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While fatigue is a common daily phenomenon, the exact relationship between perception of effort and fatigue is still unknown. Existing tools for assessing perception of effort are effectively limited to whole body exercise, while current methods for assessing voluntary activation are painful and not feasible for clinical application. The main aims of this thesis were to evaluate existing methodologies for their appropriateness in assessing perception of effort and voluntary activation following isolated muscle function testing, and to examine the relationship between subjective perception of effort and objective changes in the healthy motor control system. The implementation of reliable and valid assessment tools in clinical practice may enable clarification of the pathogenesis of many neurological conditions that have chronic fatigue as a key feature. Four studies of within-subjects repeated measures design have been conducted. Sixtynine healthy volunteers were recruited among staff and students of Brunel University. Magnetic stimulation was tested as a valid alternative to electrical stimulation in the conventional single-pulse Twitch Interpolation Technique. The 0–10 Numeric Rating Scale (NRS) was also tested for its reliability and validity in assessing the perception of effort during isometric exercise of elbow flexors. The changes of perception of effort following a submaximal elbow flexion fatiguing task, as well as following transcranial direct current stimulation (tDCS) over the motor cortex were also tested. The main findings showed significant differences between peripheral and magnetic stimulation in conventional single-pulse Twitch Interpolation Technique. The 0–10 NRS demonstrated linear properties and reported excellent test-retest reliability and good concurrent criterion validity in recording perception of effort under repeated isometric contractions of elbow flexors. Ten minutes of a submaximal intermittent isometric fatiguing exercise produced a significant elevation in rating of perceived effort, which was associated with central and peripheral neurophysiological changes of the motor control system. In contrast, perception of effort did not change significantly following 10 minutes of tDCS. The major findings of this thesis suggest the 0–10 NRS is a valid and reliable scale for rating perception of effort in healthy individuals. Further testing of the scale on patients is needed to establish its validity in clinical settings. Additionally, the findings indicate a substantial role of perception of effort in the voluntary motor control system. However, further research towards revealing the underlying mechanisms of perceived effort regulation in both health and disease is required.

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

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

Water is arguably the most important nutrient given that even minor deficits lead to performance detriment for athletes and, in a matter of days, total absence causes fatality for all. Despite this, several reports suggest that an overwhelming amount of the athletic population competes and trains in a dehydrated state. The impact of dehydration on leisure sports, such as golf, is less certain given that fine motor skill sports have received less attention in the literature and that existing research on dehydration and golfers is largely limited to males. In this randomized, controlled, crossover pilot experiment, elite female golfers on the Virginia Tech Women’s Golf Team (n=6) completed four laboratory simulated golf holes in both euhydrated and dehydrated states. Euhydration (mean urinary specific gravity [USG]=1.009; range=1.003–1.021) was attained by following the NCAA hydration guidelines, and dehydration (mean USG=1.021; range=1.018–1.026) was attained via a 12 hour overnight fast from fluids. No significant interactions of condition by time for perceived effort, 7-iron distance and accuracy, putting accuracy, reaction time, and executive cognitive function were found between euhydrated and dehydrated states. However, although not significant, euhydrated participants demonstrated improved 7-iron and putting accuracy and reported less perceived effort as compared to performance during their dehydrated state. Based on USG levels, NCAA hydration recommendations may not be adequate to induce a euhydrated state for all athletes. More research is needed with larger sample sizes to further elicit the impact of hydration status on variance in motor and cognitive function for elite golfers. / Masters of Science / Besides oxygen, our bodies need water more than anything else to function. Water is so vital to health that its absence can cause death in just three days. Athletic populations, in particular, should aim for adequate hydration to optimize sport performance, to avoid heat illness, and to promote overall health and wellbeing. Despite this importance, few studies have investigated the impact of hydration status on athletic performance of golfers, and of these studies, none have been done with females. In this experiment, female golfers on the Virginia Tech Women’s Golf Team (n=6) completed four laboratory simulated golf holes in both euhydrated and dehydrated states. Adequate hydration (euhydration) was attained by following the NCAA hydration guidelines, and dehydration was attained by restricting participants from drinking any fluid for 12 hours overnight. Performance in both adequate hydration and dehydration was measured by perceived effort, 7-iron distance and accuracy, putting accuracy, reaction time, and executive cognitive function. No significant interactions for any of the measures resulting in differences over time were found. However, although not significant, euhydrated participants demonstrated greater 7-iron and putting accuracy and reported less perceived effort as compared to performance during their dehydrated state. One participant did not reach adequate hydration by following the fluid intake guidelines during the hydration visit; therefore, NCAA hydration recommendations may not adequately hydrate all collegiate athletes. More research is needed with larger sample sizes to determine the impact of hydration status on motor and cognitive function of elite female golfers.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-06-24T13:12:45Z No. of bitstreams: 1 victorhugodefreitas.pdf: 1041704 bytes, checksum: 5dd391fff68063cedd3bcac2d195b278 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-07-13T15:44:24Z (GMT) No. of bitstreams: 1 victorhugodefreitas.pdf: 1041704 bytes, checksum: 5dd391fff68063cedd3bcac2d195b278 (MD5) / Made available in DSpace on 2016-07-13T15:44:24Z (GMT). No. of bitstreams: 1 victorhugodefreitas.pdf: 1041704 bytes, checksum: 5dd391fff68063cedd3bcac2d195b278 (MD5) Previous issue date: 2012-03-23 / A intensificação da carga de treinamento é uma estratégia utilizada em momentos da periodização, entretanto, poucos estudos fazem essa abordagem no voleibol, modalidade esportiva de característica peculiar, com um calendário esportivo também peculiar, necessitado assim conhecer o comportamento da carga de treinamento durante um período de treinamento nessa modalidade utilizando variáveis de simples e fácil aplicação. Desse modo, essa dissertação objetivou: Analisar o comportamento de marcadores da carga de treinamento em um grupo com atletas de voleibol submetidos a cargas de treinamento intensificadas e em um grupo submetido a cargas de treinamento sem intensificação; e Analisar e descrever o comportamento da carga de treinamento e da recuperação ao longo de um período de treinamento no voleibol. A princípio, atletas de voleibol do sexo masculino, foram divididos em 2 grupos, um submetido a treinamento intensificado (IT) com 8 atletas (23,37 ± 2,94 anos) e um, à treinamento com cargas normais (NT) com 8 atletas (19,75 ± 1,48 anos). O Questionário de Estresse e Recuperação para atletas (RESTQ-Sport), Creatina quinase (CK) o teste de Impulsão vertical (IV) foram avaliados, no primeiro, no 12º e no 26º dias de treinamento. A TQR (escala de qualidade total de recuperação) foi aplicada no primeiro e ultimo dia de treinamento de cada microciclo. A carga de treinamento quantificada através do método PSE da sessão mostrou que no grupo IT a carga de treinamento esteve aumentada nos dois primeiros microciclos, diminuiu nos 2 microciclos posteriores, foi maior no primeiro período de treinamento e foi maior que a carga de treinamento apresentada pelo grupo NT, grupo em que a carga não apresentou modificações. A IV e o RESTQ-Sport não se modificaram. A CK esteve aumentada no 12º dia em ambos os grupos, sendo maior no grupo IT, com retorno de seus valores ao estado inicial após o segundo período no grupo IT. A TQR no grupo IT, apresentou valores mais baixos que o grupo NT, bem como nos dois primeiros microciclos. Posteriormente, 12 atletas de voleibol do sexo masculino, com média de idade de 23,50 ± 3,39 anos, foram monitorados durante 22 semanas de treinamento através do método PSE da sessão e da escala TQR. Foram calculadas a carga de treinamento semanal total, monotonia e strain. A carga de treinamento semanal total (p<0,01), a monotonia (p<0,01) e o strain (p<0,01), foram significativamente diferentes ao longo das 22 semanas analisadas, mostrando um comportamento oscilatório. A recuperação não 6 se modificou ao longo das 22 semanas. Conclui-se que, o grupo submetido à intensificação da carga de treinamento não modificou o desempenho, entretanto apresentou maior dano muscular, maior estresse e menor estado de recuperação que o grupo que não sofreu intensificação, no qual, também não modificou o desempenho. Também, que a carga de treinamento apresentou um caráter oscilatório ao longo das semanas, com progressão de seus valores, intercalando períodos de altas e baixas cargas de treinamento e a recuperação mostrou-se regular ao longo desse mesmo período. / The intensification of the training load is a strategy used in moments of periodization, however, few studies make use of this approach in volleyball, a peculiar kind of sports, with an also peculiar schedule, which makes it necessary to know the behavior of the training load during a training period of this kind of sport by means of simple and easy to apply variables. Due to that, this dissertation aimed to: analyze the behavior of training load markers in a group of volleyball athletes submitted to intensified training loads compared to another group submitted to training loads without intensification; analyze and describe the behavior of the training load and that of recuperation along the training period in volleyball. At first, the male volleyball players were divided into 2 groups: the intensified training group (IT) with 8 athletes (23.37 ± 2.94 years old) and the training group with normal training (NT), also with 8 athletes (19.75 ± 1.48 years old). The Recovery-Stress Questionnaire for athletes (RESTQ-Sport), Creatine kinase (CK) and the vertical jump test (IV) were assessed on the 1st, 12th ans 26th days of training. The TQR (Total Quality Recovery) was applied on the first and last training days of each microcycle. The training load, quantified through the PSE method of the session, showed that in the IT group the load was higher in the first two microcycles, decreased in the two subsequent ones, was highest in the first training period and was also higher than that of the NT group, whose loads remained constant. The IV and the RESTQ-Sport did not present changes. The CK was higher on the 12th day in both groups, but higher in the IT group, while the values returned to the initial state after the second period in the IT group. The TQR in the IT presented lower values than those of the NT group, and the same happened in the two first microcycles. Later, 12 male volleyball athletes, with average age of 23.50 ± 3.39 years old, were monitored for 22 training weeks with the use of the session RPE method and the TQR scale. The total weekly training load, monotony and strain were calculated. The total weekly training load (p<0.01), monotony (p<0.01) and strain (p<0.01) were significantly different along the 22 weeks analyzed, showing an oscillatory behavior. The recovery remained constant along the 22 weeks. It can be concluded that the group submitted to the intensification of the training load did not present changes in performance. Nevertheless, it had more muscular damage, more stress and less recovery than the group which did not had intensification (and whose performance also remained 8 steady). The training load presented an oscillatory character along the weeks studied, with a progression in the values, alternating periods of high and low training loads, and recovery showed to be regular along the same period.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-10-03T12:15:23Z No. of bitstreams: 1 jonasalmeidanevesmartins.pdf: 670644 bytes, checksum: 679ac9b33c9908bca7ef8da0cda4dd02 (MD5) / Approved for entry into archive by Diamantino Mayra (mayra.diamantino@ufjf.edu.br) on 2016-10-03T15:16:49Z (GMT) No. of bitstreams: 1 jonasalmeidanevesmartins.pdf: 670644 bytes, checksum: 679ac9b33c9908bca7ef8da0cda4dd02 (MD5) / Made available in DSpace on 2016-10-03T15:16:49Z (GMT). No. of bitstreams: 1 jonasalmeidanevesmartins.pdf: 670644 bytes, checksum: 679ac9b33c9908bca7ef8da0cda4dd02 (MD5) Previous issue date: 2010-04-20 / A bicicleta aquática Hidrocycle® possui sistema para gerar resistência, denominado Evolution®, que consiste em quatro calhas retangulares dispostas perpendicularmente movimentadas pelo giro dos pedais. Neste sistema há duas maneiras para controlar a carga: 1) velocidade de pedalada (RPM) e 2) alteração da área frontal das calhas (AF) em três níveis, AF1, AF2 e AF3. Para utilização mais precisa no treinamento, torna-se necessário o estudo das variáveis que atuam no controle da intensidade do exercício do sistema Evolution®, freqüência cardíaca (FC), percepção do esforço (PE), tensão muscular, consumo de oxigênio (VO2), gasto calórico e concentração de lactato [La] em resposta às variações de RPM e AF. Portanto, os objetivos do estudo foram verificar: 1) A resposta da FC e PE em teste progressivo de esforço realizado em duas profundidades, cicatriz umbilical e processo xifóide; 2) Identificar VO2max, [La]max, FCmax e PE para cada AF do sistema Evolution® em protocolo progressivo de cargas e predizer o gasto calórico e potência gerada protocolo de carga submáxima constante. Para o estudo 1, a amostra foi constituída por 10 homens e mulheres ativos, submetidos a dois testes progressivos, um em cada profundidade. Para o estudo 2, 15 homens, fisicamente ativos realizaram 3 testes máximos, um com cada AF e um teste de carga constante submáxima para predição do gasto calórico e potência gerada. No estudo 1, os valores máximos de FC e PE apresentaram diferenças estatisticamente significantes ao serem comparados nas duas profundidades. Já a FC por estágio de RPM, apresentou a partir do terceiro estágio tendência a ser mais alta, sendo evidente a diferença a partir do sétimo estágio na altura do processo xifóide. O estudo 2 verificou-se que não há diferença nos valores máximos de FC, VO2, [La] e PE nas 3 AF estudadas em teste máximo, porém os valores ocorrem em RPM diferentes, revelando que quanto maior a AF, menor é a RPM para se atingir os máximos para FC, VO2, [La1] e PE. Para o mesmo estudo, permitiu predizer o VO2 a partir das variáveis AF, RPM. Conclui-se que o sistema Evolution® da bicicleta aquática Hidrocycle® permite adequar a sobrecarga de exercício, assim como sua predição facilitando a aplicação do equipamento nas diversas áreas do treinamento físico. / The aquatic bicycle Hidrocycle® has a system to generate resistance, called Evolution®, which consists of four rectangular troughs arranged perpendicularly moved by the rotation of the pedals. In this system there are two ways to control the load: 1) the pedaling speed (rpm) and 2) change in the frontal area of ducting (AF) in three levels, AF1, AF2 and AF3. To use more precise training, it is necessary to study the variables that act in the control of exercise intensity Evolution® system, heart rate (HR), perceived exertion (PE), muscle tension, oxygen consumption (VO2) and lactate concentration [La] in response to changes in RPM and AF. Therefore, the objectives of the study were: 1) The response of HR and PE in the progressive effort test performed at two depths, umbilicus and xiphoid process, 2) Identify VO2max, [La]max, and PE for each AF system Evolution ® protocol in progressive loads and to predict the VO2. For study 1, the sample consisted of 10 active men and women who underwent two progressive tests, one in depth. For study 2, 15 men, physically active performed area submitted to 3 maximal tests, one each with AF and a test of submaximal constant workload to predict the caloric expenditure and power generated. In study 1, the maximum values of HR and PE showed no statistically significant differences when comparing the two depths. The HR for stage RPM, presented from the third stage tend to be higher in height of the xiphoid process. In study 2, there was no difference in the maximum values of HR, VO2, [La] and PE in 3 AF studied in maximal test, but the values occur at different rpm, showing that the higher the AF, the less RPM to achieve the maximum for HR, VO2, [La1] and PE. Since the study incremental load predicted VO2 from the variables AF, RPM. We conclude that the system Evolution ® aquatic bicycle Hidrocycle ® to tailor the exercise overload, as well as the prediction equity to facilitate the implementation of the equipment in the various areas of physical training.

De multiples événements sportifs majeurs vont se dérouler prochainement dans des environnements chauds voire tropicaux, justifiant l’intérêt scientifique actuel pour les questions associées à l’effet de la chaleur sur la performance en endurance. Il est admis que l’effort est subjectivement perçu comme plus difficile, en parallèle de la dégradation de la performance, à mesure que la température ambiante s’élève au cours d’une épreuve prolongée. Contrecarrer les effets délétères de la chaleur passe notamment par une exposition répétée dans des conditions écologiques ou simulées d’exercice (i.e. stratégie d’acclimatation). Toutefois, le décalage actuel entre les recommandations d’application issues d’études scientifiques et les conditions réelles de préparation et d’organisation des athlètes de haut niveau est à l’origine d’un faible engouement actuel pour de telles méthodes. Par conséquent, ce travail de thèse a eu pour ambition de répondre à certaines inconnues relatives à l’application de contenus d’entraînement classiques en ambiance chaude, en particulier (i) leur conséquence sur la capacité de performance de l’athlète et (ii) les moyens d’optimiser le contrôle et la régulation de la charge d’entraînement. Dans ce contexte, nous avons proposé à des sujets entraînés de soutenir la production de seuils de RPE (i.e. exercice à RPE fixe) dans un cadre expérimental puis d’entraînement. Au-delà de la validité de ce modèle, nous soutenons que la régulation volontaire de l’intensité dépend, au-delà de la perception de l’effort, de l’état émotionnel et de la motivation de l’individu. Lors d’une première étude, nous avons recherché à comparer les performances de solutions techniques pour le suivi de la température centrale en conditions écologiques (i.e. température gastro-intestinale vs. température frontale par capteur à annulation de flux). Les résultats obtenus ont validé l’usage du capteur à annulation de flux comme alternative pendant l’exercice, en dépit de l’absence de corrélation avec les mesures gastro-intestinales. Ceci suggère d’éventuelles perspectives en matière de contrôle de la température corporelle pendant l’exercice. La seconde étude s’est intéressée aux possibles conséquences de la répétition de sessions d’entraînement exigeantes et des contraintes logistiques d’un stage d’acclimatation (i.e. accumulation de fatigue mentale) sur la perception de l’effort et la performance. En dépit de l’absence d’effets combinés de la tâche cognitive préexercice et de la chaleur ambiante, les résultats tendent à démontrer le rôle-clé de la température cutanée et de la sensation de chaleur sous-jacente dans la régulation de la puissance soutenue à RPE-15 (chaud vs. tempéré : -0,022 vs. -0,008 W.kg-1.min-1). Enfin, la troisième étude suggère un potentiel intérêt de l’application de hautes intensités autorégulées, associée à une diminution du volume d’entraînement (-23%), lors d’une période d’acclimatation de courte durée (i.e. 5 jours). Le moindre effet observé, en comparaison d’un protocole à intensité fixe, sur la performance au cours d’un exercice de contre-la-montre (i.e. expérimental vs. fixe : 1,4 vs. 2,8 %) soulève toutefois l’importance du rapport volume-intensité dans la construction d’un protocole d’acclimatation. De manière générale, l’ensemble des résultats de cette thèse offrent des perspectives pour une individualisation et une adaptation spécifique à l’activité sportive des protocoles d’acclimatation à la chaleur. / The increasing number of major sport events that will take place in hot and/or tropical environments justify the current scientific interest in the effects of heat strain on endurance performance. During a prolonged self-paced exercise, it is well known that the subjectively perceived effort is higher as the ambient temperature increases and the performance level decreases. A repeated exposure to the heat in ecological and/or simulated exercise conditions may counteract the subsequent deleterious effects. However, the discrepancy between guidelines from scientific research and training priorities of well-trained athletes causes a lack of interest in these methods. Therefore, we aimed through the current thesis work to improve the current knowledge about heat acclimation strategies, more precisely about i) its effects on athlete’s performance capacity and ii) the optimization of training load monitoring and building. To shed light on these issues, we proposed to our trained and/or well-trained subjects to cycle at a fixed RPE first in an experimental framework, and then during a training program. We submit that the self-regulation of fixed-RPE exercise work rate depends not only of perceived exertion but also on emotional and motivational parameters. The first study aimed to compare the performance of technical devices for core temperature monitoring in ecological conditions (i.e. gastrointestinal point vs. forehead point from a zero-heat-flux sensor). Results showed that zero-heat-flux measurements might be considered as relevant during exercise. In this way, some opportunities may be considered for the monitoring of body temperature during field-based exercise. The second study investigated the subsequent effects of repeated strenuous training sessions and logistical constraints during a heat camp (i.e. higher mental fatigue) on perceived exertion and endurance performance. Despite the lack of combined effects from the prior cognitive task and the ambient condition during exercise, skin temperature and underlying heat sensation impact the linear decrease of power output at RPE-15 (hot vs. neutral: -0,022 vs. -0,008 W.kg-1.min-1). Lastly, the third study suggested an interest for self-regulated high intensities, associated with a decrease of the total exposure duration (-23%), during a short-term heat acclimation protocol (i.e. 5 days). However, the slighter effect on the improvement of performance in comparison with a classic constant-power training program, (HIT vs. constant-power: 1,4 vs. 2,8 %) provides scope for the building of training load (i.e. volume vs. intensity) in this context. In summary, the overall results of this thesis work open some perspectives for individualizing or adapting heat acclimation strategies to sport-specific conditions.

L’asymétrie de mise en charge (MEC) lors du passage assis à debout (PAD) chez les personnes hémiparétiques est une observation clinique connue mais peu expliquée. Ce projet visait donc le développement de connaissances sur les facteurs explicatifs de l’asymétrie de MEC chez cette clientèle en s’intéressant plus spécifiquement au lien entre la distribution des efforts aux genoux lors du PAD et l’asymétrie de MEC observée ainsi qu’à la perception de ces deux éléments lors de cette tâche. Ainsi, les objectifs généraux étaient de : 1) déterminer si l’exécution spontanée asymétrique du PAD des sujets hémiparétiques est expliquée par une distribution des efforts symétriques aux genoux en quantifiant ces efforts par le Taux d’utilisation musculaire électromyographique (TUMEMG) et, 2) déterminer si les individus hémiparétiques sont conscients des stratégies motrices qu’ils utilisent en évaluant leurs perceptions de MEC et d’efforts aux genoux durant le PAD. La première étude a évalué la capacité des personnes hémiparétiques à percevoir leur distribution de MEC aux membres inférieurs lors du PAD. Par rapport aux participants sains, leur distribution de MEC fut davantage asymétrique et leurs erreurs de perception plus élevées. La deuxième étude a quantifié la distribution des efforts aux genoux chez les sujets sains et hémiparétiques lors du PAD spontané. Les deux groupes ont montré une association entre leur distribution de MEC et leur distribution d’effort. Toutefois, la relation était plus faible chez les patients. Le classement des participants hémiparétiques en sous-groupes selon leur degré d’asymétrie de force maximale des extenseurs des genoux (faible, modéré, sévère) a révélé une similarité des efforts aux genoux parétique et non parétique chez le groupe ayant une atteinte sévère. La troisième étude a déterminé si la perception de la distribution des efforts aux genoux des sujets hémiparétiques était reliée à leur distribution réelle d’effort mesurée lors de PAD exécutés dans différentes positions de pieds. En plus d’être incapables de percevoir les changements de distribution d’effort induits par les différentes positions de pieds, leurs erreurs de perception d’effort furent plus élevées que celles de MEC. Par le biais du test fonctionnel assis-debout de cinq répétitions, la dernière étude a déterminé l’influence du nombre de répétitions du PAD sur les distributions de MEC et d’efforts aux genoux chez les sujets sains et hémiparétiques. Contrairement aux contrôles, les distributions des sujets hémiparétiques furent plus asymétriques à la première répétition du test fonctionnel que lors de l’exécution spontanée unique du PAD. En somme, les résultats de cette thèse ont démontré que la distribution des efforts aux genoux doit être considérée parmi les facteurs explicatifs de l’asymétrie de MEC des individus hémiparétiques lors du PAD et qu’il y a un besoin de mieux documenter la perception des personnes hémiparétiques lorsqu’elles exécutent des tâches fonctionnelles. / Weight-bearing (WB) asymmetry during sit-to-stand (STS) in hemiparetic individuals is frequently observed in clinical practice but it has never been well explained. The aim of this project, therefore, was to develop our knowledge of the factors accounting for the WB asymmetry in this population by focusing more specifically on the relationship between the knee effort distribution during the STS task and the WB asymmetry observed as well as on the perception of these two elements during this task. Thus, the general objectives were to: 1) determine whether the spontaneous asymmetrical execution of the STS task in hemiparetic subjects can be explained by a symmetrical distribution of the efforts at the knees by quantifying these efforts using the Electromyographic Muscular Utilization Ratio (EMUR) and, 2) determine whether these hemiparetic individuals are aware of their motor strategies by evaluating their perception of both knee effort and WB distributions during the STS task. The first study evaluated the capacity of hemiparetic persons to perceive their WB distribution at their lower limbs during the STS task. Compared to the healthy participants, their WB distribution was more asymmetrical and they showed greater errors in perception. The second study quantified the distribution of efforts at the knees among healthy and hemiparetic subjects during a spontaneous STS task. Both groups showed an association between their WB distribution and their distribution of efforts but the relationship was not as strong in the hemiparetic group. Dividing the hemiparetic participants into subgroups, according to their knee extensors’ strength asymmetries (mild, moderate, severe), revealed symmetrical knee efforts between sides for the severe group. The third study determined whether hemiparetic individuals’ perception of their knee effort distribution was related to their real distribution of efforts measured during STS tasks performed in various foot positions. Not only were they unable to perceive the changes in the distribution of effort induced by the different foot positions but their errors in perception of effort were greater than in WB. With the use of the five-repetition sit-to-stand test, the last study determined the influence of the number of repetitions of the STS on the distributions of WB and effort at the knees among healthy and hemiparetic subjects. Unlike the controls, the distributions of the hemiparetic subjects were more asymmetrical at the first repetition of the functional test than in the single spontaneous execution of the STS. To summarize, the results of this thesis showed that the distribution of efforts at the knees should be considered among other factors explaining the WB asymmetry of hemiparetic individuals during STS and that there is a need to better document the perception of hemiparetic persons when they execute functional tasks.

L’asymétrie de mise en charge (MEC) lors du passage assis à debout (PAD) chez les personnes hémiparétiques est une observation clinique connue mais peu expliquée. Ce projet visait donc le développement de connaissances sur les facteurs explicatifs de l’asymétrie de MEC chez cette clientèle en s’intéressant plus spécifiquement au lien entre la distribution des efforts aux genoux lors du PAD et l’asymétrie de MEC observée ainsi qu’à la perception de ces deux éléments lors de cette tâche. Ainsi, les objectifs généraux étaient de : 1) déterminer si l’exécution spontanée asymétrique du PAD des sujets hémiparétiques est expliquée par une distribution des efforts symétriques aux genoux en quantifiant ces efforts par le Taux d’utilisation musculaire électromyographique (TUMEMG) et, 2) déterminer si les individus hémiparétiques sont conscients des stratégies motrices qu’ils utilisent en évaluant leurs perceptions de MEC et d’efforts aux genoux durant le PAD. La première étude a évalué la capacité des personnes hémiparétiques à percevoir leur distribution de MEC aux membres inférieurs lors du PAD. Par rapport aux participants sains, leur distribution de MEC fut davantage asymétrique et leurs erreurs de perception plus élevées. La deuxième étude a quantifié la distribution des efforts aux genoux chez les sujets sains et hémiparétiques lors du PAD spontané. Les deux groupes ont montré une association entre leur distribution de MEC et leur distribution d’effort. Toutefois, la relation était plus faible chez les patients. Le classement des participants hémiparétiques en sous-groupes selon leur degré d’asymétrie de force maximale des extenseurs des genoux (faible, modéré, sévère) a révélé une similarité des efforts aux genoux parétique et non parétique chez le groupe ayant une atteinte sévère. La troisième étude a déterminé si la perception de la distribution des efforts aux genoux des sujets hémiparétiques était reliée à leur distribution réelle d’effort mesurée lors de PAD exécutés dans différentes positions de pieds. En plus d’être incapables de percevoir les changements de distribution d’effort induits par les différentes positions de pieds, leurs erreurs de perception d’effort furent plus élevées que celles de MEC. Par le biais du test fonctionnel assis-debout de cinq répétitions, la dernière étude a déterminé l’influence du nombre de répétitions du PAD sur les distributions de MEC et d’efforts aux genoux chez les sujets sains et hémiparétiques. Contrairement aux contrôles, les distributions des sujets hémiparétiques furent plus asymétriques à la première répétition du test fonctionnel que lors de l’exécution spontanée unique du PAD. En somme, les résultats de cette thèse ont démontré que la distribution des efforts aux genoux doit être considérée parmi les facteurs explicatifs de l’asymétrie de MEC des individus hémiparétiques lors du PAD et qu’il y a un besoin de mieux documenter la perception des personnes hémiparétiques lorsqu’elles exécutent des tâches fonctionnelles. / Weight-bearing (WB) asymmetry during sit-to-stand (STS) in hemiparetic individuals is frequently observed in clinical practice but it has never been well explained. The aim of this project, therefore, was to develop our knowledge of the factors accounting for the WB asymmetry in this population by focusing more specifically on the relationship between the knee effort distribution during the STS task and the WB asymmetry observed as well as on the perception of these two elements during this task. Thus, the general objectives were to: 1) determine whether the spontaneous asymmetrical execution of the STS task in hemiparetic subjects can be explained by a symmetrical distribution of the efforts at the knees by quantifying these efforts using the Electromyographic Muscular Utilization Ratio (EMUR) and, 2) determine whether these hemiparetic individuals are aware of their motor strategies by evaluating their perception of both knee effort and WB distributions during the STS task. The first study evaluated the capacity of hemiparetic persons to perceive their WB distribution at their lower limbs during the STS task. Compared to the healthy participants, their WB distribution was more asymmetrical and they showed greater errors in perception. The second study quantified the distribution of efforts at the knees among healthy and hemiparetic subjects during a spontaneous STS task. Both groups showed an association between their WB distribution and their distribution of efforts but the relationship was not as strong in the hemiparetic group. Dividing the hemiparetic participants into subgroups, according to their knee extensors’ strength asymmetries (mild, moderate, severe), revealed symmetrical knee efforts between sides for the severe group. The third study determined whether hemiparetic individuals’ perception of their knee effort distribution was related to their real distribution of efforts measured during STS tasks performed in various foot positions. Not only were they unable to perceive the changes in the distribution of effort induced by the different foot positions but their errors in perception of effort were greater than in WB. With the use of the five-repetition sit-to-stand test, the last study determined the influence of the number of repetitions of the STS on the distributions of WB and effort at the knees among healthy and hemiparetic subjects. Unlike the controls, the distributions of the hemiparetic subjects were more asymmetrical at the first repetition of the functional test than in the single spontaneous execution of the STS. To summarize, the results of this thesis showed that the distribution of efforts at the knees should be considered among other factors explaining the WB asymmetry of hemiparetic individuals during STS and that there is a need to better document the perception of hemiparetic persons when they execute functional tasks.