All movement abilities are improved during the sport game lessons. A special warm-up exercise with a ball should not only improve the manipulation with the ball but also help to make the sports with ball more attractive for children at the second stage of the primary school. The main goal of this graduation thesis is to compose a set of special exercises with ball for sport game lessons at the primary school and to check whether it is more convenient and more interesting to use this special exercise than the classics gymnastics exercises. In my work, it is assumed that using this special warm-up exercise will conclude in the improvement in the fields of the children{\crq}s manipulation skills with the ball, their preferred sport game and that the lessons will be more attractive and entertaining for them.

The aim of this work was to create a 3D model of an asynchronous motor on which it is possible to perform temperature and other simulations using the Ansys Workbench computational software. The whole work consists of the theory of warming of electric machines, the separate construction of a 3D model and its temperature analysis.

Dans le cadre du projet européen « Optimized Products for Elderly Populations (OPTIFEL) » (ou « produits optimisés pour des gens âgés »), des produits alimentaires sont conçus pour les besoins particuliers des personnes âgées. Puisque cette population est souvent mal-nourrie, l’objectif du projet consistait à produire des aliments riches en nutriments et appétants. Ce but a été mis en œuvre en enrichissant des produits à base de fruits et légumes avec des protéines, des minéraux et vitamines, dont la vitamine C et les folates. Cependant, les deux dernières vitamines sont connues pour être fragiles et pour être rapidement perdues lors du chauffage. Pour atteindre le but de la supplémentation, c’est-à-dire augmenter l’absorption des nutriments, l’étude de leur stabilité est d’une grande importance. Ce travail, en particulier, a été dédié à l’étude de la stabilité de la vitamine C et des folates lors du réchauffage des aliments. Le réchauffage des aliments nécessite de respecter une température minimum de 60°C afin d’éviter la croissance des bactéries sporulées. Une deuxième contrainte, qui se démarque des méthodes de cuisson, est la durée du maintien en température. Selon que le réchauffage se déroule à la maison ou dans un système de restauration collective en liaison chaude, le temps de réchauffage est de courte durée ou peut atteindre quelques heures. La pomme et la carotte ont été choisies en tant qu’exemple d’un fruit et un légume pour le projet OPTIFEL et aussi pour le travail présent. La pomme et la carotte sont des produits qui sont appréciés à travers l’Europe et contiennent des quantités naturelles négligeables en vitamine C et folates. La stabilité de la vitamine C a fait objet de nombreuses études dans la littérature. Cependant, les facteurs qui impactent sa stabilité ont été principalement examinés en solution modèle et leur importance respective dans un vrai aliment manque d’études. Bien que la disponibilité de l’oxygène ait un impact primordial, et qu’il soit connu que l’oxygène est soluble jusqu’à 100°C, sa disponibilité dans le milieu alimentaire est très mal connue pendant le chauffage à des températures intermédiaires. L’acide folique est un vitamère synthétique, qui est habituellement utilisé pour la supplémentation mais qui a l’inconvénient de pouvoir masquer un déficit en vitamine B12. C’est pourquoi le vitamère naturellement abondant, l’acide 5-méthyltétrahydrofolate, a été proposé comme alternative pour l’enrichissement. Son inconvénient majeur, outre le prix, est qu’il est fragile et se dégrade rapidement en l’absence de réducteurs. L’objectif de cette thèse de doctorat consistait à comprendre la stabilité de la vitamine C et de l’acide 5-méthyltétrafolique à des températures intermédiaires. Une attention particulière a été portée à la stabilité dans des matrices alimentaires et à la disponibilité de l’oxygène. Dans un premier temps, la stabilité de la vitamine C et de l’acide 5-méthyltétrahydrofolique a été étudiée à une échelle laboratoire. Ensuite, l’impact des différentes méthodes de réchauffage a été examiné. Le travail a été divisé en quatre chapitres. Le premier chapitre a été consacré à l’étude de la stabilité de la vitamine C. Dans le deuxième chapitre, la disponibilité de l’oxygène a été étudiée. La troisième étude a été dédiée à la stabilité de l’acide 5-méthyltétrahydrofolique. Et dans le quatrième chapitre, trois méthodes de réchauffage ont été comparées. / The European project « Optimized Products for Elderly Populations (OPTIFEL) » was launched to ameliorate elderlies’ nutritional status. Since this population often suffers from malnutrition, it was envisaged to conceive food products based on fruit and vegetables, with a dense nutritive value. Therefore, products were enriched with important nutrients, among vitamin C and folates. To comply with the intention of supplementations consisting in an increased intake of nutrients, the study of their stability, especially of easy degradable molecules, is of utmost importance. The present work in particular, was dedicated to the stability of vitamin C and 5-methyltetrahydrofolate when food is warmed-up that is heated at an intermediate temperature range (60-80°C). It turned out that the deterioration pace of vitamin C is principally influenced by the filling volume of recipients on a lab-scale. A negligible effect was found for the food matrix meaning that products based on apples and carrots can interchangeably be used for fortifications. Concentration adaptions are easy to control as the degradation loss per time in the concentration range 2-5 mmol/kg, is independent of the initial concentration. Increasing temperature in the range 60-80°C, does not have an impact in a real food matrix either. The latter indicates that another factor, probably oxygen, becomes limiting as enhancing the supply of energy does not increase degradation rates anymore. Thus, by heating products at 80°C, the microbial safety margin can be increased while the nutritional value is kept as if heated at 60°C. From literature it is known that degradation at this temperature range only proceeds via the aerobic degradation pathway. It has been shown in the present work that in food products, the oxygen availability decreases down to anaerobic conditions, also near the surface, during heat treatments at 80°C while oxygen in model solutions stays abundant. Hence, the headspace gains in importance during long warm holding of real food products and dynamics of oxygen and ascorbic acid might determine degradation paces. However, oxygen is not alone responsible for the degradation initiation since ascorbic acid in ultrapure water does not degrade at 80°C during 8 h, even if oxygen is abundant during the whole length of time. An additional trigger, as Fe3+ ions or maybe also other constituents in food matrices, must be present. An interaction between oxygen and the trigger might result in the generation of reactive oxygen species that finally deteriorate the vitamin. For complete stabilization of 5-methyltetrahydrofolate, the amount of ascorbic acid is crucial in contrast to the food matrix that is used for supplementation. The protective effect of ascorbic acid is however time-limited even if it remains in excess. The duration of complete stability can be prolonged by increasing the initial ascorbic acid concentration. Heat treatments under real conditions that is when food products are warmed-up by a microwave, an Actifry ® device or held warm by a water bath, lead to minor to negligible vitamin losses. These are good news for the project since the vitamin amount that is added, is preserved during warming-up of products and must not be controlled. The results indicate the complexity of vitamin degradation since the stability depends crucially on the experimental set-up. It can be concluded that predictive modeling should be performed under real conditions. Vitamin C and 5-methyltetrahydrofolate, which are generally referred to be very susceptible to oxygen and heat, are fairly stable under reheating conditions in real food products.

The aim of the study is to determine effects of passive warming up on muscle contraction force while performing maximum intensity short veloergometric test and vertical jumps. Untrained healthy males took part in both experiments within the study. Subjects (n=13) had to perform maximal veloergometric effort with different resistance (3% and 10% of their own weight) for 5 seconds during first test. Then they performed passive warming up and repeated the test. Maximal motion frequency and power output were determined. Other subjects (n=14) had to perform maximal single jumps (one with squat and one without) during second test. Then they performed passive warming up and repeated the test. Maximal set off speed, strength, power output and jump height were determined. Maximal motion frequency and maximal power output after passive warming up in veloergometric test were significantly (p<0, 05) greater than before it. Maximal set off speed after passive warming up in jumping test was significantly (p<0, 05) greater, but maximal set off strength did not differ significantly performing both types of jumps. However jump height significantly increased in both cases. In conclusion, the results indicate that in untrained subjects, passive warming up improves muscles’ power output in both experiments. Another conclusion is that passive warming up has much greater effect on contraction speed than on muscles’ strength.