Optimal interaction between vision and other somatosensory systems guaranties the control of human body segment stability and change in position. The lack of visual information causes changes in equilibrium, regulation of body segment position and in response to surrounding stimuli. The objective of the study: to carry out the research on the influence of the degree of visual impairment on equilibrium and simple and psychomotor reactions, and to establish the possible manifestation of compensatory reactions of vestibular and proprioception sensory systems when vision disorders are being faced. To investigate the influence of the degree of visual impairment on equilibrium and simple and psychomotor reactions, the sighted subjects, legally blind and totally blind subjects voluntarily participated in the study. A static posturography (or stabilography) method has been used for the equilibrium testing. A force plate and computerized equipment for analysis of the signals was applied for posturography. Centre of pressure coordinates have been started to be registered since the moment when the subject in bare feet stands on the force plate in the position required. Posturogram registration in every position of standing lasted 60 s. To investigate a simple reaction, we have employed an electromyoreflexometer, which consists of the equipment emitting light or sound signals, a response device and a unit for the data registration. The testing has been conducted during two parts when a... [to full text]

Context: It has been suggested that muscle fatigue can lead to injury, however, research investigating this phenomenon in functional ankle instability (FAI) subjects is lacking. Aim: The purpose of this thesis was to research postural sway and muscular latency in FAI subjects and healthy controls, both before and immediately after localised and globalised fatigue protocols. Subjects: All subjects used in this project were males, between the ages of 18 and 25 years, and participated in regular (>2 x week) aerobic exercise. Subjects were categorised into healthy subjects, or subjects with a history of FAI using the FAI questionnaire. Methods: Neuromuscular control was analysed in FAI subjects and healthy controls through measures of muscular latency and postural sway. These measures were repeated both before and immediately after localised and globalised fatigue protocols. Results: The induction of localised and globalised fatigue had no effect on muscle latency in the FAI or healthy subjects. However, postural sway was significantly increased in the FAI subjects, following localised and globalised fatigue, with globalised fatigue also significantly increasing postural sway in the healthy subjects. The globalised football-specific fatigue protocol caused the greatest deficits in the FAI subjects, but also the healthy controls. Conclusions: In terms of muscle latency individuals that participate in sports, as well as sports clinicians and coaches, should not be concerned about the theorised relationship between the onset of fatigue and an increased injury risk at the ankle. However, in terms of postural sway the globalised football-specific fatigue protocol caused the greatest deficits. This highlights that the fatigued individual may be at greater risk of musculoskeletal injury during prolonged exercise that involves multiple joints, such as a football match.

Tyrimo problema: Pasaulyje išsėtine skleroze serga apie 2,5 mln. žmonių. Lietuva priklauso didelio sergamumo išsėtine skleroze zonai (Klizaitienė, 2008). Vienas iš pagrindinių simptomų, pasireiškiančių jau ankstyvoje šios ligos stadijoje, yra pusiausvyros sutrikimas (Prosperini et al., 2010; Cameron et al., 2008; Martin & Phillips, 2006). Darbo aktualumas: Kinezioteipas yra pigi, lengvai prieinama ir neinvazinė priemonė, galinti pagerinti sergančiųjų išsėtine skleroze statinę pusiausvyrą ir gyvenimo kokybę, sumažinti atsitiktinių griuvimų riziką. Tyrimo hipotezė: Kinezioteipas, užklijuotas ant dvilypio ir priekinio blauzdos, gali pagerinti sergančiųjų išsėtine skleroze statinę pusiausvyrą. Tyrimo tikslas: Nustatyti kinezioteipo poveikį sergančiųjų išsėtine skleroze statinei pusiausvyrai. Tyrimo uždaviniai: 1. Įvertinti tiriamųjų statinę pusiausvyrą stovint atsimerkus ir užsimerkus be kinezioteipo ir su kinezioteipu, užklijuotu ant dvilypio ir priekinio blauzdos raumens funkcine korekcine technika. 2. Įvertinti tiriamųjų statinę pusiausvyrą stovint atsimerkus ir užsimerkus be kinezioteipo ir su kinezioteipu, užklijuotu placebo ant keturgalvio raumens. 3. Įvertinti skirtingų kinezioteipavimo technikų efektyvumą tiriamųjų statinei pusiausvyrai. Tyrimo metodai: Tyrimas buvo atliktas ,,Palangos reabilitacijos ligoninėje“ 2012 m. sausio 19-20 dienomis kuriame dalyvavo 16 darbingų asmenų, kuriems diagnozuota išsėtinė sklerozė. • Buvo atliekamas aklas vienpusis tyrimas. •... [toliau žr. visą tekstą] / About 2,5 million people suffer from multiple sclerosis. Lithuania belongs to a zone of high rate of people suffering from this desease (Klizaitienė, 2008). On of the main symptoms, appearing in the early stage of this desease is imbalance (Prosperini et al., 2010; Cameron et al., 2008; Martin & Phillips, 2006). Relevance of the topic: Kinesio Tape is a cheap, available and non-invasive means which can improve static balance, quality of life and reduce coincidental risk of falls for those who have multiple sclerosis. Hypothesis: Kinesio Tape sticked to gastrocnemius and tibialis anterior muscle can improve the postural stability of those who have multiple sclerosis. The aim of the research: To establish the effect of the Kinesio Tape of those who suffer fro multiple sclerosis and to estimate the postural stability. The task of the research: 1. Estimate the posture while standing with tight legs with open and closed eyes with Kinesio Tape and with Kinesio Tape, sticked on the gastrocnemius and tibialis anterior muscle with the help of functional correctional technique. 2. Estimate the posture while standing with tight legs with open and closed eyes with Kinesio Tape and with Kinesio Tape, sticked on the quadriceps muscle with the placebo technique. 3. Estimate the efficiency of Kinesio Tape on postural stability of those who were in the research. Methods of the research: The research was performed on 19th and 20th of January in 2012 in rehabilitation hospital Palanga. There... [to full text]

Made available in DSpace on 2016-06-02T20:19:16Z (GMT). No. of bitstreams: 1 3544.pdf: 6258983 bytes, checksum: 5cd47bab5793fd9a48d598b072ae845e (MD5) Previous issue date: 2011-02-25 / Universidade Federal de Minas Gerais / Pregnancy causes considerable physiologic, hormonal and anatomic changes in women that may affect the lower limbs and trunk movements, lead to instability of postural control and increased risk of falls, causing a direct impact on mother´s health and quality of life. We conducted three studies to examine the changes in static postural control (STUDY I), in dynamic postural control (STUDY II) and the relationship of these changes with quality of life (STUDY III) of 13 pregnant women during the gestational period (G1, G2 and G3), and a control group of 29 non-pregnant women. For static postural control assessment, a force plate (Bertec®) was used and to assess the quality of life was used the WHOQOL-Bref. In STUDY I posturographic tests were applied in four still standing positions, for three trials, with a combination of different visual conditions (eyes open - EO/eyes closed - EC) and support base configurations. The variables analyzed, derived from the center of pressure (COP), were statokinesigram, displacement amplitude, displacement velocity and sway frequency. In STUDY II were analyzed variables of ground reaction force during the stance phase of gait: time and value of the first peak (P1), second peak (P2) and the valley of the vertical component; time and maximum and minimum value found in the anteroposterior horizontal component (max Fy / min Fy) and the difference between the maximum and minimum values in the mediolateral horizontal component ( max min Fx). And in the STUDY III we used data from the first two studies, plus the assessment of quality of life of pregnant women. The results demonstrate that, early in pregnancy, the woman's body seems to be already adapted for postural control, probably due to hormonal factors, and during the trimesters there was a decrease in postural stability. Compared to the control group, pregnant women had larger areas, an increase in the amplitudes and velocities of COP displacement, more time in the first phase of weight acceptance, lower values of peak 1 and 2 of the vertical component and lower maximum and minimum values of anteroposterior horizontal component of ground reaction force, possibly indicating a reduction in speed and thrust of the gait. With respect to quality of life, the physical domain was the most affected in the first trimester, with lower values mainly during late gestation. / A gestação ocasiona consideráveis alterações fisiológicas, hormonais e anatômicas na mulher que podem afetar os membros inferiores e os movimentos do tronco, levar a uma instabilidade do controle postural e aumentar o risco de quedas, podendo gerar um impacto direto na saúde e qualidade de vida da gestante. Foram realizados três estudos com o objetivo de analisar as adaptações no controle postural estático (ESTUDO I), no controle postural dinâmico (ESTUDO II) e a relação dessas adaptações com a qualidade de vida (ESTUDO III) de 13 gestantes, ao longo dos trimestres gestacionais (G1, G2 e G3), além de um grupo controle formado por 29 mulheres não-gestantes. Para avaliação do controle postural utilizou-se uma Plataforma de Força (Bertec®), e para a avaliação da qualidade de vida utilizou-se o instrumento WHOQOL-bref. No ESTUDO I foram aplicados testes posturográficos em quatro posições eretas estáticas, por três tentativas, combinando diferentes condições visuais (olhos abertos OA/ olhos fechados OF) e diferentes configurações da base de suporte. As variáveis analisadas, relacionadas com o centro de pressão, foram a área elíptica do estatocinesigrama, a amplitude de deslocamento, a velocidade de deslocamento e a freqüência de oscilação. No ESTUDO II foram analisadas as variáveis da força de reação do solo na fase de apoio da marcha: tempo e valor do primeiro pico (P1), segundo pico (P2) e vale da componente vertical; tempo e valor máximo e mínimo encontrado na direção ântero-posterior da componente horizontal (max Fy/min Fy) e a diferença entre os valores máximo e mínimo na direção médiolateral do componente horizontal (max-min Fx). E no ESTUDO III foram utilizados dados dos dois primeiros estudos, acrescidos da avaliação da qualidade de vida das gestantes. Os resultados mostraram que, logo no início da gestação, o organismo feminino pareceu já sofrer adaptações no controle postural, provavelmente por fatores hormonais e, no decorrer dos trimestres, ocorreu uma tendência à redução da estabilidade postural. Comparadas ao grupo controle, as gestantes apresentaram maiores áreas, amplitudes e velocidades de deslocamento do centro de pressão, maior período de tempo na primeira fase de aceitação do peso, menores valores dos picos 1 e 2 da componente vertical e menores valores máximo e mínimo da componente horizontal ântero-posterior da força de reação do solo, possivelmente indicando uma redução na velocidade e na força de propulsão da marcha. Com relação à qualidade de vida, o domínio físico foi o mais afetado logo no primeiro trimestre, apresentando menores valores principalmente ao final da gestação.

This thesis provides insights to what is peculiar about a solar sail attitude and orbit control system and provides the assessment, in the form of a feasibility study, of the effectiveness of sail tip vanes as a control hardware to escape the Earth sphere of influence. The demonstrator aims to prove the technology for the Sunshade project, a constellation of solar sails located at the Lagrangian point L1 to obscure part of the solar radiation directed towards earth. Solar sailing poses a few fundamental challenges to spaceflight and it is a yet-to-be-proven branch of space engineering. Other tentative design exist but there is no standard to follow or off-the-shelf component that can be straightforward used. Moreover the scalability to the final project has to be accounted for in every step of the project.</p><p>The project is divided in a preliminary dimensioning, followed by a Simulink® based simulation which tests preliminary decisions. The simulation, performed on an orbit on the ecliptic plane, integrates models of Earth’s eclipse and environmental disturbance torques.  The escape time for a 100 m solar sail is found to be 1215 days, with a nonlinear PD control algorithm and sail tip vanes as the only control hardware. Attention is also posed on the consequence of a simplified sail film deformation in terms of centre of pressure to centre of mass off-set. / I detta examensarbete studeras vad som är speciellt med solsegels system för attityd- och bankontroll och ger en bedömning, i form av en möjlighetsstudie, av effektiviteten hos flöjlar som sätts på seglets hörn som kontrollhårdvara för att lämna jordens inflytelsesfär. Demonstratorn syftar till att bevisa tekniken för Sunshade-projektet, en konstellation av solsegel belägen vid lagrangepunkten L1 för att skugga en del av solstrålningen riktad mot jorden. Solsegling innebär några grundläggande utmaningar för rymdfärden och det är en ännu inte bevisad gren av rymdteknik. Annan preliminär design finns, men det finns ingen standard att följa eller standardkomponenter som enkelt kan användas. Dessutom måste skalbarheten till det slutliga projektet redovisas i varje steg i projektet.Projektet är uppdelat i en preliminär dimensionering, följt av en Simulink-baserad simulering som testar preliminära beslut. Simuleringen, utförd på en omloppsbana påekliptikan, integrerar modeller av jordens skugga och störningar av vridmoment från ett antal källor.Flykttiden för ett 100m solsegel blir 1215 dagar, med en icke-linjär PD kontrollalgoritm och segelhörnsflöjlar som den enda styrhårdvaran. Dessutom studeras förskjutningen av tryckcentrum i förhållande till masscentrum under en förenklad modell av segeldeformation.

The aim of this thesis was to investigate roller ski characteristics; classical and freestyle roller skis’ rolling resistance coefficients (μR) and classical style roller skis’ static friction coefficients (μS), and to study the influence of different μR and μS on cross-country skiers’ performance and both physiological and biomechanical indices. The aim was also to study differences in skiing economy and efficiency between recreational skiers, female and male junior and senior elite cross-country skiers.The experiments showed that during a time period of 30 minutes of rolling on a treadmill (warm-up), μR decreased significantly (p<0.05) to about 60-65 % and 70-75 % of its initial value for freestyle and classical roller skis respectively. Also, there was a significant influence of normal force on μR, while different velocities and inclinations of the treadmill only resulted in small changes in μR.The study of the influence on physiological variables of a ~50 % change in μR showed that during submaximal steady rate exercise, external power, oxygen uptake, heart rate and blood lactate were significantly changed, while there were non-significant or only small changes to cycle rate, cycle length and ratings of perceived exertion. Incremental maximal tests showed that time to exhaustion was significantly changed and this occurred without a change in maximal power, maximal oxygen uptake, maximal heart rate and blood lactate, and that the influence on ratings of perceived exertion was non-significant or small.The study of classical style roller skis μS showed values that were five to eight times more than the values of μS reported from on-snow skiing with grip-waxed cross-country skis.The subsequent physiological and biomechanical experiments with different μS showed a significantly lower skiing economy (~14 % higher v̇O2), higher heart rate, lower propulsive forces coming from the legs and shorter time to exhaustion (~30 %) when using a different type of roller ski with a μS similar to on-snow skiing, while there was no difference between tests when using different pairs of roller skis with a (similar) higher μS.The part of the thesis which focused on skiing economy and efficiency as a function of skill, age and gender, showed that the elite cross-country skiers had better skiing economy and higher gross efficiency (5-18 %) compared with the recreational skiers, and the senior elite had better economy and higher efficiency (4-5 %) than their junior counterparts, while no differences could be found between the genders. / Syftet med denna avhandling var att undersöka fristils- och klassiska rullskidors rullmotståndskoefficienter (μR) och klassiska rullskidors statiska friktionskoefficienter (μS) samt effekter av olika μR och μS på längdskidåkares prestation vid rullskidåkning på rullande band. Syftet var även att undersöka s.k. åkekonomi och mekanisk verkningsgrad mellan motionärer och kvinnliga och manliga junior- och seniorlängdskidåkare på elitnivå.Experimenten visade att under en period av 30 minuters kontinuerligt rullande, på rullande band, så sjönk μR signifikant (p<0.05) till 60-65 % och 70-75 % av initiala värden, för fristils- respektive klassiska rullskidor. Undersökandet av olika normalkrafter, hastigheter och lutningars påverkan på μR resulterade i en signifikant, negativ korrelation för μR som funktion av normalkraft, medan olika hastigheter och lutningar endast medförde små förändringar av μR.Studien som undersökte fysiologiska effekter av olika μR visade, vid submaximala konstanta arbetsbelastningar, att yttre effekt, syreupptagning, hjärtfrekvens och blodlaktat förändrades signifikant vid ~50 % förändring av μR. Försökspersonernas frekvens och sträcka per frekvens samt skattning av upplevd ansträngning resulterade dock i mestadels icke signifikanta eller små förändringar. Protokollen med successivt ökande arbetsbelastning (maxtest) resulterade i signifikant förändrad tid till utmattning, vid ~50 % förändring av μR. Detta inträffade utan signifikant skillnad i maximal syreupptagning, hjärtfrekvens och blodlaktat, vilket även mestadels gällde för skattning av upplevd ansträngning.Experimenten som undersökte klassiska rullskidors μS visade att dessa erhöll värden som är fem till åtta gånger högre än vad som rapporterats från studier av μS på snö med fästvallade skidor.Den efterföljande studien som undersökte fysiologiska och biomekaniska influenser av olika μS visade, vid submaximala konstanta arbetsbelastningar, att åkekonomin försämrades (~14 % högre syreförbrukning), hjärtfrekvensen ökade, den framåtdrivande kraften från benen på rullskidorna minskade samt att det blev kortare tid till utmattning (~30 %), vid maxtest, när skidåkarna använde rullskidor med en μS i likhet med vad som rapporterats för skidåkning på snö. För arbetsförsöken med olika rullskidor av olika fabrikat med en högre, och likartad, μS förelåg ingen skillnad i de undersökta variablerna.Studien som undersökte åkekonomi och mekanisk verkningsgrad som funktion av prestationsnivå, ålder och kön, visade att elitskidåkarna hade bättre åkekonomi och verkningsgrad (5-18 %) i jämförelse med motionärerna, att seniorerna hade bättre åkekonomi och verkningsgrad (4-5 %) än juniorerna och att ingen skillnad kunde konstateras mellan könen.

In children, joint hypermobility (typified by structural instability of joints) manifests clinically as neuro-muscular and musculo-skeletal conditions and conditions associated with development and organization of control of posture and gait (Finkelstein, 1916; Jahss, 1919; Sobel, 1926; Larsson, Mudholkar, Baum and Srivastava, 1995; Murray and Woo, 2001; Hakim and Grahame, 2003; Adib, Davies, Grahame, Woo and Murray, 2005:). The process of control of the relative proportions of joint mobility and stability, whilst maintaining equilibrium in standing posture and gait, is dependent upon the complex interrelationship between skeletal, muscular and neurological function (Massion, 1998; Gurfinkel, Ivanenko, Levik and Babakova, 1995; Shumway-Cook and Woollacott, 1995). The efficiency of this relies upon the integrity of neuro-muscular and musculo-skeletal components (ligaments, muscles, nerves), and the Central Nervous System’s capacity to interpret, process and integrate sensory information from visual, vestibular and proprioceptive sources (Crotts, Thompson, Nahom, Ryan and Newton, 1996; Riemann, Guskiewicz and Shields, 1999; Schmitz and Arnold, 1998) and development and incorporation of this into a representational scheme (postural reference frame) of body orientation with respect to internal and external environments (Gurfinkel et al., 1995; Roll and Roll, 1988). Sensory information from the base of support (feet) makes significant contribution to the development of reference frameworks (Kavounoudias, Roll and Roll, 1998). Problems with the structure and/ or function of any one, or combination of these components or systems, may result in partial loss of equilibrium and, therefore ineffectiveness or significant reduction in the capacity to interact with the environment, which may result in disability and/ or injury (Crotts et al., 1996; Rozzi, Lephart, Sterner and Kuligowski, 1999b). Whilst literature focusing upon clinical associations between joint hypermobility and conditions requiring therapeutic intervention has been abundant (Crego and Ford, 1952; Powell and Cantab, 1983; Dockery, in Jay, 1999; Grahame, 1971; Childs, 1986; Barton, Bird, Lindsay, Newton and Wright, 1995a; Rozzi, et al., 1999b; Kerr, Macmillan, Uttley and Luqmani, 2000; Grahame, 2001), there has been a deficit in controlled studies in which the neuro-muscular and musculo-skeletal characteristics of children with joint hypermobility have been quantified and considered within the context of organization of postural control in standing balance and gait. This was the aim of this project, undertaken as three studies. The major study (Study One) compared the fundamental neuro-muscular and musculo-skeletal characteristics of 15 children with joint hypermobility, and 15 age (8 and 9 years), gender, height and weight matched non-hypermobile controls. Significant differences were identified between previously undiagnosed hypermobile (n=15) and non-hypermobile children (n=15) in passive joint ranges of motion of the lower limbs and lumbar spine, muscle tone of the lower leg and foot, barefoot CoP displacement and in parameters of barefoot gait. Clinically relevant differences were also noted in barefoot single leg balance time. There were no differences between groups in isometric muscle strength in ankle dorsiflexion, knee flexion or extension. The second comparative study investigated foot morphology in non-weight bearing and weight bearing load conditions of the same children with and without joint hypermobility using three dimensional images (plaster casts) of their feet. The preliminary phase of this study evaluated the casting technique against direct measures of foot length, forefoot width, RCSP and forefoot to rearfoot angle. Results indicated accurate representation of elementary foot morphology within the plaster images. The comparative study examined the between and within group differences in measures of foot length and width, and in measures above the support surface (heel inclination angle, forefoot to rearfoot angle, normalized arch height, height of the widest point of the heel) in the two load conditions. Results of measures from plaster images identified that hypermobile children have different barefoot weight bearing foot morphology above the support surface than non-hypermobile children, despite no differences in measures of foot length or width. Based upon the differences in components of control of posture and gait in the hypermobile group, identified in Study One and Study Two, the final study (Study Three), using the same subjects, tested the immediate effect of specifically designed custom-made foot orthoses upon balance and gait of hypermobile children. The design of the orthoses was evaluated against the direct measures and the measures from plaster images of the feet. This ascertained the differences in morphology of the modified casts used to mould the orthoses and the original image of the foot. The orthoses were fitted into standardized running shoes. The effect of the shoe alone was tested upon the non-hypermobile children as the non-therapeutic equivalent condition. Immediate improvement in balance was noted in single leg stance and CoP displacement in the hypermobile group together with significant immediate improvement in the percentage of gait phases and in the percentage of the gait cycle at which maximum plantar flexion of the ankle occurred in gait. The neuro-muscular and musculo-skeletal characteristics of children with joint hypermobility are different from those of non-hypermobile children. The Beighton, Solomon and Soskolne (1973) screening criteria successfully classified joint hypermobility in children. As a result of this study joint hypermobility has been identified as a variable which must be controlled in studies of foot morphology and function in children. The outcomes of this study provide a basis upon which to further explore the association between joint hypermobility and neuro-muscular and musculo-skeletal conditions, and, have relevance for the physical education of children with joint hypermobility, for footwear and orthotic design processes, and, in particular, for clinical identification and treatment of children with joint hypermobility.

Title: Neurophysiologic intervention induced changes of the functional foot characteristics in school children. Objectives: The aim of the research was to identify the functional characteristics of the foot in school children selected on the basis of the activity of physical activity in the highest intensity (sporting children) and in the lowest intensity (non-sporting children) and to find out possibilities of influencing the functional characteristics of the foot by targeted neurophysiological intervention. The whole research study was divided into 3 related parts, which were examined separately. The first study aim was an identification of group specific functional characteristics of the foot in 2 groups of school children - actively sporting children and non-sporting children. The second study aim was the influence determination of long-term duration high performance sport activity on the functional characteristics of the school children foot in adolescent elite soccer players. And the aim of the third study was to verify the effect of the targeted neurophysiologic active intervention on the functional foot characteristics in actively sporting children with foot dysfunction of pronated foot and/or flatfoot type. Methods: The research study was divided into three study parts consisted of...