ix Flexibility has traditionally been considered an important component of human physical fitness but this conjecture lacks supporting empirical evidence. While there is extensive published research examining the relative importance of flexibility and the impact of various methods of stretching on levels of flexibility, performance and injury risk, the quality of studies has varied considerably, reliability and validity of methodology has not always been proven, and rationale has at times been questionable. Additionally, much literature has focused on static flexibility which is not necessarily related to properties of the musculotendinous unit and thus dynamic flexibility. This thesis was designed to fill gaps in the existing literature by using accepted methods to establish relative and absolute reliability of hamstring flexibility tests, consider the comparability of static and dynamic components of the global concept of flexibility and explore how dynamic flexibility and performance are influenced by fatiguing exercise and subsequent static stretching. The first aim was realised by a repeated measures study designed to establish the intraday and interday, intrarater reliability and measurement error of static and dynamic measures of hamstring flexibility. Significant relative reliability for measures of static and dynamic hamstring flexibility was demonstrated via intraclass correlation coefficient (3,1) but limits of agreement analysis indicated there was a degree of absolute measurement error that must be interpreted in relation to analytical goals. The second aim required evaluation of relationships shared by static and dynamic measures of hamstring flexibility. Significant relationships between the different static flexibility tests were established but the extent of unexplained variance indicated that only measurements from the same tests should be directly compared to each other. Relationships between different measures of dynamic flexibility and static flexibility varied from non-significant to moderately strong, suggesting that measures of static and dynamic flexibility are not identical and results should not be interchanged between the two types of tests. Due to a lack of explanatory empirical evidence, the final chapter aimed via a prospective randomised repeated measures study to investigate the impact of fatigue and post-exercise static stretching on measures of dynamic flexibility and performance. Fatigue resulted in no significant changes to passive or active dynamic flexibility measures but a significant worsening of static flexibility levels and perceived stiffness. Post-exercise stretch resulted in significantly increased passive and active energy absorption immediately and 18 hours post-exercise and in significantly reduced joint position sense immediately post-exercise. Effect sizes were small so the clinical meaningfulness of performing post-exercise static stretching is questionable, particularly if performed in place of other, potentially more beneficial practices. / Thesis (DPhil)--University of Pretoria, 2013. / gm2014 / Biokinetics, Sport and Leisure Sciences / unrestricted

Title: Influence of a complex stretching exercise of lower limb on postural stability Objectives:: The main objective of this diploma these is to find out, using dynamic computerized posturography, whether the increased mobility of the lower limbs has a positive influence on postural stability. Another partial objective is to determine efficiency of the practised stretching exercises. Methods: This is a pilot study where in research participated five probands whose measurement results were evaluated qualitatively. The aged of probands at the time of the first measurement was from 13 to 18 years. All probands are male volleyball league players and during the last two years occurred to a marked grow by all of them. Given their tall stature, it was expected a decrease in the mobility of the lower limbs and muscle shortening. To the data acquisition was used clinical examination of active range of motion and shortened muscle testing according to Janda. Postural stability was measured using computerized dynamic posturography SMART EquiTest System from Neurocom. Measured data were processed using the program NeuroCom Balance Manager software. In the Framework of study were conducted two intrumental measurements in the range of two months. After the first measurement all probands were instructed how to...

Title: Acute effect of a warm-up on the force of a punch Objectives: The aim of this diploma thesis is to test whether a warm-up before a performance affects the force of a punch at a sample participants practicing full-contact combat sports. Further goal is to analyze a change in the force of a punch depending on elapsed time after warming up. Methods: Each participant in this experimental study with intra-subject design went through all phases of the measurement, where the force of a punch was tested in four specified times (before a warm-up and then 4, 10 and 25 minutes after the warm-up). Results: No statistically significant effect of a warm-up on the force of a punch was observed, nor was there a statistically significant change in the force of a punch during the time following a warm-up. However, a warm-up did have a significant effect on change in heart rate and body temperature. Keywords: Combat sports, performance, fight, dynamic stretching, explosive power, punch sensor

Title: Assessing the importance of stretching among women floorball players and its impact on shortened muscles Objectives: The main goal of the diploma thesis was to determine the functional state of the muscular system and the rate of shortened muscles in a selected group of women in the age range from 18 to 34 years old in the floorball club Banes Florbal Soběslav playing the 1st woman's league. Based on the examination, a set of specific stretching exercises was created and subsequently their effect was verified. The partial goal was to find out the level of stretching before and after the training unit or match using an online questionnaire for players playing in the 1st woman's league. Methods: The diploma thesis was processed as an experimental study. The research involved 16 probands who have been actively involved in floorball for at least 5 years. The research group was equally divided into experimental and contol groups. To obtain the data, a standardized test of shortened muscles according to Janda and palpation examination of trigger points were used. Entrance and exit tests of both groups were performed at intervals of 3 months. During this period the experimental group completed an intervention program. There was no intervention in the control group. An online questionnaire sent via...

The overall goal of this investigation was to elucidate specific structure-property relationships in perfluorosulfonate ionomers (PFSIs)-related materials. The project can be broken into two primary foci. First, we explored the current state of understanding related to morphology-property relationships in PFSIs with specific attention to the nano-scale organization of the ionic and crystalline domains. Specifically, the effect of uniaxial orientation on the structure and transport properties of Nafion® membranes was examined. Small angle X-ray scattering (SAXS) experiments on dry membranes that were uniaxially elongated showed a strong anisotropic morphology which was shown to persist over the swelling process without a significant relaxation. Herman's order parameters for the ionomer peak were strongly influenced by uniaxial deformation, which supports the presence of cylindrical rather than spherical morphology for ionic domains. Comparison of the water diffusion coefficients between unoriented and oriented samples revealed that uniaxial deformation of Nafion® membranes essentially enhances transport ability in one direction (i.e., the parallel to draw direction) and suppresses in the other two directions (i.e., two orthogonal directions relative to the stretching direction). Based on 1-dimensional analyses of oriented SAXS patterns at the azimuthal angle 90o, three recent models (lamellar model, semicrystalline rod-like model and fringed-micelle model) for the morphology of PFSIs were critically evaluated. The loss of meridional scattering, different orientation behavior of the crystalline and ionic domains, and inherent chain stiffness precludes the possibility of a chain-folded lamellar morphology. While the inter-aggregate dimensions remain constant at high draw ratios, the inter-crystalline spacings decrease significantly. Coupled with the distinctly different orientation behavior, these observations preclude the existence of crystallites solely within rod-like aggregates. While the worm-like ionic channel model was able to explain the behavior of SAXS and wide angle X-ray scattering (WAXS) relatively well, this model also had limitations such as (1) crystalline domains directly linked to the ionic domain (and thus a lack of amorphous domains) and (2) a presence of only a single ionic channel between two neighboring crystallites. Second, electroactive materials, specifically ionic polymer-metal composites (IPMCs) that undergo bending motions with the stimulus of a relatively weak electric field were fabricated. To understand the role of the nanoscale morphology of the membrane matrix in affecting the actuation behavior of IPMC systems, we evaluated actuation performance of IPMCs subjected to uniaxial orientation. The PFSI nanostructure altered by uniaxial orientation mimicked the fibrillar structure of biological muscle tissue and yielded a new anisotropic actuation response. It was evident that IPMCs cut from films oriented perpendicular to the draw direction yielded displacement values that were significantly greater than that of unoriented IPMCs. In contrast, IPMCs cut from films oriented parallel to the draw direction appeared to resist bending and yield displacement values that were much less than that of the unoriented IPMC. This anisotropic actuation behavior was attributed to the contribution of the nanoscale morphology to the bulk bending modulus. Overall, this study clearly demonstrated, for the first time, the importance of the nanoscale morphology in affecting/controlling the actuation behavior in IPMC systems. / Ph. D.

Osteoarthritis is an inflammation-related disease that progressively destroys joint cartilage. This disease causes pain and stiffness of the joints, and at advanced stages, limitations to the movement or bending of injured joints. Therefore, it often restricts daily activities and the ability to work. Currently, there is no cure to prevent its progression, although certain damaged joints, such as fingers, knees and hips, can be treated with joint replacement surgeries. However, joint replacement surgeries of larger joints are very invasive operations and the joint replacements have a limited lifetime. Cell-based therapies could offer a way to treat cartilage injuries before the ultimate damage of osteoarthritis on articular cartilage. The development of novel treatments needs both a good knowledge of articular cartilage biology and tissue engineering methods. This thesis primarily investigates the effects of mechanical cyclic stretching, a 5% low oxygen atmosphere and the Rho-kinase inhibitor, Y-27632, on protein responses in chondrocytic human chondrosarcoma (HCS-2/8) cells. Special focus is placed on Rho-kinase inhibition, relating to its potential to promote and support extracellular matrix production in cultured chondrocytes and its role in fibroblast cells as a part of direct chemical cellular differentiation. The means to enhance the production of cartilage-specific extracellular matrix is needed for cell-based tissue engineering applications, since cultured chondrocytes quickly lose their cartilage-specific phenotype. A mechanical 8% cyclic cell stretching at a 1 Hz frequency was used to model a stretching rhythm similar to walking. The cellular stretching relates to stresses, which are directed to chondrocytes during the mechanical load. The stretch induced changes in proteins related, e.g., to certain cytoskeletal proteins, but also in enzymes associated with protein synthesis, such as eukaryotic elongation factors 1-beta and 1-delta. Hypoxic conditions were used to model the oxygen tension present in healthy cartilage tissue. Long-term hypoxia changed relative amounts in a total of 44 proteins and induced gene expressions of aggrecan and type II collagen, in addition to chondrocyte differentiation markers S100A1 and S100B. A short-term inhibition of Rho-kinase failed to induce extracellular matrix production in fibroblasts or in HCS-2/8 cells, while its long-term exposure increased the expressions of chondrocyte-specific genes and differentiation markers, and also promoted the synthesis of sulfated glycosaminoglycans by chondrocytic cells. Interestingly, Rho kinase inhibition under hypoxic conditions produced a more effective increase in chondrocyte-specific gene expression and synthesis of extracellular matrix components by HCS-2/8 cells. The treatment induced changes in the synthesis of 101 proteins and ELISA analysis revealed a sixfold higher secretion of type II collagen compared to control cells. The secretion of sulfated glycosaminoglycans was simultaneously increased by 65.8%. Thus, Rho-kinase inhibition at low oxygen tension can be regarded as a potential way to enhance extracellular matrix production and maintain a chondrocyte phenotype in cell-based tissue engineering applications.

Fascial tissues form a continuous whole-body three-dimensional network penetrating all parts of the human body. They include all fibrous connective tissue that significantly contributes both to themaintaining of the integrity of the organism and the functioning of body systems and the somesthetic perception.That is because of the facia is richly populated by proprioceptiveand mechanosensitive nociceptive nerve endings. Although the stretching is a routine method used in sports and rehabilitation, its exact mechanism of influence and effects on the body are not fully understood so far. Stretching exercises affect the mechanical state of the myofascial tissues and also the quality of the nociception and proprioception by alteration of their preload. There is evidence about some differences of the mechanical properties of the tissuesboth between thesexes and hypermobile individuals. The theses assesses the effect of static stretching m. QF on the somesthetic perception by measuring pressure pain threshold (PPT) using pressure algometry and the quality of propcioception bygoniometric measurement considering the interindividual variance in quality of the connective tissues. Our research includes testing of 29 healthy subjects (14 women and 15 men) and it has proved significant impact of the intervention on the...

Title Influence of dynamic and static warm-up on muscle strength in climbers. Objective The aim of the thesis is to assess the influence of dynamic warm-up with Thera-Band and static stretching on maximal muscle strength and its time parameters of finger flexors in dominant upper extremity in climbers. Methods Eight active climbers participated in this testing (age 32.4 ± 5.5, body weight 69.4 ± 6.5, height 176 ± 6.4). Actual performance RP was according to the French scale ranging 6b to 8a. Probands' measurements proceeded in three different days. After a specific warm-up on "boulder wall" and static stretching and dynamic warm-up with Thera-Band without stretching, there was maximal muscle strength of fingers flexors on dominant (preferred) upper limb measured by using a specific climbing test on hangboard. The second measurement assessed maximal strength of finger flexors muscle and its time parameters while proceeding of the maximum hand-grip using a hand dynamometer. Results In the experiment, none of the hypotheses came to be confirmed. There was no significant influence of static stretching and dynamic warm-up with Thera-Band on maximal muscle strength of finger flexors and the time parameters in climbers. Conclusion Despite the failure to prove the influence of the static stretching and...

Objetivo: Investigar o efeito da laserterapia de baixa intensidade (LBI) e do alongamento estático, combinados ou não, em pessoas com osteoartrite de joelho (OAJ). Método: Foram randomizados 145 sujeitos de 50 a 75 anos com OAJ em cinco grupos de intervenção (n=29 cada): Laserativo+Along; Laserplacebo+Along; Along; Laserativo e controle. A laserterapia (GaAs; 904nm; 40mW; 3J/ponto; 27J/joelho) consistiu de nove sessões nos grupos de terapia combinada e 24 quando monoterapia. O alongamento foi composto por sete exercícios repetidos por 24 sessões. O controle recebeu uma cartilha educacional. A frequência de tratamento foi de 3x/sem. A variável primária foi a intensidade da dor medida pela Escala Visual Analógica e as variáveis secundárias incluídas foram domínios dor, função, rigidez e escore total do questionário Western Ontario and McMaster Universities Arthritis Index (WOMAC), funcionalidade avaliado pelo Lequesne, mobilidade pelo Timed Up and Go, amplitude de movimento do joelho (ADMJ) pela goniometria e encurtamento de isquiotibiais (IQT) pelo ângulo poplíteo. O nível de significância foi de ?=0,05. Resultados: Nos grupos de terapia combinada, não foi observada diferença entre o laser ativo e placebo (p>0,05). Ao final do estudo, os grupos demonstraram, em média, ganho relativo significativo na dor durante AVDs (50%), WOMAC total (39%), funcionalidade (30%) e mobilidade (20%) em comparação ao controle (p < 0,001). Houve melhora de 43% no encurtamento de IQT e de 9% no ganho de ADMJ nos grupos de terapia combinada em relação ao controle (p < 0,001 e p=0,02, respectivamente). Conclusão: LBI e alongamento estático, quando isolados, foram efetivos na melhora da dor, funcionalidade, mobilidade e nos domínios dor, função e escore total do WOMAC. A LBI nos grupos de terapia combinada não foi superior à aplicação placebo. Portanto, não devemos desconsiderar a contribuição do efeito placebo no resultado do tratamento isolado. A LBI combinada ao alongamento não promoveu benefícios adicionais em relação ao alongamento de forma isolada / Objective: To investigate the effect of low-level laser therapy (LLLT) and static stretching, in combination and as monotherapy, in people with knee osteoarthritis (KOA). Methods: 145 people aged 50-75 years with KOA were randomly allocated to five groups (each n=29): Laseractive+Stretch, Laserplacebo+Stretch, Stretch, Laseractive and control. The laser therapy (GaAs; 904nm; 40mW; 3J/point; 27J/knee) consisted of nine sessions in the combined treatment groups and 24 when used as monotherapy. Stretching consisted of seven exercises repeated for 24 sessions. The control group received an educational booklet. Treatment frequency was 3 times/week. The primary outcome was pain intensity measured by Visual Analogue Scale and the secondary outcomes included pain, function and stiffness\' domains and total score of Western Ontario and McMaster Universities Arthritis Index (WOMAC), function assessed by Lequesne, mobility by Timed Up and Go, knee range of motion (KROM) by goniometry and hamstring shortening by popliteal angle. Results: In the combined treatment groups, there was no difference between the laser active and placebo (p > 0.05). At the end of the study, the treatment groups demonstrated, on average, a significant relative gain in pain (50%), total WOMAC (39%), function (30%) and mobility (20%) when compared to control (p < .001). For the combined treatment groups there was a 43% improvement in hamstring shortening (p <.001) and 9% improvement in KROM (p=0.02) when compared to control group. Conclusion: LLLT and stretching exercises, as monotherapy, were effective in reducing pain and improving function, mobility and the domains pain and function as well as the total score of WOMAC. The LLLT in the combined groups was not superior to the placebo application. Thus, we should not discard the contribution of the placebo effect in the result of the LLLT as monotherapy. The LLLT combined with stretching did not promote additional benefits compared to stretching alone

A instabilidade articular é responsável pelo desenvolvimento de lesões degenerativas incapacitantes que comprometem o desempenho funcional. Compreender os processos desenvolvidos para estabilização dinâmica articular é um desafio para pesquisadores das mais diversas áreas. O presente estudo propõe o uso da abordagem Biomecânica para reconhecer os mecanismos relacionadas ao processo de estabilização dinâmica articular, por meio de três diferentes condições experimentais. No experimento 1 foi analisada a Força de Reação do Solo (FRS) e a cinemática 3-D no andar, correr e saltar de portadores (n=10) e não portadores de instabilidade crônica (n=10) do tornozelo. No experimento 2 foi analisada a Eletromiografia dos músculos tibial anterior, fibular longo, fibular curto e gastrocnêmio lateral de portadores (n=14) e não portadores de instabilidade crônica (n=14) do tornozelo antes e após um protocolo de indução à fadiga muscular. No experimento 3 (n=20) foi analisado o efeito do exercício de alongamento muscular estático passivo dos músculos fibular longo e fibular curto na simulação da entorse do tornozelo. Nos protocolos de locomoção foram encontrados no lado acometido picos tardios e aumento dos Impulsos da FRS. No início da fase de apoio o tornozelo instável no andar aumentou a dorsiflexão, no correr aumentou a eversão e no saltar diminuiu a inversão e aumentou a dorsiflexão. Tais estratégias representam a tentativa de melhorar a estabilidade dinâmica articular. No entanto, a variação angular da articulação no plano sagital e frontal aumentaram, sugerindo que há mais amplitude de movimento no tornozelo acometido e maior estresse sobre os estabilizadores passivos locais. Em condições de fadiga muscular, após simulação da entorse, indivíduos com articulações saudáveis aumentam a rigidez articular e a intensidade de contração dos eversores do tornozelo, antecipadamente a perturbação, diferente de portadores de instabilidade crônica. A execução do exercício de alongamento dos músculos fibulares longo e curto, seguido da simulação da entorse, gerou o retardo da resposta motora e diminuição da intensidade de ativação. Desta forma, as estratégias desenvolvidas por portadores de instabilidade crônica podem ser relacionadas à causa e/ou consequência do quadro, a fadiga muscular altera o desenvolvimento de estratégias de proteção e o exercício de alongamento pode prejudicar a estabilização dinâmica articular / Joint instability is associated with degenerating injuries that lead to functional incapacitation. Knowing the process involved in joint dynamic stabilization is a challenge to researchers in many fields. This study proposes the use of a biomechanical approach to recognize the mechanisms involved in joint stabilization through three different experimental conditions. The first experiment analyzed the Ground Reaction Force (GRF) and the 3D kinematics in participants with (n=10) and without (n=10) chronic ankle instability during walking, running and jumping. The second experiment analyzed the Electromyography signal of tibialis anterior, peroneus longus, peroneus brevis e gastrocnemius lateralis in participants with (n=14) and without (n=14) chronic ankle instability before and after a muscle fatigue protocol. The third experiment (n=20) analyzed the effect of static passive stretching of peroneus longus and peroneus brevis muscles on the ankle sprain simulation. During the locomotion protocols the injured side showed late peaks and an increase of the GRF impulses. The instable ankle showed an increase of dorsiflexion during the initial phase of gait and an increase of eversion during running. The instable ankle also showed a decrease of inversion and an increase of dorsiflexion during jumping. These strategies represent an attempt to improve the joint dynamic stability. There was an increase in sagittal and frontal angular displacement, suggesting more range of motion as well as more stress in the passive structures that are responsible for stabilization in the injured ankle. During muscular fatigue, after an ankle sprain simulation, subjects with healthy joints increase the joint stiffness and the intensity of the ankle eversion muscles activation, before the intervention, differently from subjects with chronic instability. The peroneus longus and brevis stretching exercise followed by the ankle sprain simulation caused a delay on the motor response and a decrease in the activation intensity. The strategies developed by the subjects with chronic instability can be related to the cause and/or the consequence of the dysfunction. The muscular fatigue changes the development of strategies of protection and the stretching exercise can weaken the dynamic stability of the joint