Noninvasive viscoelasticity imaging, or “dynamic elastography”, methods have recently been developed to objectively quantify the local viscoelastic properties of soft tissues by measuring the local propagation velocity of mechanical shear vibrations (e.g. faster velocity indicates stiffer material). But, the existing elastography technologies require a potentially uncomfortable external mechanical stimulation (e.g. vibrations probe) to induce muscle vibrations; and sophisticated and expensive imaging equipments (such as MRI and ultrafast ultrasound elastography), involving complex signal processing, to record and analyze these muscle vibrations. The work in this dissertation lays the foundation for the development of a low cost, passive, non-invasive elastography by analyzing and processing Surface Mechanomyograms (S-MMGs) measured with one dimensional accelerometers from the biceps brachii muscle. Aim 1 of this dissertation focused on the 3-dimensional aspect of vibrations measured by accelerometers on the skin surface above the biceps brachii. While Aim 2 focused on using one-dimensional accelerometers to determine the propagation direction of the propagating S-MMG waves. Using this newly developed knowledge on S-MMG Aim 3 was accomplished, a method to analyze the propagating wave and develop a metric that can track the changes in the muscle was developed, namely, the coherence length. The coherence length was found to significantly increase with increased contraction levels for all seven of the subjects. Overall the results of this study show that the propagation features of S-MMG vibrations reflect the architecture and contraction level of the biceps brachii muscle. Hence S-MMG could potentially be used for monitoring physiological changes of skeletal muscles.

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.

M. Tech. / OBJECTIVE: The aim of the study was to explore whether dry needle therapy delivered to latent myofascial trigger points of the biceps brachii muscle had an immediate effect on muscle activity and strength . DESIGN: One hundred participants with latent myofascial trigger points of the biceps brachii muscle and who were suitable for the study were drawn from the community. They were al located in to either a controlor treatment group so that each group contained fifty participants . The control and treatment group were divided in such a way to ensure that the two groups were comparable with one another un terms of age and gender. The International Physical Activity Questionnaire was completed by each participant to ensure that the two groups were also comparable with one another in terms of the total amount of physical activity performed per week. The results of this study were statistically analysed by STATKON at the University of Johannesburg.

The purpose of this study was to examine changes in muscle ultrastructure and strength performance following a single bout of elbow flexor resistance exercise. Eight untrained males performed 8 sets of 8 repetitions at 80% concentric 1 RM. One arm performed only the concentric (CON) phase of the movement while the other performed only the eccentric (ECC) phase. Maximum isometric (MVC), low (LV} and high velocity (HV} concentric peak torque, and evoked contractile property measurements of the elbow flexors were made before and after the bout, and at 24, 48, 72 and 96 h. Needle biopsies were obtained from the biceps brachii prior to the exercise, immediately post-exercise from each arm (POSTCON, POST-ECC}, and 48 h post-exercise from each arm (48H-CON, 48H-ECC). Electron microscopy was used to quantify the extent of fiber disruption in each sample. The severity of disruption was classified as focal (FOC}, moderate (MOD}, or extreme (EXT}. All strength measurements decreased (P s; o. 05} below pre-exercise values immediately post-ex in both arms, but dramatic differences were observed between arms during the subsequent recovery period. MVC, LV, HV and peak twitch torque (PTT) recovered to pre-ex values by 24 h in the CON arm. In the ECC arm, HV did not recover for at least 72 h, and MVC, LV and PTT remained depressed at 96 h. ANOVA revealed a greater (P s; 0.05) number fibers were disrupted in the POST-CON, POST-ECC, 48H-CON and 48H-ECC samples compared to BASE. Significantly more fibers appeared disrupted in the POST-ECC (82%) and 48H-ECC (80%) samples compared to the POSTCON (33%) and 48H-CON (37%) samples, respectively. In addition, the POST-ECC (41%) and 48H-ECC (50%) samples contained a greater number of fibers with EXT disruption compared to the POST-CON (13%) and 48H-CON (17%) samples. Decreases in MVC at 48 h correlated (P ~ 0.05) with the extent of EXT disruption in the 48H-CON and 48H-ECC samples. These data indicate that both the CON and ECC phase of weightlifting produce myofibrillar disruption, with the greatest disruption occurring during the ECC phase. This study was supported by the Natural Sciences and Engineering Research Council of Canada. / Thesis / Master of Science (MSc)

No description available.

Abstract Background. The pre-exhaustion (PE) method is a way to target a stronger muscle in a multi-joint exercise by isolating the stronger muscle immediately before the multi-joint exercise. It has been shown that this principle give greater magnitude of muscular activation in the synergistic secondary mover. There is also some indications that the PE method gives a greater neuromuscular activation of the primary mover when PE the synergist. If there are any differences between men and women in muscle activity has never been investigated before. Men have a greater absolute strength than women, especially in their upper body. There are still conflicting results if they also have greater relative strength. Aim. The purpose of the present study was to investigate if there were any neuromuscular differences between men and women when PE triceps brachii before bench press and if there was any differences in relative strength during 10RM bench press. Methods. 15 men and 15 women was randomly signed up in two different protocols. Protocol 1 started with bench press at 10 repetition maximum (10RM) and after five minutes of recovery, they performed the pre-exhaustion exercise (triceps extensions to failure) immediately before a second round of bench press with the same load on the barbell. Protocol 2 started with triceps extensions to failure immediately before bench press at their 10RM. They also had five minutes of recovery before they performed 10 repetitions of bench press. The magnitude of muscular activation were collected with surface electromyography and then processed through average root mean square (RMS). The values were normalized to muscular voluntary isometric contraction (MVIC) and expressed as percent of MVIC. The muscles that was analysed was triceps brachii (TB), pectoralis major (PM) and deltoideus anterior (DA). Results. The results showed that women had a statistically significantly higher muscular activity in all three muscles; PM (p=0.001) TB (p=0.023) and DA (p=0.047) after pre-exhaustion of TB before bench press compared to only bench press. Men showed only a statistical significant higher activation in PM (p=0.003) and a trend of higher activation in DA (p=0.061). There was a statistically significant difference in muscle activity between women and men in TB (p=0.015) but not in DA (p=0.902) and PM (p=0.436). There was no statistically significant difference between relative strength (volume load/fat free mass) (p=0.775) nor number of repetitions in bench press after PE of TB (p=0.713) between the sexes. Conclusion. The main findings in this study is that it was a statistically significant difference in neuromuscular activity in TB between men and women when PE was applied to TB before the bench press compared to bench press only, but no difference in relative strength.

Muscle spindles are skeletal muscle mechanoreceptors that mediate the stretch reflex and provide axial and limb position information to the central nervous system. They have been proposed to play a major role in the pathophysiology of muscle pain. Knowledge about the normal human muscle spindles is needed in order to understand their role in muscle disease or dysfunction. The aim of this study was to investigate the fiber content and MyHC composition of the muscle spindles in the human biceps brachii (BB) and deep muscles of the neck (DN); to determine whether there are age-related changes in human muscle spindles with respect to structure and MyHC composition; to investigate the distribution of SERCA isoforms and to evaluate whether there is a coordinated expression of SERCA and MyHC isoforms in intrafusal fibers. The myosin heavy chain (MyHC) content correlates to contraction velocity and force and the sarcoplasmic reticulum Ca2+ ATPase (SERCA) is a major determinant of muscle fiber relaxation velocity. Muscle specimens obtained from young and old subjects were serially sectioned and the pattern of distribution of different proteins along the length of the intrafusal fibers was revealed by immunocytochemistry. The MyHC content of single muscle spindles was assessed with SDS-PAGE and immunoblots. There were clear differences between BB and DN with regard to the morphology and MyHC composition of muscle spindles. Virtually each muscle spindle in the BB, but not in the DN, had a unique allotment of numbers of bag1, bag2 and chain fibers. In DN, a number of muscle spindles lacked either bag1 or bag2 fibers. Four major MyHC isoforms (MyHCI, IIa, α-cardiac and intrafusal) were detected by SDS-PAGE. In both BB and DN, immunocytochemistry revealed co-expression of several MyHC isoforms in each intrafusal fiber and regional heterogeneity. Both nuclear bag1 and bag2 fibers contained slow tonic MyHC uniformly and MyHCI, α-cardiac, embryonic and fetal with regional variations. Nuclear chain fibers contained MyHCIIa, embryonic and fetal and in the BB also MyHCIIx. The total number of intrafusal fibers per spindle decreased significantly with aging, due to a significant reduction in the number of nuclear chain fibers. The patterns of MyHC expression were also affected by aging. The bag1 fibers predominantly contained both SERCA isoforms in the encapsulated region. The bag2 fibers were more heterogeneous in their SERCA composition and 16-27% of them lacked both isoforms. Chain fibers contained SERCA1. There was a poor correlation between the MyHC and SERCA isoforms in nuclear bag fibers, whereas a strong correlation existed between MyHCIIa and SERCA1 in the nuclear chain fibers. Human muscle spindles, each being unique, proved to be more complex than anticipated. The clear differences shown between the BB and DN muscle spindles suggest functional specialization in the control of movement among different human muscles. Aging apparently had profound effects on intrafusal fiber content and MyHC composition. The age-related changes in muscle spindle phenotype may reflect deterioration in sensory and motor innervation and are likely to have a detrimental impact on motor control in the elderly.

El objetivo general del trabajo fue realizar aportaciones al conocimiento dinamométrico y electromiográfico de la articulación del codo. Para ello se analizó la fuerza isométrica máxima y su variabilidad inter e intraobservador, así como el comportamiento electromiográfico de bíceps y tríceps en diferentes ejercicios dinámicos sobre una población de 23 sujetos sanos. Se determinó también la influencia del género y de la dominancia. Los resultados de las mediciones dinamométricas mostraron valores más altos de fuerza isométrica en los varones, observándose una alta correlación con la talla y el peso corporal. Un CCI>0.71 en todas las mediciones demostró la fiabilidad y reproductibilidad de este método a 90º de flexión. No se encontraron diferencias en cuanto a la lateralidad. La actividad EMGs aumentó con la carga e intensidad del ejercicio dinámico, principalmente en el bíceps. Se demostró la gran influencia del sexo y la dominancia sobre los resultados. / The aim of this study was to make contributions to the knowledge of isometric dynamometry and surface electromyography of the elbow joint. We analyzed the maximal isometric force and inter-intraobserver variability also the electromyographic behavior of biceps and triceps brachii in different dynamic exercises on a population of 23 healthy people. We determined the influence of gender and dominance too. Dynamometric measurements showed higher values of isometric strength in men, showing a high correlation with height and body weight. An ICC>0.71 for all measurements demonstrated the reliability and reproducibility of this method at 90º of elbow flexion. There were no differences between dominant and nondominant side. The sEMG activity increased with the load and intensity of dynamic exercise mainly in the biceps brachii. It showed the great influence of sex and dominance on the results.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-05-31T14:03:18Z No. of bitstreams: 1 felipecostaalvim.pdf: 1024726 bytes, checksum: 960e31300fb235185572e16e58bf4a19 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-07-02T12:42:12Z (GMT) No. of bitstreams: 1 felipecostaalvim.pdf: 1024726 bytes, checksum: 960e31300fb235185572e16e58bf4a19 (MD5) / Made available in DSpace on 2016-07-02T12:42:12Z (GMT). No. of bitstreams: 1 felipecostaalvim.pdf: 1024726 bytes, checksum: 960e31300fb235185572e16e58bf4a19 (MD5) Previous issue date: 2012-03-30 / FAPEMIG - Fundação de Amparo à Pesquisa do Estado de Minas Gerais / Introdução: O sistema nervoso central (SNC) utiliza o recrutamento de unidades motoras e a modulação da frequência de ativação dessas unidades para controlar a força voluntária exercida por um músculo. A eletromiografia de superfície (sEMG) pode ser utilizada para captar o sinal elétrico resultante do somatório dos potenciais de ação das fibras musculares recrutadas durante o processo de produção de força. A análise da variável root mean square (RMS) e da frequência mediana (Fm) tem sido utilizada para extrair informações a respeito dos mecanismos de controle da força utilizados pelo SNC. Objetivos: Investigar as propriedades do sinal eletromiográfico de indivíduos adultos através das variáveis RMS, Fm e da análise da distribuição da potência por faixas de frequência em contrações isométricas para os níveis de força iguais a 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% e 90% da contração isométrica voluntária máxima (CIVM). Metodogia: Os sinais eletromiográficos foram obtidos a partir da contração isométrica voluntária do bíceps braquial de vinte voluntários jovens saudáveis bilateralmente nos níveis submáximos de força. Um algoritmo foi elaborado visando identificar o trecho ideal do sinal eletromiográfico a ser analisado. As variáveis RMS, Fm e a densidade de potências por faixa de 5 Hz e 10 Hz foram calculadas. Resultados e discussão: A variável RMS apresentou aumento linear com o incremento da força, conforme esperado. A variável Fm apresentou aumento entre 10% e 30% da CIVM e diminuiu para níveis de força superiores. Esse comportamento pode estar relacionado ao protocolo experimental conforme indicado na literatura. A análise da densidade de potência por faixa mostrou uma concentração da densidade de potência na faixa entre 40 e 50 Hz em 10% da CIVM. Essa concentração de potência diminuiu progressivamente em 20% e 30% do nível de força e voltou a ocorrer, na mesma faixa de frequência, em 40% da CIVM. Esse comportamento pode estar relacionado ao acréscimo de fibras de contração dos tipos IIa e IIb ao processo produção de força. Entre 40 e 90% da CIVM a concentração de potência na faixa entre 40 e 50 Hz diminui. Conclusões: As variáveis extraídas do sinal eletromiográfico apresentaram comportamento compatível com o descrito na literatura em protocolos contendo contrações em diversos níveis submáximos da CIVM. Suas variações podem estar relacionadas a diferenças no protocolo experimental. A análise da densidade de potência por faixa de frequências pode trazer informações adicionais estando relacionadas ao processo de recrutamento e ativação das unidades motoras durante o incremento de força. / Introduction: Central nervous system (CNS) uses the motor unit recruitment and the rate coding of the recruited units to control the voluntary force exerted by a muscle. Surface electromyography (sEMG) can be used to capture the electrical signal resulting from the summation of the action potentials of the muscle fibers recruited during the force production. The analysis of the variable root mean square (RMS) and median frequency (Fm) has been used to extract information about the control mechanisms of force used by the CNS. Objectives: To investigate the properties of the electromyographic signal through RMS and Fm variables and analyze the power density distribution in frequency bands in isometric force levels equal to 10%, 20%, 30%, 40%, 50%, 60%, 70%, 80% and 90% of maximal voluntary isometric contraction (MIVC). Methods: The signals were obtained bilaterally from the isometric contraction of the biceps brachii muscle of twenty young healthy volunteers in submaximals force levels. An algorithm was developed to identify the ideal section of the electromyographic signal to be analyzed. The variable RMS, Fm and power density distribution in frequency bands of 5 Hz and 10 Hz were calculated. Results and discussion: The variable RMS increased linearly with increasing force, as expected. The variable Fm had increased between 10% and 30% MVIC and than decreased toward high force levels. This behavior can be related to the experimental protocol as described in the literature. The analysis of the power density distribution in frequency bands showed a concentration of power density in the range between 40 Hz and 50 Hz in 10% MIVC. This power density concentration progressively reduced in 20% to 30% of the MIVC and occurs again on the same frequency range in 40% MVIC. This behavior may be related to increased fibers type IIa and IIb to the force production process. From 40% to 90% of the MIVC the concentration in power density in range between 40 Hz and 50 Hz decreases. Conclusions: The variables extracted from the EMG signal showed behavior compatible with the protocols described in the literature containing submaximal contractions at different levels of MIVC. Their variations may be related to differences in experimental protocol. The analysis of power density distribution in frequency bands can provide additional information being related to the recruitment and rate coding of motor units during the increase in voluntary force.

No description available.