This study compared the effects of a non-traditional and a traditional strength training program for adolescents on measures of health-related fitness and physical activity enjoyment (PACES). Male (n = 7) and female (n = 12) adolescents between the ages of 15 and 18 years registered for a community based program and volunteered to participate in the study component. Participants were assigned to a non-traditional training group (n = 10) utilizing kettlebells or a traditional training group (n = 9) utilizing dumbbells. Health-related fitness and PACES were measured at baseline and post-training, with an additional PACES measure at mid-training. Both training groups significantly improved several health-related fitness measures, with the only significant difference between groups being seen in KB swing squats. PACES significantly decreased from baseline to mid-training, and stayed constant from mid- to post-training, for both training groups. There was no significant difference between training groups on physical activity enjoyment.

The purpose of this thesis was to investigate the potential mechanisms and sites of neural adaptations that mediate cross-limb transfer of strength and motor learning that can occur subsequent to unilateral training. Better understanding of the mechanisms should allow therapeutic benefits of this effect to be assessed. There are two main classes of mechanisms that could contribute to cross-limb transfer. The first is described by the ??bilateral access?? hypothesis, which suggests that neural adaptations induced by training reside in bilaterally projecting motor areas that are accessible to the untrained (ipsilateral) hemisphere during task execution to facilitate performance. According to the alternative ??cross-activation?? hypothesis, activation of the untrained hemisphere during unilateral training leads to adaptations in the untrained hemisphere that cause improved performance with the opposite untrained limb. A series of studies were conducted in this research. We directly tested the cross-activation hypothesis via a reliable twitch interpolation technique involving transcranial magnetic stimulation (TMS). Four-weeks of strength training for the right wrist increased neural drive (from the untrained motor cortex) to the untrained left wrist. The data demonstrate that strength training of one limb can influence the efficacy of corticospinal pathways that project to the opposite untrained limb, consistent with the cross-activation hypothesis. To investigate the contribution of each hemisphere in cross-limb transfer, we applied repetitive TMS (rTMS) to the trained or the untrained motor cortex to disrupt brain processing after unilateral ballistic training. Learning to produce ballistic movements requires optimization of motor drive to the relevant muscles in a way that resembles high-force contractions performed during strength training. Ballistic skill transferred rapidly to the untrained hand and the improved performance was accompanied by bilateral increases in corticospinal excitability. Performance improvement in each hand was specifically suppressed by rTMS of the opposite hemisphere. Thus the motor cortex ipsilateral to the trained hand is critically altered during unilateral training; and neural adaptations within this untrained hemisphere are crucial in cross-limb transfer of ballistic skill. Overall, the data are in agreement with the cross-activation hypothesis for high-force and ballistic tasks, although they do not exclude the potential involvement of bilateral access mechanisms.

The purpose of this thesis was to investigate the potential mechanisms and sites of neural adaptations that mediate cross-limb transfer of strength and motor learning that can occur subsequent to unilateral training. Better understanding of the mechanisms should allow therapeutic benefits of this effect to be assessed. There are two main classes of mechanisms that could contribute to cross-limb transfer. The first is described by the ??bilateral access?? hypothesis, which suggests that neural adaptations induced by training reside in bilaterally projecting motor areas that are accessible to the untrained (ipsilateral) hemisphere during task execution to facilitate performance. According to the alternative ??cross-activation?? hypothesis, activation of the untrained hemisphere during unilateral training leads to adaptations in the untrained hemisphere that cause improved performance with the opposite untrained limb. A series of studies were conducted in this research. We directly tested the cross-activation hypothesis via a reliable twitch interpolation technique involving transcranial magnetic stimulation (TMS). Four-weeks of strength training for the right wrist increased neural drive (from the untrained motor cortex) to the untrained left wrist. The data demonstrate that strength training of one limb can influence the efficacy of corticospinal pathways that project to the opposite untrained limb, consistent with the cross-activation hypothesis. To investigate the contribution of each hemisphere in cross-limb transfer, we applied repetitive TMS (rTMS) to the trained or the untrained motor cortex to disrupt brain processing after unilateral ballistic training. Learning to produce ballistic movements requires optimization of motor drive to the relevant muscles in a way that resembles high-force contractions performed during strength training. Ballistic skill transferred rapidly to the untrained hand and the improved performance was accompanied by bilateral increases in corticospinal excitability. Performance improvement in each hand was specifically suppressed by rTMS of the opposite hemisphere. Thus the motor cortex ipsilateral to the trained hand is critically altered during unilateral training; and neural adaptations within this untrained hemisphere are crucial in cross-limb transfer of ballistic skill. Overall, the data are in agreement with the cross-activation hypothesis for high-force and ballistic tasks, although they do not exclude the potential involvement of bilateral access mechanisms.

This study compared the effects of a non-traditional and a traditional strength training program for adolescents on measures of health-related fitness and physical activity enjoyment (PACES). Male (n = 7) and female (n = 12) adolescents between the ages of 15 and 18 years registered for a community based program and volunteered to participate in the study component. Participants were assigned to a non-traditional training group (n = 10) utilizing kettlebells or a traditional training group (n = 9) utilizing dumbbells. Health-related fitness and PACES were measured at baseline and post-training, with an additional PACES measure at mid-training. Both training groups significantly improved several health-related fitness measures, with the only significant difference between groups being seen in KB swing squats. PACES significantly decreased from baseline to mid-training, and stayed constant from mid- to post-training, for both training groups. There was no significant difference between training groups on physical activity enjoyment.

A dor muscular após a realização de exercícios intensos tem sido objeto de investigações científicas desde o início do século XX. O primeiro tópico da revisão de literatura contextualiza historicamente o estudo envolvendo a dor muscular e revisita as evidências que levaram ao conhecimento de que a dor muscular tardia é resultado de dano à estrutura muscular, associado a contrações excêntricas. O dano muscular induzido por contrações excêntricas é largamente abordado na literatura, no entanto, recentemente alguns estudos passaram a utilizar exercícios convencionais do treinamento de força para induzir dano muscular e estudar a manifestação e a recuperação de marcadores indiretos de dano muscular. Uma das principais variáveis do treino de força é a seleção dos exercícios, que podem ser divididos em multiarticulares e monoarticulares. O segundo tópico da revisão de literatura trata da definição desses tipos de exercícios e dos estudos que investigaram as diferenças entre eles. Foi constatado que não há consenso na literatura sobre o dano muscular após a execução de exercícios de força multiarticulares e monoarticulares. Portanto, o objetivo do estudo foi comparar o dano muscular induzido por um exercício multiarticular versus monoarticular em indivíduos destreinados. Vinte e quatro sujeitos saudáveis e destreinados foram divididos em dois grupos aleatoriamente: grupo multi (n=12), que realizou o exercício multiarticular Puxada pela Frente e grupo mono (n=12), que realizou o exercício monoarticular Rosca Scott. O protocolo de exercício consistiu de quatro séries de 10 repetições a 80% de uma repetição máxima (1RM). Os flexores do cotovelo foram avaliados nos momentos pré, 0, 24, 48, 72 e 96 h após o protocolo de exercício através do decréscimo na produção de força (CIVM), da dor muscular tardia (DMT) por palpação do braço e extensão do cotovelo, da espessura muscular (EM), do grau de ecogenicidade (ECO) dos músculos Braquial e Bíceps Braquial e da concentração plasmática de creatina cinase (CK). Todos os marcadores apresentaram diferenças significativas ao longo do tempo comparado com o pré. Houve diferença significativa entre os grupos apenas na DMT por palpação (DMT-p) em 24 e 48 h e na CK em 24 e 96 h. O grupo mono apresentou maior DMT-p, enquanto o grupo multi apresentou maior CK. Nenhum dos outros marcadores indireto de dano muscular apresentou diferença significativa entre os grupos. Houve variabilidade nas respostas ao dano muscular devido à responsividade dos sujeitos. Quando separados em responsivos (R) e não-responsivos (NR), grupos mais homogêneos foram formados, porém resultados semelhantes foram encontrados, exceto no ECO, o qual, nos NR, apresentou redução nos valores, o que não corrobora com o comportamento reportado na literatura para essa variável. Os achados sugerem que, em indivíduos destreinados, não há diferença no dano muscular induzido por exercícios de força multiarticulares e monoarticulares. / Muscle soreness after intense exercise has been investigated since the early twentieth century. The first topic of the literature review historically contextualizes the study of muscle soreness and revisits evidences that shed light on the fact that muscle soreness is a consequence of damage to muscle structure, associated with eccentric contractions. Eccentric-induced muscle damage is largely studied and reported on the literature. However studies recently began to use conventional strength training exercises to induce muscle damage and account for the manifestation and recovery of indirect markers of muscle damage. A major intervenient variable in strength training is exercise selection, which can be defined as multiple and single-joint exercises (MJ and SJ, respectively). The second topic of the literature review deals with these different exercise types and the investigation carried out in this field. It was found that there is no consensus concerning muscle damage after MJ and SJ exercises. Therefore, the aim of the study was to compare MJ and SJ exercises on muscle damage in untrained subjects. Twenty four healthy and untrained subjects were randomly assigned to one of two groups: MJ group (n=12), which performed a Front Pull-Down and SJ group (n=12), which performed an elbow flexion with a Scott bench. Exercise protocol consisted of four sets of 10 repetitions at 80% of one repetition maximum (1RM). Elbow flexors were evaluated at pre, 0, 24, 48, 72 and 96 h post-exercise through reduction in muscular force (CIVM), muscle soreness (DMT) by palpation and by elbow extension, muscle thickness (EM), echo intensity (ECO) of brachialis and bíceps brachii and plasma creatine kinase activity (CK). All markers of damage presented significant differences across time compared to pre-exercise. There was a statistically significant difference between groups in DMT by palpation (DMT-p) at 24 and 48 h and in CK at 24 and 96 h. SJ group presented larger DMT-p while MJ group presented higher CK. Neither of the other indirect markers of muscle damage showed stastistical differences between groups. A marked variability was demonstrated in muscle damage responses due to subjects’ responsiveness. When splitted in responders (R) and non-responders (NR), more homogenous groups were formed, yet similar trends were found, except for ECO, where a reduction in values were evident in NR, which do not corroborate with the literature. The findings of the present study suggest that there are no differences in muscle damage induced by MJ and SJ exercises in untrained individuals.

Os diferentes tipos de treinamento de força (TF) apresentam distintas adaptações do tecido muscular como o desenvolvimento de força máxima, potência e/ou força reativa muscular. Dentre estes tipos de TF, estão os treinamentos de força Tradicional, Treinamento de Potência e de Treinamento de Força Reativa, em que está presente o ciclo-alongamento-encurtamento (CAE). A habilidade de produzir força rapidamente requer a participação intensa das fibras do tipo IIX, condição esta frequentemente reduzida em mulheres idosas. A força rápida tem importância significativa para homens e mulheres de todas as idades, destacando-se ainda mais em mulheres idosas. A prescrição de um tipo de TF que melhor desenvolva as atividades de vida diária (AVD) é primordial para a manutenção da independência física e qualidade de vida de idosas. Assim o objetivo principal do trabalho foi avaliar e comparar as adaptações neuromusculares, morfológicas e funcionais em mulheres idosas submetidas a três tipos específicos de treinamento de força. Na revisão de literatura a metodologia embasou-se em pesquisa bibliográfica, utilizando artigos atuais e clássicos da literatura sobre TF em mulheres idosas (publicados, principalmente, a partir de 2000) selecionados nas bases de dados Pubmed e Sportdiscus, que comparassem e analisassem pelo menos dois tipos específicos de TF. No segundo estudo, 58 mulheres idosas saudáveis sem a prática de treinamento de força foram randomizadas em grupo experimental (GE, n= 41) e grupo controle (GC, n=17), e submetidas a seis semanas de treinamento de força resistente. Foram realizadas avaliações da qualidade muscular e sua correlação com os testes funcionais (sentar e levantar em 30s e up foot and go). Como resultado o GE apresentou incremento significativo na qualidade muscular do quadríceps (14,8%) com alta correlação com os testes funcionais sentar e levantar (r=0,62, p< 0,001) e up foot and go (r= -0,72, p< 0,001). O terceiro estudo o GC foi preservado e o grupo experimental foi dividido em Treinamento de Força Tradicional (GT, n=14), Treinamento de Potência (GP, n=13) e Treinamento de Força Reativa (GR, n=14). Foram realizadas avaliações do 1RM extensão de joelhos, espessura muscular, ativação, onset e tempo de reação muscular, taxa de produção de força e testes funcionais como o sentar e levantar e o salto com contra movimento. Como resultados, observou-se que o GR foi mais efetivo que os grupos GT e GP no onset muscular do RC, da taxa de produção de força (0-150 ms), no tempo de reação muscular e nos testes funcionais (p< 0,05). Dessa forma, conclui-se que o treinamento de força reativa é mais efetivo para o desenvolvimento da produção de força rápida do músculo que os outros tipos específicos de treinamento de força, e por conseqüência disto, melhor desenvolve as capacidades funcionais de mulheres idosas. / Differents strenght trainning (ST) are associated with distincts muscles tissues responses that comprised maximum strenght, power and/or reactive force. Among these different ST programmes there are traditional strenght training (GT), power (GP) and reactive force (GR) which is present in stretch-shortening cycle (SSC). In this context, for fast force production is necessary that IIX type fibers being recruited, condiction that to be seem decreasing among elderly women population. Furthermore, fast production of force has significant importance for all ages, however this condition could be considerate more significant for elderly women population. Consequently, prescrition of ST associated with improving activities of daily living (ADL) have been evidenciated as a important pathway for physical independence, as well as, for elderly quality of life. Thus, the mayor aim of this study was to verifiy and compare neuromuscular, morphological and functional adaptations in a sample of elderly women which were submitted in three different ST programmes. The methodology used in the first study was a sistematic literature review included classics studies about ST in this population. These studies were selected by two international scientic database (Pubmed and Sportdiscus); were published since 2000 until now and to show a comparation between at least two different kinds of ST. For the second study, 58 inactivity elderly women was randomized between control (GC=17) and experimental group (GE=41) and after submitted over a six weeks of ST. The relationship between muscle quality assesment with up foot and go and 30- second chair stand functional test was realized. Subjects included in GE showed significant improvement of quadricips muscle quality (14.8%), as well as, muscle quality showed significant strong association with 30-second chair stand (r=0.62, p< 0.001) and up foot and go (r= -0.72, p< 0.001) functional tests. For the third study, the GC was maintenced while GE was again randomized between GT (14), GP (13) and GR (14). 1 RM of knee extention, muscles thickness, activation, onset, reaction time, rate development force tests and working out as the sit and stand and countermovement jumps were measured. Results of this study showed that GR was more effective than GT and GP when comprised rectus thigh muscle onset, initial periods of production of strenght rate, reaction time and muscles function tests (p <0.05). Finnaly, considerating results of these studies we concluded that GR training was more effective when considerated fast force production of muscle if compared with other specifics ST programmes. Consequently this study suggest GR as a better ST programm for improving functional capapcities in a sample of elderaly women.

Os diferentes tipos de treinamento de força (TF) apresentam distintas adaptações do tecido muscular como o desenvolvimento de força máxima, potência e/ou força reativa muscular. Dentre estes tipos de TF, estão os treinamentos de força Tradicional, Treinamento de Potência e de Treinamento de Força Reativa, em que está presente o ciclo-alongamento-encurtamento (CAE). A habilidade de produzir força rapidamente requer a participação intensa das fibras do tipo IIX, condição esta frequentemente reduzida em mulheres idosas. A força rápida tem importância significativa para homens e mulheres de todas as idades, destacando-se ainda mais em mulheres idosas. A prescrição de um tipo de TF que melhor desenvolva as atividades de vida diária (AVD) é primordial para a manutenção da independência física e qualidade de vida de idosas. Assim o objetivo principal do trabalho foi avaliar e comparar as adaptações neuromusculares, morfológicas e funcionais em mulheres idosas submetidas a três tipos específicos de treinamento de força. Na revisão de literatura a metodologia embasou-se em pesquisa bibliográfica, utilizando artigos atuais e clássicos da literatura sobre TF em mulheres idosas (publicados, principalmente, a partir de 2000) selecionados nas bases de dados Pubmed e Sportdiscus, que comparassem e analisassem pelo menos dois tipos específicos de TF. No segundo estudo, 58 mulheres idosas saudáveis sem a prática de treinamento de força foram randomizadas em grupo experimental (GE, n= 41) e grupo controle (GC, n=17), e submetidas a seis semanas de treinamento de força resistente. Foram realizadas avaliações da qualidade muscular e sua correlação com os testes funcionais (sentar e levantar em 30s e up foot and go). Como resultado o GE apresentou incremento significativo na qualidade muscular do quadríceps (14,8%) com alta correlação com os testes funcionais sentar e levantar (r=0,62, p< 0,001) e up foot and go (r= -0,72, p< 0,001). O terceiro estudo o GC foi preservado e o grupo experimental foi dividido em Treinamento de Força Tradicional (GT, n=14), Treinamento de Potência (GP, n=13) e Treinamento de Força Reativa (GR, n=14). Foram realizadas avaliações do 1RM extensão de joelhos, espessura muscular, ativação, onset e tempo de reação muscular, taxa de produção de força e testes funcionais como o sentar e levantar e o salto com contra movimento. Como resultados, observou-se que o GR foi mais efetivo que os grupos GT e GP no onset muscular do RC, da taxa de produção de força (0-150 ms), no tempo de reação muscular e nos testes funcionais (p< 0,05). Dessa forma, conclui-se que o treinamento de força reativa é mais efetivo para o desenvolvimento da produção de força rápida do músculo que os outros tipos específicos de treinamento de força, e por conseqüência disto, melhor desenvolve as capacidades funcionais de mulheres idosas. / Differents strenght trainning (ST) are associated with distincts muscles tissues responses that comprised maximum strenght, power and/or reactive force. Among these different ST programmes there are traditional strenght training (GT), power (GP) and reactive force (GR) which is present in stretch-shortening cycle (SSC). In this context, for fast force production is necessary that IIX type fibers being recruited, condiction that to be seem decreasing among elderly women population. Furthermore, fast production of force has significant importance for all ages, however this condition could be considerate more significant for elderly women population. Consequently, prescrition of ST associated with improving activities of daily living (ADL) have been evidenciated as a important pathway for physical independence, as well as, for elderly quality of life. Thus, the mayor aim of this study was to verifiy and compare neuromuscular, morphological and functional adaptations in a sample of elderly women which were submitted in three different ST programmes. The methodology used in the first study was a sistematic literature review included classics studies about ST in this population. These studies were selected by two international scientic database (Pubmed and Sportdiscus); were published since 2000 until now and to show a comparation between at least two different kinds of ST. For the second study, 58 inactivity elderly women was randomized between control (GC=17) and experimental group (GE=41) and after submitted over a six weeks of ST. The relationship between muscle quality assesment with up foot and go and 30- second chair stand functional test was realized. Subjects included in GE showed significant improvement of quadricips muscle quality (14.8%), as well as, muscle quality showed significant strong association with 30-second chair stand (r=0.62, p< 0.001) and up foot and go (r= -0.72, p< 0.001) functional tests. For the third study, the GC was maintenced while GE was again randomized between GT (14), GP (13) and GR (14). 1 RM of knee extention, muscles thickness, activation, onset, reaction time, rate development force tests and working out as the sit and stand and countermovement jumps were measured. Results of this study showed that GR was more effective than GT and GP when comprised rectus thigh muscle onset, initial periods of production of strenght rate, reaction time and muscles function tests (p <0.05). Finnaly, considerating results of these studies we concluded that GR training was more effective when considerated fast force production of muscle if compared with other specifics ST programmes. Consequently this study suggest GR as a better ST programm for improving functional capapcities in a sample of elderaly women.

O objetivo deste estudo foi comparar o efeito de um programa de treinamento excêntrico versus concêntrico nas propriedades morfológicas, mecânicas e mioelétricas da unidade músculo-tendão do quadríceps de idosos. Vinte e três sujeitos do sexo masculino (62,74±2,20 anos de idade, 80,21±14,82 kg de massa corporal e 172,02±6,11 cm de estatura) participaram de um programa de treinamento de força durante 12 semanas, duas vezes por semana, realizando extensão unilateral concêntrica em uma articulação do joelho e flexão unilateral excêntrica na articulação do joelho contralateral, a 80% de 5 Repetições Máximas (5 RM). O tratamento estatístico foi composto por teste t de Student nas comparações das diferenças obtidas entre o período pré versus pós treinamento e por ANOVA de dois fatores para comparar as diferenças entre os treinamentos concêntrico versus excêntrico nos dois períodos (pré-treinamento versus pós-treinamento), utilizando o programa de estatística GraphPad Instat versão 3.06, adotando-se um nível de significância de 5%. Nas articulações treinadas excentricamente a força medida pelo teste de 5 RM aumentou de forma significativa (p<0,05) ao longo do programa de treinamento de força, enquanto que com o treinamento concêntrico houve um aumento da força nas primeiras 6 semanas (p<0,05) que não se repetiu nas últimas 6 semanas de treinamento. Avaliando a arquitetura do músculo vasto lateral por meio da ultrassonografia (ALOKA SSD 4000), verificamos que ambos os tipos de treinamento causaram uma redução no comprimento dos fascículos e um aumento no ângulo de penação (p<0,05) sem diferença entre os tipos de treinamento e sem alterar significativamente a espessura muscular (p>0,05). Ao utilizar a ultrassonografia para avaliar a arquitetura do tendão patelar, verificamos um aumento no comprimento do tendão com os dois tipos de treinamento e um aumento na área de seção transversa do tendão apenas da articulação treinada excentricamente (p<0,05). Utilizando um dinamômetro isocinético (Biodex System 3 PRO) verificamos que tanto o treinamento concêntrico quanto o treinamento excêntrico causaram um aumento significativo do torque articular nos ângulos de 50, 60, 70 e 90° (p<0,05), mas não no ângulo de 30° (p>0,05). Adicionalmente, verificamos que o treinamento concêntrico causou um aumento significativo nas velocidades articulares de -240, -180, -120 e -60°/seg e nas velocidades de 180 e 240°/seg (p<0,05). Já o treinamento excêntrico causou um aumento significativo apenas nas velocidades de 60, 120 e 180°/seg, tanto positivas quanto negativas (p<0,05). Utilizando a eletromiografia (Bortec Medical Systems) para comparação da ativação muscular não encontramos diferença significativa em nenhuma das análises. Nossos resultados nos permitem concluir que no que tange a arquitetura muscular o treinamento concêntrico e excêntrico proporcionam adaptações muito semelhantes, enquanto que na arquitetura tendinosa isso é válido para o comprimento muscular, mas não para a área de seção transversa. Todavia o treinamento excêntrico parece trazer um aumento de força mais consistente ao longo do treinamento, ainda que nas propriedades mecânicas não tenha sido constatadas diferenças significativas entre os tipos de treinamento. No que diz respeito as propriedades mioelétricas não encontramos diferenças significativas nas adaptações tanto ao treinamento concêntrico quando excêntrico. / The purpose of this study was to compare the effects of an eccentric training versus a concentric training concerning the morphological, mechanical and mioelectric properties of the muscle-tendon unit of the quadriceps muscle in older men. Twenty three male subjects (62.74±2.20 years old, 80.21±14.82 kg of body mass and 172.02±6.11 cm height) have participated of a strength training program for 12 weeks, two times a week, performing unilateral concentric extension of one knee joint and unilateral eccentric flexion of the other knee joint, at 80% of 5RM. The statistica analyses was perfomed by Student t test to compare the differences obtained between the pre-training versus post-training period and by two-way ANOVA to compare the diferences obtained between the concentric versus eccentric training in both periods (pre-training versus post-training) using the statistical software GraphPad Instat version 3.06 assuming a 5% level of significance. On the eccentrically trained joints the strength measured by the 5RM tests increased significantly (p<0.05) during the strength training program, while with the concentric training there was an increase in strength on the first 6 weeks (p<0.05) that didn’t repeat on the last 6 weeks of training. Through the evaluation of the muscle architecture of the vast lateral muscle (ALOKA SSD 4000), we verified that both types of training have caused a shortening of the fascicle length and an increase of the penation angle (p<0.05) without differences between the types of training and without altering significantly the muscle width (p>0.05). When we used the ultrasonography to evaluate the architecture of the patellar tendon, we have verified an increase on the tendon length with both types of training and an increase of the cross-sectional area of the tendon only on the joint trained eccentrically (p<0.05). Using an isokinetic dynamometer (Biodex System 3 PRO) we verified that both the concentric and the eccentric training have caused a significant increase of the joint torque in the angles of 50°, 60°, 70° and 90° (p<0.05), but not in the angle of 30° (p>0.05). Additionally, we verified that the concentric training did cause a significant joint speed increase of -240°, -180°, -120° and -60°/sec and on the speeds of 180° and 240°/sec (p<0.05). In the case of the eccentric training, it caused a significant increase only on the speeds of 60°, 120° and 180°/sec, both positive and negative (p<0.05). Using the electromyography (Bortec Medical Systems) to compare the muscle activation of the vast lateral in different joint angles in the pre and post concentric training periods, we have not verified significant difference in any of the analysis. Our results allow us to conclude that concerning the muscle architecture, concentric and eccentric training produce very similar adaptations, whereas in the tendon architecture this is valid for the muscle length, but not for the cross-sectional area. However, the eccentric training seems to bring a more consistent gain in strength during the training, despite that on the mechanical properties there were no significant differences stated between the types of training. Concerning to the myoelectrical properties we were not able to find any significant adaptation either in concentric or eccentric training.

O objetivo deste estudo foi comparar as adaptações neuromusculares e morfológicas de treinamentos de força realizados com amplitudes parcial e total de movimento nos músculos flexores de cotovelo e extensores de joelho. Participaram do estudo 41 voluntários do sexo masculino destreinados em força (23,78 ± 3,27 anos), divididos em três grupos: PS-TI (Parcial Superior – Total Inferior; n=14), TS-PI (Total Superior – Parcial Inferior; n=16) e GC (Grupo Controle; n=11). O grupo PS-TI realizou o treinamento de flexão de cotovelo em amplitude parcial (40°- 90°) e de extensão de joelho em amplitude total (90° - 0°). O grupo TS-PI realizou o treinamento de flexão de cotovelo em amplitude total (0° - 120°) e de extensão de joelho em amplitude parcial (60° - 30°). Os sujeitos treinaram duas vezes por semana por um período de 12 semanas. O GC não realizou o treinamento. Antes e após o período de treinamento, os sujeitos foram avaliados em parâmetros relacionados à força muscular dinâmica, resistência muscular, pico de torque isocinético, pico de torque isométrico em diferentes ângulos, ativação muscular dinâmica e isométrica em diferentes ângulos e hipertrofia muscular. Para a força muscular dinâmica, avaliada pelo teste de uma repetição máxima (1RM), o grupo TS-PI teve incrementos de 1RM de flexão de cotovelo (29,37%) maiores que PS-TI (18,42%) (p<0,001). Ainda, o grupo PS-TI teve incrementos de 1RM de extensão de joelho (25,69%) maiores que TS-PI (15,06%) (p=0,038). A resistência muscular, avaliada pelo teste de 60% de 1RM absoluto, mostrou, para a flexão de cotovelo e extensão de joelho, que o grupo que treinou em amplitude total realizou um número maior de repetições do que o que treinou em amplitude parcial o exercício avaliado. Não foram encontradas diferenças nos incrementos de picos de torque isocinético e isométrico em diferentes ângulos entre os grupos PS-TI e TS-PI na flexão de cotovelo e extensão de joelho. Não foram encontrados incrementos significativos de ativação muscular, avaliada durante os testes isocinéticos e isométricos em diferentes ângulos. Foram encontrados incrementos significativos de hipertrofia, avaliada pela espessura muscular, nos músculos flexores de cotovelo, sem diferença entre os grupos PS-TI e TS-PI. Quanto à espessura muscular nos extensores de joelho, o grupo PS-TI teve maiores incrementos quando comparado a TS-PI no somatório de todos os músculos extensores de joelho (6,74% vs. 5,02%) (p=0,001) e no somatório de três diferentes pontos avaliados no músculo vasto lateral (5,20% vs 3,37%) (p=0,033). Assim, todas as diferenças encontradas neste estudo foram a favor do treinamento em amplitude total de movimento, ainda que o grupo que treinou o exercício em amplitude parcial de movimento tenha treinado com cargas significativamente mais elevadas durante todo período de treinamento (PS-TI: 47,94% mais elevada na flexão de cotovelo; TS-PI: 61,32% mais elevada na extensão de joelho). Dessa forma, pode-se concluir que o treinamento de força em amplitude total de movimento causa melhores adaptações neuromusculares e morfológicas, sendo mais efetivo para incrementos de força, resistência e hipertrofia muscular de flexores de cotovelo e extensores de joelho em homens jovens. / The purpose of this investigation was to compare neural and morphological adaptations of a partial range of motion versus a full range of motion strength training in the elbow flexors and knee extensors. Forty-one untrained men (23.78 ± 3.27 years) were divided into three groups: PU-FL (Partial Upper – Full Lower; n=14), FU-PL (Full Upper – Partial Lower; n=16) and CG (Control Group; n=11). The PU-FL group during the training performed elbow flexion with partial range of motion (40° - 90°) and performed knee extension with full range of motion (90° - 0°). The FU-PL group during the training performed elbow flexion with full range of motion (0° - 120°) and performed knee extensor with partial range of motion (60° - 30°). The subjects trained two times per week during 12 weeks. The CG did not train. Before and after training period, subjects were evaluated in parameters related to dynamic muscle strength, muscle endurance, isokinetic peak torque, isometric peak torque at different angles, dynamic and isometric (at different angles) muscle activation and muscle hypertrophy. For the dynamic muscle strength, evaluated by one repetition maximum (1RM) test, the increase in 1RM of the elbow flexion for the FU-PL group (29.37%) was greater than PU-FL group (18.42%) (p<0.001). Moreover, the increase in 1RM of the knee extension for the PU-FL group (25.69%) was greater than FU-PL (15.06%) (p=0.038). The muscle endurance, evaluated by 60% of 1RM test with absolute load in the elbow flexion and knee extension, showed the group that trained the exercise with full range of motion performed a greater number of repetitions than those trained the evaluated exercise with partial range of motion. No differences were observed between PU-FL and FU-PL groups for the increase for isokinetic or isometrics, at different angles, peaks torque in elbow flexion and knee extension. No significant findings were observed for muscle activation measured during isokinetic and isometrics tests. There were significant increases on muscle hypertrophy, evaluated by muscle thickness, of the elbow flexors, but no difference were observed between PU-FL and FU-PL groups. For the muscle thickness of the knee extensors, the increase for the PU-FL group was greater than FU-PL group at sum of all knee extensors muscles (6.74% vs. 5.02%) (p=0.001) and at sum of three different points evaluated in the vastus lateralis muscle (5.20% vs. 3.37%) (p=0.033). Thereby, all the differences found in this investigation were in favor of full range of motion training, despite the group that trained with partial range of motion have been used higher loads throughout the training period (PU-FL: 47.94% higher in elbow flexion; FU-PL: 61.32% higher in knee extension). Thus, we can conclude that strength training with full range of motion causes better neural and morphological adaptations, being more effective for increase in strength, endurance and muscle hypertrophy in the elbow flexors and knee extensors of the young men.

O exercício excêntrico é utilizado como uma estratégia de treinamento de força em atletas e sujeitos saudáveis de diferentes faixas etárias. Esse tipo de exercício também é largamente difundido na área da reabilitação musculoesquelética, sendo o quadríceps femoral o músculo mais frequentemente investigado devido à sua relevância clínica. O tema dessa tese de Doutorado é a adaptação do sistema neuromuscular ao treinamento excêntrico de extensores de joelho. No Capítulo I, um estudo de revisão procurou descrever os diferentes métodos empregados pelos cientistas para o treinamento excêntrico de extensores de joelho, assim como avaliar as adaptações neurais, morfológicas e na produção de força muscular de sujeitos saudáveis. Após busca sistematizada nas bases de dados, 26 estudos foram incorporados ao nosso estudo de revisão. Os programas de treinamento excêntrico realizados em dinamômetro isocinético e em equipamentos isotônicos (leg-press e cadeira extensora de joelho) foram descritos e discutidos. Os resultados desses estudos indicam um efeito positivo do treinamento excêntrico sobre a força e a ativação muscular, especialmente em testes excêntricos, assim como uma significativa resposta hipertrófica. Porém, resultados conflitantes e lacunas identificadas na literatura incentivaram a realização de dois estudos originais para verificar: (1) o comportamento temporal das adaptações neurais e morfológicas ao treinamento excêntrico de extensores de joelho e suas contribuições para os ganhos de força (Capítulo II); e (2) as adaptações específicas de músculos sinergistas da extensão de joelho: reto femoral (RF) e vasto lateral (VL) (Capítulo III). Vinte homens saudáveis realizaram um período controle de quatro semanas sem treinamento, seguido por um programa de 12 semanas de treinamento excêntrico em dinamômetro isocinético. Avaliações de torque, eletromiografia e ultrassonografia de extensores de joelho foram realizadas a cada quatro semanas. Um maior ganho de força foi verificado nos testes excêntricos, seguido pelos testes isométricos e concêntricos. A ativação muscular nos testes excêntricos e isométricos aumentou após quatro e oito semanas de treinamento, respectivamente, ao passo que os testes concêntricos não apresentaram alteração da atividade eletromiográfica. Os valores de espessura muscular, área de secção transversa anatômica e comprimento de fascículo aumentaram após quatro e oito semanas de treinamento, mas não modificaram entre a oitava e a 12ª semana de intervenção. As adaptações na geometria fascicular dos músculos RF e VL foram semelhantes ao longo do programa de treinamento. Nossos achados sugerem que: (1) existe um forte efeito da especificidade do exercício excêntrico sobre os aumentos de força e ativação muscular; (2) os ganhos de força excêntrica e isométrica até a oitava semana de treinamento estão relacionados a adaptações neurais e morfológicas mensuráveis, enquanto outros mecanismos podem estar relacionados aos ganhos nas quatro últimas semanas de intervenção; (3) o ganho de força concêntrica não é afetado por adaptações neurais; (4) o treinamento excêntrico aumenta o comprimento, mas não o ângulo de penação fascicular; (5) as adaptações na arquitetura muscular podem ocorrer nas primeiras semanas de treinamento; e (6) apesar das diferenças estruturais e funcionais, RF e VL apresentam índices semelhantes de adaptação. / Eccentric exercise is used as a strategy for strength training in athletes and healthy subjects with different ages. This type of exercise is also frequently used in musculoskeletal rehabilitation, and the quadriceps femoris is the most frequently investigated muscle due its clinical relevance. The theme of this PhD thesis is the adaptation of the neuromuscular system to knee extensor eccentric training. In Chapter I, a review study aimed at describing the different methods employed by scientists for knee extensor eccentric training, as well as for evaluating the neural, morphological and muscular strength adaptations in healthy subjects. After a systematized search in related data bases, 26 studies were incorporated to our review study. Eccentric training programs performed in isokinetic dynamometers and isotonic devices (leg-press and knee extension chair) were described and discussed. Results from these studies indicate a positive effect of eccentric training on muscle strength and activation, especially in eccentric tests, as well as a significant hypertrophic response. However, conflicting results and gaps observed in the literature encouraged us to perform two original studies to verify: (1) the time course of neural and morphological adaptations to knee extensor eccentric training and their contribution to strength gains (Chapter II); and (2) the specific adaptive responses from synergistic knee extensor muscles: rectus femoris (RF) and vastus lateralis (VL) (Chapter III). Twenty healthy men performed a four-week control period without training, followed by a 12-week eccentric training on an isokinetic dynamometer. Knee extensor evaluations of torque, electromyography and ultrasonography were made every four weeks. A higher strength increase was observed in eccentric tests, followed by isometric and concentric tests. Muscle activation in eccentric and isometric tests increased after four and eight weeks of training, respectively, while the concentric tests presented no change in the electromyographic activity. Muscle thickness, anatomical cross-sectional area and fascicle length values increased after four and eight weeks of training, but did not change between the eighth and twelfth intervention week. Adaptations in RF and VL fascicular geometry were similar throughout the training program. Our findings suggest that: (1) there is a strong specificity effect of eccentric exercise on increases in muscle strength and activation; (2) eccentric and isometric strength gains up to the eighth week of training are related to measurable neural and morphological adaptations, while other mechanisms may be related to strength increase in the last four weeks of intervention; (3) concentric strength gain is not affected by neural adaptations; (4) eccentric training increases fascicle length, but not pennation angle; (5) muscle architecture adaptations may occur in the first weeks of training; and (6) despite the structural and functional differences, RF and VL present similar adaptation levels.