Mechanics Of Movement Research Articles

Motor Learning—Applications for Agility, Part 1

Part 1 of this 2-part article looks at how taking a motor learning-based approach to locomotive agility can assist in setting up a long-term agility development program. It outlines a system in which agility can be de-constructed into target movement patterns and movement mechanics, each with their target function. These classifications are then used in the construction of the development program.The article also highlights how motor learning theories can be applied to the structure of agility sessions

The natural variability of morphogenesis: a tool for exploring the mechanics of gastrulation movements in amphibian embryos

The investigation of natural variability of metric morphological characters in frog gastrulation revealed that in genetically and environmentally homogeneous samples of embryos their variability is of a higher order of magnitude than that known for quantitative metric characters in adult organisms. Matching the coefficients of variation of characters under consideration to the specific rates of their changes in normal development revealed a strong positive correlation between the rates of morphological change and the amount of morphological variance. The increase in the variance is mainly in characters concerned with shaping of moving embryonic areas and arises as a result of a positive feedback between the movement of a given area and recruitment of cells from surrounding areas into the movement. The account of natural variation suggests a new model of amphibian gastrulation whose essential feature is the intimate connection between the movement and shaping of the dorsal blastopore lip of the gastrula.

545 上肢骨格モデルを用いたCPMの運動力学特性の分析(S09-2 関節のバイオメカニズム(2),S09 関節のバイオメカニズム)

545 上肢骨格モデルを用いたCPMの運動力学特性の分析(S09-2 関節のバイオメカニズム(2),S09 関節のバイオメカニズム)

Physiological and Mechanical Response to Soccer-Specific Intermittent Activity and Steady-State Activity

The aim of this study was to quantify response to a soccer-specific intermittent (INT) treadmill protocol based on notational analysis of match-play. Ten male semiprofessional football players (age 24.7 ± 4.4 yr, body mass 77.1 ± 8.3 kg, VO2max 63.0 ± 4.8 ml·kg·min−1) completed the 90 minute INT protocol and a steady-state (SS) protocol eliciting the same distance covered. Physiological (heart rate [HR], ratings of perceived exertion [RPE], blood lactate concentration, salivary cortisol concentration) and mechanical (electromyography [EMG] of biceps femoris and rectus femoris) responses were obtained at 15 minute intervals throughout each protocol. The physiological and mechanical responses were typically greater during the INT protocol than during the SS protocol, tending to increase as a function of exercise duration. The INT activity profile induces cumulative mechanical load on the musculoskeletal system. The increased incidence of injury toward the latter stages of match-play is attributed to compromised movement mechanics, rather than physiological strain.

Mechanics of animal movement

The questions highlighted here cannot represent all the kinds of questions that biomechanists have asked about human and animal movement. In addition to the ones I have omitted, there must be many good questions that we have not yet thought of asking.

Tensile properties of embryonic epithelia measured using a novel instrument

We present the first measurements of the tensile properties of embryonic epithelia, data that are crucial to understanding the mechanics of morphogenetic movements. Fine wires were glued to the surface of an intact, live embryo using cyanoacrylate glue, after which the epithelium between the wires was separated from the remainder of the embryo by microsurgery. The wires were then separated from each other in 0.1 μm steps under computer control in order to elongate the tissue at a constant true strain rate. Force was determined from the degree of bending in the wires, and a real-time, image-based feedback system corrected for reductions in elongation that would otherwise have been caused by wire flexure. The instrument was used to determine the tensile properties of epidermis and neuroepithelia from early-stage embryos of the axolotl ( Ambystoma mexicanum), a type of amphibian. Monolayer specimens as small as 300 by 500 μm were elongated at physiological strain rates of 5–30% per hour, and the effects of developmental stage, epithelium type, specimen origin, direction of elongation and strain rate were investigated. True strains as high as 50% were observed before tearing began and equivalent moduli for the initial, linear portion of the load resultant versus strain curves ranged from 1×10 −3 to 8×10 −3 N/m.

Trafficking

In cities the world over, we are able to determine stability in daily existence, to identify with our social spaces, because modes of transport have become essential components of subjective autonomy. But would it not be just as accurate to say that in transit, modern life puts the self in abeyance? The author argues that the ways we allow ourselves to be moved around in “traffic space” create a passivity that renders almost invisible the complex mechanics of movement, which we become alert to only at the moment of breakdown, precisely when they become a threat to autonomy. Our trafficking has an almost narcotic effect, rendering us immobile against the continual movements that constitute urban life, one that also magnifies out of all proportion the accidents or aberrations that sometimes disturb our traffic space, making it seem as if we may easily descend into an uncontrollable chaos.

25 Å Resolution Structure of a Cytoplasmic Dynein Motor Reveals a Seven-member Planar Ring

Dyneins form one of the three major families of cytoskeleton-based motor proteins that together drive most of the visible forms of cell and organelle movement. We present here a 3D reconstruction of a cytoplasmic dynein motor domain obtained by electron microscopy, at 25 Å resolution. This work demonstrates a basic motor architecture of a flat, slightly elliptical ring composed of seven densities arranged around a partially enclosed central cavity. We have used specific Fab tags to localize the microtubule-binding domain; the connecting stalk emerges at one end of the motor's long axis. Through proposed fitting of representative AAA domain structures, we show that the nucleotide catalytic P-1 domain is likely located at the opposite end of the motor. Thus mechanisms that couple nucleotide hydrolysis with microtubule binding must be propagated around a ring structure, in a manner clearly distinct from kinesin or myosin-mediated movements. Analysis of the Fab tagged datasets reveals classes of particles with stalks protruding at distinct angles from the motor. There is a ∼40° variation in microtubule-binding stalk angle that may reflect linkage to dynein's mechanochemical cycle. Overall, the work provides sufficient resolution to begin the mapping of landmark features onto a dynein motor, and provides a foundation for understanding the mechanics of dynein movement.

Sports Nutrition: What the Future may Bring

The field of sports nutrition is a dynamic one. Core competencies in exercise physiology, psychology, integrated metabolism and biochemistry are the initial parameters for a successful career in sports nutrition. In addition to the academic fundamentals, it is imperative that the sports nutritionist understand the sport in which our client participates. This sport specific understanding should manifest itself in fuel utilization, mechanics of movement, as well as psychological processes that motivate the participant to perform optimally. Sports nutrition as a field has grown substantially over the past 50 years, from glycogen loading to today's scientifically validated ergogenic aids. The last ten years has seen the largest advancement of sports nutrition, with the following areas driving much of the research: the effects of exercise on protein utilization, meal timing to maximize the anabolic response, the potential for ribose to benefit those engaged in high-energy repetitive sports, and creatine and its uses within athletics and medicine. The future of sports nutrition will dictate that we 1) collectively strive for a higher standard of care and education for counseling athletes and 2) integrate different disciplines. We are in an era of unprecedented growth and the new knowledge is constantly evolving. The International Society of Sports Nutrition (ISSN) will contribute to this exciting field in many ways, and we ask for your contribution by sharing your passion, stories, research, and life experiences with us.

Effect of groundwater regime on the behaviour of clayey slopes

It is well known that many landslides, which occur every year in the world, are triggered by rainfall. The mechanics of slope movements due to pore pressure changes are not completely understood, however, and thus are the focus of this paper. Both the case of first-time slides and that of landslide reactivation are examined. It is shown that simple models can reproduce the processes of slope failure and may help in predicting slope behaviour.Key words: slope, failure, landslide, analysis, water table, clay.

Kinesiology: The Mechanics and Pathomechanics of Human Movement

Kinesiology: The Mechanics and Pathomechanics of Human Movement

Measuring the effects of layout upon visitors' spatial behaviors in open plan exhibition settings

Two arguments are made based on the analysis of traveling science exhibitions. First, sufficiently refined techniques of spatial analysis allow us to identify the impact of layout upon visitors' paths and behaviors, even in moderately sized open plans which afford almost random sequences of movement and relatively unobstructed visibility. Specifically, contact with exhibits is associated with their relative accessibility while active engagement is associated with exhibit cross-visibility. Second, newly developed or adapted techniques of analysis allow us to make a transition from modeling the mechanics of spatial movement (the way in which movement is affected by the distribution of obstacles and boundaries) to modeling the manner in which movement registers additional aspects of visual information, particularly the arrangement of exhibits according to conceptual organizing themes. The advantages of such purely spatial modes of analysis extend into providing us with a sharper understanding of some of the underlying constraints within which exhibition content is conceived and designed.

Mechanics of coupling proton movements to c-ring rotation in ATP synthase

F1F0 ATP synthases generate ATP by a rotary catalytic mechanism in which H+ transport is coupled to rotation of an oligomeric ring of c subunits extending through the membrane. Protons bind to and then are released from the aspartyl-61 residue of subunit c at the center of the membrane. Subunit a of the F0 sector is thought to provide proton access channels to and from aspartyl-61. Here, we summarize new information on the structural organization of Escherichia coli subunit a and the mapping of aqueous-accessible residues in the second, fourth and fifth transmembrane helices (TMHs). Aqueous-accessible regions of these helices extend to both the cytoplasmic and periplasmic surface. We propose that aTMH4 rotates to alternately expose the periplasmic or cytoplasmic half-channels to aspartyl-61 of subunit c during the proton transport cycle. The concerted rotation of interacting helices in subunit a and subunit c is proposed to be the mechanical force driving rotation of the c-rotor, using a mechanism akin to meshed gears.

Human motion analysis for biomechanics and biomedicine

The study of human locomotion can be described as the interdiscipline that describes, analyzes, and assesses human movement. This endeavor represents an important branch of bioscience that requires a multidisciplinary effort and has immense potential to aid mankind. The applications of human motion analysis are limitless. Researchers in the fields of biomechanics, medicine, sports, and rehabilitation study human locomotion for evaluating joint forces andmoments that control motion and posture [7,18,25]. Such studies are fundamental to understanding the mechanics of normal and pathological movement [11,29], and for the diagnosis and treatment of patients withmotor deficiencies [28]. Synthetic humans may be used to test strategies to optimize various sport movements or to animate enhanced visualization of the human form to aid in clinical analysis [4,10]. Simulation allows a physician to observe which muscles are being activated during certainmovements in order to design correctional devices that can ease joint loads caused by injury. Others in the field of biomedicine use human models for the development of functional electrical stimulation (FES) protocols to restore mobility to paralyzed individuals [3,8,9,32]. In animation and computer graphics, humanmotion analysis is important to animators who wish to generate physicallybased animations of synthetic humanoids [2,23,24], allowing the physical effects of movement to be automatically generated as a byproduct of the simulation [6,15,19,30]. In the manufacturing industry, digital humans are being used as virtual operators acting within simulated environments, manufacturing automotive components, assembling aircrafts, and maintaining next-generation power plants and nuclear submarines [21]. Humanoid robots and human exoskeletons can benefit from studies of human motion. Understanding human motion has been instrumental in developing tools for simulation and control of biped robots [1,12– 14,16,17,24,26]. In computer vision, human motion analysis has emerged as an important area of research, motivated by the desire for improved man–machine interfaces. In particular, the ability to recognize human activity by visual information processing is instrumental to making a machine interact purposefully and effortlessly within a human-inhabited environment [22,31]. Other areas that have recently received considerable attention due to security concerns include surveillance. Clearly, human motion analysis and synthesis has widespread applications spanning many disciplines. The important research questions require a unified, multidisciplinary solution that utilize theories developed in human motor control, robotics,musclemechanics, computer graphics, and computer vision.

Tensegrity I. Cell structure and hierarchical systems biology.

In 1993, a Commentary in this journal described how a simple mechanical model of cell structure based on tensegrity architecture can help to explain how cell shape, movement and cytoskeletal mechanics are controlled, as well as how cells sense and respond to mechanical forces (J. Cell Sci. 104, 613-627). The cellular tensegrity model can now be revisited and placed in context of new advances in our understanding of cell structure, biological networks and mechanoregulation that have been made over the past decade. Recent work provides strong evidence to support the use of tensegrity by cells, and mathematical formulations of the model predict many aspects of cell behavior. In addition, development of the tensegrity theory and its translation into mathematical terms are beginning to allow us to define the relationship between mechanics and biochemistry at the molecular level and to attack the larger problem of biological complexity. Part I of this two-part article covers the evidence for cellular tensegrity at the molecular level and describes how this building system may provide a structural basis for the hierarchical organization of living systems--from molecule to organism. Part II, which focuses on how these structural networks influence information processing networks, appears in the next issue.

234 Study on Mirror Surface Finishing of Cemented Carbide by Magnetic Field Assisted Polishing with Two-Dimensional Free Movement Mechanics : Application to 3 Surfaces Simultaneous Polishing of Groove of Mould

By using magnetic field assisted polishing apparatus, which has been developed by authors, to obtain a mirror surface finish on the groove of mould made from cemented carbide. As a result of the experiment, both sides and the bottom of the groove were polished simultaneously when the cross-sectional shape of the rotating pole was made geometrically similar to the groove of the workpiece, and using high speed steel powder including diamond particles as a magnetic abrasive. Furthermore, the effect of two-dimensional free movement on the processing characteristics in polishing both sides of the groove by two types of elastic rubbers, silicon and nitrile, is examined. Silicon rubber and nitrile rubber were compared, and silicon rubber was better than nitrile rubber for obtaining a finer surface of both sides of the groove, due to it being softer and more flexible.

Submarine landslides: advances and challenges

Due to the recent development of well-integrated surveying techniques of the sea floor, significant improvements were achieved in mapping and describing the morphology and architecture of submarine mass movements. Except for the occurrence of turbidity currents, the aquatic environment (marine and fresh water) experiences the same type of mass failure as that found on land. Submarine mass movements, however, can have run-out distances in excess of 100 km, so their impact on any offshore activity needs to be integrated over a wide area. This great mobility of submarine mass movements is still not very well understood, particularly for cases like the far-reaching debris flows mapped on the Mississippi Fan and the large submarine rock avalanches found around many volcanic islands. A major challenge ahead is the integration of mass movement mechanics in an appropriate evaluation of the hazard so that proper risk assessment methodologies can be developed and implemented for various human activities offshore, including the development of natural resources and the establishment of reliable communication corridors.Key words: submarine slides, hazards, risk assessment, morphology, mobility, tsunami.

The Importance of Proteases in Eye Disease

A meeting with Geert W. Schmid-Schonbein, a bioengineer at the University of California-San Diego, opened my eyes to the importance of proteases in major uncontrolled disease processes. I had known about the prevalence and diversity of proteases, which are essential to the function of practically every organ in the body. I had also heard about new clinical trials of metalloprotease inhibitors (MMPI) for cancer and heart disease. However, I did not consider the potential importance of these inhibitors in eye disease until Dr. Schmid-Schonbein, who began by studying the movement mechanics of white blood cells (WBC) in the microcirculation. He and his research group noted an accumulation of WBC in diabetic retinopathy and stroke, just like they had seen previously in the myocardium. His group discovered that these WBC had upregulated proteases that are causing destruction in these disease processes. As a result, a whole new field of pursuit began in the treatment of diabetic retinopathy and Dr. Schmid-Schonbein was a guest lecturer at ARVO. More recently he and his coworkers demonstrated in animals that much of the destruction and death from shock is due to the liberation of the huge amounts of digestive proteases in the gastrointestinal track with selfdigestion of the intestinal wall. Blockade of the digestive enzymes in the lumen of the small intestine of animals provides a significant protection against WBC activation and acute multi-organ-failure in shock. He currently awaits a physician who is willing to begin a clinical trial of protease inhibitors in acute shock. The eye maintains a delicate balance of protease activity in the trabecular meshwork and the retina. Protease activity is essential to aqueous outflow and argon laser rabeculoplasty has been shown by Michael Van Buskirk to activate protease activity and increase outflow. J. O'Tousa showed that protease contributes to cell death in retinal regeneration such as macular degeneration. More than one group of proteases are involved and specific inhibition is complicated. However, this area of investigation deserves more attention and credit should be paid to innovators like Dr. SchmidSchonbein, who have shown the light on the dark corners of eye disease. Wayne F. March, M.D. Professor of Ophthalmology

Overuse injuries in youth sports: biomechanical considerations.

Many children today participate in highly organized sports programs that involve regimented year-round repetitive training. This type of training has led to an increased incidence of overuse musculoskeletal injuries. Sports physicians have dealt with sports injuries in children for many years and, on the basis of their clinical experience, have developed guidelines to treat and to try and prevent these injuries. The purpose of this article is to provide a biomechanical perspective of sports injuries in young athletes and blend ideas from this perspective with more traditional clinical perspectives that dominate the literature relative to this topic. Basic tissue and gross movement mechanics principles are used to identify growth, morphological, and movement factors that may predispose a child to an overuse injury. Several biomechanical analyses of simple movement tasks are presented to quantify the forces developed in various tissues and to illustrate the effects that growth can have on these forces. Guidelines are given for developing injury prediction models that may be used in the future to establish safe and effective training guidelines for children.

Instabilities along ocean margins: a geomorphological and geotechnical perspective

Due to the growing development of offshore activities along margins, in the search for more natural resources, there has been a greater need for understanding the mechanics of slope formation in these areas. One aspect of this relates to the problems associated with slope stability issues. This article presents an perspective view of some geomorphological and geotechnical aspects related to instabilities along ocean margins. In order to properly address the issues of slope stability and other mass movements, we need to improve our technology in the field of sampling, high resolution seismic, and in situ measurements. Ultimately, the goal is to be able to carry out proper risk assessment analysis pertaining to submarine mass movement. This could be achieved by integrating the geotechnical characterisation of mass movements into a risk assessment methodology which can then be applied on a regional basis. With the initiation of a project on continental slope stability (COSTA) during the year 2000, major advances are expected on our understanding of the mechanics of submarine mass movements.