Thèse numérisée par la Direction des bibliothèques de l'Université de Montréal.

This study compares the effectiveness of three selected exercises (curl-up, conventional hook sit-up and modified hook sit-up) in building abdominal strength and endurance in upper elementary school girls. Ninety-nine subjects were randomly divided into four groups. The study was designed to determine (1) whether an eight week exercise program can increase abdominal strength and endurance; (2) the most effective exercise; (3) if muscle action intensity affects the results. A cable tensiometer measured abdominal strength and a timed sit-up measured abdominal endurance. An analysis of covariance determined significance. Significant gains in abdominal strength and endurance were shown by the conventional hook sit-up. Further study on the relationship between muscle development and maturation in young children is recommended.

Title: Effect of asymmetric load on the stereotype of running. Objectives: The aim of this experimental work is to evaluace the electromyographic activity of selected muscles when running without load and with load on the treadmill, and the co- current assessment of the impact of asymmetric load on the lateral weight distribution. Methods: Six recreational runners underwent the experiment during which we monitored electrical activity of m. deltoideus pars anterior, m. trapezius pars ascendes et descendens, lumbar paraspinal muscles, m. gastrocnemius lateralis and m. tibialis anterior while running without load and with load on the periphery of the upper right extremity. For the experiment a motor treadmill at a constant speed of 10 km/h was used and a 0,5 l PET bottle completely filled with water was applied as the load. Changes of lateral weight distribution were assessed having investigated stance on two scales. The measured values were statistically evaluated. Results: Within the group of all the probands it was proved that there existed an impact on normalized average amplitude of EMG signal at left-oriented m. gastrocnemius lateralis. The hypothesis of the influence of asymmetric load on the lateral weight distribution was not demonstrated. Keywords: endurance running, surface...

The objective of this dissertation was to evaluate the changes in preparedness over the course of training for a marathon in two well-trained runners. The athletes completed periodized strength training or a periodized concurrent training. This dissertation consisted of two separate investigations: Study 1 – The purpose of this study was to monitor changes in force production ability and running performance in one sub-elite marathon runner before, during, and after undertaking a short-term block periodized strength training program. The athlete ceased strength training during the off-seasons and resumed testing after 10. The athlete experienced likely true, meaningful changes in force production characteristics during the taper after the training program. Improvements in force production characteristics coincided with improvements in running economy. Both force production characteristics and running economy reversed after the withdraw from strength training. However, both measures remained improved from initial baseline. The improvement in running economy and force production likely coincided with a cardiovascular de-training period, due to a reduction in aerobic training during the off-season. Therefore, strength training may have independent effects on running economy and running performance. These results indicate that endurance runners may better optimize performance by improving force production characteristics via periodized strength training program, and should avoid prolonged periods without strength training. Study 2 – The purpose of this study was to monitor the concurrent and divergent changes in athlete preparedness and performance over a competitive training cycle in two marathon athletes. One athlete added a block periodized strength training program to a non-periodized endurance training program (NBP Athlete). The other athlete (BP Athlete) completed an integrated, concurrent block periodized program using HIT over-reach endurance training. Both athlete displayed improvements in running performance and running economy over the duration of the monitoring program. The BP Athlete displayed earlier and greater magnitudes of performance improvements. These results indicate that strength training can enhance running economy in marathon athletes, performance may be better optimized through periodized integration of strength and endurance training, and the use of HIT over-reach blocks may improve marathon relevant fitness characteristic within the ecologically valid context of an athlete’s training cycle.

Foi desenvolvido um diafragma de elevada vida útil e biocompatibilidade a ser utilizado em um dispositivo de assistência ventricular esquerda(DAV) eletromecânico de dimensões reduzidas e totalmente implantável. Foi realizado teste de resistência do diafragma de poliuretana com superfície texturizada. O teste avaliou sua resistência para experimentos In Vivo de até quinze dias com o DAV implantado em bezerro. Uma superfície de endotélio natural tem excelente tromboresistência. A quantidade e as características da neointima formada em um DAV são determinadas pela superfície do material, hemodinâmica e condições físico-patológicas. O implante de patch na aorta abdominal de porco isola as variáveis que normalmente estão presentes durante a utilização do DAV e que interferem na hemocompatibilidade do material. A avaliação das características do material foi obtida com o seu implante na parede da aorta descendente em contato com o fluxo sanguíneo. Diferentes tipos de superfície de contato foram avaliadas em sete experimentos In Vivo. Este estudo está voltado para as reações de interface sangue / material. Um estudo histológico foi realizado ao final de cada experimento para analisar as interações entre o sangue e o material, quantificando e qualificando a intima neo formada sobre a superfície de contato, calcificação e deposições de elementos constituintes do sangue / It has been developed a high lifetime and biocompatible diaphragm to be used in a Left Ventricle Assist Device (LVAD) that is a reduced dimension totally implantable electromechanical device. It has been performed an endurance test on a textured diaphragm made of polyurethane. This test has evaluated the diaphragm resistance to be used in In Vivo tests with the LVAD implanted for fifteen days in calves. A natural endothelial cell surface has excellent thromboresistant characteristics. The quantity and the characteristics of the neointima formed into LVAD are determined by the material surface, hemodynamics of the blood through the device, and the physico-pathological conditions. The patch implantation into the abdominal aorta of pigs has isolated some normal variables that usually are present during LVAD utilization and that may interfere on the material biocompatibility. The evaluation of the material’s characteristics has been enhanced through its implantation at the descending aorta wall in contact with blood flow. Different kinds of contact surfaces of specific polyurethane are tested in seven In Vivo experiments. This study is totally focused in the reaction of the blood-material interface. A histogical study is performed in the end of every animal experiment to analyze the interactions between blood and biomaterial. It’s emphasized the quantification and qualification of the neointima over the blood contact surface, calcification, and blood depositions

Com o objetivo de avaliar se o exercício físico prolongado causa alterações miocárdicas em eqüinos de enduro e se estas alterações cardíacas têm influência no desempenho dos animais durante as provas, avaliaram-se 30 cavalos, divididos em três grupos de dez animais cada, sendo G1 composto por animais que percorreram distâncias acima de 100 km, G2 por animais que percorreram distâncias menores de 100 km e G3 por animais desqualificados por alterações metabólicas. Os animais foram avaliados em três momentos distintos, T0 (pré-exercício, em repouso), T1 (entre 30 e 60 minutos após o exercício) e T2 (entre 90 e 120 minutos pós-exercício). Realizaram-se o exame físico e o exame ecocardiográfico, além de colheita de amostras de sangue para determinação de troponina I cardíaca sérica e outras provas bioquímicas. Não houve diferença nos valores de troponina I cardíaca entre os diversos grupos nem nos diferentes tempos. Observou-se diminuição dos valores do diâmetro interno do ventrículo esquerdo em diástole e aumento de espessura de septo interventricular pós-exercício. Não houve diferença nos índices funcionais cardíacos e houve manutenção do débito cardíaco por aumento da freqüência cardíaca. Estas alterações ecocardiográficas de pequena magnitude foram mais evidentes nos animais desqualificados por alterações metabólicas e não parecem estar relacionadas a injúria miocárdica e sim secundárias a outras condições orgânicas. Conclui-se que o exercício físico prolongado não leva a injúrias cardíacas severas em cavalos de enduro. / With the purpose of evaluating myocardial alterations caused by prolonged physical exercise and whether these alterations influence the endurance horses\' performance during the races, 30 horses were evaluated, divided into three groups of ten horses each, being G1 composed by animals that performed distances of more than 100 km, G2 by animals that performed distances of less than 100 km and G3 by animals disqualified by metabolic alterations. The horses were evaluated in three distinct moments, T0 (pre-exercise, at rest), T1 (between 30 and 60 minutes post-exercise) and T2 (between 90 and 120 minutes post-exercise). Physical and echocardiographic examinations and else blood sample collection for the determination of cardiac troponin I and other biochemical tests were done. There was no difference in cardiac troponin I values neither between the various groups, nor between the moments. There was a decrease in the post-exercise values of the diastolic left ventricle internal diameter and an increase in the post-exercise values of the interventricular septal thickness. There was no difference in the cardiac functional indexes and the cardiac output was maintainded by augmentation of the heart rate. These minor echocardiographic alterations were more evident in the animals that were disqualified by metabolic alterations, and they don\'t seem to be related to myocardial injury, but secondary to other organic conditions. Based on these results, prolonged physical exercise doesn\'t seem to cause severe cardiac injuries in endurance horses.

Estudos têm demonstrado separadamente, a redução do desempenho aeróbio após uma tarefa de alta demanda cognitiva, e a melhora do desempenho físico através da suplementação com bochecho de carboidrato (CHO), levando à hipótese de que o bochecho com CHO possa atenuar a redução do desempenho aeróbio induzida pela fadiga mental. Portanto, nosso objetivo foi investigar se o uso do bochecho com CHO pode melhorar o desempenho físico, atividade cortical e respostas psicofisiológicas em ciclistas mentalmente fadigados submetidos a um teste incremental máximo (TIM). Métodos: 19 ciclistas treinados (7,56 ± 5,89 anos de experiência, 4,43 ± 0,45 VO2PICO, 359,61 ± 22,92 WPICO) realizaram 5 visitas ao laboratório, sendo as duas primeiras em ordem sequencial e as últimas três balanceadas de acordo com a descrição a seguir: 1) familiarização com TIM (teste preliminar), instrumentos e protocolo de FM; 2) TIM controle (CON) e segunda familiarização com o protocolo de FM; 3) TIM+FM; 4) TIM+FM+CHO; 5) TIM+FM+placebo (PLA). Respostas cardiopulmonares, potencia, percepção subjetiva de esforço (PSE) e valências afetivas foram analisadas durante o TIM, enquanto a atividade de córtex pré-frontal (CPF) e córtex motor primário (CMP) foram analisadas em intervalos regulares (a cada 25 % do TIM preliminar). As respostas psicológicas e atividade de CPF em repouso foram comparadas através do teste t de student, enquanto todas as respostas durante o TIM foram comparadas através de uma de modelos mistos. Resultados: os ciclistas mentalmente fadigados atingiram WPICO ~ 2,18 % e ~ 2.23 % maior na manipulação FM+CHO do que na manipulação FM (P = 0,09) e FM+PLA (P = 0,02). Além disso, o tempo até a exaustão na manipulação FM+CHO foi ~ 2,01 % e ~ 2,14 % maior do que na manipulação FM (P = 0,05) e FM+PLA (P = 0,03), com tamanho de efeito grande em ambos os resultados. A atividade cerebral em CPF foi maior na manipulação MF+CHO e MF+PLA do que na manipulação MF (P = 0,00). Além disso a ativação de CMP também foi maior na manipulação MF+CHO (P = 0,00) e MF+PLA (P = 0,01) do que na manipulação FM, mas nenhuma diferença foi encontrada entre os bochechos. As respostas psicofisiológicas não tiveram diferenças significantes entre as manipulações. Conclusão: O bochecho com CHO foi capaz de atenuar a perda de desempenho comparado à manipulação FM+PLA, mas não comparado à FM. Alémdisso, tanto FM+CHO quanto FM+PLA induziram maior atividade de CPF e CMP comparados à FM / Independent studies have shown a decrease in endurance performance after a high-demand cognitive task, but an improvement on endurance performance with carbohydrate (CHO) mouth rinse, thus leading to a hypothesis that the CHO mouth rinse could attenuate the mental fatiguereduced endurance performance. Therefore, our aim was to investigate if the use of CHO mouth rinse may improve physical performance, cortical activity and psychophysiological responses in mentally fatigued cyclists underwent to a maximal incremental test (MIT). Methods: 19 endurance trained cyclists (7.56 ± 5.89 years of cycling experience, 4.43 ± 0.45 VO2PEAK, 359.61 ± 22.92 WPEAK) performed 5 trials, being the two first visits in sequential and the last three in a counterbalanced order, as it follow: 1) familiarization with MIT protocol (preliminary trial), instruments and MF task; 2) MIT control (CON) and second familiarization with MF task; 3) MIT+CHO; 4) MIT+placebo (PLA). Cardiopulmonary responses, power output, ratings of perceived exertion (RPE) and affective valences were assessed through the MIT, while prefrontal cortex (PFC) and primary motor cortex (PMC) activation were obtained at regular intervals (every 25 % of the preliminary MIT). Psychological responses and PFC activation at rest were compared as using t student test, while the responses during the MIT were compared through a number of mixed model. Results: Mentally fatigued cyclists reached a WPEAK ~ 2.18 % and ~ 2.23 % higher in MF+CHO than MF (P = 0.09) and MF+PLA (P = 0.02), respectively. Moreover, time to exhaustion in MF+CHO manipulation was ~ 2.01 % and ~ 2.14 % greater in MF+CHO than in MF (P = 0.05) and MF+PLA (P = 0.03), respectively. Both performance results showed a large effect size. Cerebral activation in CPF was greater in MF+CHO and MF+PLA than in MF (P = 0.00). Accordingly, PMC activation was also greater in MF+CHO (P = 0.00) and MF+PLA (P = 0.01) than in MF, but no differences have been observed between bouth rinses. Psychophysiological responses has no significant differences between the manipulations. Conclusion: CHO mouth rinse could attenuate the reduced performance compared to MF+PLA but not compared to MF. Moreover, both MF+CHO and MF+PLA induced greater cerebral activity in PFC and PMC compared do MF

Les buts de cette thèse étaient de définir les déterminants de la santé osseuse chez les jeunes femmes en surpoids et obèses et d'explorer les effets de deux programmes longitudinaux d'entraînement physique (force vs. endurance) sur les paramètres osseux chez les jeunes femmes en surpoids et obèses. Deux études préliminaires et six études principales ont été menées. La première étude préliminaire a montré que la VO2 max (L/mn) est un déterminant positif de la masse osseuse chez les enfants en surpoids. La deuxième étude préliminaire a démontré que l'IMC est un déterminant négatif du CSI, du BSI et de l'ISI chez les jeunes femmes. La première étude principale a montré que l'obésité est associée à de faibles valeurs de CSI, de BSI et d'ISI chez les jeunes femmes. La deuxième étude principale a montré que la VO2 max (ml/mn/kg) est positivement corrélée au CSI et à l'ISI chez les jeunes femmes. La troisième et la quatrième étude ont montré que la surcharge pondérale est associée à une augmentation du CMO et de la DMO mais pas du TBS et que le TBS est corrélé positivement à la VO2 max (L/mn). La cinquième étude principale chez 68 jeunes femmes en surpoids et obèses a montré que la détente verticale, la VO2 max (L/mn), la puissance maximale (watts) et la force maximale en demi-squat sont positivement corrélées aux paramètres osseux chez les jeunes femmes en surpoids et obèses. La sixième étude principale a montré que les deux types d'entrainement physique (force et endurance) sont efficaces pour augmenter le CMO CE et la DMO lombaire et diminuer le poids et la masse grasse. L'entrainement de force était aussi efficace pour l'augmentation du TBS et les indices de résistance osseuse du col fémoral (CSI, BSI et ISI). / The aims of this thesis were to define the determinants of bone health in young overweight and obese men and to explore the effects of two physical training programs (strength vs. endurance) on bone parameters in young overweight and obese women. Two preliminary studies and six main studies have been conducted. The first preliminary study has shown that VO2 max (L/mn) is a positive determinant of bone mass in overweight children. The second preliminary study has shown that BMI is a negative determinant of CSI, BSI and ISI in young women. The first main study has shown that obesity is associated with lower CSI, BSI and ISI values in young women. The second main study has shown that VO2 max (L/mn) is positively correlated to CSI and ISI in young women. The third and the fourth study have shown that being overweight is associated with higher BMC and BMD values but not with TBS values and that TBS is positively associated with VO2 max (L/mn). The fifth main study conducted on 68 young overweight and obese women has shown that vertical jump, VO2 max (L/min), maximal power (watts) and 1-RM half-squat are positively correlated with bone parameters in overweight and obese adult women. The sixth main study has shown that the two training programs (strength and endurance) are effective to increase whole body BMC and lumbar spine BMD, and to decrease body weight and fat mass. Strength training was also effective to increase TBS and composite indices of femoral neck strength (CSI, BSI and ISI)

The purpose of this study was to determine the acute effects of caffeine supplementation on strength and muscular endurance in resistance-trained women. In a randomized manner, 15 women consumed caffeine (6 mg/kg) or placebo (PL) seven days apart. Sixty minutes following supplementation, participants performed a one repetition maximum (1RM) barbell bench press test and repetitions to failure at 60% of 1RM. Heart rate and blood pressure were assessed at rest, 60 minutes post-consumption, and immediately following completion of repetitions to failure. Repeated measures ANOVA indicated a significantly greater bench press maximum with caffeine (p<0.05) (52.9 « 11.1 kg vs. 52.1 « 11.7 kg) with no significant differences between conditions in 60% 1RM repetitions (p=0.81). Systolic blood pressure was significantly greater post-exercise, with caffeine (p<0.05) (116.8 « 5.3 mmHg vs. 112.9 « 4.9 mmHg). Our findings indicate a moderate dose of caffeine may be sufficient for enhancing strength performance in resistance-trained women. / by Erica R. Goldstein. / Thesis (M.S.)--Florida Atlantic University, 2009. / Includes bibliography. / Electronic reproduction. Boca Raton, Fla., 2009. Mode of access: World Wide Web.

A literatura recente sugere que a fadiga mental piora o desempenho de atletas durante testes contrarrelógio (TT) de ciclismo. Assim o objetivo deste estudo foi verificar se a cafeína poderia reverter ou bloquear os efeitos negativos da fadiga mental em um contrarrelógio de 20km (TT20km). Métodos: Doze ciclistas treinados, com experiência em TT há pelo menos 2 anos, e nível de performance > 3 (34.3 ± 6.2 anos; 179.3 ± 5.1 cm; 77.6 ± 6.8 kg; 13.8 ± 4.5 % de gordura corporal; 58.9 ± 6.2 ml.kg-1.min-1; 367.0 ± 32.5 WPEAK), realizaram cinco visitas ao laboratório: 1) PRELIMINAR: para seleção dos sujeitos e familiarização com os instrumentos; 2) CONTROLE: foram realizadas três contrações voluntárias isométrica máxima (CVM), cujo maior torque encontrado entre elas definirá o valor de 70% para contração voluntária isométrica submáxima (CVIS) nas sessões seguintes. Posteriormente a CVIS, foi realizado o TT20km sem manipulação cognitiva ou suplementação; 3) FADIGA MENTAL (FM): execução do teste de atenção sustentada (RVIP), CVIS e TT20km respectivamente; 4) PLACEBO: ingestão da cápsula de placebo (FM + PLA) em seguida teste de RVIP, CVIS e TT20km; 5) CAFEÍNA: ingestão de cafeína (FM + CAF), consequentemente realizaram o teste de RVIP, CVIS e o TT20km). A atividade cerebral do córtex pré-frontal e córtex motor primário foi analisada por meio de eletroencefalografia (EEG) registrada antes e depois do teste RVIP. Igualmente, EEG do córtex pré-frontal e motor primário foi registrada durante uma contração voluntária isométrica submáxima, realizada antes do TT20km. Para as análises de comparações entre pré e pós tarefa cognitiva de atenção sustentada utilizou-se um teste T-student. Para as comparações múltiplas analisou-se por modelo misto entre a condição e a distância no TT20km, quando necessário o teste de Bonferroni foi utilizado. Resultados: CAF melhorou o desempenho em ciclistas mentalmente fatigados em ~ 1.8 % para FM e ~ 1.7 % para PLA (p = 0.00) e aumentou ~ 4.4 % para FM e ~ 3.6 % do que o placebo de WMEAN em FM + CAF (p = 0,00). A ativação cortical aumentou em ~ 4.8 % nas ondas teta de EEG após teste RVIP em FM e reduziu em FM + CAF ~ 8.8 % e FM + PLA ~ 4.8%. A razão entre PSE e WMEAN foi menor em FM + CAF do que nas outras condições (p = 0.01). Os ciclistas apresentaram maior motivação nos primeiros 2 km em FM + CAF comparado a FM e FM + PLA (p = 0.02) e maior afeto nos últimos 2 km em FM e FM + CAF do que FM + PLA (p = 0.01). Uma menor ativação cortical durante a CVIS e uma maior eficiência neuromuscular foi identificada na condição FM + CAF (p = 0.03). Conclusão: A CAF bloqueou os efeitos negativos da fadiga mental no CPF, melhorou o desempenho, diminuiu a PSE durante TT20km e aumentou a eficiência neuromuscular / Recent literature suggests that mental fatigue worsens the performance of athletes during time trial (TT) cycling tests. Thus, the aim of this study was to verify if caffeine could reverse or block the negative effects of mental fatigue in a TT of 20km (TT20km). Methods: Twelve trained cyclists with experience in TT for at least 2 years, and performance level > 3 (34.3 ± 6.2 years, 179.3 ± 5.1 cm, 77.6 ± 6.8 kg, 13.8 ± 4.5 % body fat 58.9 ± 6.2 ml .kg-1.min-1; 367.0 ± 32.5 WPEAK), carried out five visits at laboratory: 1) PRELIMINARY: for selection of subjects and familiarization with the instruments; 2) CONTROL: three maximal isometric voluntary contractions (CVM) were performed, the highest torque found between them will define the value of 70% for voluntary isometric submaximal contraction (CVIS) in the following sessions. After the CVIS, the TT20km will be performed without cognitive manipulation or supplementation; 3) MENTAL FATIGUE (FM): execution of the sustained attention test (RVIP), CVIS and TT20km respectively; 4) PLACEBO: placebo capsule intake (FM + PLA) then RVIP, CVIS and TT20km test; 5) CAFFEINE: caffeine intake (FM + CAF), consequently performed the RVIP, CVIS and TT20km tests). Brain activity of the prefrontal cortex and primary motor cortex will be analyzed by electroencephalography (EEG) recorded before and after the RVIP test. Likewise, EEG of the prefrontal cortex and primary motor will be recorded during a submaximal isometric voluntary contraction, performed before TT20km. For the analysis of comparisons between pre and post cognitive task of sustained attention was used a T-student test. For the multiple comparisons, the mixed model was analyzed for the condition and the distance in the TT20km, and the best matrix was identified for each case, when necessary the Bonferroni test was used. Results: CAF improved performance in mentally fatigued cyclists at ~ 1.8 % for FM and ~ 1.7 % for PLA (p = 0.00) and increased ~ 4.4% for FM and ~ 3.6% than WMEAN on FM + CAF (p = 0.00). Cortical activation increased by ~ 4.8 % in the theta EEG waves after RVIP test in FM and reduced in FM + CAF ~ 8.8 % and FM + PLA ~ 4.8 %. The ratio of RPE to WMEAN was lower in FM + CAF than in other conditions (p = 0.01). The ciclists started the TT20km more motivated in first 2 km (p = 0.02) and finished with more pleasure in the last 2km in FM and FM + CAF than in FM + PLA (p = 0.01). Lower cortical activation during CVIS and greater neuromuscular efficiency was identified in the FM + CAF condition (p = 0.03). Conclusion: CAF blocked the negative effects of mental fatigue on CPF, improved performance, decreased PSE over TT20km and increased neuromuscular efficiency