La pratique d’exercices intenses répétés, entrecoupés de faibles temps de récupération, est susceptible d’engendrer une altération de l’homéostasie et une diminution de la performance chez les sportifs soumis à ce type de contraintes. Dans ce contexte, l’optimisation des processus de récupération est une possibilité forte d’amélioration de la performance et de sa reproduction. Une des principales limites au maintien de la performance de type haute intensité, répété à court terme, est attribuée à la fatigue périphérique, inhérente à l’ensemble des mécanismes de l’excitabilité et de la contraction du muscle squelettique. Cette fatigue périphérique engendre une inadéquation entre les apports et les besoins cellulaires, en oxygène et en nutriments, ainsi qu’une incapacité à éliminer et/ou recycler les produits métaboliques issus de la contraction musculaire. Afin de limiter ces effets, l’augmentation du flux sanguin lors de l’exercice et de la récupération apparaît indispensable au bon rétablissement de l’état d’équilibre de l’organisme et au maintien de la performance sportive. A ce titre, l’électrostimulation neuromusculaire semble être un mode de récupération théoriquement efficace pour augmenter le flux sanguin. Cette présente thèse, comprenant trois études, visait à connaître précisément les effets de l’électrostimulation neuromusculaire - par l’utilisation d’un nouvel appareil issu du domaine médicale - sur la cinétique de récupération de marqueurs de performance, de marqueurs physiologiques et de perception, dans le contexte d’exercices intenses, répétés à court terme. Nous avons émis l’hypothèse qu’une stimulation efficace, induisant une augmentation du flux sanguin, permettrait d’optimiser la récupération à court terme, entre deux exercices de haute intensité. Ces résultats devraient permettre d’optimiser, dans le futur, les stratégies de récupération mises en place après un exercice intense, répété dans de brefs délais / The practice of intense and repeated exercises, interrupted with short recovery times, may induce alterations in homeostasis and a decrease of the performance for athletes who are subject to this type of constraints. In this context, the optimization of the recovery processes is a strong possibility to improve performance and the maintain of it all along the competitive period. One of the main limits in the preservation of performance in type high-intensity, repeated at small interval of time, is attributed to the peripheral fatigue, inherent to all the mechanisms implied in the skeletal muscle excitability and contraction. This peripheral fatigue induces an inadequacy between the contributions and the cellular needs of oxygen and nutrients, and also a disability for disposal or recycling the metabolic by-products stemming from the muscular contraction. In order to limit these effects, the increase in blood flow during exercise and recovery seems essential for the good restoring of the state of physiological balance for the body and the preservation of sport performance. Therefore, the neuromuscular electrical stimulation seems to be, in theory, an effective recovery mode to improve the blood flow. This present thesis, comprising three studies, aimed to know precisely the effects of the neuromuscular electrical stimulation - by the use of a new device stemming from the medical field - on the kinetics of recovery of performance, physiological and perceptual markers, in the context of intense exercises repeated in the short terms. We hypothesized that an effective stimulation, increasing the blood flow would allow to optimize short-term recovery between two high-intensity exercises. These results should contribute to optimize, in the future, the strategies of recovery organized after an intense exercise

Aging, obesity and increased waist circumference (WC) increases risk for metabolic syndrome (MetS). MetS is a cluster of symptoms (elevated WC, triglycerides, blood pressure, fasting glucose, and decreased high-density lipoprotein cholesterol [HDL-C]) increasing risk for chronic disease. Low-energy dense (LED) diets, emphasizing whole food eating patterns, have not been examined in combination with moderate (mod)/high-intensity physical activity (PA) or dietary protein levels to determine their impact on changes in body weight (BW) and WC in premenopausal, abdominally obese women. PURPOSE: To determine the effect of two 16-wk diet and PA interventions, differing in protein intake, on BW, WC, MetS risk factors, dietary patterns, energy density (ED), and min of Mod-Hi PA. METHODS: Healthy, abdominally obese (WC≥80cm) women (n=38; 34±10y) were randomly assigned to either a 15 or 25% (+18 g/d whey protein) en from protein diet. Individualized LED diets plans decreased energy intake (EI) by ~300kcal/d; PA 5 d/wk (30-60 min/d) consisted of supervised, high-intensity Zumba classes 3d/wk (≥65%HRmax; ≥6METs) and self-selected mod-intensity PA (≥3METs) 2d/wk. Servings of fruits/vegetables, whole grains, and low-fat/fat-free dairy (LFD), fiber, high calorie beverages (BEV), ED, and PA were monitored before (T1), during (T2) and after (T3) the intervention using repeated measures ANOVA. Bonferroni simultaneous testing procedure was used in analysis of multiple comparisons. RESULTS: At T1, groups did not differ in dietary patterns, PA, BW, WC, or MetS risk. Groups responded similarly to the interventions so data were combined, with BW and WC decreasing (p<0.0001) by -4.8±2.7kg and -7.1±3.6cm, respectively. Comparing T1 vs. T2, there were increases (p<0.0001) in fruits/vegetables, (Δ=+1.5 ser/d), whole grains (Δ=+1.0 ser/d), LFD (Δ=+0.5 ser/d), fiber (Δ=+5.7g/1000 kcal), and decreases in BEV (Δ=-165 kcal/d) and ED (Δ=-0.55 kcal/g). During the intervention high-intensity Zumba PA was 87min/wk; total min of all mod-intensity PA increased by 75 min/d (p<0.0001); VO2max improved from 29.3±4.7 (T1) to 34.4±5.3 (T3) mL/kg/min (p<0.0001). Triglycerides significantly decreased (-24±52 mg/dl; p=0.006), no other significant changes occurred in MetS risk factors. Exploratory analysis indicated that increases in fruits/vegetables and LFD, and decreases ED were associated with BW loss, while increases in whole grains, fiber, LFD, and min/wk of high-intensity PA (Zumba) were associated with WC reductions. CONCLUSION: For abdominally obese women, an intervention focused on LED foods and high-intensity PA significantly reduced BW and WC and improved dietary patterns regardless of protein intake. Helping clients identify a few key factors that positively promote reductions in BW and WC may improve weight loss success, while reducing MetS risk factors. / Graduation date: 2012