical remodeling of diabetic GI tract including alterations of residual strain and increase...

  11. Biomechanical performance of new cardiovascular needles.

    Science.gov (United States)

    Thacker, J G; Ferguson, R E; Rodeheaver, G T; Edlich, R F

    2001-01-01

    Cardiovascular needles are now being manufactured from new stainless steel alloys containing high concentrations of nickel, Surgalloy and Ethalloy. The purpose of this study was to compare the biomechanical performance of a cardiovascular needle made of Surgalloy with a comparably sized needle made of Ethalloy. The parameters of biomechanical performance included sharpness, maintenance of sharpness, resistance to bending, and ductility. Because the biomechanical performance of these needles was remarkably similar, cardiovascular needles made of either the Surgalloy or Ethalloy alloys are recommended for cardiovascular surgery. PMID:11495105

  12. Speckle photography in biomechanical testing

    Science.gov (United States)

    Kasprzak, Henryk T.; Podbielska, Halina

    1994-02-01

    The application of speckle photography in biomechanical testing of bones and surgical fixing devices is presented. Double-exposure speckle photography is used for measuring the in-plane deformation of broken lower leg bones supported with different fixing devices under axial loading. An osteosynthesis plate, an external fixator, and an intramedullar nail mounted on the tibia shaft are tested. The results for different loading conditions are analyzed and compared with those obtained by holographic interferometry. Further, the human hyoid bone is investigated by this method. The load is applied to the anterior surface of the body of the bone. All tested specimen show an asymmetric displacement, the greatest in a plane vertical to the load. An evaluation of fracture behavior can be done from the displacement pattern.

  13. Musculoskeletal Biomechanics in Cross-country Skiing

    OpenAIRE

    Holmberg, L. Joakim

    2012-01-01

    Why copy the best athletes? When you finally learn their technique, they may have already moved on. Using muscluloskeletal biomechanics you might be able to add the "know-why" so that you can lead, instead of being left in the swells. This dissertation presents the theoretical framework of musculoskeletal modeling using inverse dynamics with static optimization. It explores some of the possibilities and limitations of musculoskeletal biomechanics in cross-country skiing, especially double-pol...

  14. Biomechanical Properties of Bone and Biomechanics of Age - Related Fractures - Review

    Directory of Open Access Journals (Sweden)

    Rezzan Günaydın

    2007-06-01

    Full Text Available From a biomechanical viewpoint, fractures are due to a structural failure of the bone. This failure occurs when the forces applied to the bone exceed its load – bearing capacity. The load – bearing capacity of a bone depends on the geometry (its size, shape and distribution of bone mass, and the material properties of a bone as well as the direction and magnitude of applied load. Bone fragility can be defined by biomechanical parameters such as strength, brittleness and work to failure. Strategies to reduce fracture risk must be based on a sound understanding of the cellular, molecular and biomechanical mechanisms that underlie the increased risk of fractures while aging. In this review biomechanics of bone and the etiology of age – related fractures from a biomechanical viewpoint have been discussed in the view of current literature. (From the World of Osteoporosis 2007;13:44-8

  15. [Hoarseness: biomechanisms and quantitative laryngoscopy].

    Science.gov (United States)

    Eysholdt, U

    2014-07-01

    Every phonosurgical procedure alters endolaryngeal anatomy; be it by removing tissue, or injection or implantation of autologous or foreign material. However, the effect that an altered airflow cross section and changed soft tissue elasticity will have on the voice cannot be predicted. With the aim of promoting rational indications for phonosurgery, the current article explains the biomechanisms of the normal and the disordered voice, including the complex interdependence of tissue viscoelasticity, glottal airstream and sound production. According to European Laryngological Society (ELS) recommendations, five - not entirely mutually independent - evaluation criteria form the basis of indication assessments: self-rating (by the patient), proxy rating (by the physician), technical signal analysis (computerized), aerodynamics (spirometry) and vibration analysis (stroboscopy). The ELS evaluation standards agreed upon in 2001 enable indications and - by virtue of pre- and postoperative comparisons - therapeutic successes to be assessed. The 10-year-old ELS protocol has been updated by a real-time method for visualizing vocal fold vibrations: the phonovibrogram (PVG) has replaced stroboscopy. Independently of the morphological anatomic details of the larynx, PVG visualizes the symmetry and regularity of vocal fold motion, thus allowing preoperative estimation of tissue elasticity. PMID:25056650

  16. Role of Aquaporin 0 in lens biomechanics

    International Nuclear Information System (INIS)

    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−/−), AQP0 KO (heterozygous KO: AQP0+/−; homozygous KO: AQP0−/−; 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+/− 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 together they help to confer

  17. 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.

  18. Biomechanical analysis of lumbosacral fixation.

    Science.gov (United States)

    McCord, D H; Cunningham, B W; Shono, Y; Myers, J J; McAfee, P C

    1992-08-01

    Flexion testing was performed until failure on 66 lumbosacral bovine spinal segments comparing ten different lumbosacral instrumentation techniques. Maximum flexion moment at failure, flexural stiffness, and maximum angulation of the lumbosacral joint at failure were determined as well as strain measurements across the anterior aspect of the lumbosacral intervertebral disc using an extensometer. The maximum moment at failure was significantly greater for the only two devices that extended fixation into the ilium anterior to the projected image of the middle osteoligamentous column: ISOLA Galveston and ISOLA iliac screws (F = 12.2, P less than 0.001). The maximum stiffness at failure reinforced these findings (F = 23.7, P less than 0.001). A second subset of stability showed the advantages of S2 pedicle fixation by increasing the flexural lever arm (Cotrel-Dubousset butterfly plate, and Cotrel-Dubousset Chopin block, P less than 0.05). This exhaustive in vitro biomechanical study introduces the concept of a pivot point at the lumbosacral joint at the intersection of the middle osteoligamentous column (sagittal plane) and the lumbosacral intervertebral disc (transverse plane). A spinal surgeon can increase the stability of lumbosacral instrumentation by extending fixation through the anterior sacral cortex (Steffee plate group with pedicle screws that medially converge in a triangular fashion). A means of enhancing this fixation was to achieve more inferior purchase by extending the fixation down to the S2 pedicle (Cotrel-Dubousset Chopin and Cotrel-Dubousset butterfly groups). However, the best fixation was achieved by obtaining purchase between the iliac cortices down into the superior acetabular bone.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:1523506

  19. Biomechanics of Degenerative Spinal Disorders

    Science.gov (United States)

    Iorio, Justin A.; Jakoi, Andre M.

    2016-01-01

    The spine has several important functions including load transmission, permission of limited motion, and protection of the spinal cord. The vertebrae form functional spinal units, which represent the smallest segment that has characteristics of the entire spinal column. Discs and paired facet joints within each functional unit form a three-joint complex between which loads are transmitted. Surrounding the spinal motion segment are ligaments, composed of elastin and collagen, and joint capsules which restrict motion to within normal limits. Ligaments have variable strengths and act via different lever arm lengths to contribute to spinal stability. As a consequence of the longer moment arm from the spinous process to the instantaneous axis of rotation, inherently weaker ligaments (interspinous and supraspinous) are able to provide resistance to excessive flexion. Degenerative processes of the spine are a normal result of aging and occur on a spectrum. During the second decade of life, the intervertebral disc demonstrates histologic evidence of nucleus pulposus degradation caused by reduced end plate blood supply. As disc height decreases, the functional unit is capable of an increased range of axial rotation which subjects the posterior facet capsules to greater mechanical loads. A concurrent change in load transmission across the end plates and translation of the instantaneous axis of rotation further increase the degenerative processes at adjacent structures. The behavior of the functional unit is impacted by these processes and is reflected by changes in the stress-strain relationship. Back pain and other clinical symptoms may occur as a result of the biomechanical alterations of degeneration. PMID:27114783

  20. 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.

  1. 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...

  2. 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.

  3. Role of Aquaporin 0 in lens biomechanics.

    Science.gov (United States)

    Sindhu Kumari, S; Gupta, Neha; Shiels, Alan; FitzGerald, Paul G; Menon, Anil G; Mathias, Richard T; Varadaraj, Kulandaiappan

    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(-/-)), AQP0 KO (heterozygous KO: AQP0(+/-); homozygous KO: AQP0(-/-); 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(+/-) 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 together they help to confer

  4. Analysis of Biomechanical Factors in Bend Running

    Directory of Open Access Journals (Sweden)

    Bing Zhang

    2013-03-01

    Full Text Available 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 middle ones. Thus it provides references for training of short-distance items in biomechanics and psychology, etc.

  5. Interdisciplinary Vertical Integration: The Future of Biomechanics

    Science.gov (United States)

    Gregor, Robert J.

    2008-01-01

    The field of biomechanics has grown rapidly in the past 30 years in both size and complexity. As a result, the term might mean different things to different people. This article addresses the issues facing the field in the form of challenges biomechanists face in the future. Because the field is so diverse, strength within the different areas of…

  6. 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.…

  7. Biomechanics/risk management (Working Group 2)

    DEFF Research Database (Denmark)

    Sanz, Mariano; Naert, Ignace; Gotfredsen, Klaus

    2009-01-01

    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 manuscrip...

  8. 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 the ho

  9. Understanding the biomechanical nature of musculoskeletal tissue.

    Science.gov (United States)

    Karduna, Andrew R

    2012-01-01

    This article provides a general overview of the biomechanical principles associated with hand therapy. Specifically, it reviews the basic topics of material properties (including both theoretical principles and practical concepts), static analysis (including forces, moments, muscle forces, and Newton's laws), and ends with a clinical example involving analysis of the risk of damage to the A3 pulley. PMID:22507212

  10. 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…

  11. Developmental biomechanics of the human cervical spine.

    Science.gov (United States)

    Nuckley, David J; Linders, David R; Ching, Randal P

    2013-04-01

    Head and neck injuries, the leading cause of death for children in the U.S., are difficult to diagnose, treat, and prevent because of a critical void in our understanding of the biomechanical response of the immature cervical spine. The objective of this study was to investigate the functional and failure biomechanics of the cervical spine across multiple axes of loading throughout maturation. A correlational study design was used to examine the relationships governing spinal maturation and biomechanical flexibility curves and tolerance data using a cadaver human in vitro model. Eleven human cadaver cervical spines from across the developmental spectrum (2-28 years) were dissected into segments (C1-C2, C3-C5, and C6-C7) for biomechanical testing. Non-destructive flexibility tests were performed in tension, compression, flexion, extension, lateral bending, and axial rotation. After measuring their intact biomechanical responses, each segment group was failed in different modes to measure the tissue tolerance in tension (C1-C2), compression (C3-C5), and extension (C5-C6). Classical injury patterns were observed in all of the specimens tested. Both the functional (pmechanics exhibited significant relationships with age. Nonlinear flexibility curves described the functional response of the cervical spine throughout maturation and elucidated age, spinal level, and mode of loading specificity. These data support our understanding of the child cervical spine from a developmental perspective and facilitate the generation of injury prevention or management schema for the mitigation of child spine injuries and their deleterious effects. PMID:23415075

  12. 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

  13. 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.

  14. Biomechanical study of percutaneous lumbar diskectomy

    International Nuclear Information System (INIS)

    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

  15. Biomechanics and anterior cruciate ligament reconstruction

    OpenAIRE

    Vercillo Fabio; Dede Ozgur; Wu Changfu; Woo Savio; Noorani Sabrina

    2006-01-01

    Abstract For years, bioengineers and orthopaedic surgeons have applied the principles of mechanics to gain valuable information about the complex function of the anterior cruciate ligament (ACL). The results of these investigations have provided scientific data for surgeons to improve methods of ACL reconstruction and postoperative rehabilitation. This review paper will present specific examples of how the field of biomechanics has impacted the evolution of ACL research. The anatomy and biome...

  16. Homogenization of biomechanical models for plant tissues

    OpenAIRE

    Piatnitski, Andrey; Ptashnyk, Mariya

    2015-01-01

    In this paper homogenization of a mathematical model for plant tissue biomechanics is presented. The microscopic model constitutes a strongly coupled system of reaction-diffusion-convection equations for chemical processes in plant cells, the equations of poroelasticity for elastic deformations of plant cell walls and middle lamella, and Stokes equations for fluid flow inside the cells. The chemical process in cells and the elastic properties of cell walls and middle lamella are coupled becau...

  17. BIOMECHANICAL ANALYSIS OF HUMAN FEMUR BONE

    OpenAIRE

    RAJI NARELIYA,; VEERENDRA KUMAR

    2011-01-01

    Biomechanics is the theory of how tissues, cells, muscles, bones, organs and the motion of them and how their form and function are regulated by basic mechanical properties. A finite element model of bones with accurate geometry and material properties retrieved from CT scan data are being widely used to make realistic investigations on the mechanical behavior of bone structures. The aim of this study is to create a model of real proximal human femur bone for evaluating the finite element ana...

  18. 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

  19. SERVICE IN BADMINTON: A BIOMECHANICAL STUDY

    OpenAIRE

    Saleem Ahmed; Sartaj Khan; Manu Mishra; Touheed Akhter

    2015-01-01

    To find out the differences between forehand and backhand short services in badminton, the present study was designed to analyze the biomechanical variables and segmental angles - shuttle velocity, wrist angle, elbow angle and shoulder angle of six male badminton players. The data were recorded during “North-Zone Intervarsity Championship” held at Aligarh Muslim University, Aligarh, India. All subjects in the study were right handed badminton players. The mean age, body height ...

  20. Patient-Specific Models of Cardiac Biomechanics

    OpenAIRE

    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 CP

    2012-01-01

    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-di...

  1. 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...

  2. 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...

  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. 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. PMID:27007474

  5. Are biomechanical changes necessary for tumor progression?

    Science.gov (United States)

    Kas, Josef A.

    2014-03-01

    Already the Roman Celsus recognized rigid tissue as characteristic for solid tumors. Conversely, changes towards a weaker cytoskeleton have been described as a feature of cancer cells since the early days of tumor biology. It remains unclear if a carcinoma's rigid signature stems from more inflexible cells or is caused by the stroma. Despite that the importance of cell biomechanics for tumor progression becomes more and more evident the chicken-and-egg problem to what extent cancer cells already change their mechanical properties within the solid tumor in order to transgress its boundary or mechanical changes are induced by the microenvironment when the cell has left the tumor has been discussed highly controversial. Comprehensive clinical biomechanical measurements only exist from tumor tissue without the possibility to identify individual cells or from individual cancer cells from pleural effusions. Since the biomechanical properties of cells in carcinomas remain unknown measurements on individual cells that directly stem out of primary tumor samples are required, which we have conducted. We found in cervix and mammary carcinomas a distinctive increase of softer cells as well as contractile cells. A soft and contractile cell is like a strong elastic rope. The cell can generate a strong tensile tension to pull its self along and is soft against compression to avoid jamming.

  6. Biomechanics aspects of technique of high jump

    Directory of Open Access Journals (Sweden)

    Adashevskiy V.M.

    2013-02-01

    Full Text Available The purpose of work consists in the theoretical ground of optimum biomechanics descriptions in high jumps. A mathematical model is developed for determination of influence on the height of jump: speed and corner of flight of centre-of-mass during pushing away, positions of centre-of-mass body of sportsman in the phases of pushing away and transition through a slat, forces of resistance of air environment, influences of moment of inertia of body. The basic technical run-time errors of sportsman are selected exercises. To biomechanics descriptions, to the step-up effectiveness of high jumps belong: speed of flight of centre-of-mass sportsman (4.2-5.8 meters in a second, corner of flight of centre-of-mass body (50-58 degrees, height of flight of centre-of-mass body (0.85-1.15 meter. Directions of choice of necessary biomechanics descriptions which a sportsman can realize are shown. Offered recommendation on the increase of effectiveness of high jumps.

  7. 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.

  8. Biomechanics of the elbow joint in tennis players.

    OpenAIRE

    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 different repetitive biomechanical nature which can result in tennis related injuries. In this article a biomechanically based evaluation of tennis strokes is presented. This overview includes all...

  9. Jet-Ricci Geometry of Time-Dependent Human Biomechanics

    OpenAIRE

    Ivancevic, Tijana T.

    2009-01-01

    We propose the time-dependent generalization of an `ordinary' autonomous human biomechanics, in which total mechanical + biochemical energy is not conserved. We introduce a general framework for time-dependent biomechanics in terms of jet manifolds derived from the extended musculo-skeletal configuration manifold. The corresponding Riemannian geometrical evolution follows the Ricci flow diffusion. In particular, we show that the exponential-like decay of total biomechanical energy (due to exh...

  10. 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. PMID:25801423

  11. Relationships between job organisational factors, biomechanical and psychosocial exposures.

    Science.gov (United States)

    Bao, Stephen S; Kapellusch, Jay M; Merryweather, Andrew S; Thiese, Matthew S; Garg, Arun; Hegmann, Kurt T; Silverstein, Barbara A

    2016-02-01

    The relationships between work organisational, biomechanical and psychosocial factors were studied using cross-sectional data from a pooled dataset of 1834 participants. The work organisational factors included: job rotation, overtime work, having second jobs and work pace. Task and job level biomechanical variables were obtained through sub-task data collected in the field or analysed in the laboratory. Psychosocial variables were collected based on responses to 10 questions. The results showed that job rotations had significant effects on all biomechanical and most psychosocial measures. Those with job rotations generally had higher job biomechanical stressors, and lower job satisfaction. Overtime work was associated with higher job biomechanical stressors, and possibly self-reported physical exhaustion. Those having second jobs reported getting along with co-workers well. Work pace had significant influences on all biomechanical stressors, but its impact on job biomechanical stressors and psychosocial effects are complicated. Practitioner Summary: The findings are based on a large number of subjects collected by three research teams in diverse US workplaces. Job rotation practices used in many workplaces may not be effective in reducing job biomechanical stressors for work-related musculoskeletal disorders. Overtime work is also associated with higher biomechanical stressors. PMID:26102483

  12. 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…

  13. 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…

  14. 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…

  15. Biomechanics aspects of technique of high jump

    OpenAIRE

    Adashevskiy V.M.; Iermakov S.S.; Marchenko A. A.

    2013-01-01

    The purpose of work consists in the theoretical ground of optimum biomechanics descriptions in high jumps. A mathematical model is developed for determination of influence on the height of jump: speed and corner of flight of centre-of-mass during pushing away, positions of centre-of-mass body of sportsman in the phases of pushing away and transition through a slat, forces of resistance of air environment, influences of moment of inertia of body. The basic technical run-time errors of sportsma...

  16. High resolution extremity CT for biomechanics modeling

    International Nuclear Information System (INIS)

    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. Distributed Data Acquisition For Biomechanics Research

    Science.gov (United States)

    Myklebust, J.; Geisler, M.; Prieto, T.; Weiss, R.

    1987-01-01

    Biomechanics research at the Medical College of Wisconsin is directed to the determination of the mechanisms of head and spine injury and the evaluation of surgical treatments for these injuries. This work involves mechanical testing of components of the spine (disks, vertebral bodies, and ligaments) as well as testing of composite spines and in situ evaluation of intact human cadavers (1,3). Other studies utilize experimental animals to measure neurologic and physiologic effects due to injury producing loads and accelerations (2). An integrated system has been developed to facilitate the acquisition and analysis of the diverse types of data from these experiments.

  18. Pathophysiology and Biomechanics of the Aging Spine

    Science.gov (United States)

    Papadakis, Michael; Sapkas, Georgios; Papadopoulos, Elias C; Katonis, Pavlos

    2011-01-01

    Aging of the spine is characterized by two parallel but independent processes: the reduction of bone mineral density and the development of degenerative changes. The combination of degeneration and bone mass reduction contribute, to a different degree, to the development of a variety of lesions. This results in a number of painful and often debilitating disorders. The present review constitutes a synopsis of the pathophysiological processes that take place in the aging spine as well as of the consequences these changes have on the biomechanics of the spine. The authors hope to present a thorough yet brief overview of the process of aging of the human spine. PMID:21966338

  19. Jet Methods in Time-Dependent Lagrangian Biomechanics

    CERN Document Server

    Ivancevic, Tijana T

    2009-01-01

    In this paper we propose the time-dependent generalization of an `ordinary' autonomous human biomechanics, in which total mechanical + biochemical energy is not conserved. We introduce a general framework for time-dependent biomechanics in terms of jet manifolds associated to the extended musculo-skeletal configuration manifold, called the configuration bundle. We start with an ordinary configuration manifold of human body motion, given as a set of its all active degrees of freedom (DOF) for a particular movement. This is a Riemannian manifold with a material metric tensor given by the total mass-inertia matrix of the human body segments. This is the base manifold for standard autonomous biomechanics. To make its time-dependent generalization, we need to extend it with a real time axis. By this extension, using techniques from fibre bundles, we defined the biomechanical configuration bundle. On the biomechanical bundle we define vector-fields, differential forms and affine connections, as well as the associat...

  20. 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...

  1. Inframammary Fold Reconstruction: A Biomechanical Analysis

    Science.gov (United States)

    Schell, Julia; Uener, Jens; Prescher, Andreas; Scaal, Martin; Puppe, Julian; Warm, Mathias

    2016-01-01

    Background: Inframammary fold reconstruction has scarcely been evaluated in literature. No biomechanical analyses have been performed comparing different reconstructive methods. This evaluation compares the gold-standard suture reconstruction with an intrarib anchor system (Micro BioComposite SutureTak, Arthrex). Methods: Three analysis groups were compared including 8 Sawbone blocks, 22 embalmed cadaver, and 27 regular cadaver specimens (N = 57). Transient mechanical analysis was performed at 5 N/s using an Instron 5565 test frame. Results: Ultimate load favored the anchor system (compared with the gold-standard suture) by a factor of 9.8 (P group and a factor of 1.7 (P group. A similar statistically significant benefit was shown for stiffness and load at 2-mm displacement. Conclusions: This analysis showed an anchor system to be the biomechanically superior fixation method in terms of ultimate load, fixation stiffness, and displacement at failure when compared with the gold-standard suture method in inframammary fold reconstruction. Because of superior stability in every aspect, an anchor system may be considered for inframammary fold reconstruction. PMID:27257564

  2. Biomechanical analysis of jaw-closing movements.

    Science.gov (United States)

    Koolstra, J H; van Eijden, T M

    1995-09-01

    This study concerns the complex interaction between active muscle forces and passive guiding structures during jaw-closing movements. It is generally accepted that the ligaments of the joint play a major role in condylar guidance during these movements. While these ligaments permit a wide range of motions, it was assumed that they are not primarily involved in force transmission in the joints. Therefore, it was hypothesized that muscle forces and movement constraints caused by the articular surfaces imply a necessary and sufficient condition to generate ordinary jaw-closing movements. This hypothesis was tested by biomechanical analysis. A dynamic six-degrees-of-freedom mathematical model of the human masticatory system has been developed for qualitative analysis of the contributions of the different masticatory muscles to jaw-closing movements, it was found that the normally observed movement, which includes a swing-slide condylar movement along the articular eminence, can be generated by various separate pairs of masticatory muscles, among which the different parts of the masseter as well as the medial pterygoid muscle appeared to be the most suitable to complete this action. The results seem to be in contrast to the general opinion that a muscle with a forward-directed force component may not be suitable for generating jaw movements in which the condyle moves backward. The results can be explained, however, by biomechanical analysis which includes not only muscle and joint forces as used in standard textbooks of anatomy, but also the torques generated by these forces. PMID:7560417

  3. Integrated biomechanical and topographical surface characterization (IBTSC)

    Energy Technology Data Exchange (ETDEWEB)

    Löberg, Johanna, E-mail: Johanna.Loberg@dentsply.com [Dentsply Implants, Box 14, SE-431 21 Mölndal (Sweden); Mattisson, Ingela [Dentsply Implants, Box 14, SE-431 21 Mölndal (Sweden); Ahlberg, Elisabet [Department of Chemistry and Molecular Biology, University of Gothenburg, SE-41296 Gothenburg (Sweden)

    2014-01-30

    In an attempt to reduce the need for animal studies in dental implant applications, a new model has been developed which combines well-known surface characterization methods with theoretical biomechanical calculations. The model has been named integrated biomechanical and topographical surface characterization (IBTSC), and gives a comprehensive description of the surface topography and the ability of the surface to induce retention strength with bone. IBTSC comprises determination of 3D-surface roughness parameters by using 3D-scanning electron microscopy (3D-SEM) and atomic force microscopy (AFM), and calculation of the ability of different surface topographies to induce retention strength in bone by using the local model. Inherent in this integrated approach is the use of a length scale analysis, which makes it possible to separate different size levels of surface features. The IBTSC concept is tested on surfaces with different level of hierarchy, induced by mechanical as well as chemical treatment. Sequential treatment with oxalic and hydrofluoric acid results in precipitated nano-sized features that increase the surface roughness and the surface slope on the sub-micro and nano levels. This surface shows the highest calculated shear strength using the local model. The validity, robustness and applicability of the IBTSC concept are demonstrated and discussed.

  4. 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.

  5. Biomechanical Energy Harvester Design For Active Prostheses

    Directory of Open Access Journals (Sweden)

    Akın Oğuz Kaptı

    2012-06-01

    Full Text Available One of the factors restricting the functions of active prostheses is limited charge times and weights of the batteries. Therefore, some biomechanical energy harvesting studies are conducted for reducing the dependence on batteries and developing the systems that produce energy by utilizing one's own actions during daily living activities. In this study, as a new approach to meet energy needs of active-controlled lower limb prostheses, the design of a biomechanical energy harvester that produces electrical energy from the movements of the knee joint during gait were carried out. This harvester is composed of the generator, planetary gear system and one-way clutch that transmit just the knee extension. Low weight, low additional metabolic power consumption requirement and high electrical power generation are targeted in design process. The total reduction ratio of the transmission is 104, and the knee joint reaction torque applied by the system is 6 Nm. Average electrical powers that can be obtained are 17 W and 5,8 W for the swing extension phase and the entire cycle, respectively. These values seem to be sufficient for charging the battery units of many prostheses and similar medical systems, and portable electronic devices such as mobile phones, navigation devices and laptops.

  6. Are biomechanical changes necessary for tumor progression?

    Science.gov (United States)

    Kas, Josef A.; Fritsch, Anatol; Kiessling, Tobias; Nnetu, David K.; Pawlizak, Steve; Wetzel, Franziska; Zink, Mareike

    2011-03-01

    With an increasing knowledge in tumor biology an overwhelming complexity becomes obvious which roots in the diversity of tumors and their heterogeneous molecular composition. Nevertheless in all solid tumors malignant neoplasia, i.e. uncontrolled growth, invasion of adjacent tissues, and metastasis, occurs. Physics sheds some new light on cancer by approaching this problem from a functional, materials perspective. Recent results indicate that all three pathomechanisms require changes in the active and passive cellular biomechanics. Malignant transformation causes cell softening for small deformations which correlates with an increased rate of proliferation and faster cell migration. The tumor cell's ability to strain harden permits tumor growth against a rigid tissue environment. A highly mechanosensitive, enhanced cell contractility is a prerequisite that tumor cells can cross its tumor boundaries and that this cells can migrate through the extracellular matrix. Insights into the biomechanical changes during tumor progression may lead to selective treatments by altering cell mechanics. Such drugs would not cure by killing cancer cells, but slow down tumor progression with only mild side effects and thus may be an option for older and frail patients.

  7. Integrated biomechanical and topographical surface characterization (IBTSC)

    Science.gov (United States)

    Löberg, Johanna; Mattisson, Ingela; Ahlberg, Elisabet

    2014-01-01

    In an attempt to reduce the need for animal studies in dental implant applications, a new model has been developed which combines well-known surface characterization methods with theoretical biomechanical calculations. The model has been named integrated biomechanical and topographical surface characterization (IBTSC), and gives a comprehensive description of the surface topography and the ability of the surface to induce retention strength with bone. IBTSC comprises determination of 3D-surface roughness parameters by using 3D-scanning electron microscopy (3D-SEM) and atomic force microscopy (AFM), and calculation of the ability of different surface topographies to induce retention strength in bone by using the local model. Inherent in this integrated approach is the use of a length scale analysis, which makes it possible to separate different size levels of surface features. The IBTSC concept is tested on surfaces with different level of hierarchy, induced by mechanical as well as chemical treatment. Sequential treatment with oxalic and hydrofluoric acid results in precipitated nano-sized features that increase the surface roughness and the surface slope on the sub-micro and nano levels. This surface shows the highest calculated shear strength using the local model. The validity, robustness and applicability of the IBTSC concept are demonstrated and discussed.

  8. Modeling the biomechanics of fetal movements.

    Science.gov (United States)

    Verbruggen, Stefaan W; Loo, Jessica H W; Hayat, Tayyib T A; Hajnal, Joseph V; Rutherford, Mary A; Phillips, Andrew T M; Nowlan, Niamh C

    2016-08-01

    Fetal movements in the uterus are a natural part of development and are known to play an important role in normal musculoskeletal development. However, very little is known about the biomechanical stimuli that arise during movements in utero, despite these stimuli being crucial to normal bone and joint formation. Therefore, the objective of this study was to create a series of computational steps by which the forces generated during a kick in utero could be predicted from clinically observed fetal movements using novel cine-MRI data of three fetuses, aged 20-22 weeks. A custom tracking software was designed to characterize the movements of joints in utero, and average uterus deflection of [Formula: see text] mm due to kicking was calculated. These observed displacements provided boundary conditions for a finite element model of the uterine environment, predicting an average reaction force of [Formula: see text] N generated by a kick against the uterine wall. Finally, these data were applied as inputs for a musculoskeletal model of a fetal kick, resulting in predicted maximum forces in the muscles surrounding the hip joint of approximately 8 N, while higher maximum forces of approximately 21 N were predicted for the muscles surrounding the knee joint. This study provides a novel insight into the closed mechanical environment of the uterus, with an innovative method allowing elucidation of the biomechanical interaction of the developing fetus with its surroundings. PMID:26534772

  9. Biomechanical risk factors of non-contact ACL injuries:A stochastic biomechanical modeling study

    Institute of Scientific and Technical Information of China (English)

    Cheng-Feng; Lin; Hui; Liu; Michael; T.Gros; Paul; Weinhold; William; E.Garrett; Bing; Yu

    2012-01-01

    <正>Background:Significant efforts have been made to identify modifiable risk factors of non-contact anterior cruciate ligament(ACL) injuries in male and female athletes.However,current literature on the risk factors for ACL injury are purely descriptive.An understanding of biomechanical relationship between risk and risk factors of the non-contact ACL injury is necessary to develop effective prevention programs. Purpose:To compare lower extremity kinematics and kinetics between trials with and without non-contact ACL injuries and to determine if any difference exists between male and female trials with non-contact ACL injuries regarding the lower extremity motion patterns. Methods:In this computer simulation study,a stochastic biomechanical model was used to estimate the ACL loading at the time of peak posterior ground reaction force(GRF) during landing of the stop-jump task.Monte Carlo simulations were performed to simulate the ACL injuries with repeated random samples of independent variables.The distributions of independent variables were determined from in vivo laboratory data of 40 male and 40 female recreational athletes. Results:In the simulated injured trials,both male and female athletes had significantly smaller knee flexion angles,greater normalized peak posterior and vertical GRF.greater knee valgus moment,greater patella tendon force,greater quadriceps force,greater knee extension moment. and greater proximal tibia anterior shear force in comparison to the simulated uninjured trials.No significant difference was found between genders in any of the selected biomechanical variables in the trials with simulated non-contact ACL injuries. Conclusion:Small knee flexion angle,large posterior GRF.and large knee valgus moment are risk factors of non-contact ACL injury determined by a stochastic biomechanical model with a cause-and-effect relationship.

  10. Carpal tunnel release: do we understand the biomechanical consequences?

    Science.gov (United States)

    Morrell, Nathan T; Harris, Andrew; Skjong, Christian; Akelman, Edward

    2014-11-01

    Carpal tunnel release is a very common procedure performed in the United States. While the procedure is often curative, some patients experience postoperative scar sensitivity, pillar pain, grip weakness, or recurrent median nerve symptoms. Release of the carpal tunnel has an effect on carpal anatomy and biomechanics, including increases in carpal arch width and carpal tunnel volume and changes in muscle and tendon mechanics. Our understanding of how these biomechanical changes contribute to postoperative symptoms is still evolving. We review the relevant morphometric and biomechanical changes that occur following release of the transverse carpal ligament. PMID:25364635

  11. 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). PMID:24548899

  12. Biomechanics of knee joint — A review

    Science.gov (United States)

    Madeti, Bhaskar Kumar; Chalamalasetti, Srinivasa Rao; Bolla Pragada, S. K. Sundara siva rao

    2015-06-01

    The present paper is to know how the work is carried out in the field of biomechanics of knee. Various model formulations are discussed and further classified into mathematical model, two-dimensional model and three-dimensional model. Knee geometry is a crucial part of human body movement, in which how various views of knee is shown in different planes and how the forces act on tibia and femur are studied. It leads to know the forces acting on the knee joint. Experimental studies of knee geometry and forces acting on knee shown by various researchers have been discussed, and comparisons of results are made. In addition, static and dynamic analysis of knee has been also discussed respectively to some extent.

  13. Biomechanical Analysis of T2 Exercise

    Science.gov (United States)

    DeWitt, John K.; Ploutz-Snyder, Lori; Everett, Meghan; Newby, Nathaniel; Scott-Pandorf, Melissa; Guilliams, Mark E.

    2010-01-01

    Crewmembers regularly perform treadmill exercise on the ISS. With the implementation of T2 on ISS, there is now the capacity to obtain ground reaction force (GRF) data GRF data combined with video motion data allows biomechanical analyses to occur that generate joint torque estimates from exercise conditions. Knowledge of how speed and load influence joint torque will provide quantitative information on which exercise prescriptions can be based. The objective is to determine the joint kinematics, ground reaction forces, and joint kinetics associated with treadmill exercise on the ISS. This study will: 1) Determine if specific exercise speed and harness load combinations are superior to others in exercise benefit; and 2) Aid in the design of exercise prescriptions that will be most beneficial in maintaining crewmember health.

  14. The biomechanics of vertical hopping: a review.

    Science.gov (United States)

    Lamontagne, Mario; Kennedy, Matthew J

    2013-01-01

    Repetitive vertical hopping is a simple and relatively controlled task useful for studying basic neuromuscular properties and tissue mechanics. However, several biomechanical and physiological factors are involved. This article provides an overview of muscle and tendon properties and how these interact during vertical hopping. Muscle properties discussed are force-velocity and force-length relationships, electromechanical delay, muscle fiber type, stretch induced contraction amplification, and muscle spindle afferent feedback. Tendon properties include storage and reuse of elastic energy, tendon stiffness, afferent information from Golgi tendon organs, and failure points. These muscle and tendon properties interact to generate vertical hopping force and power. In addition to these basic properties, there are other more complicated factors to consider when analyzing vertical hopping such as balance and coordination. A wealth of information can be gathered by studying vertical hopping. Caution should be taken, however, to prevent inappropriate conclusions being drawn about hop performance due to oversimplification. PMID:24067123

  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. 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

  17. 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. PMID:21442132

  18. 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 ...

  19. The search for performance related factors in biomechanics

    OpenAIRE

    Richter, Chris

    2014-01-01

    Introduction: The identification of performance related factors (PRFs) is a major goal in sports biomechanics. However, PRFs identified across studies are inconsistent and this might be explained by the limitations of discrete point analysis, which is commonly used. New data analysis techniques involving continuous waveform analysis (e.g. functional principal component analysis, fPCA) have been suggested, but their use in biomechanics is not widespread, and they also have limitations. Anot...

  20. Carpal Tunnel Release: Do We Understand the Biomechanical Consequences?

    OpenAIRE

    Morrell, Nathan T.; Harris, Andrew; Skjong, Christian; Akelman, Edward

    2014-01-01

    Carpal tunnel release is a very common procedure performed in the United States. While the procedure is often curative, some patients experience postoperative scar sensitivity, pillar pain, grip weakness, or recurrent median nerve symptoms. Release of the carpal tunnel has an effect on carpal anatomy and biomechanics, including increases in carpal arch width and carpal tunnel volume and changes in muscle and tendon mechanics. Our understanding of how these biomechanical changes contribute to ...

  1. BIOMECHANICAL PRINCIPLES PHYSICAL REHABILITATION OF CHILDREN WITH CEREBRAL PALSY

    OpenAIRE

    S. D. Korshunov; K. V. Davletyarova; L. V. Kapilevich

    2016-01-01

    Aim. We studied the basic biomechanical principles of physical rehabilitation of children with cerebral palsy.Materials and methods. Methods of Motion Tracking and electromyography investigated the biomechanical characteristics of gait in children with cerebral palsy. It is shown that the main differences between dynamic stereotype walk pediatric patients is to delay moving forward center of gravity and the disorganization of the lower limb movements (especially knee) in the vertical plane. P...

  2. Biomechanics and Cycling BIOMECÁNICA Y CICLISMO

    OpenAIRE

    M. Gutierrez

    2010-01-01

    The aim of this essay is giving a general overview about sport cycling from a biomechanical perspective. Although it is necessary to say that the extraordinary dimension of the huge scientific production related to the topic makes difficult to deal this area in just one essay. Due to the variety of contents included into cycling biomechanics, contents in this essay have been restricted into three units: the first, focusing the study of forces opposed to displacement, and specially to the anal...

  3. Single Cell Biomechanical Phenotyping using Microfluidics and Nanotechnology

    OpenAIRE

    Babahosseini, Hesam

    2016-01-01

    Cancer progression is accompanied with alterations in the cell biomechanical phenotype, including changes in cell structure, morphology, and responses to microenvironmental stress. These alterations result in an increased deformability of transformed cells and reduced resistance to mechanical stimuli, enabling motility and invasion. Therefore, single cell biomechanical properties could be served as a powerful label-free biomarker for effective characterization and early detection of single ca...

  4. Biomechanics and control of vocalization in a non-songbird

    OpenAIRE

    Elemans, Coen P.H; Zaccarelli, Riccardo; Herzel, Hanspeter

    2007-01-01

    The neuromuscular control of vocalization in birds requires complicated and precisely coordinated motor control of the vocal organ (i.e. the syrinx), the respiratory system and upper vocal tract. The biomechanics of the syrinx is very complex and not well understood. In this paper, we aim to unravel the contribution of different control parameters in the coo of the ring dove (Streptopelia risoria) at the syrinx level. We designed and implemented a quantitative biomechanical syrinx model that ...

  5. Jet Methods in Time-Dependent Lagrangian Biomechanics

    OpenAIRE

    Ivancevic, Tijana T.

    2009-01-01

    In this paper we propose the time-dependent generalization of an `ordinary' autonomous human biomechanics, in which total mechanical + biochemical energy is not conserved. We introduce a general framework for time-dependent biomechanics in terms of jet manifolds associated to the extended musculo-skeletal configuration manifold, called the configuration bundle. We start with an ordinary configuration manifold of human body motion, given as a set of its all active degrees of freedom (DOF) for ...

  6. Biomechanics of occlusion--implications for oral rehabilitation.

    Science.gov (United States)

    Peck, C C

    2016-03-01

    The dental occlusion is an important aspect of clinical dentistry; there are diverse functional demands ranging from highly precise tooth contacts to large crushing forces. Further, there are dogmatic, passionate and often diverging views on the relationship between the dental occlusion and various diseases and disorders including temporomandibular disorders, non-carious cervical lesions and tooth movement. This study provides an overview of the biomechanics of the masticatory system in the context of the dental occlusion's role in function. It explores the adaptation and precision of dental occlusion, its role in bite force, jaw movement, masticatory performance and its influence on the oro-facial musculoskeletal system. Biomechanics helps us better understand the structure and function of biological systems and consequently an understanding of the forces on, and displacements of, the dental occlusion. Biomechanics provides insight into the relationships between the dentition, jaws, temporomandibular joints, and muscles. Direct measurements of tooth contacts and forces are difficult, and biomechanical models have been developed to better understand the relationship between the occlusion and function. Importantly, biomechanical research will provide knowledge to help correct clinical misperceptions and inform better patient care. The masticatory system demonstrates a remarkable ability to adapt to a changing biomechanical environment and changes to the dental occlusion or other components of the musculoskeletal system tend to be well tolerated. PMID:26371622

  7. 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.

  8. Brain injury biomechanics in closed-head impact : Studies on injury epidemiology, tolerance criteria, biomechanics and traffic injury prevention

    OpenAIRE

    Viano, David

    1997-01-01

    Permanent disability from traumatic brain injury is a devastating consequence of traffic crashes. Injury prevention is a fruitful approach to reduce the incidence and severity of disabling brain injury. However, the development of effective prevention techniques requires better knowledge on the mechanisms and biomechanics of brain injury in closed-head impact. The overall aim of this study is focused on brain injury mechanisms, biomechanics, and tolerances in closed-head ...

  9. 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 < 0.05. The goodness of fit of the proposed models was determined using Akaike information criteria. Aesthetic proficiency and smoothness rankings of the dance movements revealed differences between groups and condition, p < 0.0001. EXP dancers were rated more aesthetically proficient than INT dancers. The slow and fast conditions were judged more aesthetically proficient than slow with relevé (p < 0.0001). Of the metrics, PCA best captured the differences due to group and condition. PCA also provided the most parsimonious model to explain aesthetic proficiency and smoothness rankings. By permitting organization of large data sets into simpler groupings, PCA may mirror the phenomenon of chunking in which the 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

  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. SERVICE IN BADMINTON: A BIOMECHANICAL STUDY

    Directory of Open Access Journals (Sweden)

    Saleem Ahmed

    2015-03-01

    Full Text Available To find out the differences between forehand and backhand short services in badminton, the present study was designed to analyze the biomechanical variables and segmental angles - shuttle velocity, wrist angle, elbow angle and shoulder angle of six male badminton players. The data were recorded during “North-Zone Intervarsity Championship” held at Aligarh Muslim University, Aligarh, India. All subjects in the study were right handed badminton players. The mean age, body height and body weight were reported as 18.33 years (±1.71, 166.5cm (±3.30 and 57.17kg (±7.93 respectively. The movements were recorded by ‘Canon Legria HF S10 Comcorder’ operating at 60 Hz. The identified clips were analyzed with the help of ‘Silicon Coach Pro 7’ motion analysis software. The result revealed that there was significant difference found between forehand and backhand short service in respect to shoulder angle at 0.05 level of significance.

  12. Functional anatomy and biomechanics of the carpus

    International Nuclear Information System (INIS)

    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.)

  13. The biomechanics of throwing: simplified and cogent.

    Science.gov (United States)

    Weber, Alexander E; Kontaxis, Andreas; O'Brien, Stephen J; Bedi, Asheesh

    2014-06-01

    The majority of shoulder injuries occur due to repetitive overhead movements, with baseball pitching being the most common mechanism for overuse injury. Before studying the treatment of these shoulder injuries, it is paramount that the health professional have an understanding of the etiology of and the underlying mechanisms for shoulder pathology. The act of overhead throwing is an eloquent full-body motion that requires tremendous coordination from the time of force generation to follow-through. The shoulder complex is a crucial component of the upper body kinetic chain as it transmits force created in the lower body to the arm and hand to produce velocity and accuracy with ball release. The focus of this article is on the biomechanics of the throwing motion, with emphasis on the kinematics of the shoulder. The established phases of the throwing motion will be reviewed in a stepwise manner and the contributions of osseous and soft-tissue structures to the successful completion of each phase will be discussed. PMID:24787720

  14. 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.

  15. New Trends in Dental Biomechanics with Photonics Technologies

    Directory of Open Access Journals (Sweden)

    Lídia Carvalho

    2015-11-01

    Full Text Available Engineering techniques used to evaluate strain-stress fields, materials’ mechanical properties, and load transfer mechanisms, among others, are useful tools in the study of biomechanical applications. These engineering tools, as experimental and numerical ones, were imported to biomechanics, in particular in dental biomechanics, a few decades ago. Several experimental techniques have been used in dental biomechanics, like photoelasticity, ESPI (Electronic Speckle Pattern Interferometry, strain gages, and other kinds of transducers. However, these techniques have some limitations. For instance, photoelasticity and ESPI give the overall field pattern of the strain, showing the stress-strain concentration points. These methods cannot give an accurate measurement at all points. On the contrary, strain gages can be used to perform local measurements. However, as they use electrical resistances, their use is limited to perform in vivo measurements. Optical fiber sensors have already been used in dentistry, for diagnostic and therapeutic purposes, and in dental biomechanics studies. Lasers have also been used in clinical dentistry for a few decades. Other optical technologies, like optical coherence tomography (OCT, became suitable for dental practice and nowadays it is perhaps one that has had more development in dentristry, along with lasers.

  16. Biomechanical analysis of plate stabilization on cervical part of spine

    Directory of Open Access Journals (Sweden)

    M. Kiel

    2009-07-01

    Full Text Available Purpose: The main aim of the work was determination of biomechanical analysis of cervical spine – stabilizer system made of stainless steel (Cr-Ni-Mo and Ti-6Al-4V alloy.Design/methodology/approach: To define biomechanical characteristic of the system the finite elements method (FEM was applied. Geometric model of part of spine C5-C7 and stabilizer were discretized by SOLID95 element. Appropriate boundary conditions imitating phenomena in real system with appropriate accuracy were established.Findings: The result of biomechanical analysis was calculation of displacements and stresses in the vertebras and the stabilizer in a function of the applied loading: 50-300 N for the stabilizer made of stainless steel (Cr-Ni-Mo and Ti-6Al-4V alloy.Research limitations/implications: The result of biomechanical analysis for plate stabilizer obtained by FEM can be use to determine a construction features of the stabilizer, and to select mechanical properties of metallic biomaterial and estimation of stabilization quality. The calculation of displacements for part C5-C7 show that the proposed type of stabilizer enables correct stabilization used to clinical apply.Practical implications: The results of biomechanical analysis showed correct mechanical properties used to made the plate stabilizer.Originality/value: The obtained numerical results should be verified in “in vitro” tests.

  17. A selection of biomechanical research problems: From modeling to experimentation

    Science.gov (United States)

    Abbasi, Cyrus Omid

    The research undertakings within this manuscript illustrate the importance of biomechanics in today's science. Without doubt, biomechanics can be utilized to obtain a better understanding of many unsolved mysteries involved in the field of medicine. Moreover, biomechanics can be used to develop better prosthetic or surgical devices as well. Chapter 2 represents a medical problem, which has not been solved for more than a century. With the use of fundamental principles of biomechanics', a better insight of this problem and its possible causes were obtained. Chapter 3 investigates the mechanical interaction between the human teeth and some processed food products during mastication, which is a routine but crucial daily activity of a human being. Chapter 4 looks at a problem within the field of surgery. In this chapter the stability and reliability of two different Suturing-Techniques are explored. Chapters 5 and 6 represent new patent designs as a result of the investigations made in Chapter 4. Chapter 7 studies the impact and load transfer patterns during the collision between a child's head and the ground. All of the above mentioned chapters show the significance of biomechanics in solving a range of different medical problems that involve physical and or mechanical characters.

  18. Biomechanics of Kuzushi-Tsukuri and Interaction in Competition

    CERN Document Server

    Sacripanti, Attilio

    2010-01-01

    In this paper it is performed the comparative biomechanical analysis of the Kuzushi (Unbalance) -Tsukuri (the entry and proper fitting of Tori's body into the position taken just before throwing) phases of Judo Throwing techniques. The whole effective movement is without separation, as already stated by old Japanese biomechanical studies (1972 -1978), only one skilled connected action, but the biomechanical analysis is able to separate the whole in didactic steps called Action Invariants. The first important finding singled out is the existence of two classes of Action Invariants the first the General one' connected to the whole body motion is specific of shortening distance in the Kuzushi Tsukuri Phase. The second one, the Specific Action Invariants is connected to the superior and inferior kinetic chains motion and right positioning connected both to Kuzushi and Tsukuri phases. Some interesting findings derive from this analysis: among throwing techniques, couple techniques could be independent from Kuzushi...

  19. 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.

  20. 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.

  1. 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.

  2. The increasing importance of the biomechanics of impact trauma

    Indian Academy of Sciences (India)

    Murray Mackay

    2007-08-01

    The evolution of experimental biomechanics and crash injury research is summarized briefly to show that they both play a major role in mitigating traffic deaths and injuries. Historically, the subject has been based largely in western countries and thus focused on vehicle occupants, whereas some 80% of traffic casualties in the world are outside the vehicle as pedestrians, cyclists and motorcyclists. The subject is close to the regulatory process which controls vehicle design and is thus heavily influenced by government and industry, yet it is now in an expanding period because of new techniques to replicate the human frame’s response to impact forces. New knowledge is likely to emerge from addressing population variations and combining real world accident investigations with experimental biomechanics. The application of impact biomechanics to the vulnerable road users is of particular importance.

  3. The biomechanical and structural properties of CS2 fimbriae

    CERN Document Server

    Mortezaei, Narges; Zakrisson, Johan; Bullitt, Esther; Andersson, Magnus

    2015-01-01

    Enterotoxigenic Escherichia coli (ETEC) are a major cause of diarrhea worldwide, and infection of children in underdeveloped countries often leads to high mortality rates. Isolated ETEC express a plethora of colonization factors (fimbriae/pili), of which CFA/I and CFA/II that are assembled via the alternate chaperone pathway (ACP), are amongst the most common. Fimbriae are filamentous structures, whose shafts are primarily composed of helically arranged single pilin-protein subunits, with a unique biomechanical capability allowing them to unwind and rewind. A sustained ETEC infection, under adverse conditions of dynamic shear forces, is primarily attributed to this biomechanical feature of ETEC fimbriae. Recent understandings about the role of fimbriae as virulence factors are pointing to an evolutionary adaptation of their structural and biomechanical features. In this work, we investigated the biophysical properties of CS2 fimbriae from the CFA/II group. Homology modelling its major structural subunit CotA ...

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

    Directory of Open Access Journals (Sweden)

    Batieieva N.P.

    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.

  5. 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...

  6. 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.

  7. 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......) with a suspected degenerative medial meniscal tear participated in this study. Three dimensional knee biomechanics were assessed on the injured and contralateral leg before and three months after APM. The visual analogue scale was used to assess knee pain and the Knee Injury Osteoarthritis Outcome Score was used...

  8. Advances in compression nails - principles and biomechanical photoelastic evaluation

    Energy Technology Data Exchange (ETDEWEB)

    Mittelmeier, W.; Hauschild, M.; Bader, R.; Steinhauser, E. [Technische Univ. Muenchen (Germany). Klinik fuer Orthopaedie und Sportorthopaedie

    2001-12-01

    The nail-osteosynthesis is an established concept for shaft-fractures of long bones. The compression-nail ICN enables a favourable primary-stability and also a former full weight-bearing over a precompression of the nail-bone-system. The indications of the compression-nail include beside more diaphyseal cross fractures and short oblique fractures non-unions and correction-osteotomies. Newer modular nail-types like the tandem compression nail (TCN) can improve the biomechanical prerequisites of the compression nail principle. Key-words: internal fixation - interlocking-nail - modular - compression - biomechanics - non-union (orig.)

  9. Biomechanical exploration on dynamic modes of lifting.

    Science.gov (United States)

    Gagnon, M; Smyth, G

    1992-03-01

    Whatever the lifting method used, dynamic factors appear to have an effect on the safe realization of movement, and NIOSH guidelines recommend smooth lifting with no sudden acceleration effects. On the other hand, inertial forces may play an important role in the process of transfer of momentum to the load. The direction by which these inertial forces may affect the loadings on body structures and processes of energy transfers cannot be determined a priori. A biomechanical experiment was performed to examine if there were differences in the execution processes between a slow-continuous lift and an accelerated-continuous lift, and also between accelerated lifts either executed continuously or interrupted with a pause. The lifts were executed from a height of 15 cm to a height of 185 cm above the head and with two different loads (6.4 and 11.6 kg). Five experienced workers in manual materials handling were used as subjects. Films and force platforms recordings supplied the data; dynamic segmental analyses were performed to calculate net muscular moments at each joint; a planar single-muscle equivalent was used to estimate compression loadings at L5/S1; total mechanical work, joint work distribution, and energy transfers were determined from a kinetic approach based on the integration of joint power as a function of time. Analyses of variance with repeated measures were applied to the three treatments. The results showed that joint muscular moments, spinal loadings, mechanical work, and muscular utilization ratios were generally increased by the presence of acceleration without inducing benefits of improved energy transfers; therefore slower lifts with reduced acceleration may be safer when handling moderately heavy loads. The maximum values of kinematic and kinetic factors were generally not affected by the pause, but the occurrence of jerks in the movement (acceleration, ground forces, and muscular moments) suggests that the pause may not be indicated when

  10. Expandable intramedullary nail - experimental biomechanical evaluation

    Directory of Open Access Journals (Sweden)

    A. Kajzer

    2010-01-01

    Full Text Available Purpose: The paper presents results of experimental analysis of femur and femur – expandable intramedullary nail system. The aim of the work was to determine displacement in three models. In addition, the torsion of the system aiming at determining the moments depending on the torsional angle of the bone was carried out.Design/methodology/approach: Three femurs were selected for studies. The analysis was carried out on the femur – expandable intramedullary nail system. The influence of the loads and displacements on the bone – nail system on the results of experimental analysis was analysed. In order to carry out calculations, three models were selected: model I – bone without fracture gap, model II and III – femur with expansion intramedullary nails – fracture gap was located 100 mm under greater trochanter. The studies were performed on femur models produced by Swedish company Sawbones. The intramedullary „Fixion IM” nails (Ti-6Al-4V alloy were implanted into the bone. Displacements of determinated models were being recorded from the sensors every 100 N from 10 N to 2000 N.Findings: The analyses showed the difference in displacements, depending on the selected models.Research limitations/implications: The limitations were connected with simplification of boundary conditions during analysis which were the result of the simplification of the models. While studying, muscles and ligaments supporting the bone in anatomic position were not taken into consideration. Instead, the system has been loaded with the axial force (compression.Practical implications: The obtained results can be useful in clinical practice. They can be applied in selection of stabilization methods or rehabilitation as well as in describing the biomechanical conditions connected with type of bone fracture obtained from medical imaging.Originality/value: . The work compares the values of displacement of characteristic points of femur (healthy – model I with the

  11. Anthropometry and Biomechanics Facility Spring 2016 Internship

    Science.gov (United States)

    Boppana, Abhishektha

    2016-01-01

    The Anthropometry and Biomechanics Facility (ABF) at Johnson Space Center supports the Space Human Factors Engineering portfolio of the Human Research Program. ABF provides capability to verify the accommodation and comfort of crewmembers through anthropometry and biomechanics analyses. Anthropometric measurements are derived from three-dimensional (3D) whole body scan images. The scans are currently taken by a Human Solutions Vitus 3D Laser Scanning System. ABF has purchased a 3dMD photogrammetry scanner system to speed up the process of collecting 3D scans. The photogrammetry scanner system features a faster data collection time, as well as fewer holes in the scans. This internship was mainly focused on developing calibration, measurement, data acquisition, and analysis processes for the new system. In addition, I also participated in a project to validate the use of a pressure mat sensor on the shoulder during in-suit testing. My duties for the scanner validation project started with identifying and documenting a calibration process. The calibration process proved vital to using the system as the quality of the scans was directly related to the success of the calibration. In addition, the calibration process suggested by the system vendor required the user to hold a large calibration board at precise locations. To aid in this, I built a calibration stand which held a calibration board at constant positions throughout numerous calibration process. The calibration process was tested extensively until proven acceptable. The standardized process reduced calibration time from over 10 minutes to just below three minutes. As a result, the calibration process could be completed painlessly and precisely, and scan quality was constant between sessions. After standardizing the calibration process, I proceeded to modify the locations of the cameras in order to capture the full volume of a person. The scanning system needed to capture a full T-pose of a person in one scan

  12. 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…

  13. 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...

  14. 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.…

  15. 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…

  16. Corneal biomechanical changes following toric soft contact lens wear

    Directory of Open Access Journals (Sweden)

    Somayeh Radaie-Moghadam

    2016-01-01

    Conclusion: CH and CRF decreased significantly one month after fitting toric soft contact lenses while CCT and K mean did not change significantly. Corneal biomechanical parameters may alter with toric soft contact lens use and such changes may have implications with long-term use such lenses.

  17. 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...

  18. 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. PMID:26765780

  19. Computational modelling of biomechanical behaviour of skeletal elements and implants

    Czech Academy of Sciences Publication Activity Database

    Jíra, J.; Jiroušek, Ondřej; Jírová, Jitka

    Anaheim Calgary Zurich : ACTA Press, 2004 - (Hamza, M.), s. 170 ISBN 0-88986-448-9. [Biomechanics /2./. Honolulu (US), 23.08.2004-25.08.2004] Institutional research plan: CEZ:AV0Z2071913 Keywords : FE model of pelvis * skull and long bone * CT scan Subject RIV: FI - Traumatology, Orthopedics

  20. A review of probabilistic analysis in orthopaedic biomechanics

    OpenAIRE

    Laz, P.J.; Browne, M.

    2010-01-01

    Probabilistic analysis methods are being increasingly applied in the orthopaedics and biomechanics literature to account for uncertainty and variability in subject geometries, properties of various structures, kinematics and joint loading, as well as uncertainty in implant alignment. As a complement to experiments, finite element modelling, and statistical analysis, probabilistic analysis provides a method of characterizing the potential impact of variability in parameters on performa...

  1. The Biomechanical Implications of Obesity in K-12 Learners

    Science.gov (United States)

    Strohmeyer, Scott

    2007-01-01

    Few biomechanical studies have examined obese individuals as primary subjects. However, some mechanical differences have been identified between overweight or obese individuals and nonoverweight movers. It is not clear how obesity affects the onset of osteoarthritis, for example, but it is evident that obesity does place significant limitations on…

  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. LUMBAR SPINAL STENOSIS. A REVIEW OF BIOMECHANICAL STUDIES

    Institute of Scientific and Technical Information of China (English)

    戴力扬; 徐印坎

    1998-01-01

    ObjectS. To investigate the biomechanical aspects of etiology, pathology, clinical manifestation, diagnosis and surgical treatment of the lumbar spinal stenosis. Methods. A series of biomechanical methods, such as three-dimensional finite element models, threedimensional kinematic measurement, cadeveric evaluation, and imaging assessment was applied to correlate lumbar biomechanics and lumber spinal stenosls. Surgery of lumber spinal stenosis has been improved. Results.The stresses significantly concentrate on the posterolateral part of the annulus fibrcsms of disc, the posterior surface of vertebral body, the pedlcle, the interarticularis and the beet joints. This trend is intensified by disc degeneration and lumber backward extension. Posterior elcxnent resection has a definite effect upon the biomechanical behavior of lumbar vertebrae. The improved operations proved satisfactory. Conclusion. Stress concentration in the lumber vertebrae is of importance to the etiology of degenerative lumbar spinal stenosls, and disc degeneratkm is the initial key of this process. Than these will be aggravatnd by backward extension. Functloval radiography and myelography are of assistance to the diagnosis of the lumhar spinal stenosls. For the surgcal treatment of the lumber spinal stenosis, destruction of the posterior element should be avoid as far as possible based upon the thorough decmnpression. Maintaining the lumbar spine in flexion by fusion after decorapression has been proved a useftd method. When developmental spinal stenoals is combined with disc herniation, discectoray through laminotomy is recommend for decompression.

  4. 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.

  5. 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. T

  6. 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.

  7. 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

  8. 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

  9. 3D printed guides for controlled alignment in biomechanics tests.

    Science.gov (United States)

    Verstraete, Matthias A; Willemot, Laurent; Van Onsem, Stefaan; Stevens, Cyriëlle; Arnout, Nele; Victor, Jan

    2016-02-01

    The bone-machine interface is a vital first step for biomechanical testing. It remains challenging to restore the original alignment of the specimen with respect to the test setup. To overcome this issue, we developed a methodology based on virtual planning and 3D printing. In this paper, the methodology is outlined and a proof of concept is presented based on a series of cadaveric tests performed on our knee simulator. The tests described in this paper reached an accuracy within 3-4° and 3-4mm with respect to the virtual planning. It is however the authors' belief that the method has the potential to achieve an accuracy within one degree and one millimeter. Therefore, this approach can aid in reducing the imprecisions in biomechanical tests (e.g. knee simulator tests for evaluating knee kinematics) and improve the consistency of the bone-machine interface. PMID:26810696

  10. Valgus torque in youth baseball pitchers: A biomechanical study.

    Science.gov (United States)

    Sabick, Michelle B; Torry, Michael R; Lawton, Richard L; Hawkins, Richard J

    2004-01-01

    The purpose of this study was to determine the biomechanical and anthropometric factors contributing to elbow valgus torque during pitching. Video data of 14 youth pitchers throwing fastballs were used to calculate shoulder and elbow kinematics and kinetics. Peak elbow valgus torque averaged 18 Nm and occurred just before maximal shoulder external rotation. The magnitude of valgus torque was most closely correlated with the thrower's weight. When subject weight and height were controlled for, maximum shoulder abduction torque and maximum shoulder internal rotation torque were most strongly associated with elbow valgus torque, accounting for 85% of its variance (P <.001). When only kinematic variables were considered, maximum shoulder external rotation accounted for 33% of the variance in valgus torque. Given that the biomechanical variables correlated with peak valgus torque are not easily modifiable, limiting the number of innings pitched is likely the best way to reduce elbow injury in youth pitchers. PMID:15111908

  11. Biomechanical Evaluation of 6.5-mm Cannulated Screws.

    Science.gov (United States)

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

    2016-01-01

    Although biomechanical and clinical evidence exists regarding smaller compression screws, biomechanical data regarding the larger headless screws are not currently available. Headed and headless 6.5-mm cannulated compression screws were examined, with analysis of interfragmentary compression, insertion torque, and resistance of the construct to a shear force. No significant differences were seen between the maximum insertion torque of the headless or headed screws. Maximum and steady-state compression forces were also not significantly different between groups. Countersinking the headless model 2 mm led to a 77.01% decrease in steady-state compression levels. Shear testing did not reveal any significant differences in peak load at ultimate failure, specimen stiffness, or final block displacement, although a trend to increased peak load and stiffness was seen with the headless specimens. PMID:27082882

  12. Smart Materials in Structural Health Monitoring, Control and Biomechanics

    CERN Document Server

    Soh, Chee-Kiong; Bhalla, Suresh

    2012-01-01

    "Smart Materials in Structural Health Monitoring, Control and Biomechanics" presents the latest developments in structural health monitoring, vibration control and biomechanics using smart materials. The book mainly focuses on piezoelectric, fibre optic and ionic polymer metal composite materials. It introduces concepts from the very basics and leads to advanced modelling (analytical/ numerical), practical aspects (including software/ hardware issues) and case studies spanning civil, mechanical and aerospace structures, including bridges, rocks and underground structures. This book is intended for practicing engineers, researchers from academic and R&D institutions and postgraduate students in the fields of smart materials and structures, structural health monitoring, vibration control and biomedical engineering. Professor Chee-Kiong Soh and Associate Professor Yaowen Yang both work at the School of Civil and Environmental Engineering, Nanyang Technological University, Singapore. Dr. Suresh Bhalla is an A...

  13. 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.

  14. [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. PMID:26072625

  15. 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\tthe 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.

  16. Scapholunate Interosseous Ligament Anatomy and Biomechanics.

    Science.gov (United States)

    Rajan, Prashant V; Day, Charles S

    2015-08-01

    Injury to the scapholunate interosseous ligament is one of the most common causes of carpal instability and can impart considerable compromise to the patient's hand function. However, the management of scapholunate ligament injuries remains a dynamic concept, especially with regard to the multitude of options and techniques that exist for its surgical treatment. We present a thorough review of scapholunate anatomy and morphology, and the role of the scapholunate articulations in the kinetics and pathomechanics of wrist instability. We also review the current literature on the biomechanical properties of the scapholunate ligament and its subcomponents. A sound understanding of the anatomy and biomechanics of the scapholunate ligament can clarify its instability and may better orient current reconstructive procedures or pioneer better future techniques. PMID:26143029

  17. Musculoskeletal demands on flamenco dancers: a clinical and biomechanical study.

    Science.gov (United States)

    Bejjani, F J; Halpern, N; Pio, A; Dominguez, R; Voloshin, A; Frankel, V H

    1988-04-01

    The flamenco dancer acts on the floor like a drummer. The percussive footwork and vibration patterns created during dancing impose unusual demands on the musculoskeletal system. This study investigated the clinical and biomechanical aspects of this task. Using the electrodynogram and skin-mounted accelerometers, foot pressures as well as hip and knee vibrations were recorded in 10 female dancers after a thorough clinical evaluation. A health questionnaire was also distributed to 29 dancers. Foot pressures and acceleration data reveal the percussive nature of the dance. Some clinical findings, like calluses, are related to pressure distribution. Urogenital disorders, as well as back and neck pain, may be related to the vibrations generated by the flamenco dance form. The hip joint seems to absorb most of the impacts. "Vibration-pressure" diagrams are suggested as a useful tool for evaluating a dancer's biomechanical behavior, as well as the effect of floors and footwear on this behavior. PMID:3366430

  18. The biomechanics of kicking in soccer: a review.

    Science.gov (United States)

    Lees, A; Asai, T; Andersen, T B; Nunome, H; Sterzing, T

    2010-06-01

    Kicking is the defining action of soccer, so it is appropriate to review the scientific work that provides a basis of our understanding of this skill. The focus of this review is biomechanical in nature and builds on and extends previous reviews and overviews. While much is known about the biomechanics of the kicking leg, there are several other aspects of the kick that have been the subject of recent exploration. Researchers have widened their interest to consider the kick beginning from the way a player approaches the ball to the end of ball flight, the point that determines the success of the kick. This interest has encapsulated characteristics of overall technique and the influences of the upper body, support leg and pelvis on the kicking action, foot-ball impact and the influences of footwear and soccer balls, ball launch characteristics and corresponding flight of the ball. This review evaluates these and attempts to provide direction for future research. PMID:20509089

  19. 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.

  20. Biomechanical tactics of chiral growth in emergent aquatic macrophytes

    Science.gov (United States)

    Zhao, Zi-Long; Zhao, Hong-Ping; Li, Bing-Wei; Nie, Ben-Dian; Feng, Xi-Qiao; Gao, Huajian

    2015-07-01

    Through natural selection, many plant organs have evolved optimal morphologies at different length scales. However, the biomechanical strategies for different plant species to optimize their organ structures remain unclear. Here, we investigate several species of aquatic macrophytes living in the same natural environment but adopting distinctly different twisting chiral morphologies. To reveal the principle of chiral growth in these plants, we performed systematic observations and measurements of morphologies, multiscale structures, and mechanical properties of their slender emergent stalks or leaves. Theoretical modeling of pre-twisted beams in bending and buckling indicates that the different growth tactics of the plants can be strongly correlated with their biomechanical functions. It is shown that the twisting chirality of aquatic macrophytes can significantly improve their survivability against failure under both internal and external loads. The theoretical predictions for different chiral configurations are in excellent agreement with experimental measurements.

  1. Derivation, simulation and validation of poroelastic models in dental biomechanics

    OpenAIRE

    Favino, Marco; Krause, Rolf

    2015-01-01

    Poroelasticity and mechanics of growth are playing an increasingly relevant role in biomechanics. This work is a self- contained and holistic presentation of the modeling and simulation of non-linear poroelasticity with and without growth inhomogeneities. Balance laws of poroelasticity are derived in Cartesian coordinates. These allow to write the governing equations in a form that is general but also readily implementable. Closure relations are formally derived from the study of dissipati...

  2. Biomechanical simulation of thorax deformation using finite element approach

    OpenAIRE

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

    2016-01-01

    Background 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. Methods We constructed a finite element model of t...

  3. 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.

  4. Biomechanical analysis of the camelid cervical intervertebral disc

    OpenAIRE

    Dean K. Stolworthy; R. Amy Fullwood; Tyler M. Merrell; Bridgewater, Laura C.; Anton E. Bowden

    2015-01-01

    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 o...

  5. Biomechanical evaluation of an expansive pedicle screw in calf vertebrae

    OpenAIRE

    Lei, Wei; Wu, Zixiang

    2005-01-01

    The main objective of the present study is to evaluate biomechanically a newly designed expansive pedicle screw (EPS) using fresh pedicles from calf lumber vertebrae in comparison with conventional pedicle screws, (CDH) CD Horizon, Universal Spine System pedicle screw (USS) and Tenor (Sofamor Denek). Pull-out and turning-back tests were performed on these pedicle screws to compare their holding strength. Additionally, revision tests were undertaken to evaluate the mechanical properties of EPS...

  6. A Microfluidic Platform for Profiling Biomechanical Properties of Bacteria

    OpenAIRE

    Sun, Xuanhao; Weinlandt, William D; Patel, Harsh; WU, Mingming; Hernandez, Christopher J.

    2014-01-01

    The ability to resist mechanical forces is necessary for the survival and division of bacteria and has traditionally been probed using specialized, low-throughput techniques such as atomic force microscopy and optical tweezers. Here we demonstrate a microfluidic technique to profile the stiffness of individual bacteria and populations of bacteria. The approach is similar to micropipette aspiration used to characterize the biomechanical performance of eukaryotic cells. However, the small size ...

  7. Application of optimal control to a biomechanics model

    OpenAIRE

    Krasovskii, A.

    2015-01-01

    A model of sport biomechanics describing short-distance running (sprinting) is developed by applying methods of optimal control. In the considered model, the motion of a sportsman is described by a second-order ordinary differential equation. Two interconnected optimal control problems are formulated and solved: the minimum energy and time-optimal control problems. Based on the comparison with real data, it is shown that the proposed approach to sprint modeling provides realistic results.

  8. Biomechanical considerations on tooth-implant supported fixed partial dentures

    OpenAIRE

    Michalakis, Konstantinos X.; Calvani, Pasquale; Hirayama, Hiroshi

    2012-01-01

    This article discusses the connection of teeth to implants, in order to restore partial edentulism. The main problem arising from this connection is tooth intrusion, which can occur in up to 7.3% of the cases. The justification of this complication is being attempted through the perspective of biomechanics of the involved anatomical structures, that is, the periodontal ligament and the bone, as well as that of the teeth- and implant-supported fixed partial dentures.

  9. 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.

  10. Corneal Structure and Biomechanics in Collagen Vascular Diseases

    OpenAIRE

    Colaço, Maria Luisa; Franco, Mónica; Pinto, Rita; Maia Sêco, José

    2015-01-01

    Purpose: The purpose of this study was to evaluate corneal biomechanics and structure in asymptomatic individuals with Collagen Vascular Diseases (CVD), and compare with an age- -matched control group. Methods: In this prospective study 23 patients with the diagnosis of CVD (46 eyes) and 17 healthy age and gender-matched controls (34 eyes) underwent Ocular Response Analyzer and Specular Microscopy measurements. CH and CRF were recorded for each eye using the ORA, pachymetry and endothelial ce...

  11. Biomechanical models to simulate consequences of maxillofacial surgery

    OpenAIRE

    Payan, Yohan; Chabanas, Matthieu; Pelorson, Xavier; Vilain, Coriandre; Levy, Patrick; Luboz, Vincent; Perrier, Pascal

    2002-01-01

    This paper presents the biomechanical finite element models that have been developed in the framework of the computer-assisted maxillofacial surgery. After a brief overview of the continuous elastic modelling method, two models are introduced and their use for computer-assisted applications discussed. The first model deals with orthognathic surgery and aims at predicting the facial consequences of maxillary and mandibular osteotomies. For this, a generic three-dimensional model of the face is...

  12. On seed physiology, biomechanics and plant phenology in Eragrostis tef

    OpenAIRE

    Delden, van, J.

    2011-01-01

    • Key words: Teff (Eragrostis tef (Zuccagni) Trotter), germination, temperature, model, leaf appearance, phyllochron, development rate, lodging, biomechanics, safety factor, flowering, heading, day length, photoperiod. • Background Teff (Eragrostis tef (Zuccagni) Trotter) is a C4 annual grass species (Poaceae) originating from Ethiopia. Teff cultivation in the Netherlands is thought to be economically feasible because teff grains and flour do not contain gluten and are rich in iron....

  13. Absorbable scaphoid screw development: a comparative study on biomechanics

    OpenAIRE

    Xu, Yongqing

    2016-01-01

    Yi Wang, Muguo Song, Yongqing Xu, Xiaoqing He, YueLiang Zhu Department of Orthopedic Surgery, Kunming General Hospital, Chengdu Military Command, People’s Liberation Army, Kunming, Yunnan, People’s Republic of China Background: The scaphoid is critical for maintaining the stability and movement of the wrist joints. This study aimed to develop a new internal fixator absorbable scaphoid screw (ASS) for fixation of the scaphoid waist after fracture and to test the biomechan...

  14. Absorbable scaphoid screw development: a comparative study on biomechanics

    OpenAIRE

    Wang Y; Song MG; Xu YQ; He XQ; Zhu YL

    2016-01-01

    Yi Wang, Muguo Song, Yongqing Xu, Xiaoqing He, YueLiang Zhu Department of Orthopedic Surgery, Kunming General Hospital, Chengdu Military Command, People’s Liberation Army, Kunming, Yunnan, People’s Republic of China Background: The scaphoid is critical for maintaining the stability and movement of the wrist joints. This study aimed to develop a new internal fixator absorbable scaphoid screw (ASS) for fixation of the scaphoid waist after fracture and to test the biomechanical cha...

  15. Absorbable scaphoid screw development: a comparative study on biomechanics

    OpenAIRE

    Wang, Yi; Song, Muguo; Xu, Yongqing; He, Xiaoqing; Zhu, Yueliang

    2016-01-01

    Background The scaphoid is critical for maintaining the stability and movement of the wrist joints. This study aimed to develop a new internal fixator absorbable scaphoid screw (ASS) for fixation of the scaphoid waist after fracture and to test the biomechanical characteristics of ASS. Materials and methods An ASS was prepared using polylactic acids and designed based on scaphoid measurements and anatomic features. Twenty fractured scaphoid waist specimens were randomly divided into experimen...

  16. Biomechanical Evaluation of Capsulotomy and Capsular Repair in the Hip

    OpenAIRE

    Wuerz, Thomas H.; Song, Sang Hoon; Grzybowski, Jeffrey S.; Greenberg, Mitchell; Espinoza, Alejandro; Nho, Shane Jay

    2015-01-01

    Objectives: The use of hip arthroscopy has increased over recent years to treat various forms of hip pathologies including femoroacetabular impingement. While a capsulotomy facilitates adequate visualization and access for diagnostic and interventional purposes, the current literature remains divided over the use of routine capsular closure to address the iatrogenic instability that may be induced by an excessive or unclosed capsulotomy. The purpose of this biomechanical study was to determin...

  17. Biomechanical evaluation of fixation degree of fragments by periosteal osteosynthesis

    Directory of Open Access Journals (Sweden)

    Barabash Yu.A.

    2010-09-01

    Full Text Available Expansion of indications for surgery and plate osteosynthesis of long bones points to increased number of complications caused by instability of fragments, that can be associated in their turn with constructive features or iatrogenic factors. Insufficient rigidity of fragment fixation is due to incorrect technical treatment and wrong choice of fixator. Biomechanical parameters of periosteal fixation rigidity have been experimentally proved, depending on fixator lever

  18. Biomechanics of DNA structures visualized by 4D electron microscopy

    OpenAIRE

    Lorenz, Ulrich J.; Zewail, Ahmed H.

    2013-01-01

    We present a technique for in situ visualization of the biomechanics of DNA structural networks using 4D electron microscopy. Vibrational oscillations of the DNA structure are excited mechanically through a short burst of substrate vibrations triggered by a laser pulse. Subsequently, the motion is probed with electron pulses to observe the impulse response of the specimen in space and time. From the frequency and amplitude of the observed oscillations, we determine the normal modes and eig...

  19. Biomechanical properties of peripheral nerve after acellular treatment

    Institute of Scientific and Technical Information of China (English)

    MA Xin-long; SUN Xiao-lei; YANG Zhao; LI Xiu-lan; MA Jian-xiong; ZHANG Yang; YUAN Zhen-zhen

    2011-01-01

    Background Peripheral nerve injury causes a high rate of disability and a huge economic burden,and is currently one of the serious health problems in the world.The use of nerve grafts plays a vital role in repairing nerve defects.Acellular nerve grafts have been widely used in many experimental models as a peripheral nerve substitute.The purpose of this study was to test the biomechanical properties of acellular nerve grafts.Methods Thirty-four fresh sciatic nerves were obtained from 17 adult male Wistar rats (age of 3 months) and randomly assigned to 3 groups:normal control group,nerve segments underwent no treatment and were put in phosphate buffered saline (pH 7.4) and stored at 4℃ until further use; physical method group,nerve segments were frozen at -196℃ and then thawed at 37℃; and chemical method group,nerve segments were chemically extracted with the detergents Triton X-200,sulfobetaine-10 (SB-10) and sulfobetaine-16 (SB-16).After the acellularization process was completed,the structural changes of in the sciatic nerves in each group were observed by hematoxylin-eosin staining and field emission scanning electron microscopy,then biomechanical properties were tested using a mechanical apparatus (Endura TEC ELF 3200,Bose,Boston,USA).Results Hematoxylin-eosin staining and field emission scanning electron microscopy demonstrated that the effects of acellularization,demyelination,and integrity of nerve fiber tube of the chemical method were better than that of the physical method.Biomechanical testing showed that peripheral nerve grafts treated with the chemical method resulted in some decreased biomechanical properties (ultimate load,ultimate stress,ultimate strain,and mechanical work to fracture) compared with normal control nerves,but the differences were not statistically significant (P >0.05).Conclusion Nerve treated with the chemical method may be more appropriate for use in implantation than nerve treated with the physical method.

  20. Verification, Validation and Sensitivity Studies in Computational Biomechanics

    OpenAIRE

    Anderson, Andrew E.; Ellis, Benjamin J.; Weiss, Jeffrey A.

    2007-01-01

    Computational techniques and software for the analysis of problems in mechanics have naturally moved from their origins in the traditional engineering disciplines to the study of cell, tissue and organ biomechanics. Increasingly complex models have been developed to describe and predict the mechanical behavior of such biological systems. While the availability of advanced computational tools has led to exciting research advances in the field, the utility of these models is often the subject o...

  1. Biomechanics and clinical implications of complete edentulous state

    OpenAIRE

    Lalit Kumar, MDS

    2014-01-01

    The edentulous state represents a compromise in the integrity of the masticatory system. It is frequently accompanied by adverse functional and esthetic sequelae, which are varyingly perceived by the affected patient. Perceptions of the edentulous state may range from feelings of inconvenience to feelings of severe handicap because many regard total loss of teeth as equivalent to the loss of a body part. Consequently, the required treatment addresses a range of biomechanical problems that inv...

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

    OpenAIRE

    Wu M; Kalyanasundaram A; Zhu J

    2013-01-01

    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...

  3. Biomechanics and evolution of flight in stick insects

    OpenAIRE

    Zeng, Yu

    2013-01-01

    Many unresolved questions in animal flight evolution relate to the transition between flightless and volant forms. Functional analysis of transitional modes using anatomical intermediates may help to assess the biomechanical underpinnings to such transitional processes. The group of stick insects exhibits tremendous diversity in wing sizes, which is potentially correlated with selection gradient for wing size. This dissertation work uses stick insects as a model system to address the ecologic...

  4. Biomechanics of spontaneous overground walk-to-run transition

    OpenAIRE

    Segers, Veerle; Smet, de, M.D.; Caekenberghe, van, I.; Aerts, Peter; Clercq, de, Willem

    2013-01-01

    Abstract: The purpose of the present study was to describe the biomechanics of spontaneous walk-to-run transitions (WRTs) in humans. After minimal instructions, 17 physically active subjects performed WRTs on an instrumented runway, enabling measurement of speed, acceleration, spatiotemporal variables, ground reaction forces and 3D kinematics. The present study describes (1) the mechanical energy fluctuations of the body centre-of-mass (BCOM) as a reflection of the whole-body dynamics and (2)...

  5. Three-Dimensional Biomechanical Analysis of the Bovine Humerus

    OpenAIRE

    Bouza-Rodríguez, José Benito; Miramontes-Sequeiros, Luz Calia

    2014-01-01

    There are few reports on the biomechanical analysis of the animal humerus. In this study, a three-dimensional finite element model of the bovine humerus was created, and loaded with the physiological forces acting when the cow is falling or jumping (weight and impact forces). Subsequently the corresponding stress and strain distribution in the humerus for different inclined positions of bone was determined.The highest stress concentration occurred in the distal humeral diaphysis, both when on...

  6. 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.

  7. Evidence for biomechanics and motor learning research improving golf performance.

    Science.gov (United States)

    Keogh, Justin W L; Hume, Patria A

    2012-06-01

    The aim of this review was to determine how the findings of biomechanics and motor control/learning research may be used to improve golf performance. To be eligible, the biomechanics and motor learning studies had to use direct (ball displacement and shot accuracy) or indirect (clubhead velocity and clubface angle) golf performance outcome measures. Biomechanical studies suggested that reducing the radius path of the hands during the downswing, increasing wrist torque and/or range of motion, delaying wrist motion to late in the downswing, increasing downswing amplitude, improving sequential acceleration of body parts, improving weight transfer, and utilising X-factor stretch and physical conditioning programmes can improve clubhead velocity. Motor learning studies suggested that golf performance improved more when golfers focused on swing outcome or clubhead movement rather than specific body movements. A distributed practice approach involving multiple sessions per week of blocked, errorless practice may be best for improving putting accuracy of novice golfers, although variable practice may be better for skilled golfers. Video, verbal, or a combination of video and verbal feedback can increase mid-short iron distance in novice to mid-handicap (hcp) golfers. Coaches should not only continue to critique swing technique but also consider how the focus, structure, and types of feedback for practice may alter learning for different groups of golfers. PMID:22900408

  8. Biomechanical analysis of tibia – double threaded screw fixation

    Directory of Open Access Journals (Sweden)

    W. Walke

    2008-03-01

    Full Text Available Purpose: The aim of the work was determination of biomechanical characteristics of a tibia – double threaded screw system with the use of finite element method.Design/methodology/approach: Geometrical model of the tibia was worked out on the basis of data from computer tomography of real bone. Geometrical model of the double threaded screw was prepared in ANSYS v. 11. Meshing was realized with the use of SOLID95 elements, applied in analyses of volumes. The model was loaded with forces in the range F = 100-2000 N.Findings: Initial biomechanical analysis, carried out with the use of finite element method, showed usefulness of the analyzed form of the double threaded screw made of Ti6Al4V alloy in fractured tibia treatment.Research limitations/implications: Due to applied simplifications of the tibia – double threaded screw fixation model, the analysis results should be experimentally verified in laboratory conditions.Originality/value: The obtained biomechanical characteristics of the tibia – double threaded screw system (u = f(F, σmax = f(F are the basis for selection of degree of strain hardening of the applied metallic biomaterial and optimization of geometrical features of the analyzed form of implant. Appropriate selection of mechanical properties and geometrical features of the implant is the main factor determining a stability of the fixation.

  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. Biomechanical response of two fast-growing tropical seagrass species subjected to in situ shading and sediment fertilization

    NARCIS (Netherlands)

    La Nafie, Y.A.; de los Santos, C.B.; Brun, F.G.; Mashoreng, S.; van Katwijk, M.M.; Bouma, T.J.

    2013-01-01

    Although seagrasses experience strong hydrodynamic forces, little is known about their biomechanical response in spite of the potential importance for their ecological success. We investigated how light reduction and sediment-nutrient enrichment affect biomechanical and morphological properties of t

  11. 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

  12. 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

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

    Energy Technology Data Exchange (ETDEWEB)

    Izzo, Roberto, E-mail: roberto1766@interfree.it [Neuroradiology Department, “A. Cardarelli” Hospital, Napoli (Italy); Guarnieri, Gianluigi, E-mail: gianluigiguarnieri@hotmail.it [Neuroradiology Department, “A. Cardarelli” Hospital, Napoli (Italy); Guglielmi, Giuseppe, E-mail: g.gugliemi@unifg.it [Department of Radiology, University of Foggia, Foggia (Italy); Muto, Mario, E-mail: mutomar@tiscali.it [Neuroradiology Department, “A. Cardarelli” Hospital, Napoli (Italy)

    2013-01-15

    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.

  14. Absorbable scaphoid screw development: a comparative study on biomechanics

    Science.gov (United States)

    Wang, Yi; Song, Muguo; Xu, Yongqing; He, Xiaoqing; Zhu, YueLiang

    2016-01-01

    Background The scaphoid is critical for maintaining the stability and movement of the wrist joints. This study aimed to develop a new internal fixator absorbable scaphoid screw (ASS) for fixation of the scaphoid waist after fracture and to test the biomechanical characteristics of ASS. Materials and methods An ASS was prepared using polylactic acids and designed based on scaphoid measurements and anatomic features. Twenty fractured scaphoid waist specimens were randomly divided into experimental and control groups (n=10/group). Reduction and internal fixation of the scaphoid were achieved with either Kirschner wires (K-wires) or ASS. A moving target simulator was used to test palmar flexion and dorsal extension, with the range of testing (waist movement) set from 5° of palmar flexion to 25° of dorsal extension. Flexion and extension were repeated 2,000 times for each specimen. Fracture gap displacements were measured with a computerized tomography scanning. Scaphoid tensile and bending strengths were measured by using a hydraulic pressure biomechanical system. Results Prior to biomechanical fatigue testing, fracture gap displacements were 0.16±0.02 mm and 0.22±0.02 mm in the ASS and K-wire groups, respectively. After fatigue testing, fracture gap displacements in the ASS and the K-wire groups were 0.21±0.03 mm and 1.52±0.07 mm, respectively. The tensile strengths for the ASS and K-wire groups were 0.95±0.02 MPa and 0.63±0.02 MPa, respectively. Conclusion Fixation using an ASS provided sufficient mechanical support for the scaphoid after fracture. PMID:27217756

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

    International Nuclear Information System (INIS)

    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

  16. Blunt impacts to the back: Biomechanical response for model development.

    Science.gov (United States)

    Forman, Jason; Perry, Brandon; Henderson, Kyvory; Gjolaj, Joseph P; Heltzel, Sara; Lessley, David; Riley, Patrick; Salzar, Robert; Walilko, Tim

    2015-09-18

    The development of advanced injury prediction models requires biomechanical and injury tolerance information for all regions of the body. While numerous studies have investigated injury mechanics of the thorax under frontal impact, there remains a dearth of information on the injury mechanics of the torso under blunt impact to the back. A series of hub-impact tests were performed to the back surface of the mid-thorax of four mid-size male cadavers. Repeated tests were performed to characterize the biomechanical and injury response of the thorax under various impact speeds (1.5m/s, 3m/s and 5.5m/s). Deformation of the chest was recorded with a 59-gage chestband. Subject kinematics were also recorded with a high-speed optoelectronic 3D motion capture system. In the highest-severity tests, peak impact forces ranged from 6.9 to 10.5 kN. The peak change in extension angle measured between the 1st thoracic vertebra and the lumbar spine ranged from 39 to 62°. The most commonly observed injuries were strains of the costovertebral/costotransverse joint complexes, rib fractures, and strains of the interspinous and supraspinous ligaments. The majority of the rib fractures occurred in the rib neck between the costovertebral and costotransverse joints. The prevalence of rib-neck fractures suggests a novel, indirect loading mechanism resulting from bending moments generated in the rib necks caused by motion of the spine. In addition to the injury information, the biomechanical responses quantified here will facilitate the future development and validation of human body models for predicting injury risk during impact to the back. PMID:26184586

  17. 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. PMID:27322099

  18. A review of biomechanically informed breast image registration

    Science.gov (United States)

    Hipwell, John H.; Vavourakis, Vasileios; Han, Lianghao; Mertzanidou, Thomy; Eiben, Björn; Hawkes, David J.

    2016-01-01

    Breast radiology encompasses the full range of imaging modalities from routine imaging via x-ray mammography, magnetic resonance imaging and ultrasound (both two- and three-dimensional), to more recent technologies such as digital breast tomosynthesis, and dedicated breast imaging systems for positron emission mammography and ultrasound tomography. In addition new and experimental modalities, such as Photoacoustics, Near Infrared Spectroscopy and Electrical Impedance Tomography etc, are emerging. The breast is a highly deformable structure however, and this greatly complicates visual comparison of imaging modalities for the purposes of breast screening, cancer diagnosis (including image guided biopsy), tumour staging, treatment monitoring, surgical planning and simulation of the effects of surgery and wound healing etc. Due primarily to the challenges posed by these gross, non-rigid deformations, development of automated methods which enable registration, and hence fusion, of information within and across breast imaging modalities, and between the images and the physical space of the breast during interventions, remains an active research field which has yet to translate suitable methods into clinical practice. This review describes current research in the field of breast biomechanical modelling and identifies relevant publications where the resulting models have been incorporated into breast image registration and simulation algorithms. Despite these developments there remain a number of issues that limit clinical application of biomechanical modelling. These include the accuracy of constitutive modelling, implementation of representative boundary conditions, failure to meet clinically acceptable levels of computational cost, challenges associated with automating patient-specific model generation (i.e. robust image segmentation and mesh generation) and the complexity of applying biomechanical modelling methods in routine clinical practice.

  19. 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…

  20. 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…

  1. 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 a given…

  2. Mathematical simulation of the biomechanical system bone-fixator

    Science.gov (United States)

    Krasnoschekov, Viktor V.; Maslov, Leonid B.

    2001-02-01

    Problems of static and dynamic simulation of the biomechanical system consisting of the human tibia bone and external fixator apparatus as the simplest frame construction are considered. The finite element method implemented as the program code MechanicsFE3D_ESO on the basis of 20 nodal isoparametric elements is utilized. Both general stressed-deformed state of the construction under transversal loading and basic frequencies and forms of free oscillations of the system were defined by the numerical analysis. The results obtained can be used as the theoretical fundament to developing of static and vibration resonance methods for physiological state diagnostics of the regenerating osseous tissue in fracture zone.

  3. Radiological features and biomechanical patterns in Perthes disease

    International Nuclear Information System (INIS)

    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

  4. Interpretation Of Biomechanical Data To A Gymnastics Coach

    Science.gov (United States)

    Shierman, Gail

    1982-02-01

    Several trials of many different gymnastics skills on various pieces of apparatus were filmed and the results were studied with the coach. The time to accomplish the entire skill as well as the time for each segment of the skill was important to the coach. He was also interested in angle of release or push-off and the path of the center of gravity. Lastly, graphs of velocities and accelerations of limb segments were revealing to the coach. Biomechanical analysis has helped him see why the performances were good; he is more interested in working with the investigator in all the events in gymnastics through the medium of cinematography.

  5. Towards a Biomechanical Understanding of Tempo in the Golf Swing

    CERN Document Server

    Grober, R D; Cholewicki, Jacek; Grober, Robert D.

    2006-01-01

    It is proposed that aspects of the tempo of the golf swing can be understood in terms of a biomechanical clock. This model explains several aspects of tempo in the golf swing; including total duration of the golf swing, the ratio of backswing to downswing time, and the relative insensitivity of tempo on the length of the golf shot. We demonstrate that this clock and the resulting tempo are defined by of the rotational inertia of the body/club system and the elastic properties of the body, yielding a system which can be modeled as a simple harmonic oscillator.

  6. Absorbable scaphoid screw development: a comparative study on biomechanics

    Directory of Open Access Journals (Sweden)

    Wang Y

    2016-04-01

    Full Text Available Yi Wang, Muguo Song, Yongqing Xu, Xiaoqing He, YueLiang Zhu Department of Orthopedic Surgery, Kunming General Hospital, Chengdu Military Command, People’s Liberation Army, Kunming, Yunnan, People’s Republic of China Background: The scaphoid is critical for maintaining the stability and movement of the wrist joints. This study aimed to develop a new internal fixator absorbable scaphoid screw (ASS for fixation of the scaphoid waist after fracture and to test the biomechanical characteristics of ASS.Materials and methods: An ASS was prepared using polylactic acids and designed based on scaphoid measurements and anatomic features. Twenty fractured scaphoid waist specimens were randomly divided into experimental and control groups (n=10/group. Reduction and internal fixation of the scaphoid were achieved with either Kirschner wires (K-wires or ASS. A moving target simulator was used to test palmar flexion and dorsal extension, with the range of testing (waist movement set from 5° of palmar flexion to 25° of dorsal extension. Flexion and extension were repeated 2,000 times for each specimen. Fracture gap displacements were measured with a computerized tomography scanning. Scaphoid tensile and bending strengths were measured by using a hydraulic pressure biomechanical system.Results: Prior to biomechanical fatigue testing, fracture gap displacements were 0.16±0.02 mm and 0.22±0.02 mm in the ASS and K-wire groups, respectively. After fatigue testing, fracture gap displacements in the ASS and the K-wire groups were 0.21±0.03 mm and 1.52±0.07 mm, respectively. The tensile strengths for the ASS and K-wire groups were 0.95±0.02 MPa and 0.63±0.02 MPa, respectively.Conclusion: Fixation using an ASS provided sufficient mechanical support for the scaphoid after fracture. Keywords: absorbable scaphoid screw, biomechanics, internal fixator, Kirschner wires

  7. Implementation of reflex loops in a biomechanical finite element model.

    Science.gov (United States)

    Salin, Dorian; Arnoux, Pierre-Jean; Kayvantash, Kambiz; Behr, Michel

    2016-11-01

    In the field of biomechanics, the offer of models which are more and more realistic requires to integrate a physiological response, in particular, the controlled muscle bracing and the reflexes. The following work aims to suggest a unique methodology which couples together a sensory and motor loop with a finite element model. Our method is applied to the study of the oscillation of the elbow in the case of a biceps brachial stretch reflex. The results obtained are promising in the purpose of the development of reactive human body models. PMID:27108871

  8. 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

  9. Biomechanical Factors and Injury Risk in High-Severity Rollovers

    OpenAIRE

    Moore, Tara L. A.; Vijayakumar, Vinod; Steffey, Duane L.; Ramachandran, Karuna; Corrigan, Catherine Ford

    2005-01-01

    The number of rolls, as well as other factors, has been associated with increased injury risk in rollovers. Data from NASS-CDS from 1995–2003 were used to evaluate the biomechanical implications of vehicle kinematics during multiple rolls and to evaluate the risk of injuries to different body regions during rollovers. The data showed that the risk of injury increased with increasing number of rolls. The rate of increase in risk varied by the region of the body affected and injury severity. Th...

  10. Biomechanical Analysis of the Swim-Start: A Review

    OpenAIRE

    Julien Vantorre, Didier Chollet, Ludovic Seifert

    2014-01-01

    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 e...

  11. Endothelial cells and cathepsins: Biochemical and biomechanical regulation.

    Science.gov (United States)

    Platt, Manu O; Shockey, W Andrew

    2016-03-01

    Cathepsins are mechanosensitive proteases that are regulated not only by biochemical factors, but are also responsive to biomechanical forces in the cardiovascular system that regulate their expression and activity to participate in cardiovascular tissue remodeling. Their elastinolytic and collagenolytic activity have been implicated in atherosclerosis, abdominal aortic aneurysms, and in heart valve disease, all of which are lined by endothelial cells that are the mechanosensitive monolayer of cells that sense and respond to fluid shear stress as the blood flows across the surfaces of the arteries and valve leaflets. Inflammatory cytokine signaling is integrated with biomechanical signaling pathways by the endothelial cells to transcribe, translate, and activate either the cysteine cathepsins to remodel the tissue or to express their inhibitors to maintain healthy cardiovascular tissue structure. Other cardiovascular diseases should now be included in the study of the cysteine cathepsin activation because of the additional biochemical cues they provide that merges with the already existing hemodynamics driving cardiovascular disease. Sickle cell disease causes a chronic inflammation including elevated TNFα and increased numbers of circulating monocytes that alter the biochemical stimulation while the more viscous red blood cells due to the sickling of hemoglobin alters the hemodynamics and is associated with accelerated elastin remodeling causing pediatric strokes. HIV-mediated cardiovascular disease also occurs earlier in than the broader population and the influence of HIV-proteins and antiretrovirals on endothelial cells must be considered to understand these accelerated mechanisms in order to identify new therapeutic targets for prevention. PMID:26458976

  12. Biomechanical modelling and evaluation of construction jobs for performance improvement.

    Science.gov (United States)

    Parida, Ratri; Ray, Pradip Kumar

    2012-01-01

    Occupational risk factors, such as awkward posture, repetition, lack of rest, insufficient illumination and heavy workload related to construction-related MMH activities may cause musculoskeletal disorders and poor performance of the workers, ergonomic design of construction worksystems was a critical need for improving their health and safety wherein a dynamic biomechanical models were required to be empirically developed and tested at a construction site of Tata Steel, the largest steel making company of India in private sector. In this study, a comprehensive framework is proposed for biomechanical evaluation of shovelling and grinding under diverse work environments. The benefit of such an analysis lies in its usefulness in setting guidelines for designing such jobs with minimization of risks of musculoskeletal disorders (MSDs) and enhancing correct methods of carrying out the jobs leading to reduced fatigue and physical stress. Data based on direct observations and videography were collected for the shovellers and grinders over a number of workcycles. Compressive forces and moments for a number of segments and joints are computed with respect to joint flexion and extension. The results indicate that moments and compressive forces at L5/S1 link are significant for shovellers while moments at elbow and wrist are significant for grinders. PMID:22317733

  13. 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. PMID:25039605

  14. Biomechanical properties of decellularized porcine pulmonary valve conduits.

    Science.gov (United States)

    Seebacher, Gernot; Grasl, Christian; Stoiber, Martin; Rieder, Erwin; Kasimir, Marie-Theres; Dunkler, Daniela; Simon, Paul; Weigel, Günter; Schima, Heinrich

    2008-01-01

    Tissue-engineered heart valves constructed from a xenogeneic or allogeneic decellularized matrix might overcome the disadvantages of current heart valve substitutes. One major necessity besides effective decellularization is to preserve the biomechanical properties of the valve. Native and decellularized porcine pulmonary heart valve conduits (PPVCs) (with [n = 10] or without [n = 10] cryopreservation) were compared to cryopreserved human pulmonary valve conduits (n = 7). Samples of the conduit were measured for wall thickness and underwent tensile tests. Elongation measurement was performed with a video extensometer. Decellularized PPVC showed a higher failure force both in longitudinal (+73%; P < 0.01) and transverse (+66%; P < 0.001) direction compared to human homografts. Failure force of the tissue after cryopreservation was still higher in the porcine group (longitudinal: +106%, P < 0.01; transverse: +58%, P < 0.001). In comparison to human homografts, both decellularized and decellularized cryopreserved porcine conduits showed a higher extensibility in longitudinal (decellularized: +61%, P < 0.001; decellularized + cryopreserved: +51%, P < 0.01) and transverse (decellularized: +126%, P < 0.001; decellularized + cryopreserved: +118%, P < 0.001) direction. Again, cryopreservation did not influence the biomechanical properties of the decellularized porcine matrix. PMID:18181800

  15. Rotational biomechanics of the elite golf swing: benchmarks for amateurs.

    Science.gov (United States)

    Meister, David W; Ladd, Amy L; Butler, Erin E; Zhao, Betty; Rogers, Andrew P; Ray, Conrad J; Rose, Jessica

    2011-08-01

    The purpose of this study was to determine biomechanical factors that may influence golf swing power generation. Three-dimensional kinematics and kinetics were examined in 10 professional and 5 amateur male golfers. Upper-torso rotation, pelvic rotation, X-factor (relative hip-shoulder rotation), O-factor (pelvic obliquity), S-factor (shoulder obliquity), and normalized free moment were assessed in relation to clubhead speed at impact (CSI). Among professional golfers, results revealed that peak free moment per kilogram, peak X-factor, and peak S-factor were highly consistent, with coefficients of variation of 6.8%, 7.4%, and 8.4%, respectively. Downswing was initiated by reversal of pelvic rotation, followed by reversal of upper-torso rotation. Peak X-factor preceded peak free moment in all swings for all golfers, and occurred during initial downswing. Peak free moment per kilogram, X-factor at impact, peak X-factor, and peak upper-torso rotation were highly correlated to CSI (median correlation coefficients of 0.943, 0.943, 0.900, and 0.900, respectively). Benchmark curves revealed kinematic and kinetic temporal and spatial differences of amateurs compared with professional golfers. For amateurs, the number of factors that fell outside 1-2 standard deviations of professional means increased with handicap. This study identified biomechanical factors highly correlated to golf swing power generation and may provide a basis for strategic training and injury prevention. PMID:21844613

  16. Fusion of intraoperative force sensoring, surface reconstruction and biomechanical modeling

    Science.gov (United States)

    Röhl, S.; Bodenstedt, S.; Küderle, C.; Suwelack, S.; Kenngott, H.; Müller-Stich, B. P.; Dillmann, R.; Speidel, S.

    2012-02-01

    Minimally invasive surgery is medically complex and can heavily benefit from computer assistance. One way to help the surgeon is to integrate preoperative planning data into the surgical workflow. This information can be represented as a customized preoperative model of the surgical site. To use it intraoperatively, it has to be updated during the intervention due to the constantly changing environment. Hence, intraoperative sensor data has to be acquired and registered with the preoperative model. Haptic information which could complement the visual sensor data is still not established. In addition, biomechanical modeling of the surgical site can help in reflecting the changes which cannot be captured by intraoperative sensors. We present a setting where a force sensor is integrated into a laparoscopic instrument. In a test scenario using a silicone liver phantom, we register the measured forces with a reconstructed surface model from stereo endoscopic images and a finite element model. The endoscope, the instrument and the liver phantom are tracked with a Polaris optical tracking system. By fusing this information, we can transfer the deformation onto the finite element model. The purpose of this setting is to demonstrate the principles needed and the methods developed for intraoperative sensor data fusion. One emphasis lies on the calibration of the force sensor with the instrument and first experiments with soft tissue. We also present our solution and first results concerning the integration of the force sensor as well as accuracy to the fusion of force measurements, surface reconstruction and biomechanical modeling.

  17. Biomechanical Analysis of Force Distribution in Human Finger Extensor Mechanisms

    Directory of Open Access Journals (Sweden)

    Dan Hu

    2014-01-01

    Full Text Available The complexities of the function and structure of human fingers have long been recognised. The in vivo forces in the human finger tendon network during different activities are critical information for clinical diagnosis, surgical treatment, prosthetic finger design, and biomimetic hand development. In this study, we propose a novel method for in vivo force estimation for the finger tendon network by combining a three-dimensional motion analysis technique and a novel biomechanical tendon network model. The extensor mechanism of a human index finger is represented by an interconnected tendinous network moving around the phalanx’s dorsum. A novel analytical approach based on the “Principle of Minimum Total Potential Energy” is used to calculate the forces and deformations throughout the tendon network of the extensor mechanism when subjected to an external load and with the finger posture defined by measurement data. The predicted deformations and forces in the tendon network are in broad agreement with the results obtained by previous experimental in vitro studies. The proposed methodology provides a promising tool for investigating the biomechanical function of complex interconnected tendon networks in vivo.

  18. Biomechanical changes in endothelial cells result from an inflammatory response

    Science.gov (United States)

    Vaitkus, Janina; Stroka, Kimberly; Aranda-Espinoza, Helim

    2012-02-01

    During periods of infection and disease, the immune system induces the release of TNF-α, an inflammatory cytokine, from a variety of cell types, such as macrophages. TNF-α, while circulating in the vasculature, binds to the apical surface of endothelial cells and causes a wide range of biological and mechanical changes to the endothelium. While the biological changes have been widely studied, the biomechanical aspects have been largely unexplored. Here, we investigated the biomechanical changes of the endothelium as a function of TNF-α treatment. First, we studied the traction forces applied by the endothelium, an effect that is much less studied than others. Through the use of traction force microscopy, we found that TNF-α causes an increase in traction forces applied by the endothelial cells as compared to non-treated cells. Then, we investigated cell morphology, cell mechanics, migration, and cytoskeletal dynamics. We found that in addition to increasing applied traction forces, TNF-α causes an increase in cell area and aspect ratio on average, as well as a shift in the organization of F-actin filaments within the cell. Combining these findings together, our results show that an inflammatory response heavily impacts the morphology, cell mechanics, migration, cytoskeletal dynamics, and applied traction forces of endothelial cells.

  19. 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. PMID:26183820

  20. Biomechanical modeling and optimal control of human posture.

    Science.gov (United States)

    Menegaldo, Luciano Luporini; Fleury, Agenor de Toledo; Weber, Hans Ingo

    2003-11-01

    The present work describes the biomechanical modeling of human postural mechanics in the saggital plane and the use of optimal control to generate open-loop raising-up movements from a squatting position. The biomechanical model comprises 10 equivalent musculotendon actuators, based on a 40 muscles model, and three links (shank, thigh and HAT-Head, Arms and Trunk). Optimal control solutions are achieved through algorithms based on the Consistent Approximations Theory (Schwartz and Polak, 1996), where the continuous non-linear dynamics is represented in a discrete space by means of a Runge-Kutta integration and the control signals in a spline-coefficient functional space. This leads to non-linear programming problems solved by a sequential quadratic programming (SQP) method. Due to the highly non-linear and unstable nature of the posture dynamics, numerical convergence is difficult, and specific strategies must be implemented in order to allow convergence. Results for control (muscular excitations) and angular trajectories are shown using two final simulation times, as well as specific control strategies are discussed. PMID:14522212

  1. Biomechanics and control of vocalization in a non-songbird.

    Science.gov (United States)

    Elemans, Coen P H; Zaccarelli, Riccardo; Herzel, Hanspeter

    2008-07-01

    The neuromuscular control of vocalization in birds requires complicated and precisely coordinated motor control of the vocal organ (i.e. the syrinx), the respiratory system and upper vocal tract. The biomechanics of the syrinx is very complex and not well understood. In this paper, we aim to unravel the contribution of different control parameters in the coo of the ring dove (Streptopelia risoria) at the syrinx level. We designed and implemented a quantitative biomechanical syrinx model that is driven by physiological control parameters and includes a muscle model. Our simple nonlinear model reproduces the coo, including the inspiratory note, with remarkable accuracy and suggests that harmonic content of song can be controlled by the geometry and rest position of the syrinx. Furthermore, by systematically switching off the control parameters, we demonstrate how they affect amplitude and frequency modulations and generate new experimentally testable hypotheses. Our model suggests that independent control of amplitude and frequency seems not to be possible with the simple syringeal morphology of the ring dove. We speculate that songbirds evolved a syrinx design that uncouples the control of different sound parameters and allows for independent control. This evolutionary key innovation provides an additional explanation for the rapid diversification and speciation of the songbirds. PMID:17999946

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

    Science.gov (United States)

    Soares, Alex Sandra Oliveira de Cerqueira; Yamaguti, Edward Yuji; Mochizuki, Luis; Amadio, Alberto Carlos; Serrão, Júlio Cerca

    2009-09-01

    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. PMID:20169280

  3. Biomechanical properties of acellular sciatic nerves treated with a modified chemical method

    Institute of Scientific and Technical Information of China (English)

    Xinlong Ma; Zhao Yang; Xiaolei Sun; Jianxiong Ma; Xiulan Li; Zhenzhen Yuan; Yang Zhang; Honggang Guo

    2011-01-01

    Nerve grafts are able to adapt to surrounding biomechanical environments if the nerve graft itself exhibits appropriate biomechanical properties (load, elastic modulus, etc.). The present study was designed to determine the differences in biomechanical properties between fresh and chemically acellularized sciatic nerve grafts. Two different chemical methods were used to establish acellular nerve grafts. The nerve was chemically extracted in the Sondell method with a combination of Triton X-100 (nonionic detergent) and sodium deoxycholate (anionic detergent), and in the modified method with a combination of Triton X-200 (anionic detergent), sulfobetaine-10 (SB-10, amphoteric detergents), and sulfobetaine-16 (SB-16, amphoteric detergents). Following acellularization, hematoxylin-eosin staining and scanning electron microscopy demonstrated that the effect of acellularization via the modified method was similar to the traditional Sondell method. However, effects of demyelination and nerve fiber tube integrity were superior to the traditional Sondell method. Biomechanical testing showed that peripheral nerve graft treated using the chemical method resulted in decreased biomechanical properties (ultimate load, ultimate stress, ultimate strain, and mechanical work to fracture) compared with fresh nerves, but the differences had no statistical significance (P > 0.05). These results demonstrated no significant effect on biomechanical properties of nerves treated using the chemical method. In conclusion, nerve grafts treated via the modified method removed Schwann cells, preserved neural structures, and ensured biomechanical properties of the nerve graft, which could be more appropriate for implantation studies.

  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.

    2016-01-01

    Background: 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. Purpose: 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. Study Design: Controlled laboratory study. Methods: 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. Results: 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 sports.

  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. 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

  7. 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

  8. Biomechanics of Thoracolumbar Burst and Chance-Type Fractures during Fall from Height

    OpenAIRE

    Ivancic, Paul C.

    2014-01-01

    Study Design In vitro biomechanical study. Objective To investigate the biomechanics of thoracolumbar burst and Chance-type fractures during fall from height. Methods Our model consisted of a three-vertebra human thoracolumbar specimen (n = 4) stabilized with muscle force replication and mounted within an impact dummy. Each specimen was subjected to a single fall from an average height of 2.1 m with average velocity at impact of 6.4 m/s. Biomechanical responses were determined using impact lo...

  9. Biomechanical behaviour of implant-reinforced subcapital humeral fractures

    Energy Technology Data Exchange (ETDEWEB)

    Fuechtmeier, B.; Nerlich, M. [Abt. fuer Unfallchirurgie, Klinikum der Univ. Regensburg, Regensburg (Germany); Hammer, J. [Fachhochschule Regensburg, Univ. of Applied Sciences, Regensburg (Germany)

    2002-08-01

    A pair-controlled study was performed to compare the biomechanical behaviour of implant-reinforced fractured humeri under bending and under torsional loading, respectively. Special interest is related to the fixation potential of a prototype version of an intramedullary nail for stabilisation of subcapital humeral fracture. This nail is especially designed in terms of application for less invasive surgery purposes. In this study, two different modifications of this prototype nail are directly compared with respect to the stabilisation potential in direct comparison to conventionally applied implant techniques (wire technique and plate fixing). First results indicate that fixing of subcapital fracture by this intramedullary nail type provides a good compromise concerning the stabilisation under both loading types, bending and torsion, respectively. (orig.)

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

    DEFF Research Database (Denmark)

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

    2010-01-01

    to September 2008. Methods were included if they were primarily based on the systematic observation of work, the observation target was the human body, and the method was clearly described in the literature. A systematic evaluation procedure was developed to assess concurrent and predictive validity...... difficult to observe correctly. Intra- and inter-observer repeatability were reported for 7 and 17 methods, respectively, and were judged mostly to be good or moderate. CONCLUSIONS: With training, observers can reach consistent results on clearly visible body postures and work activities. Many observational......OBJECTIVES: This systematic review aimed to identify published observational methods assessing biomechanical exposures in occupational settings and evaluate them with reference to the needs of different users. METHODS: We searched scientific databases and the internet for material from 1965...

  11. 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......, and the Washington state method are checklist-type methods where each item or risk factor exceeding the criteria used in each method indicates consideration of actions at work place. In RULA weights are given to the observed items and a sum score is calculated to describe the risk. In ACGIH HAL the hand activity...

  12. Biomechanical models of damage and healing processes for voice health

    DEFF Research Database (Denmark)

    Granados Corsellas, Alba; Brunskog, Jonas; Jacobsen, Finn

    2013-01-01

    In voice-loading occupations employees are required to use their voice for continuous and large periods of time, which might lead to voice problems. In this work anomalous vocal-fold vibrations due to long-time high voice-load are investigated. Laryngeal endoscopic high-speed images within the...... vocal-fold plane are available. This data is used to improve existing continuum biomechanical models of the vocal-folds by analyzing the injury processes. The project is expected to result in methods that objectively demonstrate the impact of high voice-load on voice. A detailed description of the...... currently developing work will be presented, including a rigorous analysis of the hypothesized injury processes of the vocal folds. © 2013 Acoustical Society of America....

  13. Complex dental structure and wear biomechanics in hadrosaurid dinosaurs.

    Science.gov (United States)

    Erickson, Gregory M; Krick, Brandon A; Hamilton, Matthew; Bourne, Gerald R; Norell, Mark A; Lilleodden, Erica; Sawyer, W Gregory

    2012-10-01

    Mammalian grinding dentitions are composed of four major tissues that wear differentially, creating coarse surfaces for pulverizing tough plants and liberating nutrients. Although such dentition evolved repeatedly in mammals (such as horses, bison, and elephants), a similar innovation occurred much earlier (~85 million years ago) within the duck-billed dinosaur group Hadrosauridae, fueling their 35-million-year occupation of Laurasian megaherbivorous niches. How this complexity was achieved is unknown, as reptilian teeth are generally two-tissue structures presumably lacking biomechanical attributes for grinding. Here we show that hadrosaurids broke from the primitive reptilian archetype and evolved a six-tissue dental composition that is among the most sophisticated known. Three-dimensional wear models incorporating fossilized wear properties reveal how these tissues interacted for grinding and ecological specialization. PMID:23042891

  14. The biomechanics of fast prey capture in aquatic bladderworts

    Science.gov (United States)

    Singh, Amit K.; Prabhakar, Sunil; Sane, Sanjay P.

    2011-01-01

    Carnivorous plants match their animal prey for speed of movements and hence offer fascinating insights into the evolution of fast movements in plants. Here, we describe the mechanics of prey capture in aquatic bladderworts Utricularia stellaris, which prey on swimming insect larvae or nematodes to supplement their nitrogen intake. The closed Utricularia bladder develops lower-than-ambient internal pressures by pumping out water from the bladder and thus setting up an elastic instability in bladder walls. When the external sensory trigger hairs on their trapdoor are mechanically stimulated by moving prey, the trapdoor opens within 300–700 μs, causing strong inward flows that trap their prey. The opening time of the bladder trapdoor is faster than any recorded motion in carnivorous plants. Thus, Utricularia have evolved a unique biomechanical system to gain an advantage over their animal prey. PMID:21389013

  15. Occupational biomechanics of athletes and dancers: a comparative approach.

    Science.gov (United States)

    Bejjani, F J

    1987-07-01

    Muscle strains represent more than a third of all injuries in both dancers and athletes. Although often overlooked, anatomic variations play an important role in the etiology of these injuries, as does strength imbalance between agonists and antagonists. The incidence of spondylolysis is unusually high in ballet dancers and certain athletic groups, such as gymnasts, javelin throwers, and weight-lifters. Mechanical factors play a major role and can be exacerbated by congenital abnormalities. Various permanent adaptive musculoskeletal changes have been described both in dancers and athletes, especially those that start at a very young age. Task-related adaptive changes can also be seen in isokinetic strength measurements of various muscle groups, such as the spine muscles of Flamenco dancers. Shoes and floor surfaces can be directly responsible in part or in whole for many sports and dance injuries. "Vibration-pressure" diagrams are suggested as an objective way to document their effect on biomechanical behavior. PMID:2886209

  16. Biomechanics of epithelial cell islands analyzed by modeling and experimentation

    CERN Document Server

    Coburn, Luke; Noppe, Adrian; Caldwell, Benjamin J; Moussa, Elliott; Yap, Chloe; Priya, Rashmi; Lobaskin, Vladimir; Roberts, Anthony P; Yap, Alpha S; Neufeld, Zoltan; Gomez, Guillermo A

    2016-01-01

    We generated a new computational approach to analyze the biomechanics of epithelial cell islands that combines both vertex and contact-inhibition-of-locomotion models to include both cell-cell and cell-substrate adhesion. Examination of the distribution of cell protrusions (adhesion to the substrate) in the model predicted high order profiles of cell organization that agree with those previously seen experimentally. Cells acquired an asymmetric distribution of protrusions (and traction forces) that decreased when moving from the edge to the island center. Our in silico analysis also showed that tension on cell-cell junctions (and monolayer stress) is not homogeneous across the island. Instead it is higher at the island center and scales up with island size, which we confirmed experimentally using laser ablation assays and immunofluorescence. Moreover, our approach has the minimal elements necessary to reproduce mechanical crosstalk between both cell-cell and cell substrate adhesion systems. We found that an i...

  17. Biomechanics of DNA structures visualized by 4D electron microscopy.

    Science.gov (United States)

    Lorenz, Ulrich J; Zewail, Ahmed H

    2013-02-19

    We present a technique for in situ visualization of the biomechanics of DNA structural networks using 4D electron microscopy. Vibrational oscillations of the DNA structure are excited mechanically through a short burst of substrate vibrations triggered by a laser pulse. Subsequently, the motion is probed with electron pulses to observe the impulse response of the specimen in space and time. From the frequency and amplitude of the observed oscillations, we determine the normal modes and eigenfrequencies of the structures involved. Moreover, by selective "nano-cutting" at a given point in the network, it was possible to obtain Young's modulus, and hence the stiffness, of the DNA filament at that position. This experimental approach enables nanoscale mechanics studies of macromolecules and should find applications in other domains of biological networks such as origamis. PMID:23382239

  18. Biomechanical models to simulate consequences of maxillofacial surgery

    CERN Document Server

    Payan, Y; Pelorson, X; Vilain, C; Levy, P; Luboz, V; Perrier, P; Payan, Yohan; Chabanas, Matthieu; Pelorson, Xavier; Vilain, Coriandre; Levy, Patrick; Luboz, Vincent; Perrier, Pascal

    2002-01-01

    This paper presents the biomechanical finite element models that have been developed in the framework of the computer-assisted maxillofacial surgery. After a brief overview of the continuous elastic modelling method, two models are introduced and their use for computer-assisted applications discussed. The first model deals with orthognathic surgery and aims at predicting the facial consequences of maxillary and mandibular osteotomies. For this, a generic three-dimensional model of the face is automatically adapted to the morphology of the patient by the mean of elastic registration. Qualitative simulations of the consequences of an osteotomy of the mandible can thus be provided. The second model addresses the Sleep Apnoea Syndrome. Its aim is to develop a complete modelling of the interaction between airflow and upper airways walls during respiration. Dynamical simulations of the interaction during a respiratory cycle are computed and compared with observed phenomena.

  19. Biomechanical failure of metacarpal fracture resorbable plate fixation.

    Science.gov (United States)

    Lionelli, Gerald T; Korentager, Richard A

    2002-08-01

    Metacarpal fractures are a relatively common hand injury that may require operative intervention to ensure adequate reduction and stabilization. The use of permanent hardware, although acceptable, may lead to complications and an increased number of surgical procedures. The use of resorbable hardware such as poly-L-lactic acid and polyglycolic acid copolymer plates and screws may circumvent some of these complications. In vitro studies have demonstrated that the biomechanical characteristics of these resorbable plates may provide the rigid fixation necessary to allow for union of metacarpal fractures in vivo. However, limited clinical data are available regarding the success of their use in this application. The authors present what they believe is the first reported case of the failure of a poly-L-lactic acid and polyglycolic acid copolymer miniplate after use in the fixation of a metacarpal shaft fracture. PMID:12187350

  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. Energetic and biomechanical constraints on animal migration distance.

    Science.gov (United States)

    Hein, Andrew M; Hou, Chen; Gillooly, James F

    2012-02-01

    Animal migration is one of the great wonders of nature, but the factors that determine how far migrants travel remain poorly understood. We present a new quantitative model of animal migration and use it to describe the maximum migration distance of walking, swimming and flying migrants. The model combines biomechanics and metabolic scaling to show how maximum migration distance is constrained by body size for each mode of travel. The model also indicates that the number of body lengths travelled by walking and swimming migrants should be approximately invariant of body size. Data from over 200 species of migratory birds, mammals, fish, and invertebrates support the central conclusion of the model - that body size drives variation in maximum migration distance among species through its effects on metabolism and the cost of locomotion. The model provides a new tool to enhance general understanding of the ecology and evolution of migration. PMID:22093885

  2. Biomechanical Effect of Chinese Immobilization Using Little Splint

    Institute of Scientific and Technical Information of China (English)

    WANG Mei; ZHAO Namula

    2014-01-01

    Immobilization using little splint is an original innovation of Chinese people for the fracture fixation, which is simple to use and clinically effective. It was found that Chinese immobilization using little splint can make the non-invasive, uncovering, and trouble free healing of bone fracture via harmonious unity of the structure stability and the force balance, of the motion stability and the stress adaptability, of the constant and discontinuous physiological stress. The biomechanical effect of Chinese immobilization using little splint, including entirety, dynamic, and functional fixity, is the root cause of its inheritance and the use up to now, and also is a direction of today's fracture fixation towards personalization, individuality and entirety.

  3. Development of a finger biomechanical model and its considerations.

    Science.gov (United States)

    Fok, Kim Seng; Chou, Siaw Meng

    2010-03-01

    The development of a biomechanical model for a human finger is faced with many challenges, such as extensor mechanism complexity, statistical indeterminacy and suitability of computational processes. Motivation for this work was to develop a computer model that is able to predict the internal loading patterns of tendons and joint surfaces experienced by the human finger, while mitigating these challenges. Proposed methodology was based on a non-linear optimising mathematical technique with a criterion of boundary conditions and equality equations, maximised against unknown parameters to reduce statistical indeterminacy. Initial validation was performed via the simulation of one dynamic and two static postures case studies. Past models and experiments were used, based on published literature, to verify the proposed model's methodology and results. The feasibility of the proposed methodology was deemed satisfactory as the simulated results were concordant with in-vivo results for the extrinsic flexors. PMID:19962148

  4. Clinical anatomy and biomechanics of the ankle in dance.

    Science.gov (United States)

    Russell, Jeffrey A; McEwan, Islay M; Koutedakis, Yiannis; Wyon, Matthew A

    2008-01-01

    The ankle is an important joint to understand in the context of dance because it is the connection between the leg and the foot that establishes lower extremity stability. Its function coordinates with the leg and foot and, thus, it is crucial to the dancer's ability to perform. Furthermore, the ankle is one of the most commonly injured body regions in dance. An understanding of ankle anatomy and biomechanics is not only important for healthcare providers working with dancers, but for dance scientists, dance instructors, and dancers themselves. The bony architecture, the soft tissue restraints, and the locomotive structures all integrate to allow the athletic artistry of dance. Yet, there is still much research to be carried out in order to more completely understand the ankle of the dancer. PMID:19618582

  5. Biomechanics of forearm rotation: force and efficiency of pronator teres.

    Directory of Open Access Journals (Sweden)

    Pere Ibáñez-Gimeno

    Full Text Available Biomechanical models are useful to assess the effect of muscular forces on bone structure. Using skeletal remains, we analyze pronator teres rotational efficiency and its force components throughout the entire flexion-extension and pronation-supination ranges by means of a new biomechanical model and 3D imaging techniques, and we explore the relationship between these parameters and skeletal structure. The results show that maximal efficiency is the highest in full elbow flexion and is close to forearm neutral position for each elbow angle. The vertical component of pronator teres force is the highest among all components and is greater in pronation and elbow extension. The radial component becomes negative in pronation and reaches lower values as the elbow flexes. Both components could enhance radial curvature, especially in pronation. The model also enables to calculate efficiency and force components simulating changes in osteometric parameters. An increase of radial curvature improves efficiency and displaces the position where the radial component becomes negative towards the end of pronation. A more proximal location of pronator teres radial enthesis and a larger humeral medial epicondyle increase efficiency and displace the position where this component becomes negative towards forearm neutral position, which enhances radial curvature. Efficiency is also affected by medial epicondylar orientation and carrying angle. Moreover, reaching an object and bringing it close to the face in a close-to-neutral position improve efficiency and entail an equilibrium between the forces affecting the elbow joint stability. When the upper-limb skeleton is used in positions of low efficiency, implying unbalanced force components, it undergoes plastic changes, which improve these parameters. These findings are useful for studies on ergonomics and orthopaedics, and the model could also be applied to fossil primates in order to infer their locomotor form

  6. Morphological characteristics of the developing proximal femur: A biomechanical perspective

    Directory of Open Access Journals (Sweden)

    Đurić Marija

    2012-01-01

    Full Text Available Introduction. In contrast to a plethora of studies on the proximal femur in adults, its external and internal morphology in growing children has not been sufficiently analyzed. Objective. We analyzed changes in external and internal morphology of the proximal femur during growth and development to interpret the links between them and concepts of the human femoral biomechanics. Methods. We assessed external geometry, internal trabecular and cortical arrangement, and bone mineral density (BMD of the proximal femur in 29 children (age at death from 1 month to 14 years from archaeological context by using microscopic and radiographic methods. Results. The results showed that both the femoral neck width and length increased with age, with the femoral neck becoming more elongated, while the collo-diaphyseal angle decreased. A strong relationship between age and adjusted areal BMD was found, showing continuous increase during childhood. Parallel trabecular pattern at birth changed to mature three distinct trabecular groups (longitudinal – principal compressive, transversal – tensile and randomly scattered starting from the age of 8 months. In older children the superior and inferior aspects of the femoral neck differently changed with growth, with medial neck having thicker cortex and trabeculae. Conclusion. In the light of bone adaptation principle, the observed changes in external and internal morphology are governed by mechanical forces acting on the developing femur. Our findings on the development of trabecular pattern and cortical distribution are compatible with recent views on the femoral biomechanics which point out the predominance of compressive stresses in the femoral neck, adaptation to shear stresses, multiaxial loading perspective, prevalence of muscle effects over body weight, and existence of adaptational eccentricity. [Projekat Ministarstva nauke Republike Srbije, br. 45005

  7. BIOMECHANICAL PRINCIPLES PHYSICAL REHABILITATION OF CHILDREN WITH CEREBRAL PALSY

    Directory of Open Access Journals (Sweden)

    S. D. Korshunov

    2016-01-01

    Full Text Available Aim. We studied the basic biomechanical principles of physical rehabilitation of children with cerebral palsy.Materials and methods. Methods of Motion Tracking and electromyography investigated the biomechanical characteristics of gait in children with cerebral palsy. It is shown that the main differences between dynamic stereotype walk pediatric patients is to delay moving forward center of gravity and the disorganization of the lower limb movements (especially knee in the vertical plane. Prevailing flexion - leading position of the lower extremities during locomotion cycle associated with limitation of motion in the hip joint, offset by an increase swinging body, weakening activity in the rear shock phase and its sharp increase in the fourth phase. Changes in the structure of the movement of the shoulder girdle and upper extremities can be considered as compensatory. Characteristically excessive involvement in the locomotion of the calf muscles and the rectus muscles of the back, with the central mechanisms gipersinhronizatsii activity of motor units are the primary mechanism for adaptation in a group of children that are capable of self-locomotion.Results. As a result of the research it shows that in motor rehabilitation of children with cerebral palsy should include the following elements: exercise to maintain the body balance when performing arm movements, exercises for coordination of hand movements, including motor brushes, exercises to increase mobility in the hip joints and in the back, exercises designed to exercise the calf muscles, the front thigh muscles and the rectus muscles of the back, massage to relieve hyper calf muscles. 

  8. Biomechanics of Forearm Rotation: Force and Efficiency of Pronator Teres

    Science.gov (United States)

    Ibáñez-Gimeno, Pere; Galtés, Ignasi; Jordana, Xavier; Malgosa, Assumpció; Manyosa, Joan

    2014-01-01

    Biomechanical models are useful to assess the effect of muscular forces on bone structure. Using skeletal remains, we analyze pronator teres rotational efficiency and its force components throughout the entire flexion-extension and pronation-supination ranges by means of a new biomechanical model and 3D imaging techniques, and we explore the relationship between these parameters and skeletal structure. The results show that maximal efficiency is the highest in full elbow flexion and is close to forearm neutral position for each elbow angle. The vertical component of pronator teres force is the highest among all components and is greater in pronation and elbow extension. The radial component becomes negative in pronation and reaches lower values as the elbow flexes. Both components could enhance radial curvature, especially in pronation. The model also enables to calculate efficiency and force components simulating changes in osteometric parameters. An increase of radial curvature improves efficiency and displaces the position where the radial component becomes negative towards the end of pronation. A more proximal location of pronator teres radial enthesis and a larger humeral medial epicondyle increase efficiency and displace the position where this component becomes negative towards forearm neutral position, which enhances radial curvature. Efficiency is also affected by medial epicondylar orientation and carrying angle. Moreover, reaching an object and bringing it close to the face in a close-to-neutral position improve efficiency and entail an equilibrium between the forces affecting the elbow joint stability. When the upper-limb skeleton is used in positions of low efficiency, implying unbalanced force components, it undergoes plastic changes, which improve these parameters. These findings are useful for studies on ergonomics and orthopaedics, and the model could also be applied to fossil primates in order to infer their locomotor form. Moreover, activity

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

    OpenAIRE

    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...

  10. Biomechanical interaction between the transverse carpal ligament and the thenar muscles

    OpenAIRE

    Shen, Zhilei Liu; Li, Zong-Ming

    2012-01-01

    The transverse carpal ligament (TCL) serves as the origin of the thenar muscles and is integral to thenar muscle contraction anatomically and biomechanically. TCL hypertrophy has been observed in patients with carpal tunnel syndrome and is potentially caused by repetitive hand use. The purpose of this study was to investigate the biomechanical interaction between the TCL and the thenar muscles. Specifically, the morphological changes of the carpal arch, formed by the TCL, in response to thena...

  11. 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...

  12. Influence of Age on Ocular Biomechanical Properties in a Canine Glaucoma Model with ADAMTS10 Mutation

    OpenAIRE

    Palko, Joel R.; Morris, Hugh J.; Pan, Xueliang; Harman, Christine D.; Koehl, Kristin L.; Gelatt, Kirk N.; Plummer, Caryn E.; Komáromy, András M.; Liu, Jun

    2016-01-01

    Soft tissue often displays marked age-associated stiffening. This study aims to investigate how age affects scleral biomechanical properties in a canine glaucoma model with ADAMTS10 mutation, whose extracellular matrix is concomitantly influenced by the mutation and an increased mechanical load from an early age. Biomechanical data was acquired from ADAMTS10-mutant dogs (n = 10, 21 to 131 months) and normal dogs (n = 5, 69 to 113 months). Infusion testing was first performed in the whole glob...

  13. Inter-assessor reliability of practice based biomechanical assessment of the foot and ankle

    OpenAIRE

    Jarvis Hannah L; Nester Christopher J; Jones Richard K; Williams Anita; Bowden Peter D

    2012-01-01

    Abstract Background There is no consensus on which protocols should be used to assess foot and lower limb biomechanics in clinical practice. The reliability of many assessments has been questioned by previous research. The aim of this investigation was to (i) identify (through consensus) what biomechanical examinations are used in clinical practice and (ii) evaluate the inter-assessor reliability of some of these examinations. Methods Part1: Using a modified Delphi technique 12 podiatrists de...

  14. Biomechanical Role of the Transverse Carpal Ligament in Carpal Tunnel Compliance

    OpenAIRE

    Li, Zong-Ming; Marquardt, Tamara L.; Evans, Peter J.; Seitz, William H.

    2014-01-01

    The transverse carpal ligament (TCL) is a significant constituent of the wrist structure and forms the volar boundary of the carpal tunnel. It serves biomechanical and physiological functions, acting as a pulley for the flexor tendons, anchoring the thenar and hypothenar muscles, stabilizing the bony structure, and providing wrist proprioception. This article mainly describes and reviews our recent studies regarding the biomechanical role of the TCL in the compliant characteristics of the car...

  15. WHAT IS A MOMENT ARM? CALCULATING MUSCLE EFFECTIVENESS IN BIOMECHANICAL MODELS USING GENERALIZED COORDINATES

    OpenAIRE

    Sherman, Michael A.; Seth, Ajay; Delp, Scott L.

    2013-01-01

    Biomechanics researchers often use multibody models to represent biological systems. However, the mapping from biology to mechanics and back can be problematic. OpenSim is a popular open source tool used for this purpose, mapping between biological specifications and an underlying generalized coordinate multibody system called Simbody. One quantity of interest to biomechanical researchers and clinicians is “muscle moment arm,” a measure of the effectiveness of a muscle at contributing to a pa...

  16. Mystery of alar ligament rupture: Value of MRI in whiplash injuries - biomechanical, anatomical and clinical studies

    International Nuclear Information System (INIS)

    Purpose: Whiplash injury of the cervical spine is a frequent issue in medical expertise and causes enormous consequential costs for motor insurance companies. Some authors accuse posttraumatic changes of alar ligaments to be causative for consequential disturbances. Materials and methods: Review of recent studies on biomechanics, anatomical and clinical MR imaging. Results: Biomechanical experiments can not induce according injuries of alar ligaments. Although MRI provides excellent visualization of alar ligaments, the range of normal variants is high. (orig.)

  17. Anatomical and biomechanical basis vertical position of the body and sport

    OpenAIRE

    Сак [Andrey Sak], Андрій Евгенович

    2013-01-01

    On the basis of their own and literature data analysis anatomical reconstructions of biomechanical human body designed to provide vertical position. The role of reconstruction of the skeleton and skeletal muscles to achieve these goals. Among such changes are necessary biomechanically efficient shaping of the skeleton aimed at adapting it to the perception of gravity, the acquisition of structural features that are required in a number of taxonomic indicators of bipedalism. The most important...

  18. Biomechanics of atherosclerotic coronary plaque: site, stability and in vivo elasticity modeling.

    OpenAIRE

    Ohayon, Jacques; Finet, Gérard; Le Floc’h, Simon; Cloutier, Guy; Gharib, Ahmed M.; Heroux, Julie; Pettigrew, Roderic I.

    2014-01-01

    International audience Coronary atheroma develop in local sites that are widely variable among patients and are considerably variable in their vulnerability for rupture. This article summarizes studies conducted by our collaborative laboratories on predictive biomechanical modeling of coronary plaques. It aims to give insights into the role of biomechanics in the development and localization of atherosclerosis, the morphologic features that determine vulnerable plaque stability, and emergi...

  19. Biomechanics of the elbow joint in tennis players and relation to pathology

    OpenAIRE

    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 different repetitive biomechanical nature that can result in tennis‐related injuries. In this article, a biomechanically‐based evaluation of tennis strokes is presented. This overview includes all...

  20. Biomechanics of running in weightlessness on a treadmill equipped with a subject loading system

    OpenAIRE

    Gosseye, Thierry

    2011-01-01

    One countermeasure used during long duration spaceflight to maintain bone and muscle mass is a treadmill equipped with a subject loading system (SLS) that simulates gravity. To date, little is known about the biomechanics of running in weightlessness on such a treadmill-SLS system. We have designed an instrumented treadmill/force-plate to compare the biomechanics of running in weightlessness to running on Earth. Gravity was simulated by two pneumatic pistons pulling downwards on a subject’s h...

  1. Biomechanical analysis of transfemoral amputee’s sprint running and block start

    OpenAIRE

    Ojala, Emilia

    2012-01-01

    Ojala, Paula Emilia, 2012. Biomechanical analysis of transfemoral amputee’s sprint running and block start. Department of Biology of Physical Activity, University of Jyväskylä, Master’s Thesis in Biomechanics. 87 p. Although a large number of studies about human locomotion have been reported, little is known about how to run with a prosthesis limb. The purpose of the study was to examine the difference between the healthy and prosthesis leg and between different prostheses during the spri...

  2. Biomechanics of a Fixed–Center of Rotation Cervical Intervertebral Disc Prosthesis

    OpenAIRE

    Crawford, Neil R; Baek, Seungwon; Sawa, Anna G.U.; Safavi-Abbasi, Sam; Sonntag, Volker K.H.; Duggal, Neil

    2012-01-01

    Background Past in vitro experiments studying artificial discs have focused on range of motion. It is also important to understand how artificial discs affect other biomechanical parameters, especially alterations to kinematics. The purpose of this in vitro investigation was to quantify how disc replacement with a ball-and-socket disc arthroplasty device (ProDisc-C; Synthes, West Chester, Pennsylvania) alters biomechanics of the spine relative to the normal condition (positive control) and si...

  3. Current research and development problems of mechatronics adn robotics and biomechanics

    Czech Academy of Sciences Publication Activity Database

    Ehrenberger, Zdeněk; Janíček, P.; Kratochvíl, Ctirad

    Brno: CERM Akademické nakladatelství, 2001 - (Kotek, V.; Kratochvíl, C.; Ehrenberger, Z.), s. 15-24 [International conference Mechatronics, robotronics and biomechanics 2001 /3./. Třešť (CZ), 10.09.2001-12.09.2001] R&D Projects: GA ČR GA101/01/0974 Keywords : engineering mechatronics * current robotics * biomechanics Subject RIV: JR - Other Machinery

  4. 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

    2013-11-01

    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

  5. Effects of resistance training fatigue on joint biomechanics.

    Science.gov (United States)

    Hooper, David R; Szivak, Tunde K; Distefano, Lindsay J; Comstock, Brett A; Dunn-Lewis, Courtenay; Apicella, Jenna M; Kelly, Neil A; Creighton, Brent C; Volek, Jeff S; Maresh, Carl M; Kraemer, William J

    2013-01-01

    Resistance training has been found to have a multitude of benefits. However, when performed with short rest, resistance training can result in substantial fatigue, which may have a negative impact on exercise technique. The purpose of this study is to examine the effects of fatigue from resistance exercise on joint biomechanics to determine what residual movement effects may exist after the workout. Twelve men with at least 6 months of resistance training experience (age 24 ± 4.2 years, height 173.1 ± 3.6 cm, weight 76.9 ± 7.8 kg) performed 5 body weight squats before (pretest) and after (posttest) a highly fatiguing resistance training workout. Lower extremity biomechanics were assessed using a 3-dimensional motion analysis system during these squats. Peak angle, total displacement, and rate were assessed for knee flexion, trunk flexion, hip flexion, hip rotation, and hip adduction. Results showed a significant decrease in peak angle for knee flexion (Pre: 120.28 ± 11.93°, Post: 104.46 ± 9.85°), hip flexion (Pre: -109.42 ± 12.49°, Post: -95.8 ± 12.30°), and hip adduction (Pre: -23.32 ± 7.04°, Post: -17.30 ± 8.79°). There was a significant reduction in angular displacement for knee flexion (Pre: 115.56 ± 10.55°, Post: 103.35 ± 10.49°), hip flexion (Pre: 97.94 ± 10.69°, Post: 90.51 ± 13.22°), hip adduction (Pre: 17.79 ± 7.36°, Post: 11.89 ± 4.34°), and hip rotation (Pre: 30.72 ± 12.28, Post: 20.48 ± 10.12). There was also a significant reduction in displacement rate for knee flexion (Pre: 2.20 ± 0.20, Post: 1.98 ± 0.20), hip flexion (Pre: 1.92 ± 0.20, Post: 1.76 ± 0.27), hip adduction (Pre: -0.44 ± 0.17, Post: -0.31 ± 0.17), and hip rotation (Pre: 0.59 ± 0.23, Post: 0.38 ± 0.21). This study demonstrated that there are lasting residual effects on movement capabilities after a high-intensity short rest protocol. Thus, strength and conditioning coaches must be careful to monitor movements and exercise techniques after such workouts

  6. Changes in multi-segment foot biomechanics with a heat-mouldable semi-custom foot orthotic device

    OpenAIRE

    Ferber Reed; Benson Brittany

    2011-01-01

    Abstract Background Semi-custom foot orthoses (SCO) are thought to be a cost-effective alternative to custom-made devices. However, previous biomechanical research involving either custom or SCO has only focused on rearfoot biomechanics. The purpose of this study was therefore to determine changes in multi-segment foot biomechanics during shod walking with and without an SCO. We chose to investigate an SCO device that incorporates a heat-moulding process, to further understand if the moulding...

  7. 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....

  8. Experimental techniques for single cell and single molecule biomechanics

    Energy Technology Data Exchange (ETDEWEB)

    Lim, C.T. [Nano Biomechanics Laboratory, Division of Bioengineering and Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576 (Singapore)]. E-mail: ctlim@nus.edu.sg; Zhou, E.H. [Nano Biomechanics Laboratory, Division of Bioengineering and Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576 (Singapore); Li, A. [Nano Biomechanics Laboratory, Division of Bioengineering and Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576 (Singapore); Vedula, S.R.K. [Nano Biomechanics Laboratory, Division of Bioengineering and Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576 (Singapore); Fu, H.X. [Nano Biomechanics Laboratory, Division of Bioengineering and Department of Mechanical Engineering, National University of Singapore, 9 Engineering Drive 1, Singapore 117576 (Singapore)

    2006-09-15

    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.

  9. 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.

  10. The biomechanical properties of F1C pili

    CERN Document Server

    Castelain, Mickaël; Klinth, Jeanna; Lindberg, Stina; Andersson, Magnus; Uhlin, Bernt Eric; Axner, Ove

    2014-01-01

    Uropathogenic Escherichia coli (UPEC) express various kinds of organelles, so-called pili or fimbriae, that mediate adhesion to host tissue in the urinary tract through specific receptor-adhesin interactions. The biomechanical properties of these pili have been considered important for the ability of bacteria to withstand shear forces from rinsing urine flows. Force measuring optical tweezers have been used to characterize individual organelles of F1C type expressed by UPEC bacteria with respect to such properties. Qualitatively, the force-vs.-elongation response was found to be similar to that of other types of helix-like pili expressed by UPEC, i.e. type 1, P, and S, with force-induced elongation in three regions of which one represents the important uncoiling mechanism of the helix-like quaternary structure. Quantitatively, the steady-state uncoiling force was assessed to 26.4(1.4) pN, which is similar to those of other pili (which range from 21 pN for SI to 30 pN for type 1). The corner velocity for dynam...

  11. Linking suckling biomechanics to the development of the palate

    Science.gov (United States)

    Li, Jingtao; Johnson, Chelsey A.; Smith, Andrew A.; Hunter, Daniel J.; Singh, Gurpreet; Brunski, John B.; Helms, Jill A.

    2016-02-01

    Skulls are amongst the most informative documents of evolutionary history but a complex geometry, coupled with composite material properties and complicated biomechanics, have made it particularly challenging to identify mechanical principles guiding the skull’s morphogenesis. Despite this challenge, multiple lines of evidence, for example the relationship between masticatory function and the evolution of jaw shape, nonetheless suggest that mechanobiology plays a major role in skull morphogenesis. To begin to tackle this persistent challenge, cellular, molecular and tissue-level analyses of the developing mouse palate were coupled with finite element modeling to demonstrate that patterns of strain created by mammalian-specific oral behaviors produce complementary patterns of chondrogenic gene expression in an initially homogeneous population of cranial neural crest cells. Neural crest cells change from an osteogenic to a chondrogenic fate, leading to the materialization of cartilaginous growth plate-like structures in the palatal midline. These growth plates contribute to lateral expansion of the head but are transient structures; when the strain patterns associated with suckling dissipate at weaning, the growth plates disappear and the palate ossifies. Thus, mechanical cues such as strain appear to co-regulate cell fate specification and ultimately, help drive large-scale morphogenetic changes in head shape.

  12. Tibiofemoral contact biomechanics following meniscocapsular separation and repair.

    Science.gov (United States)

    Dugas, J R; Barrett, A M; Beason, D P; Plymale, M F; Fleisig, G S

    2015-06-01

    Meniscocapsular separations are often seen in knees with other intra-articular pathology. The consequences of these tears with regard to knee contact mechanics are currently unknown, and the biomechanical advantages of repair have not been measured. We hypothesize that tears to the meniscocapsular junction will cause an increase in tibiofemoral contact pressure and a decrease in contact area, with a return to more normal conditions after repair. 10 fresh-frozen cadaver knees each underwent 10 cycles of axial compressive loading in full extension under three different testing conditions: intact, meniscocapsular separation, and repair. A pressure sensor matrix was inserted into the medial joint space and used to measure magnitude and location of contact pressure and area. Mean contact pressure increased from 0.80±0.17 MPa in the intact knee to 0.88±0.19 MPa with separation, with a decrease to 0.78±0.14 MPa following repair. Peak pressures followed a similar trend with 2.59±0.41, 3.03±0.48, and 2.84±0.40 MPa for the same three groups, respectively. While none of the changes seen was statistically significant, even these small changes would potentially create degenerative changes at the articular surface over prolonged (i. e., months or years) standing, walking, and activity in the unrepaired state. PMID:25734910

  13. Biomechanical Dynamics of Cranial Sutures during Simulated Impulsive Loading.

    Science.gov (United States)

    Zhang, Z Q; Yang, J L

    2015-01-01

    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. PMID:27019589

  14. Biomechanical determinants of transverse and rotary gallop in cursorial mammals.

    Science.gov (United States)

    Biancardi, Carlo M; Minetti, Alberto E

    2012-12-01

    Transverse and rotary gallop differ in the placement of the leading hindfeet and forefeet: ipsilateral in the former gait, contralateral in the latter. We analysed 351 filmed sequences to assess the gallop type of 89 investigated mammalian species belonging to Carnivora, Artiodactyla and Perissodactyla orders. Twenty-three biometrical, ecological and physiological parameters were collected for each species both from literature data and from animal specimens. Most of the species showed only one kind of gallop: transverse (42%) or rotary (39%), while some species performed rotary gallop only at high speed (19%). In a factorial analysis, the first principal component (PC), which accounted for 40% of the total variance, was positively correlated to the relative speed and negatively correlated to size and body mass. The second PC was correlated to the ratio between distal and proximal limb segments. Large size and longer proximal limb segments were associated with transverse gallop, while rotary and speed-dependent species showed higher metacarpus/humerus and metatarsus/femur length ratio and faster relative speeds. The resulting limb excursion angles were proportional to the square-root of the Froude number, and significantly higher in rotary gallopers. The gait pattern analysis indicated significant differences between transverse and rotary gallop in forelimb and hindlimb duty factor (t-test; Pnumber of mammalian species, and indicate that the gallop pattern depends on diverse environmental, morphometrical and biomechanical characters. PMID:22933611

  15. 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.

  16. Effects of spaceflight on rat humerus geometry, biomechanics, and biochemistry

    Science.gov (United States)

    Vailas, A. C.; Zernicke, R. F.; Grindeland, R. E.; Kaplansky, A.; Durnova, G. N.; Li, K. C.; Martinez, D. A.

    1990-01-01

    The effects of a 12.5-day spaceflight (Cosmos 1887 biosatellite) on the geometric, biomechanical, and biochemical characteristics of humeri of male specific pathogen-free rats were examined. Humeri of age-matched basal control, synchronous control, and vivarium control rats were contrasted with the flight bones to examine the influence of growth and space environment on bone development. Lack of humerus longitudinal growth occurred during the 12.5 days in spaceflight. In addition, the normal mid-diaphysial periosteal appositional growth was affected; compared with their controls, the spaceflight humeri had less cortical cross-sectional area, smaller periosteal circumferences, smaller anterior-posterior periosteal diameters, and smaller second moments of area with respect to the bending and nonbending axes. The flexural rigidity of the flight humeri was comparable to that of the younger basal control rats and significantly less than that of the synchronous and vivarium controls; the elastic moduli of all four groups, nonetheless, were not significantly different. Generally, the matrix biochemistry of the mid-diaphysial cross sections showed no differences among groups. Thus, the spaceflight differences in humeral mechanical strength and flexural rigidity were probably a result of the differences in humeral geometry rather than material properties.

  17. Biomechanical Analysis of Pedicle Screw Fixation for Thoracolumbar Burst Fractures.

    Science.gov (United States)

    McDonnell, Matthew; Shah, Kalpit N; Paller, David J; Thakur, Nikhil A; Koruprolu, Sarath; Palumbo, Mark A; Daniels, Alan H

    2016-05-01

    Treatment of unstable thoracolumbar burst fractures remains controversial. Long-segment pedicle screw constructs may be stiffer and impart greater forces on adjacent segments compared with short-segment constructs, which may affect clinical performance and long-term out come. The purpose of this study was to biomechanically evaluate long-segment posterior pedicle screw fixation (LSPF) vs short-segment posterior pedicle screw fixation (SSPF) for unstable burst fractures. Six unembalmed human thoracolumbar spine specimens (T10-L4) were used. Following intact testing, a simulated L1 burst fracture was created and sequentially stabilized using 5.5-mm titanium polyaxial pedicle screws and rods for 4 different constructs: SSPF (1 level above and below), SSPF+L1 (pedicle screw at fractured level), LSPF (2 levels above and below), and LSPF+L1 (pedicle screw at fractured level). Each fixation construct was tested in flexion-extension, lateral bending, and axial rotation; range of motion was also recorded. Two-way repeated-measures analysis of variance was performed to identify differences between treatment groups and functional noninstrumented spine. Short-segment posterior pedicle screw fixation did not achieve stability seen in an intact spine (P.1). Long-segment posterior pedicle screw fixation constructs were not associated with increased adjacent segment motion. Al though the sample size of 6 specimens was small, this study may help guide clinical decisions regarding burst fracture stabilization. [Orthopedics. 2016; 39(3):e514-e518.]. PMID:27135451

  18. 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.

  19. Which biomechanical models are currently used in standing posture analysis?

    Science.gov (United States)

    Crétual, A

    2015-11-01

    In 1995, David Winter concluded that postural analysis of upright stance was often restricted to studying the trajectory of the center of pressure (CoP). However, postural control means regulation of the center of mass (CoM) with respect to CoP. As CoM is only accessible by using a biomechanical model of the human body, the present article proposes to determine which models are actually used in postural analysis, twenty years after Winter's observation. To do so, a selection of 252 representative articles dealing with upright posture and published during the four last years has been checked. It appears that the CoP model largely remains the most common one (accounting for nearly two thirds of the selection). Other models, CoP/CoM and segmental models (with one, two or more segments) are much less used. The choice of the model does not appear to be guided by the population studied. Conversely, while some confusion remains between postural control and the associated concepts of stability or strategy, this choice is better justified for real methodological concerns when dealing with such high-level parameters. Finally, the computation of the CoM continues to be a limitation in achieving a more complete postural analysis. This unfortunately implies that the model is chosen for technological reasons in many cases (choice being a euphemism here). Some effort still has to be made so that bioengineering developments allow us to go beyond this limit. PMID:26388359

  20. [Biomechanics of whiplash injuries of the cervical spine].

    Science.gov (United States)

    Schmidt, G

    1989-07-01

    1. The whiplash injury of the cervical spine is a typical, but not very often observed injury of occupants of automotive vehicles involved in moderate collisions. 2. There still exist great uncertainties in the elaboration of expertises concerning the minor whiplash injury, so that the great part of the disturbances cannot be objectivated under a clinical point of view. And on the other hand, serious whiplash injuries often are superposed or veiled by secondary injuries. 3. Thus, the aim of the present paper was to point out injury mechanisms, to give a rough scaling of the whiplash severity under biomechanical aspects and finally to set these injury mechanisms in correlation to the following criteria of accident: a) vehicle velocity change (energy equivalent speed--EES); b) deformation of vehicles on the impact-exposed structure; c) loading of occupants by acceleration or deceleration. 4. The tolerance limit of the cervical spine generally decreases to a lower limit, if the cervical spine is changed in a pathological way, e.g. by preexisting diseases. 5. It is evident and important, that the difficult work of giving an expert's opinion on this field must be performed in an interdisciplinary collaboration of engineers for collision-analysis and physicians experienced in accident-traumatology. PMID:2669311

  1. Experimental techniques for single cell and single molecule biomechanics

    International Nuclear Information System (INIS)

    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

  2. Growth Cone Biomechanics in Peripheral and Central Nervous System Neurons

    Science.gov (United States)

    Urbach, Jeffrey; Koch, Daniel; Rosoff, Will; Geller, Herbert

    2012-02-01

    The growth cone, a highly motile structure at the tip of an axon, integrates information about the local environment and modulates outgrowth and guidance, but little is known about effects of external mechanical cues and internal mechanical forces on growth-cone mediated guidance. We have investigated neurite outgrowth, traction forces and cytoskeletal substrate coupling on soft elastic substrates for dorsal root ganglion (DRG) neurons (from the peripheral nervous system) and hippocampal neurons (from the central) to see how the mechanics of the microenvironment affect different populations. We find that the biomechanics of DRG neurons are dramatically different from hippocampal, with DRG neurons displaying relatively large, steady traction forces and maximal outgrowth and forces on substrates of intermediate stiffness, while hippocampal neurons display weak, intermittent forces and limited dependence of outgrowth and forces on substrate stiffness. DRG growth cones have slower rates of retrograde actin flow and higher density of localized paxillin (a protein associated with substrate adhesion complexes) compared to hippocampal neurons, suggesting that the difference in force generation is due to stronger adhesions and therefore stronger substrate coupling in DRG growth cones.

  3. Hierarchical Dragonfly Wing: Microstructure-Biomechanical Behavior Relations

    Institute of Scientific and Technical Information of China (English)

    Yinglong Chen; Xishu Wang; Huaihui Ren; Hang Yin; Su Jia

    2012-01-01

    The dragonfly wing,which consists of veins and membrane,is of biological hierarchical material.We observed the cross-sections of longitudinal veins and membrane using Environmental Scanning Electron Microscopy (ESEM).Based on the experiments and previous studies,we described the longitudinal vein and the membrane in terms of two hierarchical levels of organization of composite materials at the micro- and nano-scales.The longitudinal vein of dragonfly wing has a complex sandwich structure with two chitinous shells and a protein layer,and it is considered as the first hierarchical level of the vein.Moreover,the chitinous shells are concentric multilayered structures.Clusters of nano-fibrils grow along the circumferential orientation embedded into the protein layer.It is considered as the second level of the hierarchy.Similarly,the upper and lower epidermises of membrane constitute the first hierarchical level of organization in micro scale.Similar to the vein shell,the membrane epidermises were found to be a paralleled multilayered structure,defined as the second hierarchical level of the membrane.Combining with the mechanical behavior analysis of the dragonfly wing,we concluded that the growth orientation of the hierarchical structure of the longitudinal vein and membrane is relevant to its biomechanical behavior.

  4. [Biomechanics of the bones and skeleton. III. Microstructure].

    Science.gov (United States)

    Martinko, V; Belay, M; Machay, S; Jelínek, L

    1989-04-01

    The authors analyzed micro- and ultrastructure of Haversian system--osteon--from the aspect of mechanics--biomechanics. The evaluation takes into account biological factors and instead of mathematical formulae and calculations prefer a comparison with technical constructions, particularly for emphasizing differences or similarities. The analysis of osteon revealed that it consists of fibres, net and tubes. The orientation of tube-like lamellae is in the direction of compressive strain, whereas the resultant course of torison and bending stress may be well observed in the direction of collagen fibres. A slight assymetry of osteons suggests that they are stressed by pressure in a slightly excentric direction. In the course of stress lengthwise there is the development of extension of the Haversian canal supporting the blood flow in the capillary. In the course of stress in the osteon lengthwise there are developing pressure, torsion and bending strains. Liquid phase can, together with collagen, absorb considerable portion of kinetic energy, thereby decreasing the strain of external strengths to act on the fragile mineralized component. Without the viscous and collagen elements the mineralized component would not be able to resist the dynamic forces which develop during the stresses in the bone tissue. Identification of mechanic phenomena of osteon provides information on structural principle of the whole bones. The authors applied in their study the knowledge from the discovery of USSR No. 181 and a discovery of CSSR No. 43. PMID:2750425

  5. Biomechanics and biomimetics in insect-inspired flight systems.

    Science.gov (United States)

    Liu, Hao; Ravi, Sridhar; Kolomenskiy, Dmitry; Tanaka, Hiroto

    2016-09-26

    Insect- and bird-size drones-micro air vehicles (MAV) that can perform autonomous flight in natural and man-made environments are now an active and well-integrated research area. MAVs normally operate at a low speed in a Reynolds number regime of 10(4)-10(5) or lower, in which most flying animals of insects, birds and bats fly, and encounter unconventional challenges in generating sufficient aerodynamic forces to stay airborne and in controlling flight autonomy to achieve complex manoeuvres. Flying insects that power and control flight by flapping wings are capable of sophisticated aerodynamic force production and precise, agile manoeuvring, through an integrated system consisting of wings to generate aerodynamic force, muscles to move the wings and a control system to modulate power output from the muscles. In this article, we give a selective review on the state of the art of biomechanics in bioinspired flight systems in terms of flapping and flexible wing aerodynamics, flight dynamics and stability, passive and active mechanisms in stabilization and control, as well as flapping flight in unsteady environments. We further highlight recent advances in biomimetics of flapping-wing MAVs with a specific focus on insect-inspired wing design and fabrication, as well as sensing systems.This article is part of the themed issue 'Moving in a moving medium: new perspectives on flight'. PMID:27528780

  6. Muscular activity and its relationship to biomechanics and human performance

    Science.gov (United States)

    Ariel, Gideon

    1994-01-01

    The purpose of this manuscript is to address the issue of muscular activity, human motion, fitness, and exercise. Human activity is reviewed from the historical perspective as well as from the basics of muscular contraction, nervous system controls, mechanics, and biomechanical considerations. In addition, attention has been given to some of the principles involved in developing muscular adaptations through strength development. Brief descriptions and findings from a few studies are included. These experiments were conducted in order to investigate muscular adaptation to various exercise regimens. Different theories of strength development were studied and correlated to daily human movements. All measurement tools used represent state of the art exercise equipment and movement analysis. The information presented here is only a small attempt to understand the effects of exercise and conditioning on Earth with the objective of leading to greater knowledge concerning human responses during spaceflight. What makes life from nonliving objects is movement which is generated and controlled by biochemical substances. In mammals. the controlled activators are skeletal muscles and this muscular action is an integral process composed of mechanical, chemical, and neurological processes resulting in voluntary and involuntary motions. The scope of this discussion is limited to voluntary motion.

  7. The feeding biomechanics and dietary ecology of Australopithecus africanus.

    Science.gov (United States)

    Strait, David S; Weber, Gerhard W; Neubauer, Simon; Chalk, Janine; Richmond, Brian G; Lucas, Peter W; Spencer, Mark A; Schrein, Caitlin; Dechow, Paul C; Ross, Callum F; Grosse, Ian R; Wright, Barth W; Constantino, Paul; Wood, Bernard A; Lawn, Brian; Hylander, William L; Wang, Qian; Byron, Craig; Slice, Dennis E; Smith, Amanda L

    2009-02-17

    The African Plio-Pleistocene hominins known as australopiths evolved a distinctive craniofacial morphology that traditionally has been viewed as a dietary adaptation for feeding on either small, hard objects or on large volumes of food. A historically influential interpretation of this morphology hypothesizes that loads applied to the premolars during feeding had a profound influence on the evolution of australopith craniofacial form. Here, we test this hypothesis using finite element analysis in conjunction with comparative, imaging, and experimental methods. We find that the facial skeleton of the Australopithecus type species, A. africanus, is well suited to withstand premolar loads. However, we suggest that the mastication of either small objects or large volumes of food is unlikely to fully explain the evolution of facial form in this species. Rather, key aspects of australopith craniofacial morphology are more likely to be related to the ingestion and initial preparation of large, mechanically protected food objects like large nuts and seeds. These foods may have broadened the diet of these hominins, possibly by being critical resources that australopiths relied on during periods when their preferred dietary items were in short supply. Our analysis reconciles apparent discrepancies between dietary reconstructions based on biomechanics, tooth morphology, and dental microwear. PMID:19188607

  8. Zygomatic implants: the impact of zygoma bone support on biomechanics.

    Science.gov (United States)

    Romeed, Shihab A; Malik, Raheel; Dunne, Stephen M

    2014-06-01

    Maxillectomy and severely resorbed maxilla are challenging to restore with provision of removable prostheses. Dental implants are essential to restore esthetics and function and subsequently quality of life in such group of patients. Zygomatic implants reduce the complications associated with bone grafting procedures and simplify the rehabilitation of atrophic maxilla and maxillectomy. The purpose of this study was to compare, by means of 3-dimensional finite element analysis, the impact of different zygomatic bone support (10, 15, and 20 mm) on the biomechanics of zygomatic implants. Results indicated that maximum stresses within the fixture were increased by 3 times when bone support decreased from 20 to 10 mm and were concentrated at the fixture/bone interface. However, stresses within the abutment screw and the abutment itself were not significantly different regardless of the bone support level. Supporting bone at 10 mm sustained double the stresses of 15 and 20 mm. Fixture's deflection was decreased by 2 to 3 times when bone support level increased to 15 mm and 20 mm, respectively. It was concluded that zygomatic bone support should not be less than 15 mm, and abutment screw is not at risk of fracture regardless of the zygomatic bone support. PMID:24914908

  9. 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.

    Directory of Open Access Journals (Sweden)

    Zhijie Jack Tseng

    Full Text Available 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.

  10. 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

  11. Age-related changes in biomechanical properties of transgenic porcine pulmonary and aortic conduits

    International Nuclear Information System (INIS)

    The limitations associated with conventional valve prosthesis have led to a search for alternatives. One potential approach is tissue engineering. Most tissue engineering studies have described the biomechanical properties of heart valves derived from adult pigs. However, because one of the factors affecting the function of valve prosthesis after implantation is appropriate sizing for a given patient, it is important to evaluate the usefulness of a heart valve given the donor animal’s weight and age. The aim of this study was to evaluate how the age of a pig can influence the biomechanical and hemodynamical properties of porcine heart valve prosthesis after acellularization. Acellular porcine aortic and pulmonary valve conduits were used. Hearts were harvested from animals differing in weight and age. The biomechanical properties of the valves were then characterized using a uniaxial tensile test. Moreover, computer simulations based on the finite element method (FEM) were used to study the influence of biomechanical properties on the hemodynamic conditions. Studying biomechanical and morphological changes in porcine heart valve conduits according to the weight and age of the animals can be valuable for developing age-targeted therapy using tissue engineering techniques. (paper)

  12. Tibiofemoral cartilage contact biomechanics in patients after reconstruction of a ruptured anterior cruciate ligament.

    Science.gov (United States)

    Hosseini, Ali; Van de Velde, Samuel; Gill, Thomas J; Li, Guoan

    2012-11-01

    We investigated the in vivo cartilage contact biomechanics of the tibiofemoral joint in patients after reconstruction of a ruptured anterior cruciate ligament (ACL). A dual fluoroscopic and MR imaging technique was used to investigate the cartilage contact biomechanics of the tibiofemoral joint during in vivo weight-bearing flexion of the knee in eight patients 6 months following clinically successful reconstruction of an acute isolated ACL rupture. The location of tibiofemoral cartilage contact, size of the contact area, cartilage thickness at the contact area, and magnitude of the cartilage contact deformation of the ACL-reconstructed knees were compared with those previously measured in intact (contralateral) knees and ACL-deficient knees of the same subjects. Contact biomechanics of the tibiofemoral cartilage after ACL reconstruction were similar to those measured in intact knees. However, at lower flexion, the abnormal posterior and lateral shift of cartilage contact location to smaller regions of thinner tibial cartilage that has been described in ACL-deficient knees persisted in ACL-reconstructed knees, resulting in an increase of the magnitude of cartilage contact deformation at those flexion angles. Reconstruction of the ACL restored some of the in vivo cartilage contact biomechanics of the tibiofemoral joint to normal. Clinically, recovering anterior knee stability might be insufficient to prevent post-operative cartilage degeneration due to lack of restoration of in vivo cartilage contact biomechanics. PMID:22528687

  13. Analysing physical fitness and biomechanical factors that determine tennis serve performance

    Directory of Open Access Journals (Sweden)

    Ertuğrul Gelen

    2009-11-01

    Full Text Available The purpose of the study is to analyse the fitness and the biomechanical factors which determine the velocity of the ball during serve in tennis (VBTS. The subjects of the study were fifteen male tournament level tennis player between the ages of sixteen and twenty five (18,8 ± 2,70 age/year. The physical fitness measurement of the study were; length, body weight, skinfold, diameter, circumference and length of the body, body composition, isometric handgrip strength, vertical jump, upper extremity range of motion (ROM and isokinetic strength. The angular velocity of racket head, racket handhold, middle finger, wrist, elbow, shoulder and hip joints on three axis during serve shoot were used for the biomechanical measurement. The relationship between VBTS with physical fitness and biomechanical factors were measured with Pearson Correlation.The analysis showed that there was significant positive relation between VBTS and length, negative relation with mesomorphy; positive relation between ROM of shoulder dominant internal and external rotation, trunk hyper-extension, left lateral flexion and right rotation, negative relation in dominant wrist flexion, positive relation between isokinetic strength characteristics such as shoulder and elbow extension, shoulder internal and external rotation, wrist flexion, handgrip isometric strength, also in biomechanical measures, positive relation between in Y axis elbow, wrist, finger and head of the racket.As a result, fitness and biomechanical parameters that are intensively used in tennis determine VBTS. We think trainers may speed up VBTS by improved parameters and accelerated training programmes.

  14. Biomechanical Implications of Corrective Surgery for FAI: An Evidence-based Review.

    Science.gov (United States)

    Sampson, Joshua D; Safran, Marc R

    2015-12-01

    Femoroacetabular impingement (FAI) has been identified as a potential cause of hip osteoarthritis. The goal of FAI surgery is to relieve pain, and hopefully delay or prevent osteoarthritis of the hip. Several studies have now demonstrated favorable clinical outcomes after arthroscopic and open surgical correction of symptomatic FAI. The concept is restoration of normal hip anatomy may result in improved biomechanical function and kinematics of the hip, which may prevent or delay the progression of osteoarthritis. Although many clinical studies demonstrate restoration of "normal" anatomy, there are few studies evaluating improvement of biomechanics and function. To date, only 5 studies have been published in the English literature that study biomechanics and/or kinematics of the hip both preoperatively and postoperatively. At this point in the understanding of FAI, critical analysis of the literature suggests that FAI surgery can improve several parameters of biomechanical hip function. However, the impact of these improved biomechanics on the natural history and progression of degenerative changes in patients that are treated for symptomatic FAI has not been demonstrated. PMID:26524550

  15. Biomechanics of cross-sectional size and shape in the hominoid mandibular corpus.

    Science.gov (United States)

    Daegling, D J

    1989-09-01

    Mandibular cross sections of Pan, Pongo, Gorilla, Homo, and two fossil specimens of Paranthropus were examined by computed tomography (CT) to determine the biomechanical properties of the hominoid mandibular corpus. Images obtained by CT reveal that while the fossil hominids do not differ significantly from extant hominoids in the relative contribution of compact bone to total subperiosteal area, the shape of the Paranthropus corpora indicates that the mechanical design of the robust australopithecine mandible is fundamentally distinct from that of modern hominoids in terms of its ability to resist transverse bending and torsion. It is also apparent that, among the modern hominoids, interspecific and sexual differences in corpus shape are not significant from a biomechanical perspective. While ellipse models have been used previously to describe the size, shape, and subsequent biomechanical properties of the corpus, the present study shows that such models do not predict the biomechanical properties of corpus cross-sectional geometry in an accurate or reliable manner. The traditional "robusticity" index of the mandibular corpus is of limited utility for biomechanical interpretations. The relationship of compact bone distribution in the corpus to dimensions such as mandibular length and arch width may provide a more functionally meaningful definition of mandibular robusticity. PMID:2508480

  16. 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

  17. A Biomechanical Approach to Assessing Hip Fracture Risk

    Science.gov (United States)

    Ellman, Rachel

    2009-01-01

    Bone loss in microgravity is well documented, but it is difficult to quantify how declines in bone mineral density (BMD) contribute to an astronaut's overall risk of fracture upon return. This study uses a biomechanical approach to assessing hip fracture risk, or Factor of Risk (Phi), which is defined as the ratio of applied load to bone strength. All long-duration NASA astronauts from Expeditions 1-18 were included in this study (n=25), while crewmembers who flew twice (n=2) were treated as separate subjects. Bone strength was estimated based on an empirical relationship between areal BMD at the hip, as measured by DXA, and failure load, as determined by mechanical testing of cadaver femora. Fall load during a sideways fall was calculated from a previously developed biomechanical model, which takes into account body weight, height, gender, and soft tissue thickness overlying the lateral aspect of the hip that serves to attenuate the impact force. While no statistical analyses have been performed yet, preliminary results show that males in this population have a higher FOR than females, with a post- flight Phi of 0.87 and 0.36, respectively. FOR increases 5.1% from preflight to postflight, while only one subject crossed the fracture "threshold" of Phi = 1, for a total of 2 subjects with a postflight Phi > 1. These results suggest that men may be at greater risk for hip fracture due largely in part to their relatively thin soft tissue padding as compared to women, since soft tissue thickness has the highest correlation (R(exp 2)= .53) with FOR of all subject-specific parameters. Future work will investigate changes in FOR during recovery to see if baseline risk levels are restored upon return to 1-g activity. While dual x-ray absorptiometry (DXA) is the most commonly used clinical measure of bone health, it fails to provide compartment-specific information that is useful in assessing changes to bone quality as a result of microgravity exposure. Peripheral

  18. 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

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

    Science.gov (United States)

    Ledogar, Justin A; Dechow, Paul C; Wang, Qian; Gharpure, Poorva H; Gordon, Adam D; 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

  20. 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. PMID:24438531

  1. Craniofacial biomechanics and functional and dietary inferences in hominin paleontology.

    Science.gov (United States)

    Grine, Frederick E; Judex, Stefan; Daegling, David J; Ozcivici, Engin; Ungar, Peter S; Teaford, Mark F; Sponheimer, Matt; Scott, Jessica; Scott, Robert S; Walker, Alan

    2010-04-01

    Finite element analysis (FEA) is a potentially powerful tool by which the mechanical behaviors of different skeletal and dental designs can be investigated, and, as such, has become increasingly popular for biomechanical modeling and inferring the behavior of extinct organisms. However, the use of FEA to extrapolate from characterization of the mechanical environment to questions of trophic or ecological adaptation in a fossil taxon is both challenging and perilous. Here, we consider the problems and prospects of FEA applications in paleoanthropology, and provide a critical examination of one such study of the trophic adaptations of Australopithecus africanus. This particular FEA is evaluated with regard to 1) the nature of the A. africanus cranial composite, 2) model validation, 3) decisions made with respect to model parameters, 4) adequacy of data presentation, and 5) interpretation of the results. Each suggests that the results reflect methodological decisions as much as any underlying biological significance. Notwithstanding these issues, this model yields predictions that follow from the posited emphasis on premolar use by A. africanus. These predictions are tested with data from the paleontological record, including a phylogenetically-informed consideration of relative premolar size, and postcanine microwear fabrics and antemortem enamel chipping. In each instance, the data fail to conform to predictions from the model. This model thus serves to emphasize the need for caution in the application of FEA in paleoanthropological enquiry. Theoretical models can be instrumental in the construction of testable hypotheses; but ultimately, the studies that serve to test these hypotheses - rather than data from the models - should remain the source of information pertaining to hominin paleobiology and evolution. PMID:20227747

  2. 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

  3. Biomechanics of spontaneous overground walk-to-run transition.

    Science.gov (United States)

    Segers, Veerle; De Smet, Kristof; Van Caekenberghe, Ine; Aerts, Peter; De Clercq, Dirk

    2013-08-15

    The purpose of the present study was to describe the biomechanics of spontaneous walk-to-run transitions (WRTs) in humans. After minimal instructions, 17 physically active subjects performed WRTs on an instrumented runway, enabling measurement of speed, acceleration, spatiotemporal variables, ground reaction forces and 3D kinematics. The present study describes (1) the mechanical energy fluctuations of the body centre-of-mass (BCOM) as a reflection of the whole-body dynamics and (2) the joint kinematics and kinetics. Consistent with previous research, the spatiotemporal variables showed a sudden switch from walking to running in one transition step. During this step there was a sudden increase in forward speed, the so-called speed jump (0.42 m s(-1)). At total body level, this was reflected in a sudden increase in energy of the BCOM (0.83±0.14 J kg(-1)) and an abrupt change from an out-of-phase to an in-phase organization of the kinetic and potential energy fluctuations. During the transition step a larger net propulsive impulse compared with the preceding and following steps was observed due to a decrease in the braking impulse. This suggests that the altered landing configuration (prepared during the last 40% of the preceding swing) places the body in an optimal configuration to minimize this braking impulse. We hypothesize this configuration also evokes a reflex allowing a more powerful push off, which generates enough power to complete the transition and launch the first flight phase. This powerful push-off was also reflected in the vertical ground reaction force, which suddenly changed to a running pattern. PMID:23619411

  4. Do Cells Contribute to Tendon and Ligament Biomechanics?

    Science.gov (United States)

    Hammer, Niels; Huster, Daniel; Fritsch, Sebastian; Hädrich, Carsten; Koch, Holger; Schmidt, Peter; Sichting, Freddy; Wagner, Martin Franz-Xaver; Boldt, Andreas

    2014-01-01

    Introduction 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. Material and Methods 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. Results 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. Discussion 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

  5. 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…

  6. The mathematical whisker: A review of numerical models of the rat׳s vibrissa biomechanics.

    Science.gov (United States)

    Lucianna, Facundo Adrián; Albarracín, Ana Lía; Vrech, Sonia Mariel; Farfán, Fernando Daniel; Felice, Carmelo José

    2016-07-01

    The vibrissal system of the rat refers to specialized hairs the animal uses for tactile sensory perception. Rats actively move their whiskers in a characteristic way called "whisking". Interaction with the environment produces elastic deformation of the whiskers, generating mechanical signals in the whisker-follicle complex. Advances in our understanding of the vibrissal complex biomechanics is of interest not only for the biological research field, but also for biomimetic approaches. The recent development of whisker numerical models has contributed to comprehending its sophisticated movements and its interactions with the follicle. The great diversity of behavioral patterns and complexities of the whisker-follicle ensemble encouraged the creation of many different biomechanical models. This review analyzes most of the whisker biomechanical models that have been developed so far. This review was written so as to render it accessible to readers coming from different research areas. PMID:27260019

  7. 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.

  8. 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.

  9. Biomechanical evaluation of wrist-driven flexor hinge orthosis in persons with spinal cord injury

    Directory of Open Access Journals (Sweden)

    Yeoun-Seung Kang, MD, PhD, CPO

    2013-11-01

    Full Text Available The wrist-driven flexor hinge orthosis (WDFHO is a device used to restore hand function in persons with tetraplegic spinal cord injury by furnishing three-point prehension. We assessed the effectiveness and biomechanical properties of the WDFHO in 24 persons with cervical 6 or 7 tetraplegia who have severely impaired hand function. This study introduces a mechanical operating model to assess the efficiency of the WDFHO. Experimental results showed that pinch force increased significantly (p < 0.001 after using the WDFHO and was found to positively correlate with the strength of wrist extensor muscles (r = 0.41, p < 0.001. However, when the strength of the wrist extensors acting on the WDFHO was greater, the reciprocal wrist and finger motion that generates three-point prehension was less effective (r = 0.79, p < 0.001. Reliable and valid biomechanical evaluation of the WDFHO could improve our understanding of its biomechanics.

  10. Impaired physical function, loss of muscle mass and assessment of biomechanical properties in critical ill patients

    DEFF Research Database (Denmark)

    Poulsen, Jesper Brøndum

    2012-01-01

    Intensive care unit (ICU) admission is associated with muscle weakness and ICU survivors report sustained limitation of physical capacity for years after discharge. Limited information is available on the underlying biomechanical properties responsible for this muscle function impairment. A...... potential to counteract loss of muscle mass. Despite the obvious clinical significance of muscle atrophy for the functional impairment observed in ICU survivors, no preventive therapies have been identified as yet. The overall aim of the present dissertation is to characterize aspects of physical function...... and biomechanical properties in ICU patients and to provide new insights into ICU-induced muscle wasting and the underlying biomechanical mechanisms responsible for the residual impairment of physical function in ICU survivors....

  11. Structural and biomechanical aspects of equine sacroiliac joint function and their relationship to clinical disease.

    Science.gov (United States)

    Goff, L M; Jeffcott, L B; Jasiewicz, J; McGowan, C M

    2008-06-01

    Pain originating from the sacroiliac joint (SIJ) in horses has long been associated with poor performance, yet specific diagnosis of sacroiliac dysfunction (SID) has been difficult to achieve. Clinical presentation of SID appears to fall into two categories. The first, presenting as pain and poor performance, is responsive to local analgesia of periarticular structures with poorly defined pathology. The second presents primarily as poor performance with bony pathological changes as a result of chronic instability. Diagnostic tests based on biomechanics as well as manual provocation for SIJ pain have formed the basis of tests currently used to diagnose SIJ dysfunction in humans. This review summarises the anatomy and biomechanics of the equine SIJ and current biomechanical, innervation and motor control concepts in human SID. The relationship between abnormal SIJ motion and altered neuromotor control with clinical disease of the equine SIJ are discussed. Future utilisation of these principles to develop new diagnostic and management tools for the equine SID is promising. PMID:17493851

  12. Instrumented and interactive limb models for biomechanics education: An assessment of efficacy and engagement.

    Science.gov (United States)

    Sulas, Romina; Liem, Nicholas; Kark, Lauren

    2015-08-01

    Custom anatomical and instrumented models of the human arm and leg were designed and manufactured to complement the teaching of introductory biomechanics subjects. The models were assessed for engagement and efficacy via questionnaires and unscheduled pop-quizzes, respectively. Questionnaire results demonstrated the ability of the models to provide assistance with understanding and visualising the fundamental principles of biomechanics. Additionally, the majority of students who participated also stated that the models enhanced their motivation to learn and stimulated their interest in biomechanics. Results from the pop-quizzes were ambiguous about the efficacy of the arm and leg models; only one group (out of five) showed significant improvements in pop-quiz scores following exposure to the models. Significance was not reached in the remaining groups. Further assessment is required to expose the true efficacy of the models. PMID:26737089

  13. Pilot biomechanical design of biomaterials for artificial nucleus prosthesis using 3D finite-element modeling

    Institute of Scientific and Technical Information of China (English)

    Qijin Huang; Guoquan Liu; Yong Li; Jin Gao; Zhengqiu Gu; Yuanzheng Ma; Haibin Xue

    2004-01-01

    Pilot biomechanical design of biomaterials for artificial nucleus prosthesis was carried out based on the 3D finite-element method. Two 3D models of lumbar intervertebral disc respectively with a real human nucleus and with the nucleus removed were developed and validated using published experimental and clinical data. Then the models with a stainless steel nucleus prosthesis implanted and with polymer nucleus prostheses of various properties implanted were used for the 3D finite-element biomechanical analysis. All the above simulation and analysis were carried out for the L4/L5 disc under a human worst-daily compression load of 2000 N. The results show that the polymer materials with Young's modulus of elasticity E = 0.1-100 MPa and Poisson's ratio v=0.35-0.5 are suitable to produce artificial nucleus prosthesis in view of biomechanical consideration.

  14. Consequences of biomechanically constrained tasks in the design and interpretation of synergy analyses

    Science.gov (United States)

    Tresch, Matthew C.; Perreault, Eric J.

    2015-01-01

    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

  15. 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.

  16. The relationship between patellofemoral and tibiofemoral morphology and gait biomechanics following arthroscopic partial medial meniscectomy

    DEFF Research Database (Denmark)

    Dempsey, Alasdair R.; Wang, Yuanyuan; Thorlund, Jonas Bloch;

    2013-01-01

    Purpose To examine the relationship between tibiofemoral and patellofemoral joint articular cartilage and subchondral bone in the medial and gait biomechanics following partial medial meniscectomy. Methods For this cross-sectional study, 122 patients aged 30–55 years, without evidence of knee...... with decreased patella cartilage volume (B = −17.9 (95 % CI −35.4, −0.4) p = 0.045) while knee adduction moment impulse was associated with increased medial tibial plateau area (B = 7.7 (95 % CI 0.9, 13.3) p = 0.025). A number of other variables approached significance. Conclusions Knee joint biomechanics...

  17. ASPECTS OF DESCENT METHODS AND BIOMECHANICAL BY TRIPLE JUMP BACK TO BAR FIXED MALE GYMNASTICS

    Directory of Open Access Journals (Sweden)

    Asistant lecturer LUCIAN POPA, Phd

    2012-12-01

    Full Text Available This writing is meant to set the biomechanical basis of this extreme- ly difficult element represented by the triple back flip dismount. Considering the difficulty, the extremely high risk that this dismount presents, the writing is not going to resume at just setting the basis, but is also suppose to solve the psychological difficulties-physiological, giving the gymnasts and their coaches the movement technique, the true mechanics of this move with superior mathematics calculations, the biomechanical analysis (of the muscular actions and finally based on all this factors the learning methodic is going to be elaborated.

  18. Tributes to Yuan-Cheng Fung on his 90th birthday biomechanics : from molecules to man

    CERN Document Server

    Chien, Shu; Schmid-Schönbein, Geert W

    2009-01-01

    This book is a tribute to Professor Yuan-Cheng Fung, the Father of Biomechanics and a pioneer in Bioengineering, in honor of his 90th Birthday. The book consists of articles contributed by his colleagues, students, friends and family. These articles illustrate Professor Fung's profound influence on outstanding leaders in bioengineering, especially biomechanics, and on the life and work of all people who have been in contact with him. The scientific topics covered range from fundamentals of science and engineering (e.g., residual stress, flow dynamics, and cellular signaling) to clinical disor

  19. The biomechanics of the equine foot as it pertains to farriery.

    Science.gov (United States)

    Eliashar, Ehud

    2012-08-01

    Shoes were originally applied to horses' feet to protect against excessive wear. Over the years, countless types of shoes and farriery techniques have been developed not only as a therapeutic aid to treat lameness but also to maintain or enhance functionality. The past 3 decades have provided equine veterinarians and farriers with new information relating to limb biomechanics and the effects of various farriery methods. This article describes the principles of foot biomechanics and how they are affected by some of the more common farriery and shoeing techniques. PMID:22981190

  20. 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.

  1. D.D. Donskoy and development of native biomechanics: from biocentrism to psychosemantics of moving actions.

    Directory of Open Access Journals (Sweden)

    Dmitriev S.V.

    2011-02-01

    Full Text Available The aim of this article was to analyze the main directions of domectic biomechanics's development in connection with D.D. Donskoy's ideas or under influence. The greatest methological achievement of D.D. Donskoy's biomechanical searches was the conception of movement as a living social and cultural object with its biodynamical tissue. The living movements reacts selectively and evolues and involves regularly. D.D.Donskoy had revealed the regularities of micromovements which initiated the elaboration of the new problems: psychological aspects of a man's motor action, reflecting and psychosemantic mechanisms.

  2. Biomechanics of rugby union scrummaging. Technical and safety issues.

    Science.gov (United States)

    Milburn, P D

    1993-09-01

    reinforces the importance of physical preparation for all forwards to better withstand the large forces involved in scrummaging. Despite negative publicity surrounding the risk of serious spinal injury in rugby union, limited research has been conducted to examine either the mechanisms of injury or techniques implicated in causing injury. Biomechanical information can provide systematic bases for modifying existing techniques and assessing the physical capacities necessary to efficiently and safely play in the serum. This will both improve performance of game skills and minimise the potential for injury. PMID:8235190

  3. Design and biomechanical study of a modified pedicle screw

    Institute of Scientific and Technical Information of China (English)

    LIU Tao; ZHENG Wen-jie; LI Chang-qing; LIU Guo-dong; ZHOU Yue

    2010-01-01

    body into the UHMWPE block, while the polyaxial screw group showed screw body swung up and down the screw head because of loosening of the ball-in-cup mechanism.Conclusions: The modified screw is well-designed and biomechanically improved. And it can provide sufficient stability for segment fixation as monoaxial screws.

  4. Biomechanical analysis of stair ambulation in lower limb amputees.

    Science.gov (United States)

    Schmalz, Thomas; Blumentritt, Siegmar; Marx, Björn

    2007-02-01

    Lower extremity amputees have to cope with many activities in everyday life that are substantially more difficult than walking on level ground, and such demands require a high degree of functionality from their prosthetic components. The present study is a biomechanical evaluation (kinematics, kinetics and EMG) of stair ascent and descent in a group of eight transtibial amputees (mean (standard deviation): age 51(14) years, height 176(7)cm, mass 88(19)kg); a group of 12 transfemoral amputees (age 37(8) years, height 182(7)cm, mass 83(7)kg) fitted with the electronically controlled C-LEG knee joint system; and a group of 12 able bodied persons (age 30(10) years, height 174(12)cm, mass 69(12)kg). During stair descent the transfemoral amputees presented a strong reduction of the prosthetic ankle moments (0.11Nm/kg) compared to transtibial amputees (0.93Nm/kg) and control subjects (1.26Nm/kg). Loading of the prosthetic knee joint in the transfemoral amputees more closely resembles the loading seen in the control population when compared to transtibial amputees (mean maximum flexion moment: controls 1.31Nm/kg, transfemoral amputees 1.00Nm/kg, transtibial amputees 0.50Nm/kg). Overload of the contralateral limb is more prominent in the transfemoral amputee than in the transtibial amputee. During stair ascent, the transtibial amputee presents a significant reduction of the knee flexion moment compared to the controls (mean maximum flexion moment: transtibial amputees 0.28Nm/kg, controls 1.31Nm/kg). These differences correlate with a change in the muscle activity of the knee extensor and hamstring muscles. The results also show adaptations in motor strategies during stair negotiation, for those with the partial loss of a lower limb due to the functional limits of current prosthetic components. The present data may contribute to a further enhancement of the efficiency of prosthetic feet and knee joints. PMID:16725325

  5. 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

  6. 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

  7. Biomechanical analysis of the swim-start: a review.

    Science.gov (United States)

    Vantorre, Julien; Chollet, Didier; Seifert, Ludovic

    2014-05-01

    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.e., between gliding and leg

  8. 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…

  9. 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…

  10. 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…

  11. Development of Finite Element Models from CT Scans forthe Use in Biomechanics

    Czech Academy of Sciences Publication Activity Database

    Jiroušek, Ondřej

    Praha : ČVUT, 2001 - (Navrátil, J.), s. 155-160 ISBN 80-01-02334-6 R&D Projects: GA AV ČR IAA2071003 Keywords : finite element model, computer tomography, reconstruction,biomechanics. Subject RIV: FI - Traumatology, Orthopedics

  12. Biomechanical Properties of In Vivo Human Skin From Dynamic Optical Coherence Elastography

    OpenAIRE

    Liang, Xing; Boppart, Stephen A.

    2009-01-01

    Dynamic optical coherence elastography is used to determine in vivo skin biomechanical properties based on mechanical surface wave propagation. Quantitative Young’s moduli are measured on human skin from different sites, orientations, and frequencies. Skin thicknesses, including measurements from different layers, are also measured simultaneously. Experimental results show significant differences among measurements from different skin sites, between directions parallel and orthogonal to Lange...

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

    OpenAIRE

    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 morphologi...

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

    DEFF Research Database (Denmark)

    Hansen, M.; Kongsgaard, M; Holm, Lars;

    2009-01-01

    The knowledge about the effect of estradiol on tendon connective tissue is limited. Therefore, we studied the influence of estradiol on tendon synthesis, structure, and biomechanical properties in postmenopausal women. Nonusers (control, n = 10) or habitual users of oral estradiol replacement the...

  15. 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. PMID:23072044

  16. 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.

  17. 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 months...

  18. MR morphology of triangular fibrocartilage complex: correlation with quantitative MR and biomechanical properties

    International Nuclear Information System (INIS)

    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.)

  19. 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…

  20. [Dynamics of hip joint biomechanics in patients with coxarthrosis at the time of hippotherapy].

    Science.gov (United States)

    Nareklishvili, T M

    2008-02-01

    The problems of degenerative-dystrophic abnormalities stimulate the development of new skills and methods of treatment and rehabilitation of the diseases. The goal of the study was to determine the efficacy of hippotherapy in patients with coxarthrosis, according to functional and biomechanical parameters. Hippotherapy involves the utilization of horseback riding to stimulate the patient's normal reactions and locomotion; to improve the balance and coordination of movement, normalize muscle tension, and eliminate pathological reflexes. The advantage of the hippotherapy is in the specific posture, which is adopted by hip joint at the time of riding and in movement, which is accomplished by rider, at different paces of the horse. 10 female patients from 14 to 32 years old with coxarthrosis were under the observation. The rehabilitation of the patients was carried out by means of hippotherapy, which consisted of three months riding three times a week. To evaluate the efficacy of treatment, a new method of biomechanical registration of hip joint movement during hippotherapy on pacing horse was developed. The dynamics of biomechanical curves before and after the treatment, as well as the clinical and functional parameters of the patients allowed the authors to conclude: hippotherapy improves a hip joint functional state in patients with coxarthrosis; improves the muscle-tendineous component of hip joint movement. Hippotherapy may be considered as the pathogenetic method of treatment of coxarthrosis. Drawing the biomechanical curve of hip joint movement at the time of riding is the objective method of studying its function. PMID:18401052

  1. Biomechanics of Ergometric Stress Test: regional and local effects on elastic, transitional and muscular human arteries

    International Nuclear Information System (INIS)

    Ergometric exercise stress tests (EST) give important information about the cardiovascular (CV) response to increased demands. The expected EST-related changes in variables like blood pressure and heart rate are known, but those in the arterial biomechanics are controversial and incompletely characterized. In this context, this work aims were to characterize the regional and local arterial biomechanical behaviour in response to EST; to evaluate its temporal profile in the post-EST recovery phase; and to compare the biomechanical response of different to EST. Methods: In 16 non-trained healthy young subjects the carotid-femoral pulse wave velocity and the carotid, femoral and brachial arterial distensibility were non-invasively evaluated before (Rest) and after EST. Main results: The EST resulted in an early increase in the arterial stiffness, evidenced by both, regional and local parameters (pulse wave velocity increase and distensibility reduction). When analyzing conjunctly the different post-EST recovery stages there were quali-quantitative differences among the arterial local stiffness response to EST. The biomechanical changes could not be explained only by blood pressure variations.

  2. 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. PMID:26153689

  3. Biomechanics of Climbing Coconut Trees and its Implications in Ankle Foot Morphology- A Video Sequence analysis

    OpenAIRE

    Bincy M George; Kumar, Arunachalam; Rao, Muddanna S

    2013-01-01

    Introduction: Few studies regarding foot changes and health of professional coconut tree climbers of south India are reported. Medical emergencies are very common, especially due to accidental fall from coconut trees, while on job. Objective of the present study is to analyze the altered biomechanics of lower limb joints used by the coconut tree climbers.

  4. Evaluation of Corneal Topography and Biomechanical Parameters after Use of Systemic Isotretinoin in Acne Vulgaris

    Directory of Open Access Journals (Sweden)

    Yusuf Yildirim

    2014-01-01

    Full Text Available Purpose. We report the effect of isotretinoin on corneal topography, corneal thickness, and biomechanical parameters in patients with acne vulgaris. Method. Fifty-four eyes of 54 patients who received oral isotretinoin for treatment of acne vulgaris were evaluated. All patients underwent a corneal topographical evaluation with a Scheimpflug camera combined with Placido-disk (Sirius, ultrasonic pachymetry measurements, and corneal biomechanical evaluation with an ocular response analyzer at baseline, in the 1st, 3rd, and 6th months of treatment, and 6 months after isotretinoin discontinuation. Results. The thinnest corneal thickness measured with Sirius differed significantly in the 1st, 3rd, and 6th months compared with the baseline measurement; there was no significant change in ultrasonic central corneal thickness measurements and biomechanical parameters (corneal hysteresis and corneal resistance factor throughout the study. Average simulated keratometry and surface asymmetry index increased significantly only in the first month of treatment according to the baseline. All changes disappeared 6 months after the end of treatment. Conclusion. Basal tear secretion and corneal morphologic properties were significantly influenced during the systemic isotretinoin treatment and the changes were reversible after discontinuation. No statistical important biomechanical differences were found to be induced by isotretinoin.

  5. 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.)

  6. 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

  7. Numerical Reconstruction and Injury Biomechanism in a Car-Pedestrian Crash Accident

    Institute of Scientific and Technical Information of China (English)

    ZOU Dong-hua; LI Zheng-dong; SHAO Yu; FENG Hao; CHEN Jian-guo; LIU Ning-guo; HUANG Ping; CHEN Yi-jiu

    2012-01-01

    Objective To reconstruct a car-pedestrian crash accident using numerical simulation technology and explore the injury biomechanism as forensic evidence for injury identification.Methods An integration of multi-body dynamic,finite elcment (FE),and classical method was applied to a car-pedestrian crash accident.The location of the collision and the details of the traffic accident were determined by vehicle trace verification and autopsy.The accident reconstruction was performed by coupling the three-dimensional car behavior from PC-CRASH with a MADYMO dummy model.The collision FE models of head and leg,developed from CT scans of human remains,were loaded with calculated dummy collision parameters.The data of the impact biomechanical responses were extracted in terms of von Mises stress,relative displacement,strain and stress fringes.Results The accident reconstruction results were identical with the examined ones and the biomechanism of head and leg injuries,illustrated through the FE methods,were consistent with the classical injury theories.Conclusion The numerical simulation technology is proved to be effective in identifying traffic accidents and exploring of injury biomechanism.

  8. Critical analysis of musculoskeletal modelling complexity in multibody biomechanical models of the upper limb.

    Science.gov (United States)

    Quental, Carlos; Folgado, João; Ambrósio, Jorge; Monteiro, Jacinto

    2015-01-01

    The inverse dynamics technique applied to musculoskeletal models, and supported by optimisation techniques, is used extensively to estimate muscle and joint reaction forces. However, the solutions of the redundant muscle force sharing problem are sensitive to the detail and modelling assumptions of the models used. This study presents four alternative biomechanical models of the upper limb with different levels of discretisation of muscles by bundles and muscle paths, and their consequences on the estimation of the muscle and joint reaction forces. The muscle force sharing problem is solved for the motions of abduction and anterior flexion, acquired using video imaging, through the minimisation of an objective function describing muscle metabolic energy consumption. While looking for the optimal solution, not only the equations of motion are satisfied but also the stability of the glenohumeral and scapulothoracic joints is preserved. The results show that a lower level of muscle discretisation provides worse estimations regarding the muscle forces. Moreover, the poor discretisation of muscles relevant to the joint in analysis limits the applicability of the biomechanical model. In this study, the biomechanical model of the upper limb describing the infraspinatus by a single bundle could not solve the complete motion of anterior flexion. Despite the small differences in the magnitude of the forces predicted by the biomechanical models with more complex muscular systems, in general, there are no significant variations in the muscular activity of equivalent muscles. PMID:24156405

  9. 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 perfor

  10. Stability of the unlinked Latitude total elbow prosthesis: A biomechanical in vitro analysis

    NARCIS (Netherlands)

    Wagener, Marc L.; Vos, de Maarten J.; Hendriks, Jan C.M.; Eygendaal, Denise; Verdonschot, Nico

    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 perform

  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. Matrix Metalloproteinase 9 (MMP-9 Regulates Vein Wall Biomechanics in Murine Thrombus Resolution.

    Directory of Open Access Journals (Sweden)

    Khanh P Nguyen

    Full Text Available Deep venous thrombosis is a common vascular problem with long-term complications including post-thrombotic syndrome. Post-thrombotic syndrome consists of leg pain, swelling and ulceration that is related to incomplete or maladaptive resolution of the venous thrombus as well as loss of compliance of the vein wall. We examine the role of metalloproteinase-9 (MMP-9, a gene important in extracellular remodeling in other vascular diseases, in mediating thrombus resolution and biomechanical changes of the vein wall.The effects of targeted deletion of MMP-9 were studied in an in vivo murine model of thrombus resolution using the FVB strain of mice. MMP-9 expression and activity significantly increased on day 3 after DVT. The lack of MMP-9 impaired thrombus resolution by 27% and this phenotype was rescued by the transplantation of wildtype bone marrow cells. Using novel biomechanical techniques, we demonstrated that the lack of MMP-9 significantly decreased thrombus-induced loss of vein wall compliance. Biomechanical analysis of the contribution of individual structural components showed that MMP-9 affected the elasticity of the extracellular matrix and collagen-elastin fibers. Biochemical and histological analyses correlated with these biomechanical effects as thrombi of mice lacking MMP-9 had significantly fewer macrophages and collagen as compared to those of wildtype mice.MMP-9 mediates thrombus-induced loss of vein wall compliance by increasing stiffness of the extracellular matrix and collagen-elastin fibers during thrombus resolution. MMP-9 also mediates macrophage and collagen content of the resolving thrombus and bone-marrow derived MMP-9 plays a role in resolution of thrombus mass. These disparate effects of MMP-9 on various aspects of thrombus illustrate the complexity of individual protease function on biomechanical and morphometric aspects of thrombus resolution.

  13. Lower limb biomechanics during running in individuals with achilles tendinopathy: a systematic review

    Directory of Open Access Journals (Sweden)

    Munteanu Shannon E

    2011-05-01

    Full Text Available Abstract Background Abnormal lower limb biomechanics is speculated to be a risk factor for Achilles tendinopathy. This study systematically reviewed the existing literature to identify, critique and summarise lower limb biomechanical factors associated with Achilles tendinopathy. Methods We searched electronic bibliographic databases (Medline, EMBASE, Current contents, CINAHL and SPORTDiscus in November 2010. All prospective cohort and case-control studies that evaluated biomechanical factors (temporospatial parameters, lower limb kinematics, dynamic plantar pressures, kinetics [ground reaction forces and joint moments] and muscle activity associated with mid-portion Achilles tendinopathy were included. Quality of included studies was evaluated using the Quality Index. The magnitude of differences (effect sizes between cases and controls was calculated using Cohen's d (with 95% CIs. Results Nine studies were identified; two were prospective and the remaining seven case-control study designs. The quality of 9 identified studies was varied, with Quality Index scores ranging from 4 to 15 out of 17. All studies analysed running biomechanics. Cases displayed increased eversion range of motion of the rearfoot (d = 0.92 and 0.67 in two studies, reduced maximum lower leg abduction (d = -1.16, reduced ankle joint dorsiflexion velocity (d = -0.62 and reduced knee flexion during gait (d = -0.90. Cases also demonstrated a number of differences in dynamic plantar pressures (primarily the distribution of the centre of force, ground reaction forces (large effects for timing variables and also showed reduced peak tibial external rotation moment (d = -1.29. Cases also displayed differences in the timing and amplitude of a number of lower limb muscles but many differences were equivocal. Conclusions There are differences in lower limb biomechanics between those with and without Achilles tendinopathy that may have implications for the prevention and management of

  14. 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. PMID:26816209

  15. Analysis on Biomechanical Characteristics of Post-operational Vertebral C5-C6 Segments

    Directory of Open Access Journals (Sweden)

    Heqiang Tian

    2016-03-01

    Full Text Available Both anterior cervical decompression and fusion (ACDF and artificial cervical disc replacement (ACDR have obvious advantages in the treatment of cervical spondylosis. To analyze the operation results, it is absolutely necessary to study the biomechanics of the movement range of post-operational vertebral C5-C6 segments, especially the biomechanical characteristics in cervical tissues in actual movements. In this study, using the human vertebral 3D graph gained by imaging diagnosis (CT, a vertebral solid model is established by the 3D reconstruction algorithm and reverse engineering technology. After that, with cervical soft tissue structure added to the solid model and set with a joint contact mechanism, a finite element model with a complete, accurate cervical C5-C6 kinematic unit is constructed, based on relevant physiological anatomical knowledge. This model includes vertebral segments, an intervertebral disc, ligament and zygopophysis in the cervical C5-C6 kinematic unit. In the created vertebral finite element model, the model is amended, referring to ACDF and ACDR, and the load and constraint are applied to a normal group, a fusion group and a displacement group, so as to analyze the biomechanical characteristics of the cervical vertebra after ACDF and ACDR. By comparing the finite element simulation results of different surgeries, this paper is intended to evaluate the functions and biomechanical behaviors of the post-operational vertebra, and explore the influence of the operation on the biomechanical stability of the cervical vertebra. This will provide theoretical guidance for implementation and optimization of ACDF and ACDR.

  16. On the prospect of patient-specific biomechanics without patient-specific properties of tissues.

    Science.gov (United States)

    Miller, Karol; Lu, Jia

    2013-11-01

    This paper presents main theses of two keynote lectures delivered at Euromech Colloquium "Advanced experimental approaches and inverse problems in tissue biomechanics" held in Saint Etienne in June 2012. We are witnessing an advent of patient-specific biomechanics that will bring in the future personalized treatments to sufferers all over the world. It is the current task of biomechanists to devise methods for clinically-relevant patient-specific modeling. One of the obstacles standing before the biomechanics community is the difficulty in obtaining patient-specific properties of tissues to be used in biomechanical models. We postulate that focusing on reformulating computational mechanics problems in such a way that the results are weakly sensitive to the variation in mechanical properties of simulated continua is more likely to bear fruit in near future. We consider two types of problems: (i) displacement-zero traction problems whose solutions in displacements are weakly sensitive to mechanical properties of the considered continuum; and (ii) problems that are approximately statically determinate and therefore their solutions in stresses are also weakly sensitive to mechanical properties of constituents. We demonstrate that the kinematically loaded biomechanical models of the first type are applicable in the field of image-guided surgery where the current, intraoperative configuration of a soft organ is of critical importance. We show that sac-like membranes, which are prototypes of many thin-walled biological organs, are approximately statically determinate and therefore useful solutions for wall stress can be obtained without the knowledge of the wall's properties. We demonstrate the clinical applicability and effectiveness of the proposed methods using examples from modeling neurosurgery and intracranial aneurysms. PMID:23491073

  17. Analysing physical fitness and biomechanical factors that determine tennis serve performance

    Directory of Open Access Journals (Sweden)

    Ertuğrul Gelen

    2009-11-01

    Full Text Available Normal 0 21 false false false TR X-NONE X-NONE MicrosoftInternetExplorer4 The purpose of the study is to analyse the fitness and the biomechanical factors which determine the velocity of the ball during serve in tennis (VBTS. The subjects of the study were fifteen male tournament level tennis player between the ages of sixteen and twenty five (18,8 ± 2,70 age/year. The physical fitness measurement of the study were; length, body weight, skinfold, diameter, circumference and length of the body, body composition, isometric handgrip strength, vertical jump, upper extremity range of motion (ROM and isokinetic strength. The angular velocity of racket head, racket handhold, middle finger, wrist, elbow, shoulder and hip joints on three axis during serve shoot were used for the biomechanical measurement.  The relationship between VBTS with physical fitness and biomechanical factors were measured with Pearson Correlation. The analysis showed that there was significant positive relation between VBTS and length, negative relation with mesomorphy; positive relation between ROM of shoulder dominant internal and external rotation, trunk hyper-extension, left lateral flexion and right rotation, negative relation in dominant wrist flexion, positive relation between isokinetic strength characteristics such as shoulder and elbow extension, shoulder internal and external rotation, wrist flexion, handgrip isometric strength, also in biomechanical measures, positive relation between in Y axis elbow, wrist, finger and head of the racket. As a result, fitness and biomechanical parameters that are intensively used in tennis determine VBTS. We think trainers may speed up VBTS by improved parameters and accelerated training programmes.

  18. Sensitivity of tumor motion simulation accuracy to lung biomechanical modeling approaches and parameters

    International Nuclear Information System (INIS)

    Finite element analysis (FEA)-based biomechanical modeling can be used to predict lung respiratory motion. In this technique, elastic models and biomechanical parameters are two important factors that determine modeling accuracy. We systematically evaluated the effects of lung and lung tumor biomechanical modeling approaches and related parameters to improve the accuracy of motion simulation of lung tumor center of mass (TCM) displacements. Experiments were conducted with four-dimensional computed tomography (4D-CT). A Quasi-Newton FEA was performed to simulate lung and related tumor displacements between end-expiration (phase 50%) and other respiration phases (0%, 10%, 20%, 30%, and 40%). Both linear isotropic and non-linear hyperelastic materials, including the neo-Hookean compressible and uncoupled Mooney–Rivlin models, were used to create a finite element model (FEM) of lung and tumors. Lung surface displacement vector fields (SDVFs) were obtained by registering the 50% phase CT to other respiration phases, using the non-rigid demons registration algorithm. The obtained SDVFs were used as lung surface displacement boundary conditions in FEM. The sensitivity of TCM displacement to lung and tumor biomechanical parameters was assessed in eight patients for all three models. Patient-specific optimal parameters were estimated by minimizing the TCM motion simulation errors between phase 50% and phase 0%. The uncoupled Mooney–Rivlin material model showed the highest TCM motion simulation accuracy. The average TCM motion simulation absolute errors for the Mooney–Rivlin material model along left-right, anterior–posterior, and superior–inferior directions were 0.80 mm, 0.86 mm, and 1.51 mm, respectively. The proposed strategy provides a reliable method to estimate patient-specific biomechanical parameters in FEM for lung tumor motion simulation. (paper)

  19. Evolution in swimming science research: content analysis of the "Biomechanics and Medicine in Swimming" Proceeding books from 1971 to 2006

    OpenAIRE

    Barbosa, Tiago M; Pinto, E.,; Cruz, A; Marinho, D. A.; V. M. Reis; Silva, A. J.; Costa, M. J.; Queirós, Telma Maria Gonçalves

    2010-01-01

    The aim of this study was to analyze the evolution of the swimming science research based on the content analysis of the “Biomechanics and Medicine in Swimming” Proceedings books from 1971 to 2006

  20. Role of biomechanics in the understanding of normal, injured, and healing ligaments and tendons

    Directory of Open Access Journals (Sweden)

    Jung Ho-Joong

    2009-05-01

    Full Text Available Abstract Ligaments and tendons are soft connective tissues which serve essential roles for biomechanical function of the musculoskeletal system by stabilizing and guiding the motion of diarthrodial joints. Nevertheless, these tissues are frequently injured due to repetition and overuse as well as quick cutting motions that involve acceleration and deceleration. These injuries often upset this balance between mobility and stability of the joint which causes damage to other soft tissues manifested as pain and other morbidity, such as osteoarthritis. The healing of ligament and tendon injuries varies from tissue to tissue. Tendinopathies are ubiquitous and can take up to 12 months for the pain to subside before one could return to normal activity. A ruptured medial collateral ligament (MCL can generally heal spontaneously; however, its remodeling process takes years and its biomechanical properties remain inferior when compared to the normal MCL. It is also known that a midsubstance anterior cruciate ligament (ACL tear has limited healing capability, and reconstruction by soft tissue grafts has been regularly performed to regain knee function. However, long term follow-up studies have revealed that 20–25% of patients experience unsatisfactory results. Thus, a better understanding of the function of ligaments and tendons, together with knowledge on their healing potential, may help investigators to develop novel strategies to accelerate and improve the healing process of ligaments and tendons. With thousands of new papers published in the last ten years that involve biomechanics of ligaments and tendons, there is an increasing appreciation of this subject area. Such attention has positively impacted clinical practice. On the other hand, biomechanical data are complex in nature, and there is a danger of misinterpreting them. Thus, in these review, we will provide the readers with a brief overview of ligaments and tendons and refer them to

  1. Changes in Corneal Biomechanical Properties after Long-Term Topical Prostaglandin Therapy

    Science.gov (United States)

    Yu, Xiaobo; Li, Mengwei; Wen, Wen; Sun, Xinghuai

    2016-01-01

    Objective To compare corneal biomechanical properties, measured by a newly developed tonometer (Corneal Visualization Scheimpflug Technology, Corvis ST), in untreated primary open angle glaucoma (POAG) patients, POAG patients with long-term topical prostaglandin analog (PGA) therapy and in normal controls. Further is to investigate the potential effects of PGA on corneal biomechanics. Methods In this case-control study, 35 consecutive medication naïve eyes with POAG, 34 POAG eyes with at least 2 years treatment by PGA and 19 normal eyes were included. Intraocular pressure (IOP), central corneal thickness (CCT) and corneal biomechanical parameters, including deformation amplitude (DA), applanation time (AT1 and AT2), applanation length (AL1 and AL2), applanation velocity (AV1 and AV2), and peak distance and radius were measured using Corvis ST. Axial length and corneal curvature were measured with partial coherence interferometry (IOLMaster, Zeiss, Germany). General linear model analysis was performed to investigate the corneal biomechanical property changes among the normal controls, newly diagnosed POAG patients and POAG patients with long-term PGA treatment, and among the subgroups of different types of PGA treatment, including bimatoprost, latanoprost and travoprost. Furthermore, pairwise comparisons using Bonferroni correction for least squares means were employed. Results AT1 (p<0.0001), AV1 (p<0.0001), AT2 (p = 0.0001), AV2 (p<0.0001) and DA (p = 0.0004) in newly diagnosed glaucoma patients were significantly different from those in normal subjects and in patients underwent at least 2 years topical PGA therapy after adjusting for age and gender. After adjusting for age, gender, IOP, CCT, axial length and corneal curvature, a significant difference was detected for DA between glaucoma patients without PGA treatment and patients with long-term PGA therapy (p = 0.0387). Furthermore, there were no statistical significant differences in all of the corneal

  2. Bridging the gap between cadaveric and in vivo experiments: A biomechanical model evaluating thumb-tip endpoint forces

    OpenAIRE

    Wohlman, Sarah J.; Wendy M Murray

    2013-01-01

    The thumb is required for a majority of tasks of daily living. Biomechanical modeling is a valuable tool, with the potential to help us bridge the gap between our understanding of the mechanical actions of individual thumb muscles, derived from anatomical cadaveric experiments, and our understanding of how force is produced by the coordination of all of the thumb muscles, derived from studies involving human subjects. However, current biomechanical models do not replicate muscle force product...

  3. Murine patellar tendon biomechanical properties and regional strain patterns during natural tendon-to-bone healing after acute injury

    OpenAIRE

    Gilday, Steven D.; Casstevens, E. Chris; Kenter, Keith; Jason T Shearn; David L Butler

    2013-01-01

    Tendon-to-bone healing following acute injury is generally poor and often fails to restore normal tendon biomechanical properties. In recent years, the murine patellar tendon (PT) has become an important model system for studying tendon healing and repair due to its genetic tractability and accessible location within the knee. However, the mechanical properties of native murine PT, specifically the regional differences in tissue strains during loading, and the biomechanical outcomes of natura...

  4. Adhesive strength of hydroxyl apatite(HA) coating and biomechanics behavior of HA-coated prosthesis:an experimental study

    OpenAIRE

    Tian-yang ZHANG; Duan, Yong-hong; Zhu, Shu; Jin-yu ZHU; Zhu, Qing-sheng

    2011-01-01

    Objective To explore the influence of adhesive strength of hydroxyapatite(HA) coating on the post-implantation stability of HA-coated prosthesis.Methods The adhesive strength and biomechanics behavior of HA coating were studied by histopathological observation,material parameters and biomechanical testing,the titanium(Ti)-coated prosthesis was employed as control.Results Scratch test showed that the adhesive strength of HA coating was significantly lower than that of Ti coating(P < 0.01).Hist...

  5. Visualisation to enhance biomechanical tuning of ankle-foot orthoses (AFOs) in stroke: study protocol for a randomised controlled trial

    OpenAIRE

    Carse Bruce; Bowers Roy J; Meadows Barry C; Rowe Philip J

    2011-01-01

    Abstract Background There are a number of gaps in the evidence base for the use of ankle-foot orthoses for stroke patients. Three dimensional motion analysis offers an ideal method for objectively obtaining biomechanical gait data from stroke patients, however there are a number of major barriers to its use in routine clinical practice. One significant problem is the way in which the biomechanical data generated by these systems is presented. Through the careful design of bespoke biomechanica...

  6. Biomechanical analysis of load transmission characteristics of limited carpal fusions used to treat Kienböck’s disease

    OpenAIRE

    Gunal, Izge; Ozcan, Ozal; Uyulgan, Bahadir; Baran, Onder; Arman, Candan; Karatosun, Vasfi

    2004-01-01

    Objectives: Although limited carpal fusions used in the treatment of Kienböck’s disease are thought to act by decreasing the loads on the lunate, biomechanical studies show that capitohamate fusion acts oppositely to what is expected. This experimental study was designed to resolve this paradox, Methods: In a biomechanical cadaveric study, load transmissions at the radioulnacarpal joint were investigated under 140 and 210 newtons of load with three wrist postures, namely, neutral, ulnar an...

  7. Identification of the biomechanical performance determining factors of the 5 iron golf swing when hitting for maximum distance

    OpenAIRE

    Healy, Aoife

    2009-01-01

    Golf is a very popular sport with approximately 289,120 people playing golf in Ireland(European Golf Association, 2008). The amount of scientific research that has been conducted into the biomechanics of the golfer and club is limited, with the majority of the research focusing on the golf drive. The purpose of this study was to identify the biomechanical performance determining factors of the 5-iron golf swing when hitting for maximum distance. Golfer joint kinematics, club swing characte...

  8. Wheelchair Propulsion Biomechanics in Junior Basketball Players: A Method for the Evaluation of the Efficacy of a Specific Training Program

    OpenAIRE

    Elena Bergamini; Francesca Morelli; Flavia Marchetti; Giuseppe Vannozzi; Lorenzo Polidori; Francesco Paradisi; Marco Traballesi; Aurelio Cappozzo; Anna Sofia Delussu

    2015-01-01

    As participation in wheelchair sports increases, the need of quantitative assessment of biomechanical performance indicators and of sports- and population-specific training protocols has become central. The present study focuses on junior wheelchair basketball and aims at (i) proposing a method to identify biomechanical performance indicators of wheelchair propulsion using an instrumented in-field test and (ii) developing a training program specific for the considered population and assessing...

  9. Biomechanics of the press-fit phenomenon in dental implantology: an image-based finite element analysis

    OpenAIRE

    Frisardi Gianni; Barone Sandro; Razionale Armando V; Paoli Alessandro; Frisardi Flavio; Tullio Antonio; Lumbau Aurea; Chessa Giacomo

    2012-01-01

    Abstract Background A fundamental pre-requisite for the clinical success in dental implant surgery is the fast and stable implant osseointegration. The press-fit phenomenon occurring at implant insertion induces biomechanical effects in the bone tissues, which ensure implant primary stability. In the field of dental surgery, the understanding of the key factors governing the osseointegration process still remains of utmost importance. A thorough analysis of the biomechanics of dental implanto...

  10. Finite Element Analysis of Biomechanical Interactions of A Tooth-Implant Splinting System for Various Bone Qualities

    OpenAIRE

    Chun-Li Lin; Shih-Hao Chang; Jen-Chyan Wang

    2006-01-01

    Background: The splinting of an implant and tooth is a rational alternative in some clinicalsituations. The complex biomechanical aspects of a tooth-implant system arederived from the dissimilar mobility between the osseointegrated implantand the tooth. The aim of this study was to analyze the biomechanics in atooth-implant splinting system for various bone qualities with differentocclusal forces using non-linear finite element (FE) analysis.Methods: A 3D FE model containing one Frialit-2 imp...

  11. Tubulin bond energies and microtubule biomechanics determined from nanoindentation in silico

    CERN Document Server

    Kononova, Olga; Theisen, Kelly E; Marx, Kenneth A; Dima, Ruxandra I; Ataullakhanov, Fazly I; Grishchuk, Ekaterina L; Barsegov, Valeri

    2015-01-01

    Microtubules, the primary components of the chromosome segregation machinery, are stabilized by longitudinal and lateral non-covalent bonds between the tubulin subunits. However, the thermodynamics of these bonds and the microtubule physico-chemical properties are poorly understood. Here, we explore the biomechanics of microtubule polymers using multiscale computational modeling and nanoindentations in silico of a contiguous microtubule fragment. A close match between the simulated and experimental force-deformation spectra enabled us to correlate the microtubule biomechanics with dynamic structural transitions at the nanoscale. Our mechanical testing revealed that the compressed MT behaves as a system of rigid elements interconnected through a network of lateral and longitudinal elastic bonds. The initial regime of continuous elastic deformation of the microtubule is followed by the transition regime, during which the microtubule lattice undergoes discrete structural changes, which include first the reversib...

  12. On the inference of function from structure using biomechanical modelling and simulation of extinct organisms.

    Science.gov (United States)

    Hutchinson, John R

    2012-02-23

    Biomechanical modelling and simulation techniques offer some hope for unravelling the complex inter-relationships of structure and function perhaps even for extinct organisms, but have their limitations owing to this complexity and the many unknown parameters for fossil taxa. Validation and sensitivity analysis are two indispensable approaches for quantifying the accuracy and reliability of such models or simulations. But there are other subtleties in biomechanical modelling that include investigator judgements about the level of simplicity versus complexity in model design or how uncertainty and subjectivity are dealt with. Furthermore, investigator attitudes toward models encompass a broad spectrum between extreme credulity and nihilism, influencing how modelling is conducted and perceived. Fundamentally, more data and more testing of methodology are required for the field to mature and build confidence in its inferences. PMID:21666064

  13. Denture-Related Biomechanical Factors for Fixed Partial Dentures Retained on Short Dental Implants.

    Science.gov (United States)

    Pommer, Bernhard; Hingsammer, Lukas; Haas, Robert; Mailath-Pokorny, Georg; Busenlechner, Dieter; Watzek, Georg; Fürhauser, Rudolf

    2015-01-01

    Prosthodontically driven biomechanical considerations are essential for longterm successful outcomes in dental implant therapy. Correct protocols seek to preclude potential consequences associated with functional and parafunctional occlusal overload such as screw loosening, component fracture, compromised marginal bone maintenance, and the integrity of the induced osseointegration response. Other concerns also need to be addressed, more especially when other implants are selected, for example: bridge insertion torque (BIT) in cases of immediate loading, cantilever length-anteroposterior spread ratio (CL-AP), overall crown-to-implant ratio (oCIR), total bone-to-implant surface area (tBICA), and the status of the opposing dentition. In spite of promising clinical results, evidence-based clinical protocols demand that such biomechanical limits still need to be determined. PMID:26218027

  14. Individual athletes’ biomechanical features of interaction with objects in art gymnastics

    Directory of Open Access Journals (Sweden)

    Adashevskiy V.M.

    2014-04-01

    Full Text Available Purpose: To design a biomechanical model of interaction of athlete with the subject, as well as the development of areas of its use in practice. Material : The study involved 10 students - athletes. Results : The presented computational schemes create direction of flight of different items (rope, hoop, ball, ribbon, clubs. The characteristics of the time of flight trajectories and with regard for the resistance force of the air environment. Shows the influence of initial parameters on departure flight time items. Graphic characteristics are presented trajectories of objects depending on the parameters of their departure. Conclusions : It is recommended to improve the judicial assessment and effective implementation gymnast exercises during the flight characteristics of the various items to consider trajectories of objects. Note that age, height and distance from the athletes at the end of the flight object defined biomechanical characteristics that can realize an athlete: absolute initial velocity of departure, departure angle, height of the center of mass manufacture items.

  15. A new statistical biomechanics modeling of physical and biochemical parameters of bone strength

    Energy Technology Data Exchange (ETDEWEB)

    Soboyejo, A.B.O. [Ohio State Univ., Columbus, OH (United States). Dept. of Aerospace Engineering, Applied Mechanics and Aviation; Nestor, K.E. [Ohio State Univ., Wooster, OH (United States). Dept. of Animal Sciences

    2001-07-01

    New multiparameter biomechanics models were developed in this work for the characterization of bone strength, as functions of the major physical and biochemical parameters, which can contribute to mechanical properties of bone strength. Theoretical and experimental methods had been developed to model bone strength as functions of (a) the physical parameters and (b) the biochemical parameters, The choice of any particular methodology will depend on the availability of either the physical or biochemical parameters. Experimental data of compressive strength of tibia and femur bones of broiler chickens and turkeys together with their corresponding physical and biochemical parameters were collected and used as examples in this study. These data were used to validate the theoretical principles developed in this work. Useful practical applications of the statistical biomechanics principles developed in this study, particularly in the field of bone strength enhancement in turkeys and broiler chickens are discussed. Similar medical applications to human beings are also highlighted in the discussions. (orig.)

  16. A biomechanical approach to distal radius fractures for the emergency radiologist.

    Science.gov (United States)

    Bunch, Paul M; Sheehan, Scott E; Dyer, George S; Sodickson, Aaron; Khurana, Bharti

    2016-04-01

    Distal radius fractures are the most common upper extremity fracture and account for approximately one sixth of all fractures treated in US emergency departments. These fractures are associated with significant morbidity and have a major economic impact. Radiographic evaluation of distal radius fractures is frequently performed in the emergency department setting, has a profound impact on initial management, and is essential to assessing the quality and relative success of the initial reduction. While the most appropriate definitive management of distal radius fractures remains controversial, overarching treatment principles reflect distal radius injury mechanisms and biomechanics. An intuitive understanding of the biomechanics of the distal radius and of common mechanisms of injury informs and improves the emergency radiologist's ability to identify key imaging findings with important management implications and to communicate the critical information that emergency physicians and orthopedic surgeons need to best manage distal radius fractures. PMID:26564022

  17. Emergent cell and tissue dynamics from subcellular modeling of active biomechanical processes

    International Nuclear Information System (INIS)

    Cells and the tissues they form are not passive material bodies. Cells change their behavior in response to external biochemical and biomechanical cues. Behavioral changes, such as morphological deformation, proliferation and migration, are striking in many multicellular processes such as morphogenesis, wound healing and cancer progression. Cell-based modeling of these phenomena requires algorithms that can capture active cell behavior and their emergent tissue-level phenotypes. In this paper, we report on extensions of the subcellular element model to model active biomechanical subcellular processes. These processes lead to emergent cell and tissue level phenotypes at larger scales, including (i) adaptive shape deformations in cells responding to slow stretching, (ii) viscous flow of embryonic tissues, and (iii) streaming patterns of chemotactic cells in epithelial-like sheets. In each case, we connect our simulation results to recent experiments

  18. Degrees of freedom of tongue movements in speech may be constrained by biomechanics

    CERN Document Server

    Perrier, Pascal; Payan, Yohan; Zandipour, Majid; Guenther, Franck; Khalighi, Ali

    2007-01-01

    A number of studies carried out on different languages have found that tongue movements in speech are made along two primary degrees of freedom (d.f.s): the high-front to low-back axis and the high-back to low-front axis. We explore the hypothesis that these two main d.f.s could find their origins in the physical properties of the vocal tract. A large set of tongue shapes was generated with a biomechanical tongue model using a Monte-Carlo method to thoroughly sample the muscle control space. The resulting shapes were analyzed with PCA. The first two factors explain 84% of the variance, and they are similar to the two experimentally observed d.f.s. This finding suggests that the d.f.s. are not speech-specific, and that speech takes advantage of biomechanically based tongue properties to form different sounds.

  19. Internal fixation on the lower cervical spine – biomechanics and clinical practice of procedures and implants

    OpenAIRE

    Ulrich, Chr.; Arand, M.; Nothwang, J.

    2001-01-01

    The decision to opt for a particular internal fixation procedure of a traumatized unstable lower cervical spine should be based on analysis and implementation of scientific and clinical data on the biomechanics of the intact, the unstable and the implant-fixed spine. The following recommendations for surgical stabilization of the lower cervical spine seem, therefore, to be justified. Firstly, the surgical procedure should be to bring about decompression, realignment, and stability. Secondly, ...

  20. Impacts of Hematite Nanoparticle Exposure on Biomechanical, Adhesive, and Surface Electrical Properties of Escherichia coli Cells

    OpenAIRE

    Zhang, Wen; Hughes, Joseph; Chen, Yongsheng

    2012-01-01

    Despite a wealth of studies examining the toxicity of engineered nanomaterials, current knowledge on their cytotoxic mechanisms (particularly from a physical perspective) remains limited. In this work, we imaged and quantitatively characterized the biomechanical (hardness and elasticity), adhesive, and surface electrical properties of Escherichia coli cells with and without exposure to hematite nanoparticles (NPs) in an effort to advance our understanding of the cytotoxic impacts of nanomater...

  1. A nonlinear biomechanical model based registration method for aligning prone and supine MR breast images.

    Science.gov (United States)

    Han, Lianghao; Hipwell, John H; Eiben, Björn; Barratt, Dean; Modat, Marc; Ourselin, Sebastien; Hawkes, David J

    2014-03-01

    Preoperative diagnostic magnetic resonance (MR) breast images can provide good contrast between different tissues and 3-D information about suspicious tissues. Aligning preoperative diagnostic MR images with a patient in the theatre during breast conserving surgery could assist surgeons in achieving the complete excision of cancer with sufficient margins. Typically, preoperative diagnostic MR breast images of a patient are obtained in the prone position, while surgery is performed in the supine position. The significant shape change of breasts between these two positions due to gravity loading, external forces and related constraints makes the alignment task extremely difficult. Our previous studies have shown that either nonrigid intensity-based image registration or biomechanical modelling alone are limited in their ability to capture such a large deformation. To tackle this problem, we proposed in this paper a nonlinear biomechanical model-based image registration method with a simultaneous optimization procedure for both the material parameters of breast tissues and the direction of the gravitational force. First, finite element (FE) based biomechanical modelling is used to estimate a physically plausible deformation of the pectoral muscle and the major deformation of breast tissues due to gravity loading. Then, nonrigid intensity-based image registration is employed to recover the remaining deformation that FE analyses do not capture due to the simplifications and approximations of biomechanical models and the uncertainties of external forces and constraints. We assess the registration performance of the proposed method using the target registration error of skin fiducial markers and the Dice similarity coefficient (DSC) of fibroglandular tissues. The registration results on prone and supine MR image pairs are compared with those from two alternative nonrigid registration methods for five breasts. Overall, the proposed algorithm achieved the best registration

  2. Edentulism, beaks, and biomechanical innovations in the evolution of theropod dinosaurs

    OpenAIRE

    Lautenschlager, Stephan; Witmer, Lawrence M.; Altangerel, Perle; Rayfield, Emily J.

    2013-01-01

    Edentulism and beaks (rhamphothecae) are distinguishing features among extant birds and are traditionally regarded as a response to weight-saving demands for the evolution of flight. However, keratin-covered beaks paralleled by edentulism appeared in non-avian theropod dinosaurs and as early as the Early Cretaceous. Here, high-resolution, digital biomechanical models of the skull of the Cretaceous therizinosaur Erlikosaurus andrewsi are used to investigate the functional significance of these...

  3. Biomechanical properties of a novel biodegradable magnesium-based interference screw

    Directory of Open Access Journals (Sweden)

    Marco Ezechieli

    2016-06-01

    Full Text Available Magnesium-based interference screws may be an alternative in anterior/posterior cruciate ligament reconstruction. The well-known osteoconductive effects of biodegradable magnesium alloys may be useful. It was the purpose of this study to evaluate the biomechanical properties of a magnesium based interference screw and compare it to a standard implant. A MgYREZr-alloy interference screw and a standard implant (Milagro®; De Puy Mitek, Raynham, MA, USA were used for graft fixation. Specimens were placed into a tensile loading fixation of a servohydraulic testing machine. Biomechanical analysis included pretensioning of the constructs at 20 N for 1 min following cyclic pretensioning of 20 cycles between 20 and 60 N. Biomechanical elongation was evaluated with cyclic loading of 1000 cycles between 50 and 200 N at 0.5 Hz. Maximum load to failure was 511.3±66.5 N for the Milagro® screw and 529.0±63.3 N for magnesium-based screw (ns, P=0.57. Elongations after preload, during cyclical loading and during failure load were not different between the groups (ns, P>0.05. Stiffness was 121.1±13.8 N/mm for the magnesiumbased screw and 144.1±18.4 for the Milagro® screw (ns, P=0.32. MgYREZr alloy interference screws show comparable results in biomechanical testing to standard implants and may be an alternative for anterior cruciate reconstruction in the future.

  4. Biomechanical impact of C2 pedicle screw length in an atlantoaxial fusion construct

    OpenAIRE

    Risheng Xu; Mohamad Bydon; Mohamed Macki; Belkoff, Stephen M.; Langdale, Evan R.; Kelly McGovern; Jean-Paul Wolinsky; Gokalsan, Ziya L.; Ali Bydon

    2014-01-01

    Background: Posterior, atlantoaxial (AA) fusions of the cervical spine may include either standard (26 mm) or short (16 mm) C2 pedicle screws. This manuscript focused on an in vitro biomechanical comparison of standard versus short C2 pedicle screws to perform posterior C1-C2 AA fusions. Methods: Twelve human cadaveric spines underwent C1 lateral mass screw and standard C2 pedicle screw (n = 6) versus short C2 pedicle screw (n = 6) fixation. Six additional controls were not instrumented. ...

  5. Biomechanical testing of a unique built-in expandable anterior spinal internal fixation system

    OpenAIRE

    Zhou, Chu-Song; Xu, Yan-Fang; Zhang, Yu; Chen, Zhong; Lv, Hai

    2014-01-01

    Background Expandable screws have greater pullout strength than conventional screws. The purpose of this study was to compare the biomechanical stability provided by a new built-in expandable anterior spinal fixation system with that of 2 commonly used anterior fixation systems, the Z-Plate and the Kaneda, in a porcine partial vertebral corpectomy model. Methods Eighteen porcine thoracolumbar spine specimens were randomly divided into 3 groups of 6 each. A vertebral wedge osteotomy was perfor...

  6. Biomechanical comparison of pedicle screws versus spinous process screws in C2 vertebra A cadaveric study

    OpenAIRE

    Guan-yi Liu; Lu Mao; Rong-ming Xu; Wei-hu Ma

    2014-01-01

    Background: Biomechanical studies have shown C2 pedicle screw to be the most robust in insertional torque and pullout strength. However, C2 pedicle screw placement is still technically challenging. Smaller C2 pedicles or medial localization of the vertebral artery may preclude safe C2 pedicle screw placement in some patients. The purpose of this study was to compare the pullout strength of spinous process screws with pedicle screws in the C2. Materials and Methods: Eight fresh human cadav...

  7. Biomechanical factors related to occlusal load transfer in removable complete dentures

    OpenAIRE

    Żmudzki, Jarosław; Chladek, Grzegorz; Kasperski, Jacek

    2014-01-01

    Owing to economic conditions, removable dentures remain popular despite the discomfort and reduced chewing efficiency experienced by most denture wearers. However, there is little evidence to confirm that the level of mucosal load exceeds the pressure pain threshold. This discrepancy stimulated us to review the current state of knowledge on the biomechanics of mastication with complete removable dentures. The loading beneath dentures was analyzed in the context of denture foundation character...

  8. MRI-based Biomechanical Modeling of Carotid Atherosclerotic Plaques: The stable plaque paradigm

    OpenAIRE

    Nieuwstadt, Harm

    2015-01-01

    markdownabstract__Abstract__ Carotid atherosclerosis is a common cause of acute ischemic stroke and places a major burden on worldwide health-related quality of life. The currently-used stenosis-degree guidelines to decide on surgical intervention through carotid endarterectomy in order to prevent a future event are imperfect. This is because they insufficiently target plaque vulnerability. To provide an alternative carotid plaque vulnerability assessment, one can compute the biomechanical pe...

  9. Topography of Acoustical Properties of Long Bones: From Biomechanical Studies to Bone Health Assessment

    OpenAIRE

    Tatarinov, Alexey; Sarvazyan, Armen

    2008-01-01

    The article presents a retrospective view on the assessment of long bones condition using topographical patterns of the acoustic properties. The application of ultrasonic point-contact transducers with exponential waveguides on a short acoustic base for detailed measurements in human long bones by the surface transmission was initiated during the 1980s in Latvia. The guided wave velocity was mapped on the surface of the long bones and the topographical patterns reflected the biomechanical pec...

  10. Inter-assessor reliability of practice based biomechanical assessment of the foot and ankle

    Directory of Open Access Journals (Sweden)

    Jarvis Hannah L

    2012-06-01

    Full Text Available Abstract Background There is no consensus on which protocols should be used to assess foot and lower limb biomechanics in clinical practice. The reliability of many assessments has been questioned by previous research. The aim of this investigation was to (i identify (through consensus what biomechanical examinations are used in clinical practice and (ii evaluate the inter-assessor reliability of some of these examinations. Methods Part1: Using a modified Delphi technique 12 podiatrists derived consensus on the biomechanical examinations used in clinical practice. Part 2: Eleven podiatrists assessed 6 participants using a subset of the assessment protocol derived in Part 1. Examinations were compared between assessors. Results Clinicians choose to estimate rather than quantitatively measure foot position and motion. Poor inter-assessor reliability was recorded for all examinations. Intra-class correlation coefficient values (ICC for relaxed calcaneal stance position were less than 0.23 and were less than 0.14 for neutral calcaneal stance position. For the examination of ankle joint dorsiflexion, ICC values suggest moderate reliability (less than 0.61. The results of a random effects ANOVA highlight that participant (up to 5.7°, assessor (up to 5.8° and random (up to 5.7° error all contribute to the total error (up to 9.5° for relaxed calcaneal stance position, up to 10.7° for the examination of ankle joint dorsiflexion. Kappa Fleiss values for categorisation of first ray position and mobility were less than 0.05 and for limb length assessment less than 0.02, indicating slight agreement. Conclusion Static biomechanical assessment of the foot, leg and lower limb is an important protocol in clinical practice, but the key examinations used to make inferences about dynamic foot function and to determine orthotic prescription are unreliable.

  11. A Preliminary Study For A Biomechanical Model Of The Respiratory System

    OpenAIRE

    Saadé, Jacques; Didier, Anne-Laure; Villard, Pierre-Frédéric; Buttin, Romain; Moreau, Jean-Michel; Beuve, Michael; Shariat, Behzad

    2010-01-01

    Tumour motion is an essential source of error for treatment planning in radiation therapy. This motion is mostly due to patient respiration. To account for tumour motion, we propose a solution that is based on the biomechanical modelling of the respiratory system. To compute deformations and displacements, we use continuous mechanics laws solved with the finite element method. In this paper, we propose a preliminary study of a complete model of the respiratory system including lungs, chest wa...

  12. Biomechanical analysis on transverse tibial fixation in anterior cruciate ligament reconstructions☆

    OpenAIRE

    Edmar Stieven Filho; Mariane Henseler Damaceno Mendes; Stephanie Claudino; Filipe Baracho; Paulo César Borges; Luiz Antonio Munhoz da Cunha

    2015-01-01

    OBJECTIVE: To verify whether the combination of tibial cross pin fixation and femoral screw fixation presents biomechanical advantages when compared to femoral cross pin fixation and tibial screw fixation for the reconstruction of the anterior cruciate ligament (ACL).METHODS: Thirty-eight porcine knees and bovine extensor digitorum tendons were used as the graft materials. The tests were performed in three groups: (1) standard, used fourteen knees, and the grafts were fixated with the combina...

  13. Biomechanical Consequences of a Complete Radial Tear Adjacent to the Medial Meniscus Posterior Root Attachment Site

    OpenAIRE

    LaPrade, Robert F.; Padalecki, Jeffrey Ryan; Jansson, Kyle; Smith, Sean; Dornan, Grant; Pierce, Casey; Wijdicks, Coen A

    2014-01-01

    Objectives: Complete radial tears near the medial meniscus posterior root attachment site disrupt the circumferential integrity of the meniscus (similar to a posterior root avulsion). These tears can compromise the circumferential integrity and have been reported in biomechanical studies to simulate the meniscectomized state. The purpose of the study was to quantify the tibiofemoral contact load and contact area changes that occur in cadaveric knees from complete posterior horn radial tears a...

  14. Ulnar impaction syndrome with different operative methods: a comparative biomechanical study

    OpenAIRE

    Yu, Ya-Dong; Wu, Tao; Tian, Fang-Tao; Shang, Yun-Tao; Yu, Xiao-Fei; Bai, Yan-Bin; Han, Chang-Ling

    2015-01-01

    Objective: Ulnar impaction syndrome seriously impairs wrist and hand function. Three main treatment procedures are available; however, little systematic research on the post-operation changes in wrist biomechanics currently exists. This study aimed to determine the long-term effects of these procedures and the optimal treatment methods for ulnar impaction syndrome. Methods: Twenty-four cases of fresh upper limb specimens were randomized into four groups: (1) the control group, (2) the ulnar-s...

  15. Analysing physical fitness and biomechanical factors that determine tennis serve performance

    OpenAIRE

    Ertuğrul Gelen; Sami Mengütay; Mustafa Karahan

    2009-01-01

    The purpose of the study is to analyse the fitness and the biomechanical factors which determine the velocity of the ball during serve in tennis (VBTS). The subjects of the study were fifteen male tournament level tennis player between the ages of sixteen and twenty five (18,8 ± 2,70 age/year). The physical fitness measurement of the study were; length, body weight, skinfold, diameter, circumference and length of the body, body composition, isometric handgrip strength, vertical jump, uppe...

  16. Variations in morphological and biomechanical indices at the distal radius in subjects with identical BMD

    OpenAIRE

    Kazakia, Galateia J.; Burghardt, Andrew J.; Link, Thomas M.; Majumdar, Sharmila

    2010-01-01

    Determination of osteoporotic status is based primarily on areal bone mineral density (aBMD) obtained through dual x-ray absorptiometry (DXA). However, many fractures occur in patients with T-scores above the WHO threshold of osteoporosis, in part because DXA measures are insensitive to biomechanically important alterations in bone quality. The goal of this study was to determine – within groups of subjects with identical radius aBMD values – the extant variation in densitometric, geometric, ...

  17. Biomechanical Model for Evaluation of Pediatric Upper Extremity Joint Dynamics during Wheelchair Mobility

    OpenAIRE

    Schnorenberg, Alyssa J.; Slavens, Brooke A.; Wang, Mei; Vogel, Lawrence; Smith, Peter; Harris, Gerald F.

    2013-01-01

    Pediatric manual wheelchair users (MWU) require high joint demands on their upper extremity (UE) during wheelchair mobility, leading them to be at risk of developing pain and pathology. Studies have examined UE biomechanics during wheelchair mobility in the adult population; however, current methods for evaluating UE joint dynamics of pediatric MWU are limited. An inverse dynamics model is proposed to characterize three-dimensional UE joint kinematics and kinetics during pediatric wheelchair ...

  18. Biomechanical risk factors for carpal tunnel syndrome: a pooled study of 2474 workers

    OpenAIRE

    Harris-Adamson, Carisa; Eisen, Ellen A.; Kapellusch, Jay; Garg, Arun; Hegmann, Kurt T; Thiese, Matthew S.; Dale, Ann Marie; Evanoff, Bradley; Burt, Susan; Bao, Stephen; Silverstein, Barbara; Merlino, Linda; Gerr, Fred; Rempel, David

    2014-01-01

    Background Between 2001 and 2010, five research groups conducted coordinated prospective studies of carpal tunnel syndrome (CTS) incidence among US workers from various industries and collected detailed subject-level exposure information with follow-up of symptoms, electrophysiological measures and job changes. Objective This analysis examined the associations between workplace biomechanical factors and incidence of dominant-hand CTS, adjusting for personal risk factors. Methods 2474 particip...

  19. Biomechanical evaluation of wrist-driven flexor hinge orthosis in persons with spinal cord injury

    OpenAIRE

    Yeoun-Seung Kang, MD, PhD, CPO; Yoon-Ghil Park, MD, PhD; Bum-Suk Lee, MD; Hyung-Soon Park, PhD

    2013-01-01

    The wrist-driven flexor hinge orthosis (WDFHO) is a device used to restore hand function in persons with tetraplegic spinal cord injury by furnishing three-point prehension. We assessed the effectiveness and biomechanical properties of the WDFHO in 24 persons with cervical 6 or 7 tetraplegia who have severely impaired hand function. This study introduces a mechanical operating model to assess the efficiency of the WDFHO. Experimental results showed that pinch force increased significantly (p ...

  20. General concepts of wrist biomechanics and a view from other species.

    Science.gov (United States)

    Tang, J B

    2008-08-01

    The carpus is one of the most complex joints in the extremities both in respect of its structure and its mechanics. In this article, an overview of the structural and biomechanical characteristics of the human carpus is presented first, followed by the author's observations on the structural characteristics of the carpal equivalents of a variety of animal species compared with those of the human carpus. Finally, the implications of these observations for the functional reconstruction of the hand are outlined. PMID:18687843

  1. A Biomechanical Comparison between Taylor’s Spatial Frame and Ilizarov External Fixator

    OpenAIRE

    Tan, BB; Shanmugam, R; Gunalan, R; Chua, YP; Hossain, G; Saw, A.

    2014-01-01

    Abstract Taylor’s spatial frame (TSF) and Ilizarov external fixators (IEF) are two circular external fixator commonly used to address complex deformity and fractures. There is currently no data available comparing the biomechanical properties of these two external fixators. This study looks into the mechanical characteristics of each system. TSF rings with 6 oblique struts, 4 tube connectors, 4 threaded rods, and 6 threaded rods were compared to a standard IEF rings with 4 threaded rods. Comp...

  2. Sensitivity of quantitative UTE MRI to the biomechanical property of the temporomandibular joint disc

    Energy Technology Data Exchange (ETDEWEB)

    Bae, Won C.; Biswas, Reni; Statum, Sheronda [University of California-San Diego, Department of Radiology, San Diego, CA (United States); Sah, Robert L. [University of California-San Diego, Department of Bioengineering, La Jolla, CA (United States); Chung, Christine B. [University of California-San Diego, Department of Radiology, San Diego, CA (United States); VA San Diego Healthcare System, Department of Radiology, San Diego, CA (United States)

    2014-09-15

    To quantify MR properties of discs from cadaveric human temporomandibular joints (TMJ) using quantitative conventional and ultrashort time-to-echo magnetic resonance imaging (UTE MRI) techniques and to corroborate regional variation in the MR properties with that of biomechanical indentation stiffness. This study was exempt from the institutional review board approval. Cadaveric (four donors, two females, 74 ± 10.7 years) TMJs were sliced (n = 14 slices total) sagittally and imaged using quantitative techniques of conventional spin echo T2 (SE T2), UTE T2*, and UTE T1rho. The discs were then subjected to biomechanical indentation testing, which is performed by compressing the tissue with the blunt end of a small solid cylinder. Regional variations in MR and indentation stiffness were correlated. TMJ of a healthy volunteer was also imaged to show in vivo feasibility. Using the ME SE T2 and the UTE T1rho techniques, a significant (each p < 0.0001) inverse relation between MR and indentation stiffness properties was observed for the data in the lower range of stiffness. However, the strength of correlation was significantly higher (p < 0.05) for UTE T1rho (R{sup 2} = 0.42) than SE T2 (R{sup 2} = 0.19) or UTE T2* (R{sup 2} = 0.02, p = 0.1) techniques. The UTE T1rho technique, applicable in vivo, facilitated quantitative evaluation of TMJ discs and showed a high sensitivity to biomechanical softening of the TMJ discs. With additional work, the technique may become a useful surrogate measure for loss of biomechanical integrity of TMJ discs reflecting degeneration. (orig.)

  3. Impact biomechanics of the pelvis and lower limbs in occupants involved in an impact aircraft accident

    OpenAIRE

    Rowles, John M

    1992-01-01

    Impact biomechanics of the pelvis and lower limbs in occupants involved in an aircraft accident have been investigated using a variety of techniques. These techniques have been used to: 1) Explore whether the position adopted by the occupant of the plane at the time of impact had implications for the pelvic and lower limb injuries sustained. 2) Test and assess the relevance of hypothesised injury mechanisms for the pelvis and lower limbs, described in the automobile industry to that...

  4. Ovariectomy decreases biomechanical quality of skin via oxidative stress in rat

    OpenAIRE

    Çömelekoğlu, Ülkü; YALIN, Serap; BALLI, Ebru; Berköz, Mehmet

    2012-01-01

    To investigate the effect of ovariectomy on the skin using biomechanical, biochemical, and histological techniques in the ovariectomized rat model. Ovariectomy causes significant changes in the physical characteristics of the skin. Materials and methods: Twenty female Wistar albino rats were divided into 2 groups, with each group consisting of 10 rats: the control group and the ovariectomized group. The ovariectomized group underwent bilateral ovariectomy via ventral incision and the contr...

  5. Biomechanical energy harvesting from human motion: theory, state of the art, design guidelines, and future directions

    OpenAIRE

    Shapiro Amir; Riemer Raziel

    2011-01-01

    Abstract Background Biomechanical energy harvesting from human motion presents a promising clean alternative to electrical power supplied by batteries for portable electronic devices and for computerized and motorized prosthetics. We present the theory of energy harvesting from the human body and describe the amount of energy that can be harvested from body heat and from motions of various parts of the body during walking, such as heel strike; ankle, knee, hip, shoulder, and elbow joint motio...

  6. Effects of refrigeration and freezing on the electromechanical and biomechanical properties of articular cartilage.

    Science.gov (United States)

    Changoor, Adele; Fereydoonzad, Liah; Yaroshinsky, Alex; Buschmann, Michael D

    2010-06-01

    In vitro electromechanical and biomechanical testing of articular cartilage provide critical information about the structure and function of this tissue. Difficulties obtaining fresh tissue and lengthy experimental testing procedures often necessitate a storage protocol, which may adversely affect the functional properties of cartilage. The effects of storage at either 4°C for periods of 6 days and 12 days, or during a single freeze-thaw cycle at -20°C were examined in young bovine cartilage. Non-destructive electromechanical measurements and unconfined compression testing on 3 mm diameter disks were used to assess cartilage properties, including the streaming potential integral (SPI), fibril modulus (Ef), matrix modulus (Em), and permeability (k). Cartilage disks were also examined histologically. Compared with controls, significant decreases in SPI (to 32.3±5.5% of control values, prefrigeration at 4°C, but no significant changes were detected at day 6. A trend toward detecting a decrease in SPI (to 94.2±6.2% of control values, p=0.083) was identified following a single freeze-thaw cycle, but no detectable changes were observed for any biomechanical parameters. All numbers are mean±95% confidence interval. These results indicate that fresh cartilage can be stored in a humid chamber at 4°C for a maximum of 6 days with no detrimental effects to cartilage electromechanical and biomechanical properties, while one freeze-thaw cycle produces minimal deterioration of biomechanical and electromechanical properties. A comparison to literature suggested that particular attention should be paid to the manner in which specimens are thawed after freezing, specifically by minimizing thawing time at higher temperatures. PMID:20887036

  7. A scoping review of biomechanical testing for proximal humerus fracture implants

    OpenAIRE

    Cruickshank, David; Lefaivre, Kelly A.; Johal, Herman; MacIntyre, Norma J; Sprague, Sheila A; Scott, Taryn; Guy, Pierre; Cripton, Peter A.; McKee, Michael; Bhandari, Mohit; Slobogean, Gerard P

    2015-01-01

    Background Fixation failure is a relatively common sequela of surgical management of proximal humerus fractures (PHF). The purpose of this study is to understand the current state of the literature with regard to the biomechanical testing of proximal humerus fracture implants. Methods A scoping review of the proximal humerus fracture literature was performed, and studies testing the mechanical properties of a PHF treatment were included in this review. Descriptive statistics were used to summ...

  8. Overviews of Emerging Research Techniques in Hearing, Bioacoustics, and Biomechanics: Proceedings of the 1981 Meeting

    Energy Technology Data Exchange (ETDEWEB)

    1982-01-01

    These proceedings of the 1981 annual meeting of the Committee on Hearing, Bioacoustics, and Biomechanics cover topics of emerging research in several areas of interest to the Committee. Topics covered include: hair cell function; transduction process of hair cells; speech synthesis; machine recognition of words; neuromagnetic analysis of sensory systems; tinnitus; tactile communication of speech; and biodynamic research at the Air Force Aerospace Medical Research Laboratory.

  9. Effects of Mechanical Properties and Atherosclerotic Artery Size on Biomechanical Plaque Disruption - Mouse versus Human

    OpenAIRE

    Riou, Laurent M.; Broisat, Alexis; Ghezzi, Catherine; Finet, Gérard; Rioufol, Gilles; Gharib, Ahmed M.; Pettigrew, Roderic I.; Ohayon, Jacques

    2014-01-01

    Mouse models of atherosclerosis are extensively being used to study the mechanisms of atherosclerotic plaque development and the results are frequently extrapolated to humans. However, major differences have been described between murine and human atherosclerotic lesions and the determination of similarities and differences between these species has been largely addressed recently. This study takes over and extends previous studies performed by our group and related to the biomechanical chara...

  10. Leukocyte arrest: Biomechanics and molecular mechanisms of β2 integrin activation

    Science.gov (United States)

    Fan, Zhichao; Ley, Klaus

    2016-01-01

    Integrins are a group of heterodimeric transmembrane receptors that play essential roles in cell–cell and cell–matrix interaction. Integrins are important in many physiological processes and diseases. Integrins acquire affinity to their ligand by undergoing molecular conformational changes called activation. Here we review the molecular biomechanics during conformational changes of integrins, integrin functions in leukocyte biorheology (adhesive functions during rolling and arrest) and molecules involved in integrin activation. PMID:26684674

  11. Biomechanical consequences of gait impairment at the ankle and foot : Injury, malalignment, and co-contraction

    OpenAIRE

    Wang, Ruoli

    2012-01-01

    The human foot contributes significantly to the function of the whole lower extremity during standing and locomotion. Nevertheless, the foot and ankle often suffer injuries and are affected by many musculoskeletal and neurological pathologies. The overall aim of this thesis was to evaluate gait parameters and muscle function change due to foot and ankle injury, malalignment and co-contraction. Using 3D gait analysis, analytical analyses and computational simulations, biomechanical consequence...

  12. Relation of recurrent laryngeal nerve compound action potential to laryngeal biomechanics

    OpenAIRE

    Nasri, S.; Dulguerov, Pavel; Damrose, E J; Ye, M.; Kreiman, J; Berke, G S

    1995-01-01

    This study was designed to investigate the compound action potential (CAP) of the recurrent laryngeal nerve (RLN) and to correlate this electrophysiologic signal to laryngeal biomechanics and phonatory function. Four adult mongrel canines were anesthetized. The RLN was isolated and stimulated, and recording electrodes were applied. The electromyographic (EMG) electrode was placed in the thyroarytenoid (TA) muscle. The RLN CAP and the EMG of the TA muscle were recorded and compared to the stim...

  13. Biomechanical Behavior of a New Nucleus Prosthesis Made of Knitted Titanium Filaments

    OpenAIRE

    Kettler, Annette; Kaps, Hans-Peter; Haegele, Bodo; Wilke, Hans-Joachim

    2007-01-01

    Background One of the greatest challenges in the development of a nucleus prosthesis is to minimize the risk of implant expulsion. At the same time, the physiological flexibility, compressive behavior, and height of the disc should be restored. In this biomechanical in vitro study we investigated the ability of a new nucleus prosthesis made of knitted titanium filaments to meet these challenges. Methods Flexibility, axial deformation, and height of six bovine lumbar spine segments were measur...

  14. The effect of head trauma on fracture healing: biomechanical testing and finite element analysis

    OpenAIRE

    Ozan, Firat; Hasan YILDIZ; Bora, Osman Arslan; Pekedis, Mahmut; Coskun, Gulnihal Ay; Gore, Oya

    2010-01-01

    Objectives: We aimed to evaluate the effect of head trauma on fracture healing with biomechanical testing, to compare the results obtained from a femur model created by finite element analysis with experimental data, and to develop a finite element model that can be employed in femoral fractures. Methods: Twenty-two Wistar albino rats were randomized into two groups. The control group was subjected to femoral fracture followed by intramedullary fixation, whereas the head trauma group was ...

  15. On the prospect of patient-specific biomechanics without patient-specific properties of tissues

    OpenAIRE

    Miller, Karol; Lu, Jia

    2013-01-01

    This paper presents main theses of two keynote lectures delivered at Euromech Colloquium “Advanced experimental approaches and inverse problems in tissue biomechanics” held in Saint Etienne in June 2012. We are witnessing an advent of patient-specific biomechanics that will bring in the future personalized treatments to sufferers all over the world. It is the current task of biomechanists to devise methods for clinically-relevant patient-specific modeling. One of the obstacles standing before...

  16. Rehabilitation System based on the Use of Biomechanical Analysis and Videogames through the Kinect Sensor

    OpenAIRE

    John E. Muñoz-Cardona; Oscar A. Henao-Gallo; José F. López-Herrera

    2013-01-01

    This paper presents development of a novel system for physical rehabilitation of patients with multiple pathologies, through dynamic with exercise videogames (exergames) and analysis of the movements of patients using developed software. This system is based on the use of the Kinect sensor for both purposes: amusing the patient in therapy through of specialist exergames and provide a tool to record and analyze MoCap data taken through the Kinect sensor and processed using biomechanical analys...

  17. Heparin nanomodification improves biocompatibility and biomechanical stability of decellularized vascular scaffolds

    OpenAIRE

    Tao Y; Hu T; Wu Z.; Tang H; Hu Y; Tan Q; Wu C

    2012-01-01

    Yunming Tao,1,2 Tiehui Hu,1 Zhongshi Wu,1 Hao Tang,1 Yerong Hu,1 Qi Tan,1 Chunlin Wu11Department of Thoracic and Cardiovascular Surgery, Second Xiangya Hospital of Central South University, Changsha; 2Department of Thoracic and Cardiovascular Surgery, Ji'an Central People’s Hospital, Ji'an, Jiangxi Province, People's Republic of ChinaAbstract: Biocompatibility and biomechanical stability are two of the main obstacles limiting the effectiveness of vascular sca...

  18. BIOMECHANICS OF FLIGHT PHASE WHEN RUNNING LONG JUMP FROM PLACE OF DIFFERENT QUALIFICATION SPORTSMEN

    OpenAIRE

    A. V. Razuvanova; Ye. V. Koshelskaya; V. I. Andreyev; I. V. Kapilevich

    2015-01-01

    Biomechanical features of flight phase when running long jump from place of different qualification sportsmen were investigated by method of Motion Tracking. The obtained results showed that the effective control of body position during the phase of flight can improve the effectiveness of jump actions.. This control is performed by moving parts of the body – bending legs at the knee, extension in the hip joints, the joints of the spine, shoulder joints and, as a consequence, any additional to...

  19. Biomechanics of the anterior cruciate ligament: Physiology, rupture and reconstruction techniques

    OpenAIRE

    Domnick, Christoph; Raschke, Michael J.; Herbort, Mirco

    2016-01-01

    The influences and mechanisms of the physiology, rupture and reconstruction of the anterior cruciate ligament (ACL) on kinematics and clinical outcomes have been investigated in many biomechanical and clinical studies over the last several decades. The knee is a complex joint with shifting contact points, pressures and axes that are affected when a ligament is injured. The ACL, as one of the intra-articular ligaments, has a strong influence on the resulting kinematics. Often, other meniscal o...

  20. Energetics and biomechanics as determining factors of swimming performance: updating the state of the art

    OpenAIRE

    Barbosa, Tiago M; Bragada, José A.; V. M. Reis; Marinho, D. A.; Carvalho, C.; Silva, A. J.

    2010-01-01

    The biophysical determinants related to swimming performance are one of the most attractive topics within swimming science. The aim of this paper was to do an update of the “state of art” about the interplay between performance, energetic and biomechanics in competitive swimming. Throughout the manuscript some recent highlights are described: (i) the relationship between swimmer’s segmental kinematics (segmental velocities, stroke length, stroke frequency, stroke index and coordinati...

  1. Homogenization of a system of elastic and reaction-diffusion equations modelling plant cell wall biomechanics

    OpenAIRE

    Ptashnyk, Mariya; Seguin, Brian

    2014-01-01

    In this paper we present a derivation and multiscale analysis of a mathematical model for plant cell wall biomechanics that takes into account both the microscopic structure of a cell wall coming from the cellulose microfibrils and the chemical reactions between the cell wall's constituents. Particular attention is paid to the role of pectin and the impact of calcium-pectin cross-linking chemistry on the mechanical properties of the cell wall. We prove the existence and uniqueness of the stro...

  2. Biomechanics of the Metalloceramic Bridge Prostheses at the Dental Row Lateral Department Small Defect Substitution

    OpenAIRE

    Zhulyov E.N.; Sulyagina O.V.; Leontiev N.V.

    2009-01-01

    A method of mathematical simulation was used for prosthetics improvement of patients with the dental row lateral department small defects by combined bridge prostheses with a support on insets. Four types of the metalloceramic bridge prosthesis constructions were used at a study of a biomechanics in a system of ″bridge prosthesis—supporting teeth—periodontium—alveolar part of a jaw″. The investigation results have demonstrated that a distribution of elastic tensions is unfavorable and can cau...

  3. Biomechanical analysis of fixed bearing and mobile bearing total knee prostheses

    OpenAIRE

    Urwin, Samuel

    2014-01-01

    In total knee replacement (TKR) surgery, mobile bearing (MB) total knee prostheses were designed to more closely mimic the function of the normal knee than traditional fixed bearing (FB) designs by allowing axial mobility between the polyethylene insert and tibial tray. Despite the hypothetical benefits of the MB design, few studies have objectively analysed knee biomechanics during activities of daily living (ADLs) in the laboratory compared to FB designs. This thesis aimed to substantiate t...

  4. Biomechanical and immunohistochemical analysis of high hydrostatic pressure-treated Achilles tendons

    International Nuclear Information System (INIS)

    Reconstruction of bone defects caused by malignant tumors is carried out in different ways. At present, tumor-bearing bone segments are devitalized mainly by extracorporeal irradiation or autoclaving, but both methods have substantial disadvantages. In this regard, high hydrostatic pressure (HHP) treatment of the bone is a new, advancing technology that has been used in preclinical testing to inactivate normal cells and tumor cells without altering the biomechanical properties of the bone. The aim of this study was to examine the biomechanical and immunohistochemical properties of tendons after exposure to HHP and to evaluate whether preservation of the bony attachment of tendons and ligaments is possible. For this, 19 paired Achilles tendons were harvested from both hindlimbs of 4-month-old pigs. After preparation, the cross-sectional area of each tendon was determined by magnetic resonance imaging (MRI). For each animal, one of the two tendons was taken at random and exposed to a pressure of 300 MPa (n=9) or 600 MPa (n=10). The contralateral tendon served as an untreated control. The biomechanical properties of the tendons remained unchanged with respect to the tested parameters: Young's modulus (MPa) and tensile strength (MPa). This finding is in line with immunohistochemical labeling results, as no difference in the labeling pattern of collagen I and versican was observed when comparing the HHP group (at 600 MPa) to the untreated control group. We anticipate that during orthopedic surgery HHP can serve as a novel, promising methodical approach to inactivate Achilles tendon and bone cells without altering the biomechanical properties of the tendons. This should allow one to preserve the attachment of tendon and ligaments to the devitalized bone and to facilitate functional reconstruction. (author)

  5. Sagittal Plane Knee Biomechanics and Vertical Ground Reaction Forces Are Modified Following ACL Injury Prevention Programs

    OpenAIRE

    Padua, Darin A.; DiStefano, Lindsay J.

    2009-01-01

    Context: Injuries to the anterior cruciate ligament (ACL) occur because of excessive loading on the knee. ACL injury prevention programs can influence sagittal plane ACL loading factors and vertical ground reaction force (VGRF). Objective: To determine the influence of ACL injury prevention programs on sagittal plane knee biomechanics (anterior tibial shear force, knee flexion angle/moments) and VGRF. Data Sources: The PubMed database was searched for studies published between January 1988 an...

  6. Injury and biomechanical perspectives on the rugby scrum: a review of the literature.

    Science.gov (United States)

    Trewartha, Grant; Preatoni, Ezio; England, Michael E; Stokes, Keith A

    2015-04-01

    As a collision sport, rugby union has a relatively high overall injury incidence, with most injuries being associated with contact events. Historically, the set scrum has been a focus of the sports medicine community due to the perceived risk of catastrophic spinal injury during scrummaging. The contemporary rugby union scrum is a highly dynamic activity but to this point has not been well characterised mechanically. In this review, we synthesise the available research literature relating to the medical and biomechanical aspects of the rugby union scrum, in order to (1) review the injury epidemiology of rugby scrummaging; (2) consider the evidence for specific injury mechanisms existing to cause serious scrum injuries and (3) synthesise the information available on the biomechanics of scrummaging, primarily with respect to force production. The review highlights that the incidence of acute injury associated with scrummaging is moderate but the risk per event is high. The review also suggests an emerging acknowledgement of the potential for scrummaging to lead to premature chronic degeneration injuries of the cervical spine and summarises the mechanisms by which these chronic injuries are thought to occur. More recent biomechanical studies of rugby scrummaging confirm that scrum engagement forces are high and multiplanar, but can be altered through modifications to the scrum engagement process which control the engagement velocity. As the set scrum is a relatively 'controlled' contact situation within rugby union, it remains an important area for intervention with a long-term goal of injury reduction. PMID:24398223

  7. Astonishing Judo, first contact tactics: A Biomechanical evaluation of tactics at start of high level competitions

    CERN Document Server

    Sacripanti, Attilio

    2014-01-01

    This paper is focalized on the limit application of judo throws, by tactics at first contact time, with some astonishing information at a first seeing, but biomechanically grounded, not often applied or because against the sound common sense or out the old oral judo tradition. To do so we provide an appraisal of the grips concept and his consequences in the Olympic sport judo from a biomechanics perspective, we will try to deeper both the concept and the function of grips and define the potential application of some throws without grips. Broadening this situation we try to underline some specific throwing situation in which grips are or not at all applied or applied in non conventional way. We describe at first the problem from the theoretical point of view. And as second point we try to find practical application, original or already developed in high level competitions. The provocative words Judo without grips or throw without grips are connected to the limit application of some biomechanical tricks, ground...

  8. Does student learning style affect performance on different formats of biomechanics examinations?

    Science.gov (United States)

    Hsieh, Chengtu; Mache, Melissa; Knudson, Duane

    2012-03-01

    Students' learning style preferences have been widely adapted into teaching and learning environments. The purpose of this study was to investigate the relationship between self-reported and assessed learning style preferences (visual, auditory, reading/writing, kinesthetic: VARK) on performance in different types of multiple-choice examinations (T1: text only format and T2: visual format) given in an introductory biomechanics class. Students who enrolled in three biomechanics classes at a state university were recruited to participate in the study. Ninety students (47 males and 43 females) completed a learning style survey and two types of examinations. Results showed that approximately half of the students were assessed and self-reported as kinesthetic for their preferred learning style. There was no significant difference in test performance between students who preferred visual and reading/writing learning styles (self-reported and assessed). These students demonstrated similar learning and comprehension of biomechanical concepts regardless of whether the test material was presented in their preferred sensory mode or not. Interestingly, female students' perceptions of their learning style preference may have a positive effect on the test results when the test is presented in their preferred format. PMID:22518949

  9. The biomechanics of upper extremity kinematic and kinetic modeling: applications to rehabilitation engineering.

    Science.gov (United States)

    Slavens, Brooke A; Harris, Gerald F

    2008-01-01

    Human motion analysis has evolved from the lower extremity to the upper extremity. Rehabilitation engineering is reliant upon three-dimensional biome-chanical models for a thorough understanding of upper body motions and forces in order to improve treatment methods, rehabilitation strategies and to prevent injury. Due to the complex nature of upper body movements, a standard biomechanical model does not exist. This paper reviews several kinematic and kinetic rehabilitation engineering models from the literature. These models may capture a single joint; multijoints such as the shoulder, elbow and wrist; or a combination of joints and an ambulatory aid, which serves as the extension of the upper arm. With advances in software and hardware, new models continuously arise due to the clinical questions at hand. When designing a biomechanical upper extremity model, several key components must be determined. These include deciding on the anatomic segments of the model, the number of markers and placement on bony landmarks, the definition of joint coordinate systems, and the description of the joint motions. It is critical to apply the proper model to further our understanding of pathologic populations. PMID:19740069

  10. Vertical jumping biomechanical evaluation through the use of an inertial sensor-based technology.

    Science.gov (United States)

    Setuain, I; Martinikorena, J; Gonzalez-Izal, M; Martinez-Ramirez, A; Gómez, M; Alfaro-Adrián, J; Izquierdo, M

    2016-05-01

    Progress in micro-electromechanical systems has turned inertial sensor units (IUs) into a suitable tool for vertical jumping evaluation. In total, 9 men and 8 women were recruited for this study. Three types of vertical jumping tests were evaluated in order to determine if the data provided by an IU placed at the lumbar spine could reliably assess jumping biomechanics and to examine the validity of the IU compared with force plate platform recordings. Robust correlation levels of the IU-based jumping biomechanical evaluation with respect to the force plate across the entire analysed jumping battery were found. In this sense, significant and extremely large correlations were found when raw data of both IU and force plate-derived normalised force-time curves were compared. Furthermore, significant and mainly moderate correlation levels were also found between both instruments when isolated resultant forces' peak values of predefined jumping phases of each manoeuvre were analysed. However, Bland and Altman graphical representation demonstrated a systematic error in the distribution of the data points within the mean ±1.96 SD intervals. Using IUs, several biomechanical variables such as the resultant force-time curve patterns of the three different vertical jumps analysed were reliably measured. PMID:26256752

  11. Biomechanical rupture risk assessment of abdominal aortic aneurysms based on a novel probabilistic rupture risk index.

    Science.gov (United States)

    Polzer, Stanislav; Gasser, T Christian

    2015-12-01

    A rupture risk assessment is critical to the clinical treatment of abdominal aortic aneurysm (AAA) patients. The biomechanical AAA rupture risk assessment quantitatively integrates many known AAA rupture risk factors but the variability of risk predictions due to model input uncertainties remains a challenging limitation. This study derives a probabilistic rupture risk index (PRRI). Specifically, the uncertainties in AAA wall thickness and wall strength were considered, and wall stress was predicted with a state-of-the-art deterministic biomechanical model. The discriminative power of PRRI was tested in a diameter-matched cohort of ruptured (n = 7) and intact (n = 7) AAAs and compared to alternative risk assessment methods. Computed PRRI at 1.5 mean arterial pressure was significantly (p = 0.041) higher in ruptured AAAs (20.21(s.d. 14.15%)) than in intact AAAs (3.71(s.d. 5.77)%). PRRI showed a high sensitivity and specificity (discriminative power of 0.837) to discriminate between ruptured and intact AAA cases. The underlying statistical representation of stochastic data of wall thickness, wall strength and peak wall stress had only negligible effects on PRRI computations. Uncertainties in AAA wall stress predictions, the wide range of reported wall strength and the stochastic nature of failure motivate a probabilistic rupture risk assessment. Advanced AAA biomechanical modelling paired with a probabilistic rupture index definition as known from engineering risk assessment seems to be superior to a purely deterministic approach. PMID:26631334

  12. Using robotic systems in order to determine biomechanical properties of soft tissues.

    Science.gov (United States)

    Kunkel, M E; Moral, A; Westphal, R; Rode, D; Rilk, M; Wahl, F M

    2008-01-01

    Biomechanical properties of soft tissue are important not only during computer simulation for medical training but also for systems where tissue deformation must be estimated in real-time, for example, Robot Assisted Surgery. The purpose of this paper is to describe some biomechanical tests consisting in the measurement of contact forces and deformations in tissue phantoms and porcine soft tissues (liver, brain, stomach and intestine). During the measurements two different procedures were applied. First, we have used a 5DOF micromanipulator instrumented with a spherical probe and a 6-axis force/torque ATI sensor. In the second procedure instead of the micromanipulator a Stäubli RX60 robot was used to apply the force over the samples. During this last test a high noise-signal relationship was detected and in order to improve the accuracy of the experiments some results were obtained using a Stäubli TX40 robot. Major accuracy in research in the field of soft tissue could be reached using standard procedures. Robotic systems allow precise movements to carry on biomechanical tests, and also permit a wide range of tasks to be implemented. PMID:18376024

  13. A novel finite element method based biomechanical model for HIT-robot assisted orthopedic surgery system.

    Science.gov (United States)

    Jia, Zhiheng; Du, Zhijiang; Wang, Monan

    2006-01-01

    To build a biomechanical human model can make much sense for surgical training and surgical rehearse. Especially, it will be more meaningful to develop a biomechanical model to guide the control strategy for the medical robots in HIT-Robot Assisted Orthopedic Surgery System (HIT-RAOS). In this paper, based the successful work of others, a novel reliable finite element method based biomechanical model for HIT-RAOS was developed to simulate the force needed in reposition procedure. Geometrical model was obtained from 3D reconstruction from CT images of a just died man. Using this boundary information, the finite element model of the leg including part of femur, broken upper tibia, broken lower tibia, talus, calcaneus, Kirschner nail, muscles and other soft tissues was created in ANSYS. Furthermore, as it was too difficult to reconstruct the accurate geometry model from CT images, a new simplified muscle model was presented. The bony structures and tendons were defined as linearly elastic, while soft tissues and muscle fibers were assumed to be hyper elastic. To validate this model, the same dead man was involved to simulate the patient, and a set of data of the force needed to separate the two broken bones and the distance between them in reposition procedure was recorded. Then, another set of data was acquired from the finite element analysis. After comparison, the two sets of data matched well. The Finite Element model was proved to be acceptable. PMID:17959437

  14. Occupational stress and biomechanical risk in a high fashion clothing company.

    Science.gov (United States)

    Forcella, Laura; Bonfiglioli, Roberta; Cutilli, Piero; Antonucci, Andrea; Di Donato, Angela; Siciliano, Eugenio; Cortini, Michela; Violante, Francesco Saverio; Boscolo, Paolo

    2012-01-01

    Psychosocial discomfort may amplify job-related risk factors. The aim of this study is to evaluate job stress in a high fashion clothing company with upper limb biomechanical overload due to repetitive and forceful manual activities. Biomechanical risk was analyzed and in part reduced using the OCRA Check list. A total of 518 workers (433 females and 85 males) were investigated to determine anxiety (by STAI 1 and 2), occupational stress (using the Italian version of the Karasek Job Content Questionnaire) and perception of symptoms. Final 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, probably, to very low decision latitude. It was suggested that job strain may increase the perception of symptoms. Moreover, the result of this study indicates that musculoskeletal overload has to be further analyzed since its low level is not in agreement with the level of discomfort due to the repetitive tasks. PMID:22317171

  15. Detecting Early Biomechanical Effects of Zoledronic Acid on Femurs of Osteoporotic Female Rats

    Directory of Open Access Journals (Sweden)

    Evandro Pereira Palacio

    2012-01-01

    Full Text Available Aim. To investigate the biomechanical effects of zoledronic acid (ZA on femurs of female osteoporotic rats after follow-up periods of 9 and 12 months. Methods. Eighty female Wistar rats were prospectively assessed. At 60 days of age, the animals were randomly divided into two groups: bilateral oophorectomy (O (n=40 and sham surgery (S (n=40. At 90 days of age, groups O and S were randomly subdivided into four groups, according to whether 0.1 mg/kg of ZA or distilled water (DW was intraperitoneally administered: OZA (n=20, ODW (n=20, SZA (n=20, and SDW (n=20. The animals were sacrificed at 9 and 12 months after the administration of the substances, and then their right femurs were removed and analyzed biomechanically. Axial compression tests that focused on determining the maximum load (N, yield point (N, and stiffness coefficient (N/mm of the proximal femur were performed in the biomechanical study. Results. ZA significantly increased the maximum load and yield point, reducing the stiffness coefficient concerning the oophorectomy status and follow-up period. Conclusion. Zoledronic acid, at a dose of 0.1 mg/kg, significantly increased the maximum loads and yield points and reduced the stiffness coefficients in the femurs of female rats with osteoporosis caused by bilateral oophorectomy.

  16. Stabilizing PID controllers for a single-link biomechanical model with position, velocity, and force feedback.

    Science.gov (United States)

    Iqbal, Kamran; Roy, Anindo

    2004-12-01

    In this paper we address the problem of PID stabilization of a single-link inverted pendulum-based biomechanical model with force feedback, two levels of position and velocity feedback, and with delays in all the feedback loops. The novelty of the proposed model lies in its physiological relevance, whereby both small and medium latency sensory feedbacks from muscle spindle (MS), and force feedback from Golgi tendon organ (GTO) are included in the formulation. The biomechanical model also includes active and passive viscoelastic feedback from Hill-type muscle model and a second-order low-pass function for muscle activation. The central nervous system (CNS) regulation of postural movement is represented by a proportional-integral-derivative (PID) controller. Padé approximation of delay terms is employed to arrive at an overall rational transfer function of the biomechanical model. The Hermite-Biehler theorem is then used to derive stability results, leading to the existence of stabilizing PID controllers. An algorithm for selection of stabilizing feedback gains is developed using the linear matrix inequality (LMI) approach. PMID:15796343

  17. Biomechanical and structural parameters of tendons in rats subjected to swimming exercise.

    Science.gov (United States)

    Bezerra, M A; Santos de Lira, K D; Coutinho, M P G; de Mesquita, G N; Novaes, K A; da Silva, R T B; de Brito Nascimento, A K; Inácio Teixeira, M F H B; Moraes, S R A

    2013-12-01

    The aim of this study was to evaluate the effect of swimming exercise, without overloading, on the biomechanical parameters of the calcaneal tendon of rats. 27 male Wistar rats (70 days) were distributed randomly into 2 groups, Control Group (CG; n=15) with restricted movements inside the cage and Swimming Group (SG; n=12), subjected to exercise training in a tank with a water temperature of 30±1°C, for 1 h/day, 5 days/week for 8 weeks. All animals were kept in a reversed light/dark cycle of 12 h with access to food and water ad libitum. After that, they were anesthetized and had their calcaneus tendons collected from their left rear paws. The tendon was submitted to a mechanical test on a conventional test machine. From the stress vs. strain curve, the biomechanical data were analyzed. For the statistical analysis, the Student-T test was used (pexercise training, without overloading, was an important stimulus for improving the biomechanical parameters and structural properties of the calcaneal tendon. PMID:23740340

  18. Structural and biomechanical changes in the Achilles tendon after chronic treatment with statins.

    Science.gov (United States)

    de Oliveira, L P; Vieira, C P; Guerra, F D; Almeida, M S; Pimentel, E R

    2015-03-01

    Cases of tendinopathy and tendon ruptures have been reported as side effects associated with statin therapy. This work assessed possible changes in the structural and biomechanical properties of the tendons after chronic treatment with statins. Wistar rats were divided into the following groups: treated with atorvastatin (A-20 and A-80), simvastatin (S-20 and S-80) and the group that received no treatment (C). The doses of statins were calculated using allometric scaling, based on the doses of 80 mg/day and 20 mg/day recommended for humans. The morphological aspect of the tendons in A-20, S-20 and S-80 presented signals consistent with degeneration. Both the groups A-80 and S-80 showed a less pronounced metachromasia in the compression region of the tendons. Measurements of birefringence showed that A-20, A-80 and S-80 groups had a lower degree of organization of the collagen fibers. In all of the groups treated with statins, the thickness of the epitenon was thinner when compared to the C group. In the biomechanical tests the tendons of the groups A-20, A-80 and S-20 were less resistant to rupture. Therefore, statins affected the organization of the collagen fibers and decreased the biomechanical strength of the tendons, making them more predisposed to ruptures. PMID:25544391

  19. Comparison of Corneal Topographical and Biomechanical Properties in Cases with Atopic Dermatitis and Healthy Subjects

    Directory of Open Access Journals (Sweden)

    Yusuf Yıldırım

    2013-06-01

    Full Text Available Pur po se: To compare the topographic, biomechanical, and thickness properties of corneas of patients with atopic dermatitis (AD and of healthy individuals. Ma te ri al and Met hod: In this prospective, cross-sectional, and comparative study, 28 healthy individuals (control group and 28 patients with AD (study group were enrolled. Corneal topographical measurements using Scheimpflug camera with a Placido disc topographer (Sirius, corneal biomechanical properties using Ocular Response Analyzer (ORA, and central corneal thickness (CCT using ultrasonic pachymeter were obtained for each participant. Re sults: Topographic parameters were not significantly different between both groups (p>0.05. Corneal hysteresis (CH and corneal resistance factor (CRF were found same in both groups. CCT measured with ultrasonic pachymeter was significantly lower in patients with AD compared to health controls (p<0.05. Dis cus si on: No significant difference was found between patients with AD and age-matched healthy individuals regarding the corneal topographic findings and corneal biomechanical parameters. CCT was found to be lower in cases with AD than in healthy controls. (Turk J Ophthalmol 2013; 43: 140-4

  20. In Vivo Corneal Biomechanical Properties with Corneal Visualization Scheimpflug Technology in Chinese Population

    Directory of Open Access Journals (Sweden)

    Ying Wu

    2016-01-01

    Full Text Available Purpose. To determine the repeatability of recalculated corneal visualization Scheimpflug technology (CorVis ST parameters and to study the variation of biomechanical properties and their association with demographic and ocular characteristics. Methods. A total of 783 healthy subjects were included in this study. Comprehensive ophthalmological examinations were conducted. The repeatability of the recalculated biomechanical parameters with 90 subjects was assessed by the coefficient of variation (CV and intraclass correlation coefficient (ICC. Univariate and multivariate linear regression models were used to identify demographic and ocular factors. Results. The repeatability of the central corneal thickness (CCT, deformation amplitude (DA, and first/second applanation time (A1/A2-time exhibited excellent repeatability (CV% ≤ 3.312% and ICC ≥ 0.929 for all measurements. The velocity in/out (Vin/out, highest concavity- (HC- radius, peak distance (PD, and DA showed a normal distribution. Univariate linear regression showed a statistically significant correlation between Vin, Vout, DA, PD, and HC-radius and IOP, CCT, and corneal volume, respectively. Multivariate analysis showed that IOP and CCT were negatively correlated with Vin, DA, and PD, while there was a positive correlation between Vout and HC-radius. Conclusion. The ICCs of the recalculated parameters, CCT, DA, A1-time, and A2-time, exhibited excellent repeatability. IOP, CCT, and corneal volume significantly influenced the biomechanical properties of the eye.

  1. The effect of substrate compliance on the biomechanics of gibbon leaps.

    Science.gov (United States)

    Channon, Anthony J; Günther, Michael M; Crompton, Robin H; D'Août, Kristiaan; Preuschoft, Holger; Vereecke, Evie E

    2011-02-15

    The storage and recovery of elastic strain energy in the musculoskeletal systems of locomoting animals has been extensively studied, yet the external environment represents a second potentially useful energy store that has often been neglected. Recent studies have highlighted the ability of orangutans to usefully recover energy from swaying trees to minimise the cost of gap crossing. Although mechanically similar mechanisms have been hypothesised for wild leaping primates, to date no such energy recovery mechanisms have been demonstrated biomechanically in leapers. We used a setup consisting of a forceplate and two high-speed video cameras to conduct a biomechanical analysis of captive gibbons leaping from stiff and compliant poles. We found that the gibbons minimised pole deflection by using different leaping strategies. Two leap types were used: slower orthograde leaps and more rapid pronograde leaps. The slower leaps used a wider hip joint excursion to negate the downward movement of the pole, using more impulse to power the leap, but with no increase in work done on the centre of mass. Greater hip excursion also minimised the effective leap distance during orthograde leaps. The more rapid leaps conversely applied peak force earlier in stance where the pole was effectively stiffer, minimising deflection and potential energy loss. Neither leap type appeared to usefully recover energy from the pole to increase leap performance, but the gibbons demonstrated an ability to best adapt their leap biomechanics to counter the negative effects of the compliant pole. PMID:21270319

  2. Biomechanics of the Sensor–Tissue Interface—Effects of Motion, Pressure, and Design on Sensor Performance and the Foreign Body Response—Part I: Theoretical Framework

    OpenAIRE

    Helton, Kristen L; Ratner, Buddy D.; Wisniewski, Natalie A

    2011-01-01

    The importance of biomechanics in glucose sensor function has been largely overlooked. This article is the first part of a two-part review in which we look beyond commonly recognized chemical biocompatibility to explore the biomechanics of the sensor–tissue interface as an important aspect of continuous glucose sensor biocompatibility. Part I provides a theoretical framework to describe how biomechanical factors such as motion and pressure (typically micromotion and micropressure) give rise t...

  3. The corneoscleral shell of the eye: potentials of assessing biomechanical parameters in normal and pathological conditions

    Directory of Open Access Journals (Sweden)

    E. N. Iomdina

    2016-01-01

    Full Text Available The paper reviews modern methods of evaluating the biomechanical properties of the corneoscleral shell of the eye that can be used both in the studies of the pathogenesis of various ophthalmic pathologies and in clinical practice. The biomechanical parameters of the cornea and the sclera have been shown to be diagnostically significant in assessing the risk of complications and the effectiveness of keratorefractive interventions, in the diagnosis and the prognosis of keratoconus, progressive myopia, or glaucoma. In clinical practice, a special device, Ocular Response Analyzer (ORA, has been used on a large scale. The analyzer is used to assess two parameters that characterize viscoelastic properties of the cornea — corneal hysteresis (CH and corneal resistance factor (CRF. Reduced levels of CH and CRF have been noted after eximer laser surgery, especially that administered to patients who demonstrate a regression in the refraction effect or suffer from keratoconus. This fact justifies the use of these biomechanical parameters as additional diagnostic criteria in the evaluation of the state of the cornea. At the same time, ORA data are shown to reflect the biomechanical response to the impact of the air pulse not only from the cornea alone but also from the whole corneoscleral capsule. This is probably the cause of reduced CH in children with progressive myopia and a weakened supportive function of the sclera, as well as such reduction in glaucomatous adult patients. It is hypothesized that a low CH value is a result of remodeling of the connective tissue matrix of the corneoscleral shell of the eye and can be an independent factor testifying to a risk of glaucoma progression. Reduced CH in primary open-angle glaucoma occurs in parallel with the development of pathological structural changes of the optic disc, and deterioration of visual fields, which is an evidence of a specific character and sensitivity of this parameter. The

  4. Biomechanical and neuromuscular characteristics of male athletes: implications for the development of anterior cruciate ligament injury prevention programs.

    Science.gov (United States)

    Sugimoto, Dai; Alentorn-Geli, Eduard; Mendiguchía, Jurdan; Samuelsson, Kristian; Karlsson, Jon; Myer, Gregory D

    2015-06-01

    Prevention of anterior cruciate ligament (ACL) injury is likely the most effective strategy to reduce undesired health consequences including reconstruction surgery, long-term rehabilitation, and pre-mature osteoarthritis occurrence. A thorough understanding of mechanisms and risk factors of ACL injury is crucial to develop effective prevention programs, especially for biomechanical and neuromuscular modifiable risk factors. Historically, the available evidence regarding ACL risk factors has mainly involved female athletes or has compared male and female athletes without an intra-group comparison for male athletes. Therefore, the principal purpose of this article was to review existing evidence regarding the investigation of biomechanical and neuromuscular characteristics that may imply aberrant knee kinematics and kinetics that would place the male athlete at risk of ACL injury. Biomechanical evidence related to knee kinematics and kinetics was reviewed by different planes (sagittal and frontal/coronal), tasks (single-leg landing and cutting), situation (anticipated and unanticipated), foot positioning, playing surface, and fatigued status. Neuromuscular evidence potentially related to ACL injury was reviewed. Recommendations for prevention programs for ACL injuries in male athletes were developed based on the synthesis of the biomechanical and neuromuscular characteristics. The recommendations suggest performing exercises with multi-plane biomechanical components including single-leg maneuvers in dynamic movements, reaction to and decision making in unexpected situations, appropriate foot positioning, and consideration of playing surface condition, as well as enhancing neuromuscular aspects such as fatigue, proprioception, muscle activation, and inter-joint coordination. PMID:25663251

  5. Microrobotized blasting improves the bone-to-textured implant response. A preclinical in vivo biomechanical study.

    Science.gov (United States)

    Coelho, Paulo G; Gil, Luiz F; Neiva, Rodrigo; Jimbo, Ryo; Tovar, Nick; Lilin, Thomas; Bonfante, Estevam A

    2016-03-01

    This study evaluated the effect of microrobotized blasting of titanium endosteal implants relative to their manually blasted counterparts. Two different implant systems were utilized presenting two different implant surfaces. Control surfaces (Manual) were fabricated by manually grit blasting the implant surfaces while experimental surfaces (Microblasted) were fabricated through a microrobotized system that provided a one pass grit blasting routine. Both surfaces were created with the same ~50µm average particle size alumina powder at ~310KPa. Surfaces were then etched with 37% HCl for 20min, washed, and packaged through standard industry procedures. The surfaces were characterized through scanning electron microscopy (SEM) and optical interferometry, and were then placed in a beagle dog radius model remaining in vivo for 3 and 6 weeks. The implant removal torque was recorded and statistical analysis evaluated implant system and surface type torque levels as a function of time in vivo. Histologic sections were qualitatively evaluated for tissue response. Electron microscopy depicted textured surfaces for both manual and microblasted surfaces. Optical interferometry showed significantly higher Sa, Sq, values for the microblasted surface and no significant difference for Sds and Sdr values between surfaces. In vivo results depicted that statistically significant gains in biomechanical fixation were obtained for both implant systems tested at 6 weeks in vivo, while only one system presented significant biomechanical gain at 3 weeks. Histologic sections showed qualitative higher amounts of new bone forming around microblasted implants relative to the manually blasted group. Microrobotized blasting resulted in higher biomechanical fixation of endosteal dental implants and should be considered as an alternative for impant surface manufacturing. PMID:26703231

  6. Quadriceps tendon allografts as an alternative to Achilles tendon allografts: a biomechanical comparison.

    Science.gov (United States)

    Mabe, Isaac; Hunter, Shawn

    2014-12-01

    Quadriceps tendon with a patellar bone block may be a viable alternative to Achilles tendon for anterior cruciate ligament reconstruction (ACL-R) if it is, at a minimum, a biomechanically equivalent graft. The objective of this study was to directly compare the biomechanical properties of quadriceps tendon and Achilles tendon allografts. Quadriceps and Achilles tendon pairs from nine research-consented donors were tested. All specimens were processed to reduce bioburden and terminally sterilized by gamma irradiation. Specimens were subjected to a three phase uniaxial tension test performed in a custom environmental chamber to maintain the specimens at a physiologic temperature (37 ± 2 °C) and misted with a 0.9 % NaCl solution. There were no statistical differences in seven of eight structural and mechanical between the two tendon types. Quadriceps tendons exhibited a significantly higher displacement at maximum load and significantly lower stiffness than Achilles tendons. The results of this study indicated a biomechanical equivalence of aseptically processed, terminally sterilized quadriceps tendon grafts with bone block to Achilles tendon grafts with bone block. The significantly higher displacement at maximum load, and lower stiffness observed for quadriceps tendons may be related to the failure mode. Achilles tendons had a higher bone avulsion rate than quadriceps tendons (86 % compared to 12 %, respectively). This was likely due to observed differences in bone block density between the two tendon types. This research supports the use of quadriceps tendon allografts in lieu of Achilles tendon allografts for ACL-R. PMID:24414293

  7. Fixation performance of an ultrasonically fused, bioresorbable osteosynthesis implant: A biomechanical and biocompatibility study.

    Science.gov (United States)

    Augat, P; Robioneck, P B; Abdulazim, A; Wipf, F; Lips, K S; Alt, V; Schnettler, R; Heiss, C

    2016-01-01

    Bioresorbable implants may serve as an alternative option for the fixation of bone fractures. Because of their minor inherent mechanical properties and insufficient anchorage within bone bioresorbable implants have so far been limited to mechanically nondemanding fracture types. By briefly liquefying the surface of the biomaterial during insertion, bioresorbable implants can be ultrasonically fused with bone to improve their mechanical fixation. The objective of this study was to investigate the biomechanical fixation performance and in vivo biocompatibility of an ultrasonically fused bioresorbable polymeric pin (SonicPin). First, we biomechanically compared the fused pin with press fitted metallic and bioresorbable polymeric implants for quasi-static and fatigue strength under shear and tensile loading in a polyurethane foam model. Second, fused implants were inserted into cancellous bovine bone and tested biomechanically to verify the reproducibility of their fusion behavior. Finally, the fused pins were tested in a lapine model of femoral condyle osteotomies and were histologically examined by light and transmission electron microscopy. While comparable under static shear loads, fixation performance of ultrasonically fused pins was significantly (p = 0.001) stronger under tensile loading than press fit implants and showed no pull-out. Both bioresorbable implants withstood comparable fatigue shear strength, but less than the K-wire. In bovine bone the ultrasonic fusion process worked highly reproducible and provided consistent mechanical fixation. In vivo, the polymeric pin produced no notable foreign body reactions or resorption layers. Ultrasonic fusion of polymeric pins achieved adequate and consistent mechanical fixation with high reproducibility and exhibits good short-term resorption and biocompatibility. PMID:25678144

  8. Influence of Age on Ocular Biomechanical Properties in a Canine Glaucoma Model with ADAMTS10 Mutation

    Science.gov (United States)

    Palko, Joel R.; Morris, Hugh J.; Pan, Xueliang; Harman, Christine D.; Koehl, Kristin L.; Gelatt, Kirk N.; Plummer, Caryn E.; Komáromy, András M.; Liu, Jun

    2016-01-01

    Soft tissue often displays marked age-associated stiffening. This study aims to investigate how age affects scleral biomechanical properties in a canine glaucoma model with ADAMTS10 mutation, whose extracellular matrix is concomitantly influenced by the mutation and an increased mechanical load from an early age. Biomechanical data was acquired from ADAMTS10-mutant dogs (n = 10, 21 to 131 months) and normal dogs (n = 5, 69 to 113 months). Infusion testing was first performed in the whole globes to measure ocular rigidity. After infusion experiments, the corneas were immediately trephined to prepare scleral shells that were mounted on a pressurization chamber to measure strains in the posterior sclera using an inflation testing protocol. Dynamic viscoelastic mechanical testing was then performed on dissected posterior scleral strips and the data were combined with those reported earlier by our group from the same animal model (Palko et al, IOVS 2013). The association between age and scleral biomechanical properties was evaluated using multivariate linear regression. The relationships between scleral properties and the mean and last measured intraocular pressure (IOP) were also evaluated. Our results showed that age was positively associated with complex modulus (page. The regression slopes were not different between the groups, although the complex modulus was significantly lower in the affected group (p = 0.041). The posterior circumferential tangential strain was negatively correlated with complex modulus (R = -0.744, p = 0.006) showing consistent mechanical evaluation between the testing methods. Normalized ocular rigidity was negatively correlated with the last IOP in the affected group (p = 0.003). Despite a mutation that affects the extracellular matrix and a chronic IOP elevation in the affected dogs, age-associated scleral stiffening and loss of mechanical damping were still prominent and had a similar rate of change as in the normal dogs. PMID:27271467

  9. Biomechanics of Thoracolumbar Burst and Chance-Type Fractures during Fall from Height

    Science.gov (United States)

    Ivancic, Paul C.

    2014-01-01

    Study Design In vitro biomechanical study. Objective To investigate the biomechanics of thoracolumbar burst and Chance-type fractures during fall from height. Methods Our model consisted of a three-vertebra human thoracolumbar specimen (n = 4) stabilized with muscle force replication and mounted within an impact dummy. Each specimen was subjected to a single fall from an average height of 2.1 m with average velocity at impact of 6.4 m/s. Biomechanical responses were determined using impact load data combined with high-speed movie analyses. Injuries to the middle vertebra of each spinal segment were evaluated using imaging and dissection. Results Average peak compressive forces occurred within 10 milliseconds of impact and reached 40.3 kN at the ground, 7.1 kN at the lower vertebra, and 3.6 kN at the upper vertebra. Subsequently, average peak flexion (55.0 degrees) and tensile forces (0.7 kN upper vertebra, 0.3 kN lower vertebra) occurred between 43.0 and 60.0 milliseconds. The middle vertebra of all specimens sustained pedicle and endplate fractures with comminution, bursting, and reduced height of its vertebral body. Chance-type fractures were observed consisting of a horizontal split fracture through the laminae and pedicles extending anteriorly through the vertebral body. Conclusions We hypothesize that the compression fractures of the pedicles and vertebral body together with burst fracture occurred at the time of peak spinal compression, 10 milliseconds. Subsequently, the onset of Chance-type fracture occurred at 20 milliseconds through the already fractured and weakened pedicles and vertebral body due to flexion-distraction and a forward shifting spinal axis of rotation. PMID:25083357

  10. Effects of Ankle Arthrodesis on Biomechanical Performance of the Entire Foot.

    Directory of Open Access Journals (Sweden)

    Yan Wang

    Full Text Available Ankle arthrodesis is one popular surgical treatment for ankle arthritis, chronic instability, and degenerative deformity. However, complications such as foot pain, joint arthritis, and bone fracture may cause patients to suffer other problems. Understanding the internal biomechanics of the foot is critical for assessing the effectiveness of ankle arthrodesis and provides a baseline for the surgical plan. This study aimed to understand the biomechanical effects of ankle arthrodesis on the entire foot and ankle using finite element analyses. A three-dimensional finite element model of the foot and ankle, involving 28 bones, 103 ligaments, the plantar fascia, major muscle groups, and encapsulated soft tissue, was developed and validated. The biomechanical performances of a normal foot and a foot with ankle arthrodesis were compared at three gait instants, first-peak, mid-stance, and second-peak.Changes in plantar pressure distribution, joint contact pressure and forces, von Mises stress on bone and foot deformation were predicted. Compared with those in the normal foot, the peak plantar pressure was increased and the center of pressure moved anteriorly in the foot with ankle arthrodesis. The talonavicular joint and joints of the first to third rays in the hind- and mid-foot bore the majority of the loading and sustained substantially increased loading after ankle arthrodesis. An average contact pressure of 2.14 MPa was predicted at the talonavicular joint after surgery and the maximum variation was shown to be 80% in joints of the first ray. The contact force and pressure of the subtalar joint decreased after surgery, indicating that arthritis at this joint was not necessarily a consequence of ankle arthrodesis but rather a progression of pre-existing degenerative changes. Von Mises stress in the second and third metatarsal bones at the second-peak instant increased to 52 MPa and 34 MPa, respectively, after surgery. These variations can provide

  11. Ultrasound Elasticity Imaging System with Chirp-Coded Excitation for Assessing Biomechanical Properties of Elasticity Phantom

    Directory of Open Access Journals (Sweden)

    Guan-Chun Chun

    2015-12-01

    Full Text Available The biomechanical properties of soft tissues vary with pathological phenomenon. Ultrasound elasticity imaging is a noninvasive method used to analyze the local biomechanical properties of soft tissues in clinical diagnosis. However, the echo signal-to-noise ratio (eSNR is diminished because of the attenuation of ultrasonic energy by soft tissues. Therefore, to improve the quality of elastography, the eSNR and depth of ultrasound penetration must be increased using chirp-coded excitation. Moreover, the low axial resolution of ultrasound images generated by a chirp-coded pulse must be increased using an appropriate compression filter. The main aim of this study is to develop an ultrasound elasticity imaging system with chirp-coded excitation using a Tukey window for assessing the biomechanical properties of soft tissues. In this study, we propose an ultrasound elasticity imaging system equipped with a 7.5-MHz single-element transducer and polymethylpentene compression plate to measure strains in soft tissues. Soft tissue strains were analyzed using cross correlation (CC and absolution difference (AD algorithms. The optimal parameters of CC and AD algorithms used for the ultrasound elasticity imaging system with chirp-coded excitation were determined by measuring the elastographic signal-to-noise ratio (SNRe of a homogeneous phantom. Moreover, chirp-coded excitation and short pulse excitation were used to measure the elasticity properties of the phantom. The elastographic qualities of the tissue-mimicking phantom were assessed in terms of Young’s modulus and elastographic contrast-to-noise ratio (CNRe. The results show that the developed ultrasound elasticity imaging system with chirp-coded excitation modulated by a Tukey window can acquire accurate, high-quality elastography images.

  12. Biomechanical Effect of an Interlaminar Device on Ranges of Motion, Intradiscal Pressure, and Centers of Rotation

    Directory of Open Access Journals (Sweden)

    Giancarlo Guizzardi

    2015-06-01

    Full Text Available Introduction. The IntraSPINE is a new interlaminar device that has been proposed with the aim to decompress the spinal canal without reducing the extension motion. The purpose of this study was therefore to evaluate the biomechanical behavior of L4-L5 spinal units implanted with this interlaminar device, in terms of ranges of motion, intradiscal pressure, and centers of rotation. Material and Methods. Six human lumbar spines were harvested within 10 days after death. A specific spine testing device was used to apply moments up to 10 Nm in flexion-extension, lateral bending (left-right flexion and left-right axial rotation (torsion, with measurement of vertebral 3D motion and of intervertebral disc pressure. Protocol was repeated for each specimen in 5 configurations: intact specimen; after L4-L5 bilateral medial hemifacetectomy and both yellow ligament resection; after implantation of the interlaminar device at the L4-L5 level; after removal of the L4-L5 supraspinous ligament, resection of the posterior third of the disc and addition of an artificial ligament; after device and artificial ligament removal. Results. The implant reduced increases in segmental flexion seen following injury particularly when applied with the artificial ligament. Intradiscal pressure reduced following application of the implant without reducing extension range. A small posterior shift of the Mean Centers of Rotation (MCR was noticed after instrumentation. Torsion and lateral bending range was unaffected by the interlaminar device. Conclusion. This biomechanical study yields a better understanding of this interlaminar implant effect. A large clinical trial with follow-up would be required to evaluate and confirm in vivo the observed in vitro biomechanical behavior of the device.

  13. Biomechanical approaches to understanding the potentially injurious demands of gymnastic-style impact landings

    Directory of Open Access Journals (Sweden)

    Gittoes Marianne JR

    2012-01-01

    Full Text Available Abstract Gymnasts are exposed to a high incidence of impact landings due to the execution of repeated dismount performances. Biomechanical research can help inform recent discussions surrounding a proposed rule change in potentially injurious gymnastic dismounting. The review examines existing understanding of the mechanisms influencing the impact loads incurred in gymnastic-style landings achieved using biomechanical approaches. Laboratory-based and theoretical modelling research of inherent and regulatory mechanisms is appraised. The integration of the existing insights into injury prevention interventions studies is further considered in the appraisals. While laboratory-based studies have traditionally been favoured, the difficulty in controlling and isolating mechanisms of interest has partially restricted the understanding gained. An increase in the use of theoretical approaches has been evident over the past two decades, which has successfully enhanced insight into less readily modified mechanisms. For example, the important contribution of mass compositions and 'tuned' mass coupling responses to impact loading has been evidenced. While theoretical studies have advanced knowledge in impact landing mechanics, restrictions in the availability of laboratory-based input data have suppressed the benefits gained. The advantages of integrating laboratory-based and theoretical approaches in furthering scientific understanding of loading mechanisms have been recognised in the literature. Since a multi-mechanism contribution to impact loading has been evident, a deviation away from studies examining isolated mechanisms may be supported for the future. A further scientific understanding of the use of regulatory mechanisms in alleviating a performer's inherent injury predisposition may subsequently be gained and used to inform potential rule changes in gymnastics. While the use of controlled studies for providing scientific evidence for the

  14. Biomechanical analysis of running in weightlessness on a treadmill equipped with a subject loading system.

    Science.gov (United States)

    Gosseye, Thierry P; Willems, Patrick A; Heglund, Norman C

    2010-11-01

    One countermeasure used during long-duration spaceflight to maintain bone and muscle mass is a treadmill equipped with a subject loading system (SLS) that simulates gravity. To date, little is known about the biomechanics of running in weightlessness on such a treadmill-SLS system. We have designed an instrumented treadmill/force plate to compare the biomechanics of running in weightlessness to running on Earth. Gravity was simulated by two pneumatic pistons pulling downward on a subject's harness, with a force approximately equal to body weight on Earth. Four transducers, mounted under the treadmill, measured the three components of the reaction force exerted by the tread belt under the foot. A high-speed video camera recorded the movements of limb segments while the electromyography of the four lower limb muscles was registered. Experiments in weightlessness were conducted during the European Space Agency parabolic flight campaigns. Control experiments were performed on the same subjects on Earth. When running on the treadmill with an SLS, the bouncing mechanism of running is preserved. Depending on the speed of progression, the ground reaction forces, contact and aerial times, muscular work and bone stress differed by a maximum of ± 5-15% during running on the treadmill with an SLS, as compared to that on Earth. The movements of the lower limb segments and the EMG patterns of the lower limb muscles were also comparable. Thus, the biomechanics of running on Earth can reasonably be duplicated in weightlessness using a treadmill with an SLS that generates a pull-down force close to body weight on Earth. PMID:20582597

  15. Linking biomechanics and ecology through predator-prey interactions: flight performance of dragonflies and their prey.

    Science.gov (United States)

    Combes, S A; Rundle, D E; Iwasaki, J M; Crall, J D

    2012-03-15

    Aerial predation is a highly complex, three-dimensional flight behavior that affects the individual fitness and population dynamics of both predator and prey. Most studies of predation adopt either an ecological approach in which capture or survival rates are quantified, or a biomechanical approach in which the physical interaction is studied in detail. In the present study, we show that combining these two approaches provides insight into the interaction between hunting dragonflies (Libellula cyanea) and their prey (Drosophila melanogaster) that neither type of study can provide on its own. We performed >2500 predation trials on nine dragonflies housed in an outdoor artificial habitat to identify sources of variability in capture success, and analyzed simultaneous predator-prey flight kinematics from 50 high-speed videos. The ecological approach revealed that capture success is affected by light intensity in some individuals but that prey density explains most of the variability in success rate. The biomechanical approach revealed that fruit flies rarely respond to approaching dragonflies with evasive maneuvers, and are rarely successful when they do. However, flies perform random turns during flight, whose characteristics differ between individuals, and these routine, erratic turns are responsible for more failed predation attempts than evasive maneuvers. By combining the two approaches, we were able to determine that the flies pursued by dragonflies when prey density is low fly more erratically, and that dragonflies are less successful at capturing them. This highlights the importance of considering the behavior of both participants, as well as their biomechanics and ecology, in developing a more integrative understanding of organismal interactions. PMID:22357584

  16. A biomechanical model of the face including muscles for the prediction of deformations during speech production

    CERN Document Server

    Groleau, Julie; Marecaux, Christophe; Payrard, Natacha; Segaud, Brice; Rochette, Michel; Perrier, Pascal; Payan, Yohan

    2008-01-01

    A 3D biomechanical finite element model of the face is presented. Muscles are represented by piece-wise uniaxial tension cable elements linking the insertion points. Such insertion points are specific entities differing from nodes of the finite element mesh, which makes possible to change either the mesh or the muscle implementation totally independently of each other. Lip/teeth and upper lip/lower lip contacts are also modeled. Simulations of smiling and of an Orbicularis Oris activation are presented and interpreted. The importance of a proper account of contacts and of an accurate anatomical description is shown

  17. Application Of Biomechanics Cinematography To The Study Of Sports And Industrial Injuries

    Science.gov (United States)

    Plagenhoef, Stanley

    1982-02-01

    A personal history of biomechanical analyses from motion pictures is presented. The areas of work are of total body motions of athletes in many sports, analysis of work-related injuries in industry, measurements of synthetic turfs, diagnosis of muscular imbalance, and animal motion. A film presentation illustrates each of these areas.The filming and analysing of any motion should produce data that has practical applications. This means taking measured data, interpreting it properly, and then using the information to actually obtain useful results. The practical application of data obtained from the high speed filming of humans and animals is presented here.

  18. Biomechanical Assessment of the Strength of Volleyball Players in Different Stages of the Training Macrocycle

    Directory of Open Access Journals (Sweden)

    Śliwa Marcin

    2015-09-01

    Full Text Available Introduction. In order to help volleyball players achieve superior results, their coaches are constantly seeking new training methods. One of the methods used to improve the effectiveness of the training that is being implemented is conducting tests which make it possible to assess the player’s locomotor system in terms of its motor and biomechanical functions. The aim of the study was to determine the torque of the knee flexor and extensor muscles of volleyball players in three stages of the annual macrocycle.

  19. Nanoscale characterization of the biomechanical properties of collagen fibrils in the sclera

    Energy Technology Data Exchange (ETDEWEB)

    Papi, M. [Institute of Physics, Università Cattolica del Sacro Cuore, Largo F.Vito 1, 00168 Rome (Italy); Paoletti, P. [Centre for Engineering Dynamics, School of Engineering, Brownlow Hill, Liverpool, L69 3GH (United Kingdom); Geraghty, B.; Akhtar, R. [Centre for Materials and Structures, School of Engineering, Brownlow Hill, Liverpool, L69 3GH (United Kingdom)

    2014-03-10

    We apply the PeakForce Quantitative Nanomechanical Property Mapping (PFQNM) atomic force microscopy mode for the investigation of regional variations in the nanomechanical properties of porcine sclera. We examine variations in the collagen fibril diameter, adhesion, elastic modulus and dissipation in the posterior, equatorial and anterior regions of the sclera. The mean fibril diameter, elastic modulus and dissipation increased from the posterior to the anterior region. Collagen fibril diameter correlated linearly with elastic modulus. Our data matches the known macroscopic mechanical behavior of the sclera. We propose that PFQNM has significant potential in ocular biomechanics and biophysics research.

  20. A Review of Current Concepts in Flexor Tendon Repair: Physiology, Biomechanics, Surgical Technique and Rehabilitation.

    Science.gov (United States)

    Singh, Rohit; Rymer, Ben; Theobald, Peter; Thomas, Peter B M

    2015-12-28

    Historically, the surgical treatment of flexor tendon injuries has always been associated with controversy. It was not until 1967, when the paper entitled Primary repair of flexor tendons in no man's land was presented at the American Society of Hand Surgery, which reported excellent results and catalyzed the implementation of this technique into worldwide practice. We present an up to date literature review using PubMed and Google Scholar where the terms flexor tendon, repair and rehabilitation were used. Topics covered included functional anatomy, nutrition, biome-chanics, suture repair, repair site gapping, and rehabilitation. This article aims to provide a comprehensive and complete overview of flexor tendon repairs. PMID:26793293

  1. Biomechanical characteristics of polymeric UHMWPE composites with hybrid matrix and dispersed fillers

    Science.gov (United States)

    Panin, Sergey; Kornienko, Lyudmila; Shilko, Sergey; Thuc, Nguyen Xuan; Korchagin, Mikhail; Chaikina, Marina

    2015-11-01

    In order to develop artificial joint implants some biomechanical properties of composites with UHMWPE and hybrid (polymer-polymeric) "UHMWPE+PTFE" matrix with dispersed fillers were studied. A comparative analysis of the effectiveness of adding hydroxyapatite micron- and nanopowders as a biocompatible filler was carried out. It was shown that under dry sliding friction the wear rate of nanocomposites with the hybrid matrix is lower as compared with composites with the non-hybrid one. Mechanical activation of components further enhances the durability of nano- and microcomposites to almost double it without any significant reduction in the strength characteristics.

  2. Improving predictions of root biomechanical properties, is age a better determinant than diameter?

    Science.gov (United States)

    Loades, Kenneth; Hallett, Paul; Lynch, Jonathan; Chimungu, Joseph; Bengough, Anthony

    2014-05-01

    Roots mechanically reinforce many soils. Root tensile strength and stiffness is critical for soil stabilisation with plants potentially providing civil engineers a 'green' alternative for soil stabilisation. Relatively little is known on factors influencing root tensile strength. Through a better understanding of these factors the adoption of 'green engineering' techniques by civil engineers will improve. Existing models are limited in their accuracy due to simplistic assumptions to derive root contributions to the resistance of soil to failure. Current models typically use relationships between strength and diameter, however, there are a number of other factors potentially influencing root biomechanical properties. The effects of root age on biomechanical properties have largely been overlooked. Barley (Hordeum vulgare) was grown under differing soil conditions, waterlogged, moderate mechanical impedance and in unimpeded, control, conditions. The root system was excavated and tensile tests performed on root sections along the length of each root axis. Root tensile strength increased with increasing distance along the root axes in control soil from 0.5 MPa to 7.0 MPa at a distance of 800mm from the root tip and from 1.0 Mpa to 8.0 MPa, 500mm from the root tip when under moderate mechanical impedance. Increases in strength were also observed when plants were subjected to waterlogging with tensile strength increasing from 1.0 MPa to 3.0 MPa, 200mm from the root tip. Young's modulus increased from ~10 MPa at the root tip to ~60 MPa 400mm and 800mm from the root tip in mechanically impeded and control treatments respectively. Distance from root tip explained over 47% of the variance in root tensile strength and 34% of root stiffness. Including root diameter in the model led to further improvements in predicting root properties, explaining ~54% of root strength variance and ~49% of root stiffness. Root age has been shown to improve predictions of root tensile strength

  3. 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...... performance of hip protectors. The primary outcome of testing should be the percent reduction (compared with the unpadded condition) in peak value of the axial compressive force applied to the femoral neck during a simulated fall on the greater trochanter. To provide reasonable results, the test system should...

  4. Biomechanical Comparison of Different Volar Fracture Fixation Plates for Distal Radius Fractures

    OpenAIRE

    Sobky, Kareem; Baldini, Todd; Thomas, Kenneth; Bach, Joel; Williams, Allison; Wolf, Jennifer Moriatis

    2007-01-01

    The purpose of this study was to compare the biomechanical properties of four volar fixed-angle fracture fixation plate designs in a novel sawbones model as well as in cadavers. Four volar fixed angle plating systems (Hand Innovations DVR-A, Avanta SCS/V, Wright Medical Lo-Con VLS, and Synthes stainless volar locking) were tested on sawbones models using an osteotomy gap model to simulate a distal radius fracture. Based on a power analysis, six plates from each system were tested to failure i...

  5. Biomechanical Pressures and Upper Extremity Asymmetry: A Study on Young Laborers

    OpenAIRE

    Özener, Baris

    2007-01-01

    The purpose of this study is to reveal the impacts of biomechanical pressures of heavy working conditions on the upper extremities of young laborers. The study covers the examination of the upper extremities of 104 young laborers in the industrial workshops of Ankara, Turkey regarding bilateral asymmetry. The average age of the laborers was 18.48±0.61 years. The control group consisted of 102 non-laborers with an average age of 18.39±0.58 years. The laborers were measured with reg...

  6. Analysing physical fitness and biomechanical factors that determine tennis serve performance

    OpenAIRE

    Gelen, Ertuğrul; Mengütay, Sami; Karahan, Mustafa

    2009-01-01

    The purpose of the study is to analyse the fitness and the biomechanical factors which determine the velocity of the ball during serve in tennis (VBTS). The subjects of the study were fifteen male tournament level tennis player between the ages of sixteen and twenty five (18,8 ± 2,70 age/year). The physical fitness measurement of the study were; length, body weight, skinfold, diameter, circumference and length of the body, body composition, isometric handgrip strength, vertical jump, upper ex...

  7. The Effect of an Open Carpal Tunnel Release on Thumb CMC Biomechanics

    OpenAIRE

    Wright, Thomas W.; Dell, Paul C.; Conrad, Bryan P; Tanner, Marc A.

    2012-01-01

    Purpose. We have observed worsening thumb pain following carpal tunnel release (CTR) in some patients. Our purpose was to determine the effect of open CTR on thumb carpometacarpal (CMC) biomechanics. Methods. Five fresh-frozen cadaver arms with intact soft tissues were used. Each specimen was secured to a jig which fixed the forearm at 45° supination, and the wrist at 20° dorsiflexion, with thumb pointing up. The thumb was axially loaded with a force of 130 N. We measured 3D translation and r...

  8. Problem-Based Learning in Biomechanics: Advantages, Challenges, and Implementation Strategies.

    Science.gov (United States)

    Clyne, Alisa Morss; Billiar, Kristen L

    2016-07-01

    Problem-based learning (PBL) has been shown to be effective in biomedical engineering education, particularly in motivating student learning, increasing knowledge retention, and developing problem solving, communication, and teamwork skills. However, PBL adoption remains limited by real challenges in effective implementation. In this paper, we review the literature on advantages and challenges of PBL and present our own experiences. We also provide practical guidelines for implementing PBL, including two examples of PBL modules from biomechanics courses at two different institutions. Overall, we conclude that the benefits for both professors and students support the use of PBL in biomedical engineering education. PMID:27210616

  9. Biomechanical analysis of the sidestep cutting maneuver in football players with OpenSim

    OpenAIRE

    Da Corte, Dennis

    2014-01-01

    The use of mechanical vibrations has become a very common technique in the training of athletes. Some studies highlight that this kind of training is able to increase the force of the muscles, but is seems to decrease the capacity of controlling the movements by the subject. This aspect could increase the risk of ACL injuries. The aim of this project is to develop a computational model to analyze how a warming up with mechanical vibrations can a ect the biomechanical behavior of the low...

  10. On the ferrule effect and the biomechanical stability of teeth restored with cores, posts, and crowns

    OpenAIRE

    Mamoun, John S.

    2014-01-01

    An abutment for a fixed partial denture may not contain enough tooth structure, such that the abutment does not provide an adequate ‘ferrule effect’. A crown or bridge dental prosthesis that is cemented onto such an abutment/s may undergo biomechanical failure. Here, the tooth, core, and post complex, on which the crown is cemented, may fracture off from the abutment, causing the crown to separate from the abutment, while the cement that bonds the crown to the tooth, core, and post complex re...

  11. Distension of the renal pelvis in kidney stone patients: sensory and biomechanical responses

    DEFF Research Database (Denmark)

    Pedersen, Katja Venborg; Liao, Donghua; Osther, Susanne Sloth;

    2012-01-01

    The pathogenesis of symptoms in urolithiasis is poorly understood. Traditionally increased endoluminal pressure is considered the main mechanism causing pain in the upper urinary tract but clinical data are sparse. The aim of the present study was to develop a new model related to mechanosensation...... was a relation between pressure and pain score, the non-homogenous spatial strain distribution suggests that the 3D biomechanical properties of the renal pelvis are not reflected by simple estimates of tension based on pressure and volume....

  12. Sensory and biomechanical responses to distension of the renal pelvis in kidney stone patients

    DEFF Research Database (Denmark)

    Pedersen, Katja Venborg; Liao, Donghua; Osther, Susanne Sloth;

    The pathogenesis of symptoms in urolithiasis is poorly understood. Traditionally increased endoluminal pressure is considered the main mechanism causing pain in the upper urinary tract but clinical data are sparse. The aim of the present study was to develop a new model related to mechanosensation...... was a relation between pressure and pain score, the non-homogenous spatial strain distribution suggests that the 3D biomechanical properties of the renal pelvis are not reflected by simple estimates of tension based on pressure and volume....

  13. Ergonomic Models of Anthropometry, Human Biomechanics and Operator-Equipment Interfaces

    Science.gov (United States)

    Kroemer, Karl H. E. (Editor); Snook, Stover H. (Editor); Meadows, Susan K. (Editor); Deutsch, Stanley (Editor)

    1988-01-01

    The Committee on Human Factors was established in October 1980 by the Commission on Behavioral and Social Sciences and Education of the National Research Council. The committee is sponsored by the Office of Naval Research, the Air Force Office of Scientific Research, the Army Research Institute for the Behavioral and Social Sciences, the National Aeronautics and Space Administration, and the National Science Foundation. The workshop discussed the following: anthropometric models; biomechanical models; human-machine interface models; and research recommendations. A 17-page bibliography is included.

  14. Sequential compression biomechanical device in patients with critical limb ischemia and nonreconstructible peripheral vascular disease.

    LENUS (Irish Health Repository)

    Sultan, Sherif

    2011-08-01

    Critical limb ischemia (CLI) patients who are unsuitable for intervention face the dire prospect of primary amputation. Sequential compression biomechanical device (SCBD) therapy provides a limb salvage option for these patients. This study assessed the outcome of SCBD in severe CLI patients who otherwise would face an amputation. Primary end points were limb salvage and 30-day mortality. Secondary end points were hemodynamic outcomes (increase in popliteal artery flow and toe pressure), ulcer healing, quality-adjusted time without symptoms of disease or toxicity of treatment (Q-TwiST), and cost-effectiveness.

  15. Study of osteoporosis through the measurement of bone density, trace elements, biomechanical properties and immunocytochemicals

    International Nuclear Information System (INIS)

    Osteoporosis is defined as an absolute decrease in the amount of bone to a level below required for mechanical support. It is an important bone disease in elderly people in many countries. Unfortunately, there is no reliable statistical data in Turkey for the incidence of osteoporosis. A decrease in bone mass is the important cause in fractures in osteoporosis. Therefore, we intend to study both bone density and other variables such as trace elements, biomechanical properties and other immunocytochemicals in bone, all combined might give an information about the cause and prevention of osteoporosis. (author)

  16. Degrees of freedom of tongue movements in speech may be constrained by biomechanics

    OpenAIRE

    Perrier, Pascal; Perkell, Joseph; Payan, Yohan; Zandipour, Majid; Guenther, Franck; Khalighi, Ali

    2007-01-01

    International audience A number of studies carried out on different languages have found that tongue movements in speech are made along two primary degrees of freedom (d.f.s): the high-front to low-back axis and the high-back to low-front axis. We explore the hypothesis that these two main d.f.s could find their origins in the physical properties of the vocal tract. A large set of tongue shapes was generated with a biomechanical tongue model using a Monte-Carlo method to thoroughly sample ...

  17. [Modern biomechanical poroeslatic model of bone tissue. Part II--structure of pore space in cortical and trabecular bone].

    Science.gov (United States)

    Rogala, Piotr; Uklejewski, Ryszard; Stryła, Wanda

    2002-01-01

    In modern bone biomechanics the bone tissue is treated as a porous elastically deformed solid filled with a viscous newtonian fluid (two-phase poroelastic model) [41]. Traditional one-phase biomechanical model of bone tissue is still valid and it can be considered as an approximate model in comparison with the more realistic two-phase model of bone tissue. Hierarchical biostructure of the pore space of cortical and trabecular bone is presented, including the compartments of bone pore space after Cowin [12, 13]. Examples of clinical amplications of the poroelastic model of bone tissue such as: osteoporosis, porous coated implants, bone electromagnetostimulation in rehabilitation are indicated. PMID:12418404

  18. Risk of surgery for subacromial impingement syndrome in relation to neck-shoulder complaints and occupational biomechanical exposures

    DEFF Research Database (Denmark)

    Svendsen, Susanne Wulff; Dalbøge, Annett; Andersen, JH;

    2013-01-01

    Danish Ramazzini Centre. We linked baseline questionnaire information from 1993-2004 on neck-shoulder complaints, job titles, psychosocial work factors, body mass index, and smoking with register information on first-time surgery for SIS from 1996-2008. Biomechanical exposure measures were obtained from......OBJECTIVES: The aim of this longitudinal study was to evaluate the risk of surgery for subacromial impingement syndrome (SIS) in relation to neck-shoulder complaints and occupational biomechanical shoulder exposures. METHODS: The study was based on the Musculoskeletal Research Database at the...

  19. New Regression Models to Evaluate the Relationship between Biomechanics of Gymnastic Vault and Initial Vault Difficulty Values.

    Science.gov (United States)

    Atiković, Almir

    2012-12-01

    The main objective of this paper was to determine the relationship between biomechanical parameters of vault flights with respect to new models of initial vault difficulty values in men's artistic gymnastic. The study sample included vaults (n=64) and models (n=5) from the 2009 Code of Points (CoP) of the Federation International of Gymnastics (FIG). The dependent variable included all difficulty values ranging from 2-7.2 points, while the sample of independent variables included twelve biomechanical parameters. After implementing the regression analysis, it could be established that the best model derived only the second flight phase with 95% of explained variance. PMID:23487176

  20. Computational biomechanics of bone's responses to dental prostheses - osseointegration, remodeling and resorption

    International Nuclear Information System (INIS)

    Clinical and experimental studies showed that human bone has the ability to remodel itself to better adapt to its biomechanical environment by changing both its material properties and geometry. As a consequence of the rapid development and extensive applications of major dental restorations such as implantation and fixed partial denture (FPD), the effect of bone remodeling on the success of a dental restorative surgery is becoming critical for prosthetic design and pre-surgical assessment. This paper aims to provide a computational biomechanics framework to address dental bone's responses as a result of dental restoration. It explored three important issues of resorption, apposition and osseointegration in terms of remodeling simulation. The published remodeling data in long bones were regulated to drive the computational remodeling prediction for the dental bones by correlating the results to clinical data. It is anticipated that the study will provide a more predictive model of dental bone response and help develop a new design methodology for patient-specific dental prosthetic restoration.

  1. Judo: how to enhance tactics in competition, biomechanics of combination and action reaction

    CERN Document Server

    Sacripanti, Attilio

    2014-01-01

    This paper is an ideal continuation of the previous one - How to enhance effectiveness of Direct Attack Judo throws -in it there are analyzed the two following parts of Judo tactics in high level competitions: combination, and action-reaction. The paper start with a review of the Japanese approach to Initiative ( Sen) and follows by the biomechanical view of the same subject. High level competitions are the main argument not only of coaches match analysis , but also of a lot of scientific researches. However the connection between these two field that analyze the same subject is very hard . A lot of information are not easily transfer to coaching area. In this paper the effort to give coaching useful information is the primary aspect also at detriment of some formal mechanical information. After a new Operative Classification of throwing techniques , the biomechanical analysis of combination and action-reaction tricks flows in easy way singling out some interesting finding, useful for coaches. With this effor...

  2. Using Video Analysis and Biomechanics to Engage Life Science Majors in Introductory Physics

    Science.gov (United States)

    Stephens, Jeff

    There is an interest in Introductory Physics for the Life Sciences (IPLS) as a way to better engage students in what may be their only physical science course. In this talk I will present some low cost and readily available technologies for video analysis and how they have been implemented in classes and in student research projects. The technologies include software like Tracker and LoggerPro for video analysis and low cost high speed cameras for capturing real world events. The focus of the talk will be on content created by students including two biomechanics research projects performed over the summer by pre-physical therapy majors. One project involved assessing medial knee displacement (MKD), a situation where the subject's knee becomes misaligned during a squatting motion and is a contributing factor in ACL and other knee injuries. The other project looks at the difference in landing forces experienced by gymnasts and cheer-leaders while performing on foam mats versus spring floors. The goal of this talk is to demonstrate how easy it can be to engage life science majors through the use of video analysis and topics like biomechanics and encourage others to try it for themselves.

  3. Dynamic ultra high speed Scheimpflug imaging for assessing corneal biomechanical properties

    Directory of Open Access Journals (Sweden)

    Renato Ambrósio Jr

    2013-04-01

    Full Text Available OBJECTIVE: To describe a novel technique for clinical characterization of corneal biomechanics using non-invasive dynamic imaging. METHODS: Corneal deformation response during non contact tonometry (NCT is monitored by ultra-high-speed (UHS photography. The Oculus Corvis ST (Scheimpflug Technology; Wetzlar, Germany has a UHS Scheimpflug camera, taking over 4,300 frames per second and of a single 8mm horizontal slit, for monitoring corneal deformation response to NCT. The metered collimated air pulse or puff has a symmetrical configuration and fixed maximal internal pump pressure of 25 kPa. The bidirectional movement of the cornea in response to the air puff is monitored. RESULTS: Measurement time is 30ms, with 140 frames acquired. Advanced algorithms for edge detection of the front and back corneal contours are applied for every frame. IOP is calculated based on the first applanation moment. Deformation amplitude (DA is determined as the highest displacement of the apex in the highest concavity (HC moment. Applanation length (AL and corneal velocity (CVel are recorded during ingoing and outgoing phases. CONCLUSION: Corneal deformation can be monitored during non contact tonometry. The parameters generated provide clinical in vivo characterization of corneal biomechanical properties in two dimensions, which is relevant for different applications in Ophthalmology.

  4. Biomechanical evaluation of the locking titanium cable in the fixture of distal tibiofibular syndesmosis injury

    Directory of Open Access Journals (Sweden)

    Shu-zhi YAO

    2016-08-01

    Full Text Available Objective  The article aims at evaluating the biological properties of tibiofibular titanium cable fixation device in terms of both anti-separation and stress shielding by comparison to the interior fixation with lag screw based on experimental observation. Methods  Six corpse ankle specimens were first tested of pressure-separation and stress measurement, the data from which were compared to the normal group, and then a syndesmosis injury model was established. All the samples are randomly divided into 2 groups of 3 specimens each, which were treated with tibiofibula locked titanium cable and lag screw fixation respectively for syndesmosis injury. Then, the samples were tested for pressure-separation and stress measurement. The biomechanical properties as anti-separation ability and stress shielding were analyzed and compared between the two fixation method. Results  Both tibiofibula locked titanium cables and lag screws were able to provide enough strong lateral anti-separation ability, but strong fixation screws were inferior to tibiofibular titanium cable fixation device in fibular longitudinal stress transduction. Conclusion  Tibiofibular titanium cable fixation device not only provide sufficient lateral anti-separation, but also reduces the tibial and fibular longitudinal stress shielding, thus being superior to the traditional lag screw in biomechanical properties. DOI: 10.11855/j.issn.0577-7402.2016.07.09

  5. Biomechanical analysis on transverse tibial fixation in anterior cruciate ligament reconstructions

    Directory of Open Access Journals (Sweden)

    Edmar Stieven Filho

    2015-04-01

    Full Text Available OBJECTIVE: To verify whether the combination of tibial cross pin fixation and femoral screw fixation presents biomechanical advantages when compared to femoral cross pin fixation and tibial screw fixation for the reconstruction of the anterior cruciate ligament (ACL.METHODS: Thirty-eight porcine knees and bovine extensor digitorum tendons were used as the graft materials. The tests were performed in three groups: (1 standard, used fourteen knees, and the grafts were fixated with the combination of femoral cross pin and a tibial screw; (2 inverted, used fourteen knees with an inverted combination of tibial cross pin and a femoral screw; (3 control, ten control tests performed with intact ACL. After the grafts fixation, all the knees were subjected to tensile testing to determine yield strength and ultimate strength.RESULTS: There was no statistically significant difference in survival techniques in regard to strength, yield load and tension. There was a higher survival compared in the standard curves of yield stress (p < 0.05.CONCLUSION: There is no biomechanical advantage, observed in animal models testing, in the combination of tibial cross pin fixation and femoral screw when compared to femoral cross pin fixation and tibial screw.

  6. Wrist joint moments of walker-assisted gait:a study of biomechanics and instrumentation

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    While walkers are commonly prescribed to improve patient stability and ambulatory ability,quantitativestudy of the biomechanical and functional requirements for effective walker use is limited.To investigate the changesin wrist joint moments that occur with the use of a standard walker,a strain gauge-based walker instrumentation system was developed for the measurement of wrist joint moments.This walker dynamometer was integrated with an upper extremity biomechanical model.Preliminary system data were collected for twelve healthy,right-handed young adultsfollowing informed consent.Bilateral upper extremity kinematic data were acquired with a six-camera motion analysis system.Internal joint moments at the wrist were determined in the three clinical planes using the inverse dynamics method.Results showed that during a walker-assisted gait there were several typical demands of wrist abductor,adductor,flexor and external rotator.An interesting " bare phase " of wrist joint moments was also found in phaseangle[-30°,30°] of gait cycle.Complete description of wrist joint moments during walker-assisted gait may provide insight into walker use parameters and rehabilitative strategies.

  7. Biomechanical analysis on transverse tibial fixation in anterior cruciate ligament reconstructions☆

    Science.gov (United States)

    Filho, Edmar Stieven; Mendes, Mariane Henseler Damaceno; Claudino, Stephanie; Baracho, Filipe; Borges, Paulo César; da Cunha, Luiz Antonio Munhoz

    2015-01-01

    Objective To verify whether the combination of tibial cross pin fixation and femoral screw fixation presents biomechanical advantages when compared to femoral cross pin fixation and tibial screw fixation for the reconstruction of the anterior cruciate ligament (ACL). Methods Thirty-eight porcine knees and bovine extensor digitorum tendons were used as the graft materials. The tests were performed in three groups: (1) standard, used fourteen knees, and the grafts were fixated with the combination of femoral cross pin and a tibial screw; (2) inverted, used fourteen knees with an inverted combination of tibial cross pin and a femoral screw; (3) control, ten control tests performed with intact ACL. After the grafts fixation, all the knees were subjected to tensile testing to determine yield strength and ultimate strength. Results There was no statistically significant difference in survival techniques in regard to strength, yield load and tension. There was a higher survival compared in the standard curves of yield stress (p < 0.05). Conclusion There is no biomechanical advantage, observed in animal models testing, in the combination of tibial cross pin fixation and femoral screw when compared to femoral cross pin fixation and tibial screw. PMID:26229913

  8. Effect of gamma irradiation on the basic biomechanical properties of freeze-dried bovine pericardium (FDBP)

    International Nuclear Information System (INIS)

    This study was conducted to determine the effect of sterilization using gamma radiation on the basic biomechanical properties of freeze dried bovine pericardium (FDBP). Bovine pericardium was obtained from the Shah Alam Abattoir, Selangor. The pericardial sacs were cleaned, freeze-dried and irradiated with 25 kGy gamma rays at Malaysian Institute of Nuclear Technology (MINT), Bangi, Selangor. The biomechanical properties of one hundred strips (1 cm by 4 cm) each of the irradiated and non-irradiated of FDBP were measured respectively by instron tensometer (Instron 4301) using 5 m/min cross 'head speed. The strips thickness was measured by Mitutoyo thickness gauge. The mean values of the tensile strength (12.4±0.522 MPa/mm2), load at auto break (1 8.5±1.08 N/mm2), modulus of elasticity (stiffness) (62.69±2.48 MPa/mm2) and elongation rate (5 1 %) for non-irradiated FDBP were found to be significantly higher (P2, 9.3±4.2 N/mm2, 35.7±1.7 MPa/mm2 and 43% respectively. However, the thickness between the two groups was not significantly different (P>0.05). Although sterilization using gamma irradiation is effective against disease transmission by bioprosthesis, it can caused significant decreased in FDBP tensile strength, load at auto break, Yang modulus and elongation rate. (Author)

  9. Biomechanical Loading Modulates Proinflammatory and Bone Resorptive Mediators in Bacterial-Stimulated PDL Cells

    Directory of Open Access Journals (Sweden)

    Andressa Vilas Boas Nogueira

    2014-01-01

    Full Text Available The present study aimed to evaluate in vitro whether biomechanical loading modulates proinflammatory and bone remodeling mediators production by periodontal ligament (PDL cells in the presence of bacterial challenge. Cells were seeded on BioFlex culture plates and exposed to Fusobacterium nucleatum ATCC 25586 and/or cyclic tensile strain (CTS of low (CTSL and high (CTSH magnitudes for 1 and 3 days. Synthesis of cyclooxygenase-2 (COX2 and prostaglandin E2 (PGE2 was evaluated by ELISA. Gene expression and protein secretion of osteoprotegerin (OPG and receptor activator of nuclear factor kappa-B ligand (RANKL were evaluated by quantitative RT-PCR and ELISA, respectively. F. nucleatum increased the production of COX2 and PGE2, which was further increased by CTS. F. nucleatum-induced increase of PGE2 synthesis was significantly (P<0.05 increased when CTSH was applied at 1 and 3 days. In addition, CTSH inhibited the F. nucleatum-induced upregulation of OPG at 1 and 3 days, thereby increasing the RANKL/OPG ratio. OPG and RANKL mRNA results correlated with the protein results. In summary, our findings provide original evidence that CTS can enhance bacterial-induced syntheses of molecules associated with inflammation and bone resorption by PDL cells. Therefore, biomechanical, such as orthodontic or occlusal, loading may enhance the bacterial-induced inflammation and destruction in periodontitis.

  10. An integrated biomechanical modeling approach to the ergonomic evaluation of drywall installation.

    Science.gov (United States)

    Yuan, Lu; Buchholz, Bryan; Punnett, Laura; Kriebel, David

    2016-03-01

    Three different methodologies: work sampling, computer simulation and biomechanical modeling, were integrated to study the physical demands of drywall installation. PATH (Posture, Activity, Tools, and Handling), a work-sampling based method, was used to quantify the percent of time that the drywall installers were conducting different activities with different body segment (trunk, arm, and leg) postures. Utilizing Monte-Carlo simulation to convert the categorical PATH data into continuous variables as inputs for the biomechanical models, the required muscle contraction forces and joint reaction forces at the low back (L4/L5) and shoulder (glenohumeral and sternoclavicular joints) were estimated for a typical eight-hour workday. To demonstrate the robustness of this modeling approach, a sensitivity analysis was conducted to examine the impact of some quantitative assumptions that have been made to facilitate the modeling approach. The results indicated that the modeling approach seemed to be the most sensitive to both the distribution of work cycles for a typical eight-hour workday and the distribution and values of Euler angles that are used to determine the "shoulder rhythm." Other assumptions including the distribution of trunk postures did not appear to have a significant impact on the model outputs. It was concluded that the integrated approach might provide an applicable examination of physical loads during the non-routine construction work, especially for those operations/tasks that have certain patterns/sequences for the workers to follow. PMID:26674404

  11. Functional morphology and biomechanics of the tongue-bite apparatus in salmonid and osteoglossomorph fishes.

    Science.gov (United States)

    Camp, Ariel L; Konow, Nicolai; Sanford, Christopher P J

    2009-05-01

    The tongue-bite apparatus and its associated musculoskeletal elements of the pectoral girdle and neurocranium form the structural basis of raking, a unique prey-processing behaviour in salmonid and osteoglossomorph fishes. Using a quantitative approach, the functional osteology and myology of this system were compared between representatives of each lineage, i.e. the salmonid Salvelinus fontinalis (N = 10) and the osteoglossomorph Chitala ornata (N = 8). Divergence was found in the morphology of the novel cleithrobranchial ligament, which potentially relates to kinematic differences between the raking lineage representatives. Salvelinus had greater anatomical cross-sectional areas of the epaxial, hypaxial and protractor hyoideus muscles, whereas Chitala had greater sternohyoideus and adductor mandibulae mass. Two osteology-based biomechanical models (a third-order lever for neurocranial elevation and a modified four-bar linkage for hyoid retraction) showed divergent force/velocity priorities in the study taxa. Salvelinus maximizes both force (via powerful cranial muscles) and velocity (through mechanical amplification) during raking. In contrast, Chitala has relatively low muscle force but more efficient force transmission through both mechanisms compared with Salvelinus. It remains unclear if and how behavioural modulation and specializations in the post-cranial anatomy may affect the force/velocity trade-offs in Chitala. Further studies of tongue-bite apparatus morphology and biomechanics in a broader species range may help to clarify the role that osteology and myology play in the evolution of behavioural diversity. PMID:19438765

  12. Tumor growth prediction with reaction-diffusion and hyperelastic biomechanical model by physiological data fusion.

    Science.gov (United States)

    Wong, Ken C L; Summers, Ronald M; Kebebew, Electron; Yao, Jianhua

    2015-10-01

    The goal of tumor growth prediction is to model the tumor growth process, which can be achieved by physiological modeling and model personalization from clinical measurements. Although image-driven frameworks have been proposed with promising results, several issues such as infinitesimal strain assumptions, complicated personalization procedures, and the lack of functional information, may limit their prediction accuracy. In view of these issues, we propose a framework for pancreatic neuroendocrine tumor growth prediction, which comprises a FEM-based tumor growth model with coupled reaction-diffusion equation and nonlinear biomechanics. Physiological data fusion of structural and functional images is used to improve the subject-specificity of model personalization, and a derivative-free global optimization algorithm is adopted to facilitate the complicated model and accommodate flexible choices of objective functions. With this flexibility, we propose an objective function accounting for both the tumor volume difference and the root-mean-squared error of intracellular volume fractions. Experiments were performed on synthetic and clinical data to verify the parameter estimation capability and the prediction performance. Comparisons of using different biomechanical models and objective functions were also performed. From the experimental results of eight patient data sets, the average recall, precision, Dice coefficient, and relative volume difference between predicted and measured tumor volumes were 84.5 ± 6.9%, 85.8 ± 8.2%, 84.6 ± 1.7%, and 14.2 ± 8.4%, respectively. PMID:25962846

  13. Biomechanical testing of a polymer-based biomaterial for the restoration of spinal stability after nucleotomy

    Directory of Open Access Journals (Sweden)

    Kaps Christian

    2009-07-01

    Full Text Available Abstract Background Surgery for disc herniations can be complicated by two major problems: painful degeneration of the spinal segment and re-herniation. Therefore, we examined an absorbable poly-glycolic acid (PGA biomaterial, which was lyophilized with hyaluronic acid (HA, for its utility to (a re-establish spinal stability and to (b seal annulus fibrosus defects. The biomechanical properties range of motion (ROM, neutral zone (NZ and a potential annulus sealing capacity were investigated. Methods Seven bovine, lumbar spinal units were tested in vitro for ROM and NZ in three consecutive stages: (a intact, (b following nucleotomy and (c after insertion of a PGA/HA nucleus-implant. For biomechanical testing, spinal units were mounted on a loading-simulator for spines. In three cycles, axial loading was applied in an excentric mode with 0.5 Nm steps until an applied moment of ± 7.5 Nm was achieved in flexion/extension. ROM and NZ were assessed. These tests were performed without and with annulus sealing by sewing a PGA/HA annulus-implant into the annulus defect. Results Spinal stability was significantly impaired after nucleotomy (p Conclusion PGA/HA biomaterial seems to be well suited for cell-free and cell-based regenerative treatment strategies in spinal surgery. Its abilities to restore spinal stability and potentially close annulus defects open up new vistas for regenerative approaches to treat intervertebral disc degeneration and for preventing implant herniation.

  14. A biomechanical comparison of four different fixation methods for midshaft clavicle fractures.

    Science.gov (United States)

    Chen, Yang; Yang, Yang; Ma, Xinlong; Xu, Weiguo; Ma, Jianxiong; Zhu, Shaowen; Ma, Baoyi; Xing, Dan

    2016-01-01

    Clavicle fractures may occur in all age groups, and 70%-80% of clavicle fractures occur in the midshaft. Many methods for treating midshaft clavicular fractures have been reported and remain controversial. To provide some guidance for clinical treatment, 30 artificial polymethyl methacrylate models of the clavicle were sewn obliquely at the midshaft to simulate the most common type of clavicular fractures, and the fracture models were divided into five groups randomly and were fixed as follows: the reconstruction plates were placed at the superior position of the fracture model (R-S group), the reconstruction plates were placed at the anteroinferior position of the fracture model (R-AI group), the locking plates were placed at the superior position (L-S group), the locking plates were placed at the anteroinferior position (L-AI group); and the control models were unfixed (control group). The strain gauges were attached to the bone surface near the fracture fragments, and then, the biomechanical properties of the specimens were measured using the compression test, torsion test and three-point bending test. The results showed that plate fixation can provide a stable construct to help with fracture healing and is the preferred method in the treatment of clavicle fractures. The locking plate provides the best biomechanical stability when placed at the anteroinferior position, and this surgical method can reduce the operation time and postoperative complications; thus, it would be a better choice in clinical practice. PMID:26586526

  15. Biomechanical analyses of prolonged handwriting in subjects with and without perceived discomfort.

    Science.gov (United States)

    Chang, Shao-Hsia; Chen, Chien-Liang; Yu, Nan-Ying

    2015-10-01

    Since wrist-joint position affects finger muscle length and grip strength, we studied its biomechanical relevance in prolonged handwriting. We recruited participants from young adults, aged 18-24, and separated them into control (n=22) and in-pain (n=18) groups, based whether or not they experience pain while handwriting. The participants then performed a writing task for 30 min on a computerized system which measured their wrist-joint angle and documented their handwriting kinematics. The in-pain group perceived more soreness and had a less-extended wrist joint, longer on-paper time, and slower stroke velocity compared to control group. There was no significant difference in handwriting speed and quality between the two groups. The wrist extension angle significantly correlated with perceived soreness. Ergonomic and biomechanical analyses provide important information about the handwriting process. Knowledge of pen tip movement kinematics and wrist-joint position can help occupational therapists plan treatment for individuals with handwriting induced pain. PMID:26141665

  16. Techniques frequently used during London Olympic judo tournaments: a biomechanical approach

    CERN Document Server

    Sterkowicz, Stanislav; Sterkowicz_Przybycien, Katarina

    2013-01-01

    Feedback between training and competition should be considered in athletic training.The aim of the study was contemporary coaching tendencies in women s and men s judo with particular focus on a biomechanical classification of throws and grappling actions. Throwing technique frequencies grouped in the seven biomechanical classes were dependent on gender. A significant difference was found between frequencies of variable arm of physical lever technique scored by males and females as compared to the techniques counts. Significant differences between men who competed in extra lightweight and heavy weight concerned the frequency of the techniques used with maximum arm or variable arm of physical lever and a couple of forces applied by trunk and legs.In females a tendency to higher frequency of techniques that used couple of forces applied by arm or arms and leg was observed in extra lightweight compared to the heavy weight. Because the technique preferred in the fight depends on a gender and weight category of a ...

  17. Biomechanical aspects of bone microstructure in vertebrates: potential approach to palaeontological investigations

    Indian Academy of Sciences (India)

    S Mishra

    2009-11-01

    Biomechanical or biophysical principles can be applied to study biological structures in their modern or fossil form. Bone is an important tissue in paleontological studies as it is a commonly preserved element in most fossil vertebrates, and can often allow its microstructures such as lacuna and canaliculi to be studied in detail. In this context, the principles of Fluid Mechanics and Scaling Laws have been previously applied to enhance the understanding of bone microarchitecture and their implications for the evolution of hydraulic structures to transport fluid. It has been shown that the microstructure of bone has evolved to maintain efficient transport between the nutrient supply and cells, the living components of the tissue. Application of the principle of minimal expenditure of energy to this analysis shows that the path distance comprising five or six lamellar regions represents an effective limit for fluid and solute transport between the nutrient supply and cells; beyond this threshold, hydraulic resistance in the network increases and additional energy expenditure is necessary for further transportation. This suggests an optimization of the size of the bone’s building blocks (such as osteon or trabecular thickness) to meet the metabolic demand concomitant to minimal expenditure of energy. This biomechanical aspect of bone microstructure is corroborated from the ratio of osteon to Haversian canal diameters and scaling constants of several mammals considered in this study. This aspect of vertebrate bone microstructure and physiology may provide a basis of understanding of the form and function relationship in both extinct and extant taxa.

  18. Evaluation of corneal biomechanical properties following penetrating keratoplasty using ocular response analyzer

    Directory of Open Access Journals (Sweden)

    Vanathi Murugesan

    2014-01-01

    Full Text Available Purpose: To evaluate corneal biomechanical properties in eyes that has undergone penetrating keratoplasty (PK. Materials and Methods: Retrospective observational study in a tertiary care centre. Data recorded included ocular response analyzer (ORA values of normal and post-keratoplasty eyes [corneal hysteresis (CH, corneal resistance factor (CRF, Goldmann-correlated intraocular pressure (IOPg, and cornea-compensated intraocular pressure (IOPcc], corneal topography, and central corneal thickness (CCT. Wilcoxon signed rank test was used to analyze the difference in ORA parameter between post-PK eyes and normal eyes. Correlation between parameters was evaluated with Spearman′s rho correlation. Results: The ORA study of 100 eyes of 50 normal subjects and 54 post-keratoplasty eyes of 51 patients showed CH of 8.340 ± 1.85 and 9.923 ± 1.558, CRF of 8.846 ± 2.39 and 9.577 ± 1.631 in post-PK eyes and normal eyes, respectively. CH and CRF did not correlate with post-keratoplasty astigmatism (P = 0.311 and 0.276, respectively while a significant correlation was observed with IOPg (P = 0.004 and IOPcc (P < 0.001. Conclusion: Biomechanical profiles were significantly decreased in post-keratoplasty eyes with significant correlation with higher IOP as compared with that in normal eyes.

  19. Biomechanical evaluation of a corporectomy in porcine lumbar specimens using flexible polymer belts

    Science.gov (United States)

    Beltrán-Fernández, J. A.; Hernández-Gómez, L. H.; Ruiz-Muñoz, E.; González-Rebattú, A.; Rodríguez-Cañizo, R. G.; Urriolagoitia-Calderón, G.; Urriolagoitia-Sosa, G.; Hernández-Moreno, H.

    2009-08-01

    This paper presents the experimental results of a biomechanical evaluation in lumbar porcine specimens (L2-L4), instrumented with flexible polymer belts, under fatigue and tensile loading. The clinical effect called facetary arthrosis is evaluated. An experimental analysis was carried on 3 lumbar porcine specimens. In two of them, polyamide belts are fixed on the interspinous ligament from L2 to L4. Specimens are taken from pigs which are 6 month old. For the present work, the stiffness reduction of the spine and the biomechanical behaviour of the belts in conjunction with the interspinous ligament are evaluated. The purpose is to determine the failure conditions for the elements of the specimen (vertebral disk, supra and intraspinous ligament and vertebral body). Under static loading, which is the base line case, the elements of the specimen failed as a typical healthy structure. While in the fatigue combined with static loading, the element failed in different order. Additionally, the stiffness changed in accordance with the fatigue loading conditions. Because of the simplicity of this alternative technique, a high level of the structural integrity is preserved, as no holes are made on the spinous process in order to insert the fixation screws. Furthermore, there is a cost reduction.

  20. Biomechanical strategies for mitigating collision damage in insect wings: structural design versus embedded elastic materials.

    Science.gov (United States)

    Mountcastle, Andrew M; Combes, Stacey A

    2014-04-01

    The wings of many insects accumulate considerable wear and tear during their lifespan, and this irreversible structural damage can impose significant costs on insect flight performance and survivability. Wing wear in foraging bumblebees (and likely many other species) is caused by inadvertent, repeated collisions with vegetation during flight, suggesting the possibility that insect wings may display biomechanical adaptations to mitigate the damage associated with collisions. We used a novel experimental technique to artificially induce wing wear in bumblebees and yellowjacket wasps, closely related species with similar life histories but distinct wing morphologies. Wasps have a flexible resilin joint (the costal break) positioned distally along the leading edge of the wing, which allows the wing tip to crumple reversibly when it hits an obstacle, whereas bumblebees lack an analogous joint. Through experimental manipulation of its stiffness, we found that the costal break plays a critical role in mitigating collision damage in yellowjacket wings. However, bumblebee wings do not experience as much damage as would be expected based on their lack of a costal break, possibly due to differences in the spatial arrangement of supporting wing veins. Our results indicate that these two species utilize different wing design strategies for mitigating damage resulting from collisions. A simple inertial model of a flapping wing reveals the biomechanical constraints acting on the costal break, which may help explain its absence in bumblebee wings. PMID:24311806