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.

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.

Master of Science / Department of Animal Sciences and Industry / Michael E. Dikeman / The longissimus lumborum (LL) muscle from 117 steers and the LL, gluteus medius (GM), and triceps brachii (TB) from 132 heifers were obtained to evaluate the effects of feeding zilpaterol hydrochloride (Zilmax®; ZH) (7.56g/907kg on a 100% DM basis) on tenderness. Both genders were blocked by initial weight into 6 blocks of 4 pens. Pens were assigned to treatments of either 0, 20, 30 or 40 d on ZH, with a 3 d withdrawal. One steak was removed from each muscle for proximate analysis and three 2.54 cm thick steaks were vacuum aged for either 7, 14 or 21 d. Steaks were cooked to 70 ˚C and six 1.27 cm diameter cores were removed for Warner-Bratzler shear force (WBSF) determinations. All muscles from steers and heifers fed 30 and 40 d with ZH, had higher (P < 0.05) WBSF compared with controls. The WBSF of steer LL and heifer TB from the 20 d treatment was higher (P < 0.05) than controls. There were no treatment by aging interactions (P > 0.05) for WBSF of steaks from steer LL, heifer LL or heifer TB, but there was a treatment by aging interaction (P < 0.05) for WBSF of steaks from heifer GM. There were no differences (P > 0.05) in percent intramuscular fat for any muscle due to treatment. When using percent intramuscular fat as a covariate, differences in WBSF of steer LL and heifer TB were not altered, but there were slight differences in heifer LL and GM WBSF due to treatment when compared with not using percent fat as a covariate. Percentages of steaks with WBSF ≥ 5 kg increased as days on ZH increased and decreased as days of aging increased. Warner-Bratzler shear force values among the three aging times for steer LL control, 20 and 40 d treatments; all heifer LL treatments, and heifer TB 20 d were all positively correlated (P < 0.01) with each other. Feeding ZH for 20 d generally increased WBSF values, but means were still acceptable. Feeding ZH for 40 d was very detrimental to tenderness.

A utilização da eletroestimulação muscular é uma estratégia utilizada para investigação da fadiga neuromuscular. Entretanto, esta técnica é pouco aplicada na musculatura extensora do cotovelo em função de limitações biomecâncias (atuação de músculos sinergistas), neurais (influência de reflexo neural) e fisiológicas (facilidade em atingir estados de potencialização pós-ativação e fadiga). Portanto, o objetivo deste estudo foi padronizar procedimentos para avaliação neuromuscular da musculatura extensora do cotovelo. Para isso, foram realizados três estudos que envolveram a adequação da técnica de eletroestimulação e um \"estudo principal\" para validar um novo protocolo de avaliação neuromuscular. Após resultados positivos em estudos complementares, a presente dissertação propôs a validação de um protocolo para análise neuromuscular com contrações submáximas para a musculatura extensora do cotovelo. Vinte participantes com idade de 25,1 ± 6,8 anos foram submetidos, em dias diferentes, a dois esforços, um a fim de promover fadiga central e fadiga periférica respectivamente. Antes e após os esforços envolvendo fadiga (periférica ou central) foram realizadas avaliações de fadiga neuromuscular para musculatura extensora do joelho (protocolo já validado) e musculatura extensora do cotovelo (protocolo proposto). Verificou-se que: (i.) o modelo de análise proposto não promove nenhum tipo de fadiga ou potencialização pós-ativação; (ii) a resposta de um pulso controle no início e no fim do modelo de análise proposto promovem respostas diferentes; (iii) o modelo proposto foi capaz de identificar redução da resposta neuromuscular; (iv) o esforço envolvendo fadiga central não promoveu fadiga central significante; (v) a utilização de um modelo matemático para investigação de fadiga neuromuscular (coeficientes resultantes de uma regressão linear) com os valores de estimulação em contrações submáximas foi sensível a fadiga mas não foi capaz de discriminar fadiga central e periférica. É possível concluir que o modelo de análise proposto para a musculatura extensora do cotovelo apresentou sensibilidade para verificar a fadiga neuromuscular. Entretanto, este não foi capaz de discriminar fadiga central e periférica. A utilização da regressão linear parece ser uma boa estratégia para diferenciar os dois modelos de fadiga e deve ser estudada com mais profundidade futuramente. / Muscular electrostimulation is a strategy used to investigate neuromuscular fatigue. However, this technique is poorly applied in the elbow extensor muscles due to the limitations of biomechanics (acting of synergistic muscles), neural (influence of neural reflex) and physiological (easiness to achieve post-activation and fatigue states of potentiation). Therefore, the purpose of this study was to standardize a neuromuscular evaluation strategy for the elbow extensor musculature. Thus, three complementary studies aimed at adjusting the electrostimulation technique and one \"main study\" to validate a new neuromuscular assessment protocol were realized. After positive results in complementary studies, the present dissertation proposed a protocol validation for neuromuscular analysis with submaximal contractions on the elbow extensor musculature. Twenty participants with 25.1 ± 6.8 years old performed, on different days, two efforts, one to promote central fatigue and peripheral fatigue respectively. Before and after the exercise involving fatigue (peripheral or central) there were realized neuromuscular fatigue evaluations for knee extensor muscles (protocol already validated) and elbow extensor musculature (protocol). The results indicate that: (i) the proposed analysis model does not promote any type of fatigue or post-activation potentiation; (ii) the response of a control pulse at the beginning and end of the proposed analysis model promotes different responses; (iii) the proposed model was able to identify reduction of neuromuscular response; (iv) the effort involving central fatigue did not promote significant central fatigue; (v) the use of a mathematical model to investigate neuromuscular fatigue (coefficients resulting from a linear regression) with the values of stimulation in submaximal contractions was sensitive after fatigue but was not able to discriminate central and peripheral fatigue. It is possible to conclude that the proposed analysis model for the elbow extensor musculature presented sensitivity to verify the neuromuscular fatigue. However, it was not able to discriminate central and peripheral fatigue. The use of linear regression seems to be a good strategy to differentiate the two models of fatigue and should be studied in more depth in the future.