This project is an in-depth investigation on the impact of lighting, marking and paint schemes on the operational aspects of police vehicles. This investigation consisted of two phases that ultimately consisted of four experiments. An array of lighting and marking schemes were implemented on police vehicles in a variety of jurisdictions for evaluation. The study then investigated the change in the visibility of police officers, the public reaction to these schemes, and the operational impacts of these systems. The first phase of the project was a naturalistic observation study where the goal was to better understand how traffic behaved around traffic stops. Test vehicles were positioned in simulated traffic stops and patrol locations to determine how traffic behavior was affected by various configurations of police lighting and markings. Camera and radar systems were used to measure the changes in driver speed and when drivers responded to the move over law. Based on the results of the naturalistic studies, the impact of the lighting system on officer visibility was investigated in a controlled human factors test where the ability of a driver to see a police officer outside of their vehicle was measured in the presence of the lighting systems. The purpose of this interjected effort was to verify that the experimental schemes would not increase risk to law enforcement despite data from the first phase indicating the vehicles were more visible. A second part to that study evaluated conventional methods of bolstering an officer's visibility outside of their vehicle at night. The second phase took the findings of the first phase and implemented changes to several police vehicles from local and state agencies to be in operation for at least 18 months. This was to assess the rate of near-misses and crash rate to relate the vehicle changes to law enforcement safety. Additionally, rates of citations were assessed, and surveys offered an opportunity for law enforcement to provide their own feedback on the implementations. The lighting systems evaluated included a completely blue lighting system, an enhanced all blue lighting system with twice the light output, a red and blue system, and a single flashing blue beacon. In terms of markings, retroreflective markings along the side of the vehicle, a retroreflective contour line, chevrons on the rear of the vehicle and unmarked vehicles were evaluated. Finally, a variety of vehicle colors were used to investigate the impact of the base vehicle paint color. The results indicate that both the red and blue lighting system and the high output blue lighting system increase the distance at which drivers moved over significantly. In general, at least 95% of traffic attempted to merge away from an actively lighted police vehicle, when possible. In terms of the speed change, drivers began reducing their speed by approximately 600 m from the police vehicle. Similarly, the addition of retroreflectivity to the rear of the vehicle showed an additional benefit for causing drivers to move over sooner. However, these benefits came at a cost to the officer's visibility. When outside of their vehicle, the high output blue system significantly reduced officer detectability while the red and blue configuration only impacted detection distance by 3 meters. The investigation did find that these impacts could be overcome with retroreflective vests worn by the officers. In the second phase, a preference revealed by officers favored the red-blue configuration. They stated that this configuration provided greater comfort for them and less glare to approaching drivers. The study also revealed that the alternative configurations did not impact the operational activities of police authority. / Doctor of Philosophy / This project evaluated how lighting, marking and paint schemes on police vehicles affected their visibility and how traffic responded to them. An observational study positioned police vehicles with alternative lighting and markings in simulated traffic stops and patrol locations to evaluate traffic behavior. Camera and radar systems were used to measure the changes in driver speed and when drivers responded to the Move Over law. A second study evaluated how the lighting systems on a police car affect the visibility of an officer at night in a traffic stop scenario. A followup experiment looked into methods for bolstering the visibility of officers at night through conventional implementations such as body worn LED lighting, the use of a retroreflective vest, or by using lighting on the police vehicle's light bar to increase illumination of the police officer. A third study took the findings of the previous experiments and outfitted 64 Virginia State Police vehicles for 18 months. Another 64 Virginia State Police vehicles participated in a control condition where no changes were made to their vehicles. Data collected included the rate of near-misses or crashes and the rates of written citations. Surveys were administered to each participating officer regarding their perception of safety and comfort and allowed their open feedback and suggestions. The lighting systems evaluated included a completely blue lighting system, an enhanced all blue lighting system with twice the light output, a red and blue system, and a single flashing blue beacon. In terms of markings, retroreflective markings along the side of the vehicle, a retroreflective contour line, chevrons on the rear of the vehicle, and unmarked vehicles were evaluated. Finally, a variety of vehicle colors were used to investigate the impact of the base vehicle paint color. The results indicate that both the red and blue lighting system and the high output blue lighting system increase the distance at which drivers moved over significantly. In general, at least 95% of traffic attempted to merge away from an actively lighted police vehicle, when possible. In terms of the speed change, drivers began reducing their speed by approximately 600 m from the police vehicle. Similarly, the addition of retroreflectivity to the rear of the vehicle showed an additional benefit for causing drivers to move over sooner. However, these benefits came at a cost to the officer's visibility. When outside of their vehicle, the high output blue system significantly reduced officer detectability while the red and blue configuration only impacted detection distance by 3 meters. The investigation did find that these impacts could be overcome with retroreflective vests worn by the officers. In the second phase, a preference revealed by officers favored the red-blue configuration. They stated that this configuration provided greater comfort for them and less glare to approaching drivers. The study also revealed that the alternative configurations did not impact the rate of citations.

Este trabalho apresenta um estudo realizado com uma mistura asfáltica morna utilizando ligante aditivado com agente surfactante e borracha moída de pneus inservíveis. Um trecho experimental foi executado com a mistura asfáltica morna, localizado na SPA-248-055, Pista Oeste, entre os quilômetros 3+000 e 6+000 e comparado ao trecho de referência, localizado na mesma rodovia, entre os quilômetros 1+000 e 3+000. Foram feitos também ensaios fundamentais para caracterização do ligante modificado com borracha e com aditivo químico para mistura morna e também ensaios para verificar o comportamento mecânico da mistura de usina, de modo que possibilitou comparar seus resultados com uma mistura de referência, com produção na temperatura a quente. Os ensaios realizados para verificação do comportamento mecânico foram: resistência à tração, módulo de resiliência, fadiga e resistência à formação de trilha de roda no simulador de tráfego francês do LCPC. Comparando a mistura asfáltica morna com uma mistura de referencia, os resultados obtidos foram satisfatórios. Além destes experimentos também foram realizados ensaios de resistência ao dano por umidade induzida (DUI). No caso deste estudo, os resultados foram satisfatórios. Durante a produção da mistura asfáltica, foi realizada a análise da redução de emissões de poluentes, no momento da produção da mistura. Os resultados indicaram que há redução de poluentes como fumos totais, fumos solúveis e compostos orgânicos voláteis (VOC). Tanto o trecho experimental quanto o trecho de referência foram avaliados durante 3 anos quanto aos parâmetros de desempenho do pavimento, como irregularidade e condição de superfície. Os resultados obtidos mostram o comportamento positivo da mistura asfáltica morna, quando comparado ao pavimento do trecho de referência, ao longo de dois anos de observação. / This paper presents a study of a warm asphalt mix using binder additive with surfactant agent and tire crumb rubber. A test section was performed with the warm asphalt mixture, located in SPA-248-055, West Lane, between kilometers 3+00 to 6+000 and compared to the reference section, a hot mix section, located on the same highway, between kilometers 1 + 000 and 3 + 000. Basic tests were also made to characterize the rubber-modified binder and to verify the mechanical behavior of the plant mixture, than compared to results of a reference hot mixture. The tests performed to check the mechanical behavior were: tensile strength, resilient modulus, fatigue and rooting in French LCPC traffic simulator. Comparing the warm asphalt mixture with a mixture of reference, the results achieved were satisfactory. In addiction, in this research were also performed induced moisture damage, and check the adhesion of the binder to the aggregate. In the case of this study, the results were acceptable. During warm asphalt mix and hot mix production, analysis of reducing pollutant emissions were recorded. The results indicated that there is a reduction of pollutants such as total smoke, fumes soluble and organic volatile compounds. Both the experimental section and the reference section were evaluated for 3 years for pavement performance parameters such as roughness and surface condition. The results show a positive behavior of warm asphalt mix compared to the reference pavement section over two years of observation.

This thesis describes aspects of durability of Swedish softwood in above ground applications. The thesis consists of a summary of nine papers, which all aim to explain the existing variation in above ground microbial durability and moisture sensitivity of Norway spruce (Picea abies) and Scots pine (Pinus sylvestris). The methods used were two field tests, one accelerated durability test, and three water permeability tests. The main conclusions made in the study were that Norway spruce sapwood is more susceptible to discolouring fungi than heartwood. With respect to Scots pine, the only important factor for its natural durability above ground was whether the samples consisted of heartwood or of sapwood. There was also no systematic variation between pine heartwood from different stand origins in above ground conditions. Origin had no influence on durability in practice for neither spruce nor pine. Furthermore, in contradiction with traditional thinking, annual ring width and density had no influence on durability in any of the tests. The material came from two different samplings. The ‘old’ material was sampled in the beginning of the 1980s and consisted of Scots pine and Norway spruce from three different origins: the north, the central area, and the south of Sweden. The material was subjected to different handling conditions and surface and end-grain treatments. The ‘old’ material was used in a large above ground field test, carried out between 1985 and 1994. Unfortunately, the spruce sapwood and heartwood was not separated in this field test. In the field trial with the ‘old’ material, the most important factor for the durability of Norway spruce was the samples’ surface- and end-grain treatment. It was also observed that untreated spruce showed better durability than samples that were painted but without proper end-grain treatment. Samples originating from one of the stands were more sensitive towards air-drying than samples from the other two, which was reflected in a higher average moisture content and mass loss for the untreated samples. With respect to Scots pine, the most important factor was whether the sample consisted of heartwood or of sapwood. The heartwood samples were durable irrespective of their previous treatment. The Scots pine sapwood samples, on the other hand, had a very fluctuating moisture content if they were not surface- and end-painted. This was also reflected in higher mass losses in these samples. Even when properly surface- and end grain treated, the sapwood samples did not perform as well as the heartwood samples. The ‘new’ material consisted of Scots pine taken from six different stands, and Norway spruce from five different stands, all from areas in southern Sweden. The sampling was performed in order to achieve a large variation in wood properties. Thus, logs from areas with different climate and growth conditions were collected. This material was used for laboratory tests, and also for the second field test, which was evaluated after a test period of two years. In the second field test untreated Scots pine and Norway spruce samples from the ‘new’ material were investigated. Effects of origin and different tree diameters were examined. Furthermore, Scots pine was separated to heartwood and sapwood, and Norway spruce to mature and juvenile wood. The Norway spruce samples were sawn with vertical or horizontal annual rings. For the Norway spruce in the second field test, vertical annual rings were shown to be very beneficial for avoiding crack formation, while samples with horizontal annual rings displayed a large number of cracks. Despite this, the larger number of cracks did not result in a higher moisture content or more fungal discoloration. Juvenile wood had a slightly higher average discolouring fungal growth grading than the other spruce samples. For Scots pine, the only factor of importance was whether the samples consisted of heartwood or of sapwood. Annual ring width, density and origin had no significant effect on either fungal growth or moisture uptake. This observation held for both Norway spruce samples and Scots pine samples. An accelerated test was run in order to investigate Norway spruce sapwood and heartwood with respect to their differences in durability towards discolouring fungi and moisture uptake. The Mycologg method was used to accelerate fungal growth during a number of forced moisture cycles. The results showed that sapwood was much more sensitive to discolouring fungi than heartwood. Sapwood also recorded a higher average moisture content than heartwood. The differences that were observed between the types of samples were not due to annual ring width, density or origin. It was observed that Norway spruce sapwood samples and heartwood samples showed differences in liquid water permeability. This observation was made especially evident in a droplet absorption test. Water droplets were absorbed much faster on the sapwood samples in comparison with the heartwood samples. This higher affinity to water suggested that a sapwood surface would reach a higher moisture content than a heartwood surface. This observation provides a major explanation of why the sapwood samples showed poorer durability towards discolouring fungi in the Mycologg trials.

There is an urgent need for Bangladesh to identify the arsenic (As) contaminated tubewells (TWs) in order to assess the health risks and initiate appropriate mitigation measures. This involves testing water in millions of TWs and raising community awareness about the health problems related to chronic As exposure from drinking water, and providing alternative safe water option for the exposed population of the country. The use of spatial maps in a participatory context emerged as an important tool for an effective and rational distribution of alternative safe water options for the exposed population of the country. Field test kit offers the only practical tool available to screen all the TW water considering the time frame and financial resources of the country. A comparison of the field test kit results and laboratory measurements by atomic absorption spectrometry (AAS) as “gold standard” for As in water of 12,532 TWs in Matlab upazila (sub-district) in Bangladesh, indicates that the field test kit correctly determined the status of 87% of the As levels compared to the Bangladesh Drinking Water Standard (BDWS) of 50 μg/L, and 91% of the World Health Organization (WHO) drinking water guideline value of 10 μg/L. In order to identify the sustainable alternative safe water options, different type of safe water options were distributed in Sonargaon and Jhikargachha upazilas (sub-district) in 2001 and later revisited the options in 2004 to identify the sustainable ones. It was observed that community acceptability of the distributed options was not encouraging; less than 2% of the provided options were found to be in use. However, two new approaches emerged from people’s initiatives, which were making rapid and positive contributions to safe water coverage: switching to the existing As-safe TWs and reinstalling TWs at 50-100 m depths by looking at particular type of sediment colours. A study was conducted in Matlab upazila to validate the concept of installation/reinstallation of TWs at certain depths, a new concept promoted by local drillers (masons). The study revealed that locally a thick layer of black to grey sediments overlies an oxidized unit of yellowish-grey to reddish-brown sediments. The correlation between the colour of both units and the groundwater redox conditions was investigated to provide an easy tool for targeting low-arsenic groundwater. The water abstracted from black sediments contained high amount of As concentration but the concentration decreased towards the yeallowish to red sediments. Three boreholes verified the driller's perception of the subsurface lithologic conditions. Discrepancies between the driller's and the research team description of the sediment colours were insignificant. This study shows that sediment colour is a reliable indicator of high and low As-concentrations in TW water and can be used by local drillers to install TW. Lack of financial resources and identification of an appropriate distribution tools are some of the major obstacles to provide sustainable solution to the exposed population of the country. Spatial mapping exercise along with community participation can help maximize the safe water coverage of different alternative safe water options by reducing financial involvement. Combining people’s voice with that of spatial information gave better results and the method is already been proved useful in targeting non-served areas. Participatory Rural Appraisal (PRA) methods along with geographical information system (GIS) used in the study to obtain relevant information. Participants from different focus groups were asked to determine their ‘own priorities’ for spatial planning of alternative arsenic-safe water options. The study discusses community perspectives on demand-based safe water options and reveals the suitability of using participatory geographic information system (PGIS) technique to target non-served areas for rational distribution of safe water options. / QC 20100716

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.

Made available in DSpace on 2014-12-17T14:03:33Z (GMT). No. of bitstreams: 1 CleysyvanSM_DISSERT.pdf: 1173359 bytes, checksum: 82a094c436e4d9b81948c390ed5d9ed1 (MD5) Previous issue date: 2010-02-26 / Coordena??o de Aperfei?oamento de Pessoal de N?vel Superior / Chitin-binding vicilins from legume seeds (Erythrina velutina. Canavalia ensiformes and Phaseolus vulgares) were isolated by ammonium sulfate followed by affinity chromatography on a chitin column. Effect of these vicilins on female adults of Ceratitis capitata was examined by bioassay and in a semi-field assay model. Mechanism of action of the vicilins was determined by in vivo digestibility and chitin affinity. Among the tested vicilins, E. velutina when added to diet caused strong effect on mortality at 10% dose. This insecticidal property was tested in a semi-field assay which showed the same effect observed in laboratory conditions, where doses of 10% and 15% were lethal to female adults of C. capitata. These deleterious effects were not only associated to the binding to chitin structures present in peritrophic membrane, but principally to its low digestibility in the C. capitata digestive tract. This fact was confirmed because chiting binding proteins as WGA and the other tested vicilins were not toxic to female adults of C. capitata due susceptibility of these proteins to digestive enzymes of the insects. By other side EvV was more resistant to digestive enzymes, causing deleterious effects on female adults of C. capitata. These results showed that EvV may be part of the pest management programs or an alternative in plant improvement program in the population control of this fruticulture pest / Vicilinas ligantes a quitina de sementes de Erythrina velutina, Canavalia ensiformis e Phaseoulus vulgaris foram isoladas atrav?s de procedimento que consistiu de precipita??o com sulfato de am?nio seguida de cromatografia de afinidade em coluna de quitina. O efeito dessas vicilinas sobre f?meas adultas de Ceratitis capitata foi examinada por bioensaios em condi??es de laborat?rio e por bioensaios em condi??es de semi-campo. O mecanismo de a??o dessas vicilinas foi determinado por um ensaio de digestibilidade in vivo e pela propriedade de liga??o a uma matriz de quitina. Entre as vicilinas testadas, a vicilina de E. velutina foi a ?nica letal, causando mortalidade de 100% quando adicionada ? dieta das moscas das frutas adultas na concentra??o de 10% (p/p). Este efeito inseticida da vicilina de E. velutina foi tamb?m testado em condi??es de semi-campo, onde concentra??es de 10 % e 15% (p/p) de vicilina adicionada ? dieta foram letais para f?meas adultas de C. capitata. Esse efeito delet?rio das prote?nas ligantes ? quitina n?o foi associado somente ? propriedade de liga??o ? quitina, visto que as outras vicilinas, al?m da lectina de g?rmen de trigo (WGA) foram t?xicas quando adicionadas ? dieta das moscas das frutas. Entretanto, a resist?ncia/susceptibilidade dessas prote?nas aos processos digest?rios desses insetos poderia explicar os diferentes efeitos observados. Das prote?nas ligantes ? quitina, apenas aquelas refrat?rias ? a??o das enzimas digestivas nos processos digest?rios teve a??o inseticida. Esses resultados mostraram que vicilina de E. velutina ? um bioinseticida com potencial de uso nos programas de controle de pragas diminuindo a popula??o de moscas das frutas no campo

Este trabalho apresenta um estudo realizado com uma mistura asfáltica morna utilizando ligante aditivado com agente surfactante e borracha moída de pneus inservíveis. Um trecho experimental foi executado com a mistura asfáltica morna, localizado na SPA-248-055, Pista Oeste, entre os quilômetros 3+000 e 6+000 e comparado ao trecho de referência, localizado na mesma rodovia, entre os quilômetros 1+000 e 3+000. Foram feitos também ensaios fundamentais para caracterização do ligante modificado com borracha e com aditivo químico para mistura morna e também ensaios para verificar o comportamento mecânico da mistura de usina, de modo que possibilitou comparar seus resultados com uma mistura de referência, com produção na temperatura a quente. Os ensaios realizados para verificação do comportamento mecânico foram: resistência à tração, módulo de resiliência, fadiga e resistência à formação de trilha de roda no simulador de tráfego francês do LCPC. Comparando a mistura asfáltica morna com uma mistura de referencia, os resultados obtidos foram satisfatórios. Além destes experimentos também foram realizados ensaios de resistência ao dano por umidade induzida (DUI). No caso deste estudo, os resultados foram satisfatórios. Durante a produção da mistura asfáltica, foi realizada a análise da redução de emissões de poluentes, no momento da produção da mistura. Os resultados indicaram que há redução de poluentes como fumos totais, fumos solúveis e compostos orgânicos voláteis (VOC). Tanto o trecho experimental quanto o trecho de referência foram avaliados durante 3 anos quanto aos parâmetros de desempenho do pavimento, como irregularidade e condição de superfície. Os resultados obtidos mostram o comportamento positivo da mistura asfáltica morna, quando comparado ao pavimento do trecho de referência, ao longo de dois anos de observação. / This paper presents a study of a warm asphalt mix using binder additive with surfactant agent and tire crumb rubber. A test section was performed with the warm asphalt mixture, located in SPA-248-055, West Lane, between kilometers 3+00 to 6+000 and compared to the reference section, a hot mix section, located on the same highway, between kilometers 1 + 000 and 3 + 000. Basic tests were also made to characterize the rubber-modified binder and to verify the mechanical behavior of the plant mixture, than compared to results of a reference hot mixture. The tests performed to check the mechanical behavior were: tensile strength, resilient modulus, fatigue and rooting in French LCPC traffic simulator. Comparing the warm asphalt mixture with a mixture of reference, the results achieved were satisfactory. In addiction, in this research were also performed induced moisture damage, and check the adhesion of the binder to the aggregate. In the case of this study, the results were acceptable. During warm asphalt mix and hot mix production, analysis of reducing pollutant emissions were recorded. The results indicated that there is a reduction of pollutants such as total smoke, fumes soluble and organic volatile compounds. Both the experimental section and the reference section were evaluated for 3 years for pavement performance parameters such as roughness and surface condition. The results show a positive behavior of warm asphalt mix compared to the reference pavement section over two years of observation.

Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-06-22T14:27:00Z No. of bitstreams: 1 arthurhenriquesouzanetobossi.pdf: 861040 bytes, checksum: c3c1cec3feee16cacb22f14eb9d27f1c (MD5) / Rejected by Adriana Oliveira (adriana.oliveira@ufjf.edu.br), reason: on 2017-06-22T14:35:05Z (GMT) / Submitted by Renata Lopes (renatasil82@gmail.com) on 2017-06-22T14:39:20Z No. of bitstreams: 1 arthurhenriquesouzanetobossi.pdf: 861040 bytes, checksum: c3c1cec3feee16cacb22f14eb9d27f1c (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2017-08-07T19:21:44Z (GMT) No. of bitstreams: 1 arthurhenriquesouzanetobossi.pdf: 861040 bytes, checksum: c3c1cec3feee16cacb22f14eb9d27f1c (MD5) / Made available in DSpace on 2017-08-07T19:21:44Z (GMT). No. of bitstreams: 1 arthurhenriquesouzanetobossi.pdf: 861040 bytes, checksum: c3c1cec3feee16cacb22f14eb9d27f1c (MD5) Previous issue date: 2014-08-22 / Para maior empregabilidade do protocolo de teste contra-relógio (CR) de 20 min em campo, é necessária a compreensão (1) de como o desempenho em percurso de subida se relaciona com as medidas laboratoriais típicas e (2) do perfil de pacing adotado. Separados por pelo menos 48 horas, 15 ciclistas moderadamente treinados, incluindo 1 do sexo feminino (30,8±4,8 anos; 176,5±8,0 cm; 78,9±14,5 kg; 56,1±7,7 ml.kg-1.min-1; média ± desvio padrão), realizaram inicialmente um teste anaeróbio Wingate, um teste de esforço incremental até a exaustão e um contrarelógio de campo por 20 min em percurso de subida com 2,7% de inclinação média. Após 5 semanas de treinamento não supervisionado, 10 dos 15 voluntários realizaram um segundo CR para comparação do pacing adotado. As regressões lineares múltiplas stepwise demonstraram que 91% da variação na potência média produzida no CR (W.kg-1) pode ser explicada pelo pico do consumo de oxigênio (ml.kg-1.min-1) e pelo ponto de compensação respiratória (W.kg-1), com coeficientes beta padronizados de 0,64 e 0,39 respectivamente. A realização do CR em aclive pressupõe um ajuste de 94,6% da potência média, de modo a aperfeiçoar a concordância com a potência referente ao ponto de compensação respiratória, em que o diagrama de Bland-Altman demonstrou um viés ± erro aleatório de 0,4±49,7 W ou -0,1±19,7 %. A ANOVA two-way (CR X tempo) para medidas repetidas revelou efeito principal dos intervalos de tempo (p < 0,001) na potência média produzida em cada trecho (122,2±10,0; 97,8±1,2 e 95,1±7,1% para os trechos 0-2, 2-18 e 18-20 min, respectivamente) caracterizando perfil de pacing positivo, tanto no primeiro, quanto no segundo teste (p = 0,116). Em conjunto, estas informações indicam que o protocolo de teste CR de 20 min realizado em subida, aparentemente, seja robusto para monitorar o desempenho de ciclistas de diferentes níveis competitivos. Entretanto, novos estudos mais específicos são importantes para confirmar a reprodutibilidade do desempenho e para verificar a influência do feedback instantâneo da potência produzida. / For a wider applicability of the 20-min time trial (TT) testing protocol in field, it is necessary to understand (1) how performance in an uphill course relates with typical laboratory measures and (2) the pacing profile adopted. Separated by at least 48 hours, 15 moderately trained cyclists, including 1 female (30.8±4.8 years; 176.5±8.0 cm; 78.9±14.5 kg; 56.1±7.7 ml.kg-1.min-1; mean ± standard deviation), initially performed a Wingate anaerobic test, a graded exercise test to exhaustion and a 20-min field time trial in a 2.7% gradient uphill course. After 5 weeks of nonsupervised training, 10 from 15 volunteers performed a second TT for comparison of the pacing adopted. Stepwise multiple linear regressions demonstrated that 91% of TT mean power output variation (W.kg-1) can be explained by peak oxygen consumption (ml.kg-1.min-1) and respiratory compensation point (W.kg-1), with standardized beta coefficients of 0.64 and 0.39 respectively. Performing TT on ascents premises a 94.6% mean power output adjustment in order to improve the agreement with respiratory compensation point power output, which Bland-Altman plot showed a bias ± random error of 0.4±49.7 W or -0.1±19.7 %. Repeated measures two-way ANOVA (TT X time) revealed a main effect of the time intervals (p < 0.001) on the power output of each portion (122.2±10.0; 97.8±1.2 e 95.1±7.1% for the portions 0-2, 2-18 e 18-20 min, respectively) characterizing a positive pacing profile, either in the first and in the second test (p = 0.116). Together, this information indicates that the 20-min TT testing protocol performed on ascent is apparently robust for performance monitoring of different competitive level cyclists. However, more specific new studies are important to confirm performance reproducibility and to verify the influence of power output instant feedback.

Les objectifs de ce travail étaient d'analyser les réponses physiologiques au cours d’exercices intermittents en course à pied et de déterminer i) un test d'évaluation de la vitesse maximale aérobie (VMA) adapté aux exercices intermittents ; ii) les exercices intermittents permettant une sollicitation maximale de la consommation d'oxygène (VO2max) ; iii) les facteurs physiologiques et neuromusculaires limitant la durée des exercices intermittents.La première étude a permis de montrer que la réalisation d’un exercice intermittent alternant des périodes d'effort de 30 s avec des périodes de récupération de 30 s (30s-30s), à la VMA atteinte à la fin du test intermittent incrémental 45-15FIT, permettait à la fois de réaliser un grand nombre de répétitions et de solliciter un fort pourcentage de la VO2max pendant la durée de l'exercice. Lors de la seconde étude nous avons montré que les exercices intermittents de type 5s-15s, 30s-30s et 60s-60s, courus à la VMA permettaient de solliciter un fort pourcentage de la VO2max. L'exercice intermittent de type 30s-30s est celui qui permet néanmoins de réaliser le plus grand nombre de répétitions. Une part plus importante de la glycolyse dans la production d'énergie réduit le nombre de répétitions lors de l'exercice de type 60s-60s par rapport à l'exercice de type 30s-30s ; une fatigue musculaire causée par un plus grand nombre d'accélérations et de décélérations réduit quant à elle le nombre de répétitions lors de l'exercice de type 15s-15s, par rapport à l'exercice de type 30s-30s. Les résultats de la troisième étude ont confirmé que les exercices intermittents de type 5s-15s, courus à la VMA, induisaient une fatigue musculaire plus importante, due essentiellement aux nombreuses accélérations et décélérations. Il a également été montré qu'à la suite d'un exercice pré-fatigant des muscles extenseurs du genou (contractions musculaires évoquées par électromyostimulation vs contractions volontaires isométriques), le nombre de répétitions lors de l'exercice intermittent 30s-30s était réduit, mais que le pourcentage de temps passé à plus de 90% de la VO2max n'était pas diminué par rapport à la réalisation sans pré-fatigue.L'ensemble de nos travaux permettent de définir un ensemble d'exercices intermittents qui, lorsqu'ils sont courus à la VMA évaluée lors du test 45-15FIT, permettent d'atteindre un niveau élevé de sollicitation du système aérobie, dont l'exercice de type 30s-30s pourrait constituer un exercice "standard" / The aims of the present work were to analyze the physiological responses during intermittent exercise and to determine; i) an field test to assess the maximal aerobic velocity (MAV) for intermittent exercise; ii) the type of intermittent exercise could elicit maximal oxygen uptake (VO2max); iii) the physiological and neuromuscular factors that could limit intermittent exercise duration.The first study demonstrated that the MAV (MAV45-15) reached at the end of an incremental intermittent (45s run/ 15s rest) field test (45-15FIT) was relevant to elicit a high percentage of VO2max during a 30s-30s intermittent training session. The second and third studies demonstrated that intermittent exercises performed at MAV45-15 such as 5s-15s, 15s-15s, 30s-30s, and 60s-60s, were relevant to elicit a high percentage of VO2max. In the 60s-60s intermittent exercise, the lowest endurance time compared to 30s-30s, was explained by the predominance of the anaerobic system in the energy supply. In the 15s-15s and 5s-15s intermittent exercises, the lowest endurance time in comparison with 30s-30s was explained by the greater neuromuscular fatigue. The fourth study showed that a pre-fatigue induced by evoked contractions by electrostimulation, and isometric voluntary contraction of the knee extensor muscles reduced the time to exhaustion in a 30s-30s intermittent exercise, but was relevant to elicit a high percentage of VO2max. These results give new insights in the field of intermittent exercise training

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.