L’objectif de ce travail était 1) déterminer si la prise en charge thérapeutique journalière proposée aux patients en phase subaiguë de l’AVC était suffisamment sollicitante pour atteindre les recommandations à l’activité en hospitalisation 2) déterminer quelles méthodes étaient utilisables pour évaluer l’activité physique et leur utilité dans la prise en charge thérapeutique post-AVC.La population étudiée était constituée de patients en phase subaiguë de l’AVC, hospitalisés dans le service de Médecine Physique et de Réadaptation. Les résultats ont permis de montrer qu’un tiers des patients n’atteignait pas les recommandations à l’activité physique quand ils quittaient le service et que la majorité de la dépense énergétique (≥ 3 METs) journalière était réalisée en dehors du temps de prise en charge thérapeutique. Concernant les méthodes d’évaluation de l’activité physique, les résultats ont mis en avant que la perception de l’effort ne semblait pas utilisable pour évaluer l’intensité de l’activité physique sur une séance de rééducation et que les actimètres, à l’exception du Armband SenseWear, n’étaient pas précis pour estimer la dépense énergétique journalière des patients en phase subaiguë de l’AVC.Sachant que pour une part de la population les recommandations à l’activité physique ne sont pas atteintes, il y a un intérêt d’évaluer l’activité physique en phase subaiguë de l’AVC, pour notamment contrôler la réalisation de ces dernières. Cependant, que les méthodes d’évaluation soient subjectives ou objectives, il est difficile d’obtenir une mesure précise de l’activité physique au cours de la phase subaiguë de l’AVC. / The aim of this work was to 1) determine whether daily therapeutic care offered to patients in subacute stroke phase was demanding enough to reach hospitalization activity recommendations 2) determine the possible methods to measure physical activity and its usefulness in post-stroke therapeutic care.The studied population was composed of subacute stroke phase patients admitted to the Physical Medicine and Rehabilitation unit. The results showed that one third of the patients did not reach physical activity recommendations once they left the unit. Furthermore, most of the daily energy expenditure (3 METs) was achieved outside the therapeutic care. Regarding the physical activity evaluation methods, results highlighted that perceived exertion did not seem valuable to evaluate physical activity intensity during reeducation session. Additionally, actimeters were not accurate enough to measure patient's daily energy expenditure except for Armband SenseWear. Knowing that physical activity recommendations are not reached by part of the population, it seems useful to measure physical activity during subacute stroke phase in order to ensure these activities are performed as requested. However, should the evaluation methods be subjective or objective, it is hard to obtain an accurate physical activity measurement during subacute stroke phase.

L'obésité pédiatrique et ses pathologies associées sont devenues un problème majeur de santé publique. La reprise des activités physiques quotidiennes et de loisirs, préconisée dans les recommandations internationales, est souvent complexe chez le jeune obèse en raison d'une image de soi dévalorisée, de difficultés d'intégration et d'une faible condition physique. L'excès pondéral, associé à la sédentarité, altère progressivement l'endurance cardiorespiratoire à l'exercice, freinant le retour à une pratique physique régulière et contribuant à la non-observance des prescriptions en activité physique. Pour répondre à un besoin croissant des professionnels de l'activité physique impliqués dans la prise en charge de ces jeunes, l'objectif de ce travail de thèse a été de valider des outils cliniques explorant l'endurance cardiorespiratoire chez l'adolescent obèse :Un test de marche/course de 12 minutes, un test de marche navette adapté sur 20 mètres (4km.h^ incrémenté de 0,5 km.HAmin-1) et un test sous-maximal sur ergocycle en 4 paliers ontpermis de déterminer des indices d'endurance cardiorespiratoire (D12, Vmax, PMA).L'analyse fréquentielle en temps variant de la variabilité de la fréquence cardiaque a permisd'estimer des intensités d'exercice sous-maximales proches des seuils ventilatoires.Le "Childhood Obesity Perceived Exertion Scale" (COPE-10) a permis de quantifier l'intensitéde l'exercice perçue au cours de l'effort.Ces outils non-invasifs et peu coûteux, utiles à l'évaluation initiale et au suivi de la condition physique du jeune obèse, peuvent être facilement utilisés pour concevoir et individualiser des programmes de réentraînement adaptés à ces jeunes. / Pédiatrie obesity and its associated diseases hâve become a major public health challenge. However, thé return to daily physical and leisure activities, recommended by most international guidelines, can be difficult for obèse youths, due to low self-esteem, difficulties in integrating groups and poor physical fitness. Overweight combined with sedentarity progressively modify cardio-respiratory exercise tolérance, rendering difficult thé return to exercise and contributing to non-compliance with prescriptions for physical activity. To meet thé growing needs of professionals in thé field of physical activity responsible for thé management of thèse subjects, thé main objective of this doctoral thesis was to validate clinical tools exploring cardiorespiratory capacity in obèse adolescent.A 12 minute walk/run test, an adapted 20m shuttle walk test (starting speed 4 km.b.-1,incréments : 0.5 km.h-1.miir1) and a submaximal exercise test by cycle ergometer with 4 stageswere proposed to calculate indices of cardiorespiratory fitness (D12, Vmax, PMA).Time-varying spectral analysis of heart rate variability was studied to estimate intensitiessubmaximal exercise near ventilatory thresholds.-The "Childhood Obesity Perceived Exertion Scale" (COPE-10) was used to quantify thé intensity of exercise as perceived by thé subjects during exercise.Thèse non-invasive tools, inexpensive, useful in thé évaluation and follow-up of cardiorespiratory fitness in obèse adolescents, can easily be used to develop and personalise adapted re-training programmes in thèse overweight teenagers.

La réalisation d’une performance sportive dans un environnement chaud est un challenge majeur que doivent surmonter les athlètes de haut niveau notamment à l’occasion des Jeux Olympiques d’été. Depuis plusieurs décennies, les scientifiques ont tenté de trouver des solutions innovantes. Parmi les réponses proposées, on distingue aujourd’hui le refroidissement corporel préalable ou consécutif à l’effort (le pré et le post-cooling, respectivement), qui permettrait de minimiser les risques d’hyperthermie et améliorerait la récupération de l’athlète. Cependant, les modalités d’utilisation de ces méthodes et leur efficacité font l’objet de conclusions pour le moins contradictoires en raison notamment des techniques de refroidissement mises en œuvre (refroidissement par immersion, vêtements thermorégulants, brumisation…), de la durée d’application, du type d’exercice réalisé et des conditions environnementales explorées. La préparation des Jeux Olympiques à Pékin, en Août 2008, a été une occasion unique de faire un état de l’art sur les méthodes existantes. Nous avons testé chez des cyclistes de haut niveau l’hypothèse selon laquelle une stratégie de refroidissement utilisant une veste garnie d’accumulateurs thermiques permettrait d’améliorer le confort thermique et la performance lors d’un exercice de type anaérobie (Wingate test) et lors d’une épreuve d’endurance de 20 minutes. L’étude menée sur le test de Wingate ne montre aucun effet significatif du pré-cooling sur le pic de puissance ni sur la puissance moyenne mais permet néanmoins d’améliorer significativement (P < 0,05) l’indice de fatigue des athlètes testés. Sur l’épreuve de 20 minutes, le pré-cooling permet une amélioration significative (P < 0,05) de la puissance moyenne développée, du confort thermique et une baisse significative des températures cutanées et rectales. Une autre étude portant sur l’influence de différents maillots sur les réponses physiologiques et perceptives de coureurs cyclistes a montré qu’un maillot constitué de larges mailles offrait un meilleur confort thermique en diminuant significativement (P < 0,05) la température cutanée, mais sans modifier la perception de l’effort. Les bénéfices observés chez les cyclistes de haut niveau nous ont orientés vers la mise en œuvre d’un protocole similaire appliqué à des personnes atteintes de pathologies affectant la thermorégulation. Ainsi, nous avons débuté un protocole de recherche clinique exploratoire visant à étudier les effets du port d’une veste thermorégulante sur les performances motrices et cognitives de patients atteints de sclérose en plaques. Ce protocole, qui a obtenu l’accord du Comité de Protection des Personnes du Grand Est –II, devrait commencer fin 2012. / Abstract: Exercising in the heat and high relative humidity is a major challenge that athletes have to overcome, especially during the summer Olympic Games. For decades, scientists investigated innovative solutions amongst which the body cooling before competing (pre-cooling) or after competing (post-cooling) seemed to be a valuable mean of minimizing hyperthermia threats and increasing the recovery of the athletes. However, contradictory results have been reported concerning body cooling protocols (cold water immersion, cooling vests, water sprays, etc.), exposure time, exercise duration, environmental conditions and their efficiency. By preparing the 2008 Beijing Olympic Games, we managed to review the existing literature on those methods. We hypothesized that a cooling vest combined with a cooling headband would increase thermal comfort of elite cyclists and their performances on an anaerobic (Wingate Test) and endurance (20 minutes time-trial) exercises. The Wingate Test study showed no significant effect of pre-cooling on peak or mean power output despite a significant increase (P < 0.05) of fatigue indexes. During the endurance study, pre-cooling maneuvers induced significant improvement (P < 0.05) of the mean power output, of the thermal comfort and a significant decrease in rectal and skin temperatures. Another study concerning the influence of wearing different cycling shirt on perceived and physiological responses of cyclists showed that a large knitted shirt provided a better thermal comfort by decreasing significantly (P < 0.05) skin temperatures, but without affecting perceived exertion. Those positive results on elite athletes lead us to apply similar cooling strategies on a population experiencing disease-related thermoregulation troubles. We decided to initiate an exploratory clinical study aiming at investigating the effects of a cooling vest on motor and cognitive skills of patients with multiple sclerosis disease. This protocol obtained the clearance of the French National Ethics Committee – East Section II, and should start on the late of 2012.

INTRODUÇÃO Pacientes com doença renal crônica sofrem alterações musculoesqueléticas nos estágios iniciais da doença associadas a fatores como alteração de substratos séricos, capacidade funcional, qualidade de vida e parâmetros nutricionais. O objetivo deste estudo foi avaliar o desempenho funcional, qualidade de vida, e parâmetros respiratórios em pacientes com doença renal crônica não dialítica segundo o estágio da doença renal. MÉTODOS Foram selecionados 26 indivíduos acompanhados pelo Serviço de Nefrologia do Instituto Central da Faculdade de Medicina da Universidade de São Paulo, com diagnóstico de doença renal crônica não dialíticos, e taxa de filtração glomerular abaixo de 45 mL/min, foram excluídos pacientes com doenças reumatológicas, respiratórias, neurológicas ou que apresentassem limitações para a execução dos testes funcionais. Foram aplicados os seguintes instrumentos: questionário de Qualidade de Vida (SF-36), o questionário Internacional de Nível de Atividade Física (IPAQ), foi realizado os seguintes testes: teste de Caminhada de Seis Minutos, teste de Sentar e Levantar, e o teste de Preensão Palmar, foram aferidas também as pressões máximas inspiratórias e expiratórias e volumes pulmonares através da manuvacuometria e exames laboratoriais de rotina. RESULTADOS Os dados do grupo geral foram comparados com os encontrados na literatura demonstrando menor capacidade funcional e respiratória do que indivíduos saudáveis de mesmo gênero e faixa etária. Os indivíduos avaliados também foram subdivididos em dois grupos através da estimativa da taxa de filtração glomerular pela formula CKD-EPI, o primeiro grupo com taxa de filtração glomerular menor que 30 mL/min e o segundo grupo com taxa de filtração glomerular maior ou igual a 30 mL/min. Foram encontradas diferenças significantes quanto a: pressão expiratória máxima (P=0.04) onde os pacientes com pior função renal apresentaram maior força muscular expiratória, paratormônio (P= 0.02), fosforo (P= 0.04) e ureia (P= 0.00) . CONCLUSÃO: Concluiu se que indivíduos com doença renal crônica apresentam diferenças em relação aos parâmetros respiratórios, exames séricos diferentes estágios da doença renal crônica antes da terapia renal substitutiva / INTRODUCTION Patients with chronic kidney disease (CKD) suffer musculoskeletal disorders in the early stages of the disease associated with factors such as change in serum substrates, functional capacity, quality of life and nutritional characteristics. The aim of this study was to evaluate the functional performance, quality of life, and respiratory parameters in patients with CKD not requiring dialysis according to the stage of kidney disease. METHODS We selected 26 individuals accompanied by the Nephrology Department of the Central Institute of the Faculty of Medicine, University of São Paulo, diagnosed with chronic kidney disease not on dialysis, and glomerular filtration rate below 45 mL / min, patients were excluded with rheumatic diseases, respiratory, neurological or who present limitations for the execution of functional tests. The following instruments were applied: Quality of Life questionnaire (SF-36), the International Physical Activity Questionnaire (IPAQ), was performed the following tests: the Six Minutes Walk test, Sitting and Rising test, and Hand Grip Strength test were also measured the maximum inspiratory and expiratory pressure and lung volumes through manuvacuometria and routine laboratory tests. RESULTS The results presented by the general group were compared with those found in the literature showing lower functional and respiratory capacity than healthy individuals of the same gender and age. The evaluated individuals were also subdivided into two groups by means of the glomerular filtration rate by the formula CKD-EPI, the first group of glomerular filtration rate lower than 30 ml / min and the second group with higher glomerular filtration rate or equal to 30 ml / min. Significant differences were found regarding: maximal expiratory pressure (P 0.04) where patients with poor kidney function had higher expiratory muscle strength, parathyroid hormone (P = 0.02) and phosphorus (P 0.04). CONCLUSION: We conclude that individuals with chronic kidney disease have differences from respiratory parameters, different blood tests stages of chronic kidney disease before renal replacement therapy

Des études expérimentales examinant le rôle socialisateur de l’autorité parentale dans des contextes de transgression persistante de règles ont démontré les avantages d’utiliser la conséquence logique plutôt que d’autres stratégies d’autorité (la punition, le raisonnement et l’absence d’autorité). À l’aide d’une méthodologie par vignettes expérimentales et d’un échantillon de 214 adolescents (M = 15,28 ans), la présente étude a bonifié ces recherches en comparant ces mêmes stratégies dans un contexte de transgression à facettes multiples. Spécifiquement, le rôle modérateur des perceptions des adolescents de l’enjeu sous-jacent à la transgression (personnel c. non-personnel) sur leurs croyances quant au potentiel socialisateur des stratégies d’autorité a été évalué. Lorsque les adolescents ont catégorisé la transgression comme un enjeu non-personnel, les résultats des études antérieures ont été reproduits. En effet, la conséquence logique a été jugée comme étant aussi efficace que la punition à prévenir une transgression future (et plus efficace que le raisonnement et l’absence d’autorité) et comme la stratégie la plus acceptable. De plus, contrairement à la punition, la conséquence logique n’a pas été perçue comme frustrant plus l’autonomie que le raisonnement. En comparaison, les adolescents ayant catégorisé la transgression comme un enjeu personnel ont perçu la conséquence logique moins favorablement, laissant place au raisonnement comme stratégie d’autorité préférable. Les implications de ces résultats pour la socialisation des adolescents et les pratiques parentales optimales sont discutées. / Experimental studies focusing on the socialization role of parental authority exertion in persistent rule-breaking contexts involving non-personal issues have recently shown the advantages of using logical consequences over alternative strategies (mild punishments, reasoning and no-authority). Using an experimental vignette approach and a sample of 214 adolescents (Mage = 15.28 years), the present study extended these findings by comparing the same parental interventions in a hypothetical rule-breaking setting involving a multifaceted issue. Specifically, and based on research anchored in social domain theory, we evaluated how adolescents’ perceptions of the issue underlying the multifaceted transgression (personal vs. non-personal) moderated their beliefs regarding authority exertion strategies. When adolescents perceived the transgression as a non-personal issue, past results were replicated and enhanced. Adolescents perceived the logical consequence as at least as effective as the mild punishment to prevent future transgressions (i.e., more so than reasoning and no-authority) and as the most acceptable strategy. Furthermore, contrary to the mild punishment, they did not perceive the logical consequence as more autonomy-thwarting than reasoning. In contrast, adolescents who categorized the transgression as a personal matter rated the logical consequence less favorably, leaving reasoning as a preferred form of intervention. Implications for optimal parenting are discussed.

Modern ski-treadmills allow cross-country skiers, biathletes and ski-orienteers to test their physical performance in a laboratory environment using classical and freestyle techniques on roller skis. For elite athletes the differences in performance between test occasions are quite small, thus emphasising the importance of knowing the roller skis’ rolling resistance coefficient, µR, in order to allow correct comparisons between the results, as well as providing the opportunity to study work economy between different athletes, test occasions and core techniques. Thus, one of the aims of this thesis was to evaluate how roller skis’ µR is related to warm-up, mass, velocity and inclination of the treadmill. It was also necessary to investigate the methodological variability of the rolling resistance measurement system, RRMS, specially produced for the experiments, with a reproducibility study in order to indicate the validity and reliability of the results. The aim was also to study physiological responses to different µR during roller skiing with freestyle and classical roller skis and techniques on the treadmill as a case in which all measurements were carried out in stationary and comparable conditions. Finally, the aim was also to investigate the work economy of amateurs and female and male junior and senior cross-country skiers during treadmill roller skiing, i.e. as a function of skill, age and gender, including whether differences in body mass causes significant differences in external power per kg due to differences in the roller skis’ µR. The experiments showed that during a warm-up period of 30 minutes, µR decreased to about 60-65% and 70-75% of its initial value for freestyle and classical roller skis respectively. For another 30 minutes of rolling no significant change was found. Simultaneous measurements of roller ski temperature and mR showed that stabilized mR corresponds to a certain running temperature for a given normal force on the roller ski. The study of the influence on mR of normal force, velocity and inclination produced a significant influence of normal force on mR, while different velocities and inclinations of the treadmill only resulted in small changes in mR. The reproducibility study of the RRMS showed no significant differences between paired measurements with either classical or the freestyle roller skis. The study of the effects on physiological variables of ~50% change in µR,showed that during submaximal steady state exercise, external power, oxygen uptake, heart rate and blood lactate were significantly changed, while there were non significant or only small changes to cycle rate, cycle length and ratings of perceived exertion. Incremental maximal tests showed that time to exhaustion was significantly changed and this occurred without a significantly changed maximal power, maximal oxygen uptake, maximal heart rate and blood lactate, and that the influence on ratings of perceived exertion was non significant or small. The final part of the thesis, which focused on work economy, found no significant difference between the four groups of elite competitors, i.e. between the two genders and between the junior and senior elite athletes. It was only the male amateurs who significantly differed among the five studied groups. The study also showed that the external power per kg was significantly different between the two genders due to differences in body mass and mR, i.e. the lighter female testing groups were roller skiing with a relatively heavier rolling resistance coefficient compared to the heavier testing groups of male participants. / Sporttech

Work-related musculoskeletal disorders (WMSDs) due to overexertion and consequently the low back pain (LBP) are one of the most prevalent sources of nonfatal occupational injuries and illnesses in all over the world. In the past several years, the industrial exoskeletons especially the passive ones have been proposed as alternative intervention and assistive devices, which are capable of reducing the risk of WMSDs and LBP. However, more research is warranted to validate the applicability of these exoskeletons. In addition, because the majority of previous studies have been limited to specific lifting tasks using only one type of lift assistive exoskeleton, more research is needed to examine the effect of alteration of different lift-assistive exoskeletons on reducing the activity of back muscles and metabolic reduction. The main objective of this dissertation is to render an overview of three studies that attempt to improve the literature by providing comprehensive biomechanical evaluations and metabolic assessments of three passive lift-assistive exoskeletons (VT-Lowe's Exoskeleton (developed in ARLab at VT), Laevo and SuitX). This dissertation has been composed of three related studies. The first study aimed to investigate and examine the capability of a novel lift assistive exoskeleton, VT-Lowe's exoskeleton, in reducing the peak and mean activity of back and leg muscles. Findings revealed that the exoskeleton significantly decreased the peak and mean activity of back muscles (IL(iliocostalis lumborum) and LT(longissimus thoracis)) by 31.5% and 29.3% respectively for symmetric lifts, and by 28.2% and 29.5% respectively for asymmetric lifts. Furthermore, the peak and mean EMG of leg muscles were significantly reduced by 19.1% and 14.1% during symmetric lifts, and 17.4% and 14.6% during asymmetric lifts. Interestingly, the VT-Lowe's exoskeleton showed higher reduction in activity of back and leg muscles compared to other passive lift-assistive exoskeletons available in the literatures. In the second study, the metabolic cost reduction associated with the use of VT-Lowe's exoskeleton during freestyle lifting was theoretically modelled, validated and corresponding metabolic savings were reported. The metabolic cost and the oxygen consumption results supported the hypothesis that the VT-Lowe's exoskeleton could significantly reduce the metabolic demands (~7.9% on average) and oxygen uptake (~8.7% on average) during freestyle lifting. Additionally, we presented a prediction model for the metabolic cost of exoskeleton during repetitive freestyle lifting tasks. The prediction models were very accurate as the absolute prediction errors were small for both 0% (< 1.4%) and 20% (< 0.7%) of body weight. In the third study, the biomechanical evaluation, energy expenditure and subjective assessments of two passive back-support exoskeletons (Laevo and SuitX) were examined in the context of repetitive lifting tasks. The experimental lifting tasks in this study were simulated in a laboratory environment for two different levels of lifting symmetry (symmetric vs. asymmetric) and lifting posture (standing vs. kneeling). Results of this study demonstrated that using both exoskeletons during dynamic lifting tasks could significantly lower the peak activity of trunk extensor muscles by ~10-28%. In addition, using both exoskeletons could save the energy expenditure by ~4-13% in all conditions tested by partially offsetting the weight of the torso. Such reductions were, though, task-dependent and differed between the two tested exoskeletons. Overall, the results of all three studies in this dissertation showed the capability of passive lift-assistive exoskeletons in reducing the activity of back and leg muscles and providing metabolic savings during repetitive lifting tasks. / Doctor of Philosophy / Low back pain (LBP) due to overexertion is known as one of the most important sources of nonfatal occupational injuries especially for the workers or manual material handlers who are involved in frequent or repetitive lifting tasks. Every year, many workers are temporarily or permanently disabled due to overuse injuries at workplace. In the past several years, industrial exoskeletons have gained growing interest among biomechanist, roboticist, and other human factor researchers as potential assistive devices to reduce the risk of LBP. In general, the industrial exoskeletons are either “passive or “active”; Active exoskeletons are powered by mechanical/electrical motors and actuators, however, the passive exoskeletons often work using cheaper devices such as gas or metal springs, elastic elements, etc. The exoskeletons discussed in this dissertation are categorized as passive rigid lower-back exoskeletons and they function by storing energy in a spring when the wearer bends and returning the stored energy when the wearer lifts. This dissertation consists of three studies that attempt to provide comprehensive biomechanical evaluations and metabolic assessments of three passive lift-assistive exoskeletons (i.e., VT-Lowe’s Exoskeleton, Laevo and SuitX). The first study examined the efficacy of a novel lift-assistive exoskeleton, VT-Lowe’s exoskeleton, in reducing the peak and mean activity of back and leg muscles. The results of this study demonstrated that the exoskeleton reduced the peak and mean activity of back and leg muscles for symmetric and asymmetric lifting tasks. VT-Lowe’s exoskeleton also showed higher reduction in activity of back muscles compared to other passive lift-assistive exoskeletons available in the literature. In the second study, the metabolic cost reduction with VT-Lowe’s exoskeleton was theoretically modeled and the modeling outcomes were compared to metabolic costs measurements when the exoskeleton was worn. The experimental findings of this study supported the applicability of the exoskeleton by significantly reducing the metabolic cost and oxygen uptake during the freestyle repetitive lifting tasks. Moreover, the prediction metabolic cost model of the exoskeleton showed high accuracy as the absolute prediction errors were within 1.5%. In the third study, the biomechanical evaluation, energy expenditure and subjective assessments of two passive back-support exoskeletons (Laevo and SuitX) were examined in repetitive lifting tasks. The lifting tasks of this study were simulated in a laboratory environment for two different levels of lifting symmetry (symmetric vs. asymmetric) and lifting posture (standing vs. kneeling). Findings of this study showed that both exoskeleton significantly lowered the peak activity of back muscles during the dynamic lifting tasks. Moreover, using both exoskeletons provided metabolic cost savings in all of the studies conditions. Overall, results obtained from the three studies in this dissertation verified the capability of these passive lift- vi assistive exoskeleton in reducing the activity of back and leg muscles and providing the metabolic savings during repetitive lifting tasks.

Estratégia de corrida é forma pela qual os corredores distribuem a velocidade durante uma competição. Objetivando otimizar a utilização dos recursos energéticos, bem como melhorar o desempenho geral na prova, durante uma corrida de 5 km os atletas comumente adotam uma estratégia caracterizada por um início em alta velocidade, seguido por um trecho intermediário em velocidade inferior, e finalmente os atletas aumentam a velocidade quando se aproximam dos 400 m finais da prova. Sabe-se que o treinamento intervalado de alta intensidade (TIAI) realizado ao longo de 3 a 6 semanas é capaz de promover melhoras significativas nas variáveis fisiológicas determinantes do desempenho aeróbio, tais como VO2max, EC, VP, e OBLA. Uma vez que os atletas monitoram a PSE baseado em sinais internos (fisiológicos) e externos (ambiente), e desta forma alteram a velocidade para evitarem o término prematuro do exercício, acredita-se que melhoras em tais variáveis fisiológicas possam permitir que os corredores modifiquem a estratégia de corrida. Portanto, o principal objetivo do presente estudo foi analisar a influência de quatro semanas de TIAI sobre a PSE e também sobre a estratégia de corrida adotada por corredores durante um teste contra-relógio de 5 km (T5). Vinte sujeitos, homens, corredores recreacionais de longa distância foram distribuídos de forma contrabalançada em grupo controle (CON, n = 10; 33,5 ± 6,2 anos) e grupo treinamento intervalado (TINT, n = 10; 32,9 ± 8,6 anos). TINT realizou uma sessão de TIAI duas vezes por semana, enquanto que CON manteve seu programa regular de treinamento. Antes e após o período de intervenção, os corredores realizaram: 1) um teste incremental até exaustão para se obter o início do acúmulo de lactato sanguíneo (OBLA), o consumo máximo de oxigênio (VO2max), e a velocidade pico em esteira (VP); 2) um teste submáximo de carga constante para se medir a economia de corrida (EC); 3) e um teste contra-relógio de 5 km (T5) em pista para se estabelecer a estratégia de corrida. O programa de TIAI produziu uma melhora relevante no VO2max (effect size = 0,219), OBLA (effect size = 0,489), EC (effect size = -0,593), e VP (effect size = 0,622). Não foram detectadas alterações significativas na estratégia de corrida, TT5, VT5 e PSET5 durante o T5, comparando ambas as condições (pré e pós-treinamento) ou entre os grupos (TINT e CON; P > 0,05). Esses achados sugerem que melhoras nas variáveis fisiológicas induzidas por um programa de quatro semanas de TIAI não são acompanhadas por alterações similares na PSE e na estratégia de corrida durante um teste contra-relógio de 5 km / Pacing strategy has been defined as the manner by which the runners distribute their speed during a competition. In order to optimize the use of the energetic resources, as well as improve the general race performance, during a 5-km running race, athletes usually adopt a pacing strategy characterized by a fast start (400 m), followed by a period of slower speed during the middle (400 4600 m), and a significant increase in running speed during the last part of the race (400 m). It is well recognized that high-intensity interval training (HIIT) performed along 3 to 6 weeks is able to promote significant improvements in physiological variables determinants of endurance performance, such as VO2max, RE, PTS, and OBLA. Since athletes monitor their RPE based on the internal (physiological) and external (environment) signals, and change their running speed in order to prevent a premature exercise termination, its believed that improvements in such physiological variables could enable athletes to modify the pacing strategy. Thus, the main purpose of this study was to analyze the influence of 4 weeks of high-intensity interval training (HIIT) on the rating of perceived exertion (RPE) and the pacing strategy adopted by runners during a 5-km running time-trial (T5). Twenty male, recreational long-distance runners were randomly assigned into control group (CG, n = 10) or high-intensity interval-training group (HIITG, n = 10). The HIITG performed a high-intensity interval-training session twice per week, while CG maintained its regular training program. Before and after the training period, the runners performed the following tests: 1) an incremental exercise test to exhaustion to measure the onset of blood lactate accumulation (OBLA), maximal oxygen uptake (VO2max), and peak treadmill speed (PTS); 2) a submaximal speed-constant test to measure the running economy (RE); 3) a 5-km running time-trial on an outdoor track to establish pacing strategy. HIIT program produced a relevant improvement on the VO2max (effect size = 0.219), OBLA (effect size = 0.489), RE (effect size = -0.593), and PTS (effect size = 0.622). There were no significant differences on pacing strategy, TT5, ST5 and RPE response during the 5-km running time-trial between both conditions (pre- and post-training) or between groups (HIITG and CG; P > 0.05). These findings suggest that improvements on the physiological variables induced by a 4-week HIIT program are not accompanied by similar modifications on the RPE and running pacing strategy during a 5-km running time-trial

Estratégia de corrida é forma pela qual os corredores distribuem a velocidade durante uma competição. Objetivando otimizar a utilização dos recursos energéticos, bem como melhorar o desempenho geral na prova, durante uma corrida de 5 km os atletas comumente adotam uma estratégia caracterizada por um início em alta velocidade, seguido por um trecho intermediário em velocidade inferior, e finalmente os atletas aumentam a velocidade quando se aproximam dos 400 m finais da prova. Sabe-se que o treinamento intervalado de alta intensidade (TIAI) realizado ao longo de 3 a 6 semanas é capaz de promover melhoras significativas nas variáveis fisiológicas determinantes do desempenho aeróbio, tais como VO2max, EC, VP, e OBLA. Uma vez que os atletas monitoram a PSE baseado em sinais internos (fisiológicos) e externos (ambiente), e desta forma alteram a velocidade para evitarem o término prematuro do exercício, acredita-se que melhoras em tais variáveis fisiológicas possam permitir que os corredores modifiquem a estratégia de corrida. Portanto, o principal objetivo do presente estudo foi analisar a influência de quatro semanas de TIAI sobre a PSE e também sobre a estratégia de corrida adotada por corredores durante um teste contra-relógio de 5 km (T5). Vinte sujeitos, homens, corredores recreacionais de longa distância foram distribuídos de forma contrabalançada em grupo controle (CON, n = 10; 33,5 ± 6,2 anos) e grupo treinamento intervalado (TINT, n = 10; 32,9 ± 8,6 anos). TINT realizou uma sessão de TIAI duas vezes por semana, enquanto que CON manteve seu programa regular de treinamento. Antes e após o período de intervenção, os corredores realizaram: 1) um teste incremental até exaustão para se obter o início do acúmulo de lactato sanguíneo (OBLA), o consumo máximo de oxigênio (VO2max), e a velocidade pico em esteira (VP); 2) um teste submáximo de carga constante para se medir a economia de corrida (EC); 3) e um teste contra-relógio de 5 km (T5) em pista para se estabelecer a estratégia de corrida. O programa de TIAI produziu uma melhora relevante no VO2max (effect size = 0,219), OBLA (effect size = 0,489), EC (effect size = -0,593), e VP (effect size = 0,622). Não foram detectadas alterações significativas na estratégia de corrida, TT5, VT5 e PSET5 durante o T5, comparando ambas as condições (pré e pós-treinamento) ou entre os grupos (TINT e CON; P > 0,05). Esses achados sugerem que melhoras nas variáveis fisiológicas induzidas por um programa de quatro semanas de TIAI não são acompanhadas por alterações similares na PSE e na estratégia de corrida durante um teste contra-relógio de 5 km / Pacing strategy has been defined as the manner by which the runners distribute their speed during a competition. In order to optimize the use of the energetic resources, as well as improve the general race performance, during a 5-km running race, athletes usually adopt a pacing strategy characterized by a fast start (400 m), followed by a period of slower speed during the middle (400 4600 m), and a significant increase in running speed during the last part of the race (400 m). It is well recognized that high-intensity interval training (HIIT) performed along 3 to 6 weeks is able to promote significant improvements in physiological variables determinants of endurance performance, such as VO2max, RE, PTS, and OBLA. Since athletes monitor their RPE based on the internal (physiological) and external (environment) signals, and change their running speed in order to prevent a premature exercise termination, its believed that improvements in such physiological variables could enable athletes to modify the pacing strategy. Thus, the main purpose of this study was to analyze the influence of 4 weeks of high-intensity interval training (HIIT) on the rating of perceived exertion (RPE) and the pacing strategy adopted by runners during a 5-km running time-trial (T5). Twenty male, recreational long-distance runners were randomly assigned into control group (CG, n = 10) or high-intensity interval-training group (HIITG, n = 10). The HIITG performed a high-intensity interval-training session twice per week, while CG maintained its regular training program. Before and after the training period, the runners performed the following tests: 1) an incremental exercise test to exhaustion to measure the onset of blood lactate accumulation (OBLA), maximal oxygen uptake (VO2max), and peak treadmill speed (PTS); 2) a submaximal speed-constant test to measure the running economy (RE); 3) a 5-km running time-trial on an outdoor track to establish pacing strategy. HIIT program produced a relevant improvement on the VO2max (effect size = 0.219), OBLA (effect size = 0.489), RE (effect size = -0.593), and PTS (effect size = 0.622). There were no significant differences on pacing strategy, TT5, ST5 and RPE response during the 5-km running time-trial between both conditions (pre- and post-training) or between groups (HIITG and CG; P > 0.05). These findings suggest that improvements on the physiological variables induced by a 4-week HIIT program are not accompanied by similar modifications on the RPE and running pacing strategy during a 5-km running time-trial

O objetivo deste estudo foi verificar se existe máxima fase estável de lactato (MFEL) nos exercícios LP e SR e analisar o comportamento de variáveis ventilatórias ventilação (Ve) e consumo de oxigênio (VO2), bem como lactacidemia, freqüência cardíaca (FC) e percepção subjetiva de esforço (PSE) na intensidade da MFEL e comparar as respostas entre os exercícios. Foram avaliados 12 homens jovens (20-33 anos) saudáveis e com experiência mínima de 6 meses em treinamento resistido, que passaram por teste de 1 repetição máxima (1RM), teste crescente para determinação do limiar anaeróbio (AT) e mais três sessões para a determinação da MFEL. Todas as sessões foram realizadas no mesmo horário do dia, separadas por 48 a 72 horas de intervalo. O valor de 1RM no LP foi de 298,0 ± 36,6 kg enquanto que no SR foi 93,7 ± 21,8 kg. A intensidade máxima atingida no teste crescente no LP foi 70,00 ± 12,25% de 1RM e no SR 50,00 ± 8,16% de 1RM, sendo esta diferença estatisticamente significativa (p0,05). A lactacidemia final também foi significativamente maior (p0,05) no LP comparada ao SR (8,36 ± 2,34 vs. 5,43 ± 1,12 mmol/L, respectivamente). O AT, expresso em percentual de 1RM, no LP foi de 27,9 ± 3,7% e no SR de 24,1 ± 4,4% de 1RM, porém esta diferença não foi estatisticamente significante. A lactacidemia no momento do teste crescente em que o AT era atingido também não apresentou diferença significativa, sendo 2,29 ± 0,58 mmol/L no LP e 2,52 ± 0,65 no SR. A intensidade da MFEL, no LP foi de 29,17 ± 7,02% de 1RM, enquanto que no SR a intensidade da MFEL foi de 21,67 ± 4,44% de 1RM, sendo esta diferença estatisticamente significativa (p0,05). No LP não houve diferença significativa entre as intensidades do AT e da MFEL (27,9 ± 3,7% e 29,2 ± 7,0% de 1RM, respectivamente). No SR intensidade do AT foi significativamente maior (p0,05) que a intensidade da MFEL (24,1 ± 3,4% e 21,7 ± 4,4% de 1RM, respectivamente). Durante a realização de exercício na MFEL, a ocorreu aumento de Ve, VO2, FC e PSE seguidos de estabilização, sem diferenças entre os exercícios. Estes resultados demonstram que é possível verificar MFEL nos exercícios LP e SR, e que no LP a intensidade é maior. As diferenças encontradas no teste crescente e na intensidade da MFEL são provavelmente causadas pelas características dos exercícios. / The purpose of the study was to verify if there is a maximal lactate steady state (MLSS) for the Leg Press (LP) and Bench Press (BP) exercises and to analyse ventilatory responses ventilation (Ve) and oxygen uptake (VO2), heart rate (HR), blood lactate concentration (BLC) and ratings of perceived exertion (RPE) to those exercises performed on MLSS intensity and to compare those responses for the exercises. 12 young healthy men with a minimal experience of 6 months of resistance training volunteered for the study. Volunteers underwent a 1 repetition maximum test (1RM), na incremental test to determine anaerobic threshold (AT) and three more sessions to determine MLSS. Session were performed on the same time of Day and separeted by a 48-72h interval. 1RM values for LP and BP were 298,0 ± 36,6kg and 93,7 ± 21,8 kg, respectively. The maximal intensity in the incremental test was 70 ± 12,25% of 1RM for LP and 50,00 ± 8,16% of 1RM for BP, which was a significant difference (p0,05). Post-test blood lactate concentration (BLS) was also significantly higher for LP (8,36 ± 2,34 vs. 5,43 ± 1,12 mmol/L, respectively) (p0,05). AT intensity and was not significantly different for LP and BP (27,9 ± 3,7% vs. 24,1 ± 3,6, respectively). BLC on AT was not significantly different for LP (2,29 ± 0,58 mmol/L) and BP (2,52 ± 0,65). MLSS intensity on LP (29,17 ± 7,02% of 1RM) was significantly higher (p0,05) compared to MFEL on BP (21,67 ± 4,44% of 1RM). When compared to AT, MLSS intensity for LP was not significantly different, but for BP it was significantly lower. During exercise on MLSS, oxygen uptake and ventilation, HR and RPE rose significantly compares to rest and then stabilized. There were no differences between exercises. These results show that it is possible to identify a MLSS on the LP and BP exercises, and that for LP this intensity is higher. The differences found between exercises can be atributted to the intrinsic caractheristics of each exercise.