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Introduction: Several authors have demonstrated that, while cycling at a constant power output, EMG activity from the gastrocnemius increases systematically with increases in pedaling cadence, but that soleus EMG remains unchanged (Marsh & Martin 1995; Sanderson et al. 2006). The reason for this differential effect of cadence on the muscles of the triceps surae is unclear. Whatever factor(s) are responsible, it is assumed that, as they vary, the differential electromyographic response will vary accordingly. Decreasing the seat height has been shown to alter the kinematic characteristics of cycling (Too, 1990). The first objective of this study was to examine the effect of a decrease in seat height on the kinematics and muscle activation of the lower limb. The second objective was to investigate the effect of seat height on the relationship between cadence and triceps surae activation and, in doing so, to reveal possible factors mediating the response to changes in cadence. Methods: Participants pedaled a cycle ergometer at 200 Watts for five minutes at each of five cadences (50, 65, 80, 95, 110 rpm) and at each of two seat heights (100% and 90% trochanteric height). Kinematics of the lower limb were calculated from digitized video records of reflective markers placed on the skin over seven bony landmarks. EMG data were collected from eight lower-limb muscles. Results: The most notable findings were 1) that activation of the gastrocnemii was less in the low-seat condition and, contrary to what the findings of past research would suggest, was not associated with changes in muscle length; 2) that the medial and lateral gastrocnemii responded differently to changes in cadence at each seat height, suggesting that the functional roles of these muscles in cycling differ; 3) that several factors, including muscle length, muscle velocity, ankle angle and the direction of muscle action, were not responsible for the differential effect of cadence on activation of the soleus and gastrocnemius. Future research should investigate afferent feedback from proprioceptors in the knee joint and knee extensor muscles as possible factors mediating the effect.

Introduction: Several authors have demonstrated that, while cycling at a constant power output, EMG activity from the gastrocnemius increases systematically with increases in pedaling cadence, but that soleus EMG remains unchanged (Marsh & Martin 1995; Sanderson et al. 2006). The reason for this differential effect of cadence on the muscles of the triceps surae is unclear. Whatever factor(s) are responsible, it is assumed that, as they vary, the differential electromyographic response will vary accordingly. Decreasing the seat height has been shown to alter the kinematic characteristics of cycling (Too, 1990). The first objective of this study was to examine the effect of a decrease in seat height on the kinematics and muscle activation of the lower limb. The second objective was to investigate the effect of seat height on the relationship between cadence and triceps surae activation and, in doing so, to reveal possible factors mediating the response to changes in cadence. Methods: Participants pedaled a cycle ergometer at 200 Watts for five minutes at each of five cadences (50, 65, 80, 95, 110 rpm) and at each of two seat heights (100% and 90% trochanteric height). Kinematics of the lower limb were calculated from digitized video records of reflective markers placed on the skin over seven bony landmarks. EMG data were collected from eight lower-limb muscles. Results: The most notable findings were 1) that activation of the gastrocnemii was less in the low-seat condition and, contrary to what the findings of past research would suggest, was not associated with changes in muscle length; 2) that the medial and lateral gastrocnemii responded differently to changes in cadence at each seat height, suggesting that the functional roles of these muscles in cycling differ; 3) that several factors, including muscle length, muscle velocity, ankle angle and the direction of muscle action, were not responsible for the differential effect of cadence on activation of the soleus and gastrocnemius. Future research should investigate afferent feedback from proprioceptors in the knee joint and knee extensor muscles as possible factors mediating the effect.

Introduction: Several authors have demonstrated that, while cycling at a constant power output, EMG activity from the gastrocnemius increases systematically with increases in pedaling cadence, but that soleus EMG remains unchanged (Marsh & Martin 1995; Sanderson et al. 2006). The reason for this differential effect of cadence on the muscles of the triceps surae is unclear. Whatever factor(s) are responsible, it is assumed that, as they vary, the differential electromyographic response will vary accordingly. Decreasing the seat height has been shown to alter the kinematic characteristics of cycling (Too, 1990). The first objective of this study was to examine the effect of a decrease in seat height on the kinematics and muscle activation of the lower limb. The second objective was to investigate the effect of seat height on the relationship between cadence and triceps surae activation and, in doing so, to reveal possible factors mediating the response to changes in cadence. Methods: Participants pedaled a cycle ergometer at 200 Watts for five minutes at each of five cadences (50, 65, 80, 95, 110 rpm) and at each of two seat heights (100% and 90% trochanteric height). Kinematics of the lower limb were calculated from digitized video records of reflective markers placed on the skin over seven bony landmarks. EMG data were collected from eight lower-limb muscles. Results: The most notable findings were 1) that activation of the gastrocnemii was less in the low-seat condition and, contrary to what the findings of past research would suggest, was not associated with changes in muscle length; 2) that the medial and lateral gastrocnemii responded differently to changes in cadence at each seat height, suggesting that the functional roles of these muscles in cycling differ; 3) that several factors, including muscle length, muscle velocity, ankle angle and the direction of muscle action, were not responsible for the differential effect of cadence on activation of the soleus and gastrocnemius. Future research should investigate afferent feedback from proprioceptors in the knee joint and knee extensor muscles as possible factors mediating the effect. / Education, Faculty of / Kinesiology, School of / Graduate

JAKE J. PORTER III The association of subscapular and triceps skin-fold thickness with the risk of Diabetes in African American, Hispanic, and Caucasian Adults (Under the direction of IKE S. OKOSUN, Ph.D.) Background: Studies linking adiposity with chronic morbidity are often restricted to obesity defined by body mass index and/or waist circumference. Few studies have examined the relationship between adiposity defined using body habitus and chronic diseases. Objective: We examined the potential association of subscapular and triceps skin-fold thickness with the risk of diabetes in African American, Caucasian, and Hispanic American adults. Methods: Data (n=4,808) from The National Health and Nutrition Examination Survey were used. Multivariate logistic regression analysis was performed on each anthropometric measure. Statistical adjustments were made for several known covariates. Results: There were racial/ethnic differences in associations between subscapular and triceps skinfold thickness with type 2 diabetes. Conclusion: Skinfold thickness was associated with type 2 diabetes in White, Black and Hispanic Americans. Well designed public health strategies to enhance lifestyle modification programs to reduce weight gain may reduce aberrant fat distribution in these body regions and decreases in type 2 diabetes.

Wheelchair propulsion is an important part of daily living for many people with spinal cord injuries (SCI's). The aim of this project was to establish the validity of using a new approach for measuring wheelchair propulsion ability. The variation in methods observed by subject's hands in contacting and propelling their wheelchair, namely, using the push rims only; wedging the hands between push rims and tyre and grasping both push rims and tyres, highlighted that earlier studies using instrumented push rims (including the SMART ) for people with tetraplegia would not provide a true indication of propulsion ability for the participants in this study. As a result, a new inertia dynamometer was built and calibrated for measuring wheelchair propulsion ability. Kinetic and kinematic models were developed to calculate wheelchair propulsion parameters such as power output, wheelchair velocity and arm motion patterns. After testing 22 subjects with different SCI levels, the results indicated that arm function was a more important factor in wheelchair propulsion, in terms of power output, than trunk stability and strength. More importantly, people with C5/C6 tetraplegia had a significantly reduced capability in terms of wheelchair propulsion compared with other subjects with a lower lesion (T1-T8, T9-T12 and L1-S5). A further study for quantifying the contribution of triceps function on improving wheelchair propulsion for people with tetraplegia was performed by comparing kinetic and kinematics parameters in C5/C6 tetraplegia subjects. Depending on the control of elbow extension, the subjects were divided into groups with: no active elbow extension, deltoid to triceps transfer surgery (TROIDS) to provide elbow extension, and incomplete C5/C6 tetraplegia with retained active triceps function providing elbow extension. The results demonstrated that the restoration of triceps following TROIDS surgery not only allows active elbow extension, but also increased the amplitude and strength as well as the speed of arm movement. Finally, the results also point to TROIDS allowing a more pronounced and natural push phase and an improved arm movement pattern during both propulsion and recovery phase under normal and extreme conditions.

Submitted by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-01-05T12:45:29Z No. of bitstreams: 2 jorge_augusto_barroso.pdf: 605983 bytes, checksum: 4317652388abdb60186382b0434386ea (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-01-05T12:45:57Z (GMT) No. of bitstreams: 2 jorge_augusto_barroso.pdf: 605983 bytes, checksum: 4317652388abdb60186382b0434386ea (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) / Approved for entry into archive by Rodrigo Martins Cruz (rodrigo.cruz@ufvjm.edu.br) on 2015-01-05T12:46:36Z (GMT) No. of bitstreams: 2 jorge_augusto_barroso.pdf: 605983 bytes, checksum: 4317652388abdb60186382b0434386ea (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) / Made available in DSpace on 2015-01-05T12:46:36Z (GMT). No. of bitstreams: 2 jorge_augusto_barroso.pdf: 605983 bytes, checksum: 4317652388abdb60186382b0434386ea (MD5) license_rdf: 23898 bytes, checksum: e363e809996cf46ada20da1accfcd9c7 (MD5) Previous issue date: 2013 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior (CAPES) / Foram avaliados os Longissimus dorsi et lumborum (LTL), Semitendinosus (ST) e Triceps brachii (TB) obtidos de seis animais ?Guzer? ?Nelore ?Simmental (Tri), seis animais ?Guzer? ?Nelore (GN) e seis animais ?Guzer? ?Holand?s (GH), recriados a pasto com suplementa??o, terminados em confinamento de 82 dias e abatidos aos 24 meses. Foram mensurados o pH24horas, a capacidade de reten??o de ?gua, luminosidade (L*), teor de prote?na total, extrato et?reo, mat?ria seca, res?duo mineral fixo, teor de vermelho (a*), teor de amarelo (b*), croma (C*), matiz (H*), perdas de peso por cozimento, teor de col?geno total e sol?vel, ?ndice de fragmenta??o miofibrilar e for?a de cisalhamento. N?o houve efeito significativo (P>0,05) dos grupos gen?ticos sobre o pH24horas do LTL (5,64), do ST (5,72) e TB (5,85). Os valores de pH24horas do LTL, refer?ncia ? carca?a, estiveram dentro do intervalo de normalidade (5,3-5,7). Os grupos gen?ticos tamb?m n?o influenciaram, significativamente, o teor de extrato et?reo, os teores de prote?na e mat?ria seca, res?duo mineral fixo, teor de amarelo, o matiz, as perdas de peso por cozimento, o ?ndice de fragmenta??o miofibrilar, assim como o teor de col?geno total e sol?vel. A for?a de cisalhamento e a capacidade de reten??o de ?gua foram, no entanto, influenciados pelos grupos gen?ticos, observando maior maciez no grupo GH, em rela??o ao GN. A capacidade de reten??o de ?gua apresentou maiores valores para o grupo GN em rela??o ao grupo GH, o que n?o demonstrou impacto sobre as principais qualidades comerciais da carne. O teor de vermelho e o croma apresentaram intera??es entre os grupos gen?ticos e os m?sculos estudados, sendo a varia??o dentro do grupo GH, diferente dos demais grupos gen?ticos, apresentando valores menores no ST, em rela??o aos demais grupos gen?ticos, e, substancialmente, maiores valores no TB em rela??o aos demais m?sculos. Comparando-se as caracter?sticas entre os diferentes m?sculos, foram percebidas diferen?as significativas em todos os par?metros estudados, dentre elas a menor for?a de cisalhamento do TB, e tamb?m do ST em rela??o ao LTL. Tal fato talvez seja decorrente do maior teor de extrato et?reo, das menores perdas de peso por cozimento do TB e do maior ?ndice de fragmenta??o miofibrilar do TB e ST. Admite-se, tamb?m, que varia??es em par?metros, quando comparados LTL, ST e TB entre si, decorram de especificidades anat?micas e fisiol?gicas dos m?sculos que os originaram. Conclui-se que, os grupos gen?ticos apresentaram semelhan?a em quase todos os par?metros de qualidade estudados, demonstrando, por?m, menores valores de for?a de cisalhamento para o grupo GH. Foi tamb?m representativa a melhor qualidade do TB, medida por par?metros objetivos, em rela??o aos demais m?sculos estudados. / Disserta??o (Mestrado) ? Programa de P?s-Gradua??o em Zootecnia, Universidade Federal dos Vales do Jequitinhonha e Mucuri, 2013. / ABSTRACT Were tested Longissimus dorsi et lumborum (LTL), Semitendinosus (ST) e Triceps brachii (TB) obtained from six animals ?Guzer? ?Nellore ?Simmental (Tri), six animals ?Guzer? ?Nellore (GN) and six ?Guzer? ?Holstein (GH) recreated with pasture supplementation, 82 days in feedlot and slaughtered at 24 months. We measured the pH24hors, the ability to retain water, lightness (L*), total protein, ether extract, dry matter, fixed mineral residue, redness (a*), yellowness (b*), chroma (C*), hue (H*), cooking weight loss, total collagen and soluble, myofibrillar fragmentation index and shear force. There was no significant effect on pH 24hours (P> 0.05) between the genetic groups on the LTL (5.64), ST (5.72) and TB (5.85). The PH 24hours values of LTL, the reference substrate, were within the normal range (5.3 to 5.7). Genetic groups did not significantly influence the content of fat, the protein, dry matter and mineral, the yellowness, the hue, the weight losses by cooking, myofibrillar fragmentation index, as well as the content of total and soluble collagen. The shear force and the water retention capacity were influenced by genetic groups. The GH group was more tenderness than in the GN group. The capacity of water retention was higher in the GN group than in the GH group, which showed no impact on the main commercial qualities of meat. The content of red and chroma showed interactions among genetic groups and the muscles studied, and the variation in the GH group unlike other genetic groups had lower values in the ST and the other genetic groups had substantially higher values for TB compared to other muscles. Comparing the properties of the different muscles, significant differences were observed in all parameters studied, among them the lowest shear force of TB, and also the ST compared to LTL. This fact might be due to the higher content of fat, the less weight loss by cooking the TB and higher myofibrillar fragmentation index of TB and ST. Also it is assumed that variations in parameters when compared LTL, ST and TB among themselves, might be resulting of anatomical and physiological peculiarities of the muscles that originated them. We can conclude that the genetic groups were similar in almost all quality parameters studied, but lower values of shear force on the GH group. Also was relevant the best quality of TB, measured by objective parameters, compared to the other muscles studied.

Orientador: Mathias Vitti / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Odontologia de Piracicaba / Made available in DSpace on 2018-07-27T15:26:22Z (GMT). No. of bitstreams: 1 Verri_EdsonDonizetti_M.pdf: 2091762 bytes, checksum: 8d7b8fd3fff4ba87b179b020ea70d390 (MD5) Previous issue date: 2001 / Resumo: O objetivo deste trabalho foi estudar a influência dos músculos bíceps do braço (cabeças curta e longa), braquiorradial e tríceps do braço (cabeças lateral, longa e medial), na atividade flexora do antebraço em diferentes posições articulares do ombro. Foram testadas contrações isométricas de flexão do antebraço semipronado a 90° com flexão de ombro a 90°, ombro neutro e ombro a 90° de abdução. Foram estudados dez voluntários jovens, do sexo feminino, com idades de 20 a 30 anos, e destros. Todos os voluntários eram não treinados e sem história de doença neuromuscular ou articular. Os registros foram obtidos, utilizando-se um eletromiógrafo computadorizado modelo MCS - V2 da LynxElectronicsLtda. Com módulo condicionador de sinais de 16 canais, e placa A/D modelo CAD 12/36 da Lynx Electronics Ltda. de 12 bites de resolução de faixa dinâmica, filtro do tipo Butterworth, de passa-baixa de 509 Hz, de passa-alta de 10,6 Hz, ganho 10 vezes e freqüências de amostragem de 1.000 Hz; software Aqdados versão 4,16 da Lynx Electronics Ltda. para apresentação dos sinais de diferentes canais simultaneamente e tratamento do sinal (valor de RMS, média, mínimo, máximo, e desvio padrão). Os sinais eletromiográficos foram captados por eletrodos de superflcie ativos diferenciais de superfície (Lynx Electronics Ltda). Os valores de RMS obtidos foram submetidos à análise estatística no programa GraphPad InStat, versão 3,01, Free Demo. Os dados foram testados quando a normalidade de distribuição pelo teste de Kolmogorov-Smirnov, e as comparações entre as médias de RMS foram feitas pelos testes ANOVA e Kruskal-Wallis. A correlação de Pearson foi usada para estabelecer uma relação entre a força de contração registrada e o sinal eletromiográfico de cada um dos músculos estudados. Através destes testes, os resultados mostraram que nos músculos estudados, não houve diferenças estatísticas para a atividade eletromiográfica e força de contração isométrica causada pela variação do posicionamento articular do ombro. Os valores de correlação de Pearson mostraram, para os flexores do antebraço, maior correlação no posicionamento neutro do ombro, enquanto o valor médio de RMS do músculo tríceps foi mais correlacionado com a força registrada com a articulação do ombro posicionada em 90° de abdução. O músculo tríceps do braço age em cocontração para proteger e estabilizar as articulações do cotovelo e do ombro durante os registros da contração isométrica de flexão do antebraço em esforço máximo. A variação dos comprimentos dos músculos biarticulares não foi suficiente para alterar os níveis de força e do sinal eletromiográfico, nas contrações isométricas de flexão do antebraço, combinadas com a semipronação e as variações dos posicionamentos articulares do ombro, sugerindo uma maior contribuição destinada à estabilização das articulações do cotovelo e do ombro / Abstract: The purpose of this study was to analyze the influence of biceps raquialis, braquiorradial, and triceps braquialis on the flexon activity at different positions of the shoulder joint. It was observed the isometric semipronate elbow flexion contractions with anatomical position of the shoulder, 90° shoulder flexion and 90s houder abduction. Ten healthy female young volunteers, right-handed and no-trained were evaluate. The registers of electromyographic and force output were acquired by a 12 bit A/D converter board with a sample frequency of 1000 Hz, Butterworth filter with low-pass of 509 Hz and high-pass of 10,6 HZ (model CAD 12/36 of Lynx Electronics Ltda.), and gain of 1000 times. The Aqdados software 4.16 version (Lynx Electronics Ltda) was used to present and analyze the different signals simultaneously (RMS, mean, standard deviation, maximum, minimum values). The electromyographic signals were detected with a differential bipolar surface electrode (Lynx Electronics Ltda.) over the musc1ebelly placed between a motor point and the tendon insertion. The force output was measured with a load cell.In all trials, the load celI was positioned with it alignrnent perpendicular to the limb. The RMS and force mean values were statisticalIy evaluated by the GraphPad InStar, 3,01 Free Demo version. The data were tested with Kolmogorov-Smimov normal distribution test, and the mean RMS and force comparison were performed by ANOVA and Kruskal-Wallis tests. The Pearson correlation was used to establish a relationship between RMS and force values for each of the studied musc1es. The results showed that no statistical differences were found to electromyographic activity and force output in the isometric elbow flexion contractions caused by the variation of the shoulder position. The Pearson correlation values showed that greater correlation for the flexor musc1esoccurred at 90° of the shoulder abduction, while the greater correlation for the triceps braquialis occurred at anatomical shoulder position. The triceps braquialis musc1e act in cocontraction to protect and stabilize the shoulder and elbow joints during the isometric elbow flexion contractions in maximum effort. The length variation of the biarticular musc1e by the shoulder variation in the isometric elbow flexion contractions combined with semipronation was not enough to alter the force levels of the force output and electromyographic signals. This suggest that the greater contribution of the contraction of the studied musc1eswas destined to stabilization of the shoulder and elbow joints / Mestrado / Mestre em Biologia e Patologia Buco-Dental

La marche humaine nécessite la génération de force propulsive ainsi que des forces antigravitaires pour maintenir l’équilibre. Pour cela, le système nerveux central est requis d’orchestrer la contraction des muscles des membres inférieurs, notamment les fléchisseurs plantaire de la cheville qui interface entre le sol et le corps humain. Durant la première phase de simple appui, le triceps sural (TS) est en contraction excentrique et son activation aide à soutenir le corps en résistant à la rotation du tibia sur le Tarsus. Par contre, la phase finale de simple appui est marquée par une augmentation des forces de réactions au sol « Push-off », du couple articulaire de la cheville et de l’activité électromyographique du TS. Le rôle du TS durant la phase finale de simple appui est l’objet de débat dans la littérature, où certains lui attribut le rôle de propulseurs et d’autre de soutien du corps. Dans ce travail, nous postulons que l’augmentation de l’activité du TS en phase finale de simple d’appui sert uniquement à décélérer la chute du centre de masse. En outre, nous postulons que la modulation temporelle de l’activité du TS permet de contrôler la cinématique (cadence et longueur de pas) et la cinétique de la marche. Deux études ont été mises en places pour tester les hypothèses de travail. Des données biomécaniques mesurées à partir d’une plateforme de force et l’activité EMG du soléaire et des gastrocnémiens latéral et médial de la jambe d’appui ont été collecté pour les deux études. Dans la première études des volontaires ont initié la marche sans et avec un ajout de poids de 20 kg attaché au niveau de la ceinture abdominale. L’ajout du poids augmente les forces de propulsion. Une augmentation de l’activité EMG du triceps permettrait de comprendre si le triceps participe à la génération de force propulsive. La deuxième étude est composée de deux expérimentations. Dans la première expérimentations des volontaires ont accompli 3 conditions de initiation de marche à vitesse variée tout en maintenant la longueur de pas constante. Dans la deuxième expérimentation, les sujets ont été incliné et instruit de récupérer leur équilibre en exécutant un pas de longueur différente. Les résultats ont montré que : 1) le triceps ne participe pas au push-off mais freine la chute du centre de masse en phase finale de simple appui. 2) L'amplification d’activité électromyographique durant la marche rapide est due à l’augmentation de demande de support de corps causé par la croissance des forces inertiels du corps. 3) La durée de contraction du TS permet de déterminer la cadence et la longueur de pas, donc la cinématique de la marche. La durée d’activité du TS permet aussi de déterminer la position du centre de masse par rapport au centre de pression au moment du contact avec le sol. 4) Ceci permet au TS de moduler le couple de déséquilibre responsable des forces propulsives, donc la cinétique de la marche. / Human gait necessitates the generation of both propulsive force to propel the body forward and anti-gravitational force to maintain dynamic postural equilibrium. This requires the central nervous system to orchestrate lower limb muscles. Notably the CNS has to control ankle plantar flexors activity as the whole body rotates around the ankle, which in turn interfaces with the external environment. From early to middle stance, triceps surae (TS) contracts eccentrically thus resisting tibial rotation around the tarsus. However, late stance is marked by an increase in ground reaction forces, commonly known as « Push-off », in ankle torque and electromyographic activity of TS. The role of triceps surae during late stance is object of debate in the literature. Some believe it is responsible for the push-off other insist it is sole role is to maintain dynamic postural equilibrium. In this work, we postulate that the increase in TS activity in late stance is to decelerate vertically the fall of the centre of mass. We further hypothesise that temporal modulation of TS activity determines global gait kinematics (cadence and step length) and kinetics. Two studies have been conducted to test the work hypotheses. Ground reaction force data gathered from a large force platform and EMG activity of soleus, medial and lateral gastrocnemius of stance was measured using surface electrodes. In the first study, subjects initiated gait with and without an added mass of 20 kg attached around the waist. Adding the weight increases propulsive force. If TS activity increases as well than it is responsible for generating propulsive force. The second study is composed of two experiments. In the first volunteers performed gait initiation at three different walking velocity conditions while maintain step length constant. In the second experiment, subjects were inclined and asked to recuperate their equilibrium by performing a step. They were asked to perform three step lengths. Results showed that: 1) Triceps does not participate in push-off but brakes the fall of the centre of mass during late single stance. 2) Increasing TS EMG activity in late stance is due to an increase in the requirement of maintaining dynamic postural equilibrium. 3) Control over the duration of TS activity determines cadence and step length and thus the kinematics of gait. Temporal modulation of TS also sets the position of centre of mass with respect to centre of pressure at the moment of foot-contact. 4) By controlling the distance between the two, the CNS modulates the disequilibrium torque that is responsible for propulsive force and thus the kinetics of gait.

Title: The influence of bicycle saddle position on muscle tone of the triceps surae muscle Objectives: The aim of this thesis is to find out what is the effect of changing the bicycle saddle position on muscle tone of triceps surae muscle. And whether the higher seat position will also increase muscle tone of the calf muscle. Methods: The thesis is divided into the theoretical part, where there is the information from the scientific literature on the subject and a practical part. The theoretical part includes anatomical descriptions and rheological properties of skeletal muscles, muscle tension and its regulation. Part of it is also the biomechanics of cycling, bike geometry and the options of bicycle seat setting and also the risk implications of the incorrect bicycle seat position. The practical part was prepared as a research by measuring of muscle tone by the myotonometer. For measurement was used the triceps surae muscle of the seven probands on the dominant lower limb. The measurement were twice two weeks apart with the different bicycle seat height. Results: The measurement results confirmed that change of bicycle saddle position has an influence on the muscle tone and that the higher saddle position will also increase muscle tone of the calf muscle. Keywords: bicycle saddle position, saddle...