Biomechanics of Motion PDF
Preview Biomechanics of Motion
INTERNATIONAL CENTRE FOR MECHANICAL SCIENCES C 0 U R S E S A N D L E C T U R E S - No. 263 BIOMECHANICS OF MOTION ED11ED BY A. MORECKI TBCHNlCAL UNIVl::RSlTY OF WARSAW SPRINGER-VERLAG WIEN GMBH This work is subject to copyright. A Il righ ts are reserved, whether the whole or part of the material is concerned specifically those of translation, reprinting, re-use of illustrations, broadcasting, reproduction by photocopying machine or similar means, and storage in data banks. © 1980 by Springer-Verlag Wien Originally published by Springer-Verlag Wien New York in 1980 ISBN 978-3-211-81611-0 ISBN 978-3-7091-4366-7 (eBook) DOI 10.1007/978-3-7091-4366-7 EDITORIAL NOTE This book contains the papers presented at the Course on "Biomechanics ofM otion" held at the International Centre for Mechanical Sciences, Udine, Italy, 18 through 22 September 1978. The programme of the Course included an opening and a closing session and 5 working sessions. The papers included in this book appear in the same order as the lectures. All language corrections and alterations have been reduced to the necessary minimu"!.. The course of Biomechanics was attended by 22 attendees and lecturers from nine Countries. The convenient location of the course made it possible that a large group of scientists could attend. It was also advantageous that all the participants were accommodated in the same premises. The results of the Course confirm the constantly increasing significance of biomechanics. We hope that this type of course will be repeated. A. Morecki PREFACE Biomechanics as a study of movement and mechanisms of motion has a long history. It has grown up in a multi-disciplinary way. In the last twenty years it can be observed that to the fields which were traditionally fundamental, that is to physiology, surgery and physi cal training came engineers with new ideas, methodology and mathematical, mechanical and electronical background. That is the reason why the deve lopment of theoretical biomechanics is based on the physical and mathema tical modelling and engineering principles. Because trJe object - a living body - or its part is a very complicated one, the researchers must com bine the art of their profession with the scientific knowledge available. The non-engineers objective in furthering the development of biomechanics is to increase their activity based on science~ so their art may be bet ter fitted to the needs of their patients or athlets. The engineers ob jective is to increase their level of knowledge in biology, medicine and physical education, so they can better cooperate with non-engineers in an interdisciplinary team. At present the biomechanical science can be divided into four topics such as: engineering, medicine, sport and funda mental movements and general problems in connection with bionics, biome dical engineering and rehabilitation engineering. IV Preface The main purpose of the Course was to present the modern trends and the last scientific results obtained in the field mostly from engineering point of view in connection with rehabilitation engineering. The main topics which have been presented and discussed are as fol- lows: -identification problems of different properties of and ar.~al human movement activity, - mathematical modelling and simulation of human locomotion, - measurements and control of movement of lower limbs, - methodology and research of movements activity in sport, selected problems concerning the rehabilitation engineering. Most of the results, which were presented during the Course were based on the investigations carried on by the invited lecturers. The general idea, which can be derived from the enclosed papers lies in the possibility of application of the principles of mathematical modelling and identification to the description of the normal movement activity of a human being or some pathological cases. Rehabilitation engineering on the one hand and sport activity on the other hand present to us the full picture of human movement possibi lities under maximal and minimal conditions. As a result of such inves~ tigations a set of useful mathematical models was collected, which can be used for theoretical and practicial purposes. In the first chapter the identification procedure of the main sub systems of a humar1 movement is described and analysed. The idea of a mathematical description of possibilities of movemen~ Preface v control and supply systems is discussed. A few rrodels are proposed for cooperation of muscles operating the joint with one, two and three de grees of freedom both under static and dynamic conditions. The problem of supporting and substituting of lost functions of hunan upper extremities is one of the IIDst important in rehabilitation engineering. Some medical manipulators are presented with a special lo gic system of control designed and checked in clinical conditions. Some aspects of computer simulation of hUI!Eil IIDvements are presen ted in the second chapter. Three main problems are discussed, namely: - muscular-skeletal system which involves great dinamical complexi ty from engineering point of view, - simplified rnathematical models for human motion including many factors such as nonlinearity, necessity of numerical solution by means of modern digital computers, - measurement techniques necessary for testing such models. The purpose of this chapter was to provide a surmary of the state of knowledge with regard to certain aspects of computer simulation of hUI!Eil movements. The methods developed in this chapter are interpreted prelim:i.na.ry with respect to IIDtion of the lower extremities. It is hoped that the matherratical techniques which are general can be extended in the future to include computer simulation of manipulation tasks, hand-eye coordina tion and similar high-level skeletal activities.- The described above ideas are illustrated on the examples of single mass planar models for VI Preface gait, multiple mass planar models for biped gait and three-dimensional models. Some selected problems of engineering analysis of human gait concer ning the determination of the instantaneous (time variation of) varia bles characterizing the functioning of the system and their correlation are presented in the third chapter. These are the displacements of the various body segments, the forces at the joints, the muscle lengths and the coordination of the instantaneous lower limb muscle forces during walking. This analysis can be performed on normal and disabled subjects. Therefore it is useful for: i) studying in detail the basic aspects of the neuromuscular coordination of rrovernent, ii) determining the loss of certain muscle functions for subjects with paralytic disabilities, iii) specification of the forces, which a limb skeletal implant of a cup orthoplasty may be subjected to and hence must be designed for. The gait analysis, in turn, also provides the requisite force input for determi nation of the instantaneous stresses in the skeleton of the lower limb. Knowledge of the skeletal stresses enables prescription of the strength of bone gmfts and the choice of graft mterial and its dimen sion. Moreover, the study of neuromuscular coordination and the knowledge of the contribution of the various muscle forces in different phases of the stride permits a substantial improvement in the rehabilitative sche me of the best setting up of prograrmned stimulation in paralytic patients. This paper is divided into the followin[ topics: - gait analysis: general description of rrovement in three dimen - sions, mthematical description, Preface VII - analysis on the sagittal plane: formulation of the model, - data acquisition: kinematics, ground reaction, body parameters, - determination of the muscular torques and of the articular forces, - influence of the measurement erTors on the computer torques, - modelling of the muscular apparatus: determination of the muscle length and correlation with neural activity, - determination of the muscle forces by employing the concept of optimization of total muscle effort, - analysis of the spatial temporal evolution of the ground reaction as a method for the evaluation of gait. The next chapter presents the study and research in the area of biomechanics as applied to Physical Education and Sports which has only developed in the last few years. However, the interest to this field is growing rapidly in many countries. This growth has been characterized by a marked improvement in the instrumentation and measurement systems be ing used. Modern electronics forms the basis for accelerometry, electro goniometry, electromyography and systems which use force platforms, bio telemetry and force transducers of a wide variety. Often these are lin ked to a laboratory computer for real-time data recording and processing. Further, high speed cameras and automated film analysis system have en hanced the use of cinematography for purposes of quantyfying hurran move ments in sport. Current sport biomechanics' research requires the use of most or all of these electronics, computer and photographic systems. An introduction to these systems is presented. Up to date research has emphasized the role of fundamental studies VIII Preface of basic roovements as a means of establishing biomechanics principles which then form the basis for investigations of roore complex rootions in sport. The earlier descriptive studies involving kinerratics have gr-adual ly given way to roore sophisticated kinetic analyses. The latter appro - ach provides a more complete understanding of the biomechanical perfor mance components. L~ addition the interaction of the human with the en vironment (playing surface. etc.) and sports equipment are being inves tigated with a view to improve the safety and performance level of the participant. Examples are presented from research on running, jumping, swirmri.ng, ski-jumping and other sport roovements. In thefifthchapter very important problem concerning the possibi lities of rehabilitation eneineering in prosthetic devices is described and discussed. The development or upper-limb prostheses has, in the last rew years, brought out in particular the necessity of reexaming research carried out in this field not only from the point of view of the fitting of prostheses, bUt also from the mechanical point of view and above all of the possibility of control of movements and finally feedback information towards the patients. In a relatively short period of time it has been found possible to achieve a considerable improvement in the functionally of the upper limb prostheses. At present there is a slowin£ down in progr-ess, not because of the lack of will and the means to continue along this path, but be cause the latest development in this field have indicated trends that will revolutionize the system for upper-limb prostheses, principally in
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