Concerns over human-bear conflict and questions about the ecology of Paunsaugunt Plateau's population of black bears (Ursus americanus) arose due to their visitation to popular recreation sites. Greater insight about bears and their habitat use provides a foundation for conflict mitigation and effective management decisions. Between 2014 and 2017, seventeen black bears (11 female, 6 male) were fitted with global positioning system (GPS) radio-collars so that we could track their locations, daily activity patterns, and ambient temperatures. By analyzing bear locations, we calculated annual and seasonal home ranges for 16 bears, including 25 den sites. Home ranges typically consisted of three dominant vegetation types, Utah juniper, ponderosa pine and Douglas fir. I used mixed effects models to better understand den site selection and found that slope (27.87 ± 2.03) was the most significant factor (p < 0.001). I also used mixed effects models to understand black bear selection of annual and seasonal home ranges. Predictor variables with the greatest effect (p < 0.001) were elevation (2419.99 ± 1.35) and aspect (138.44 ± 0.64), with coefficients of 1.128 and -1.483 respectively. Male annual home ranges (327.20 km2 ± 133.58 km2) were significantly larger (p = 0.035) than female home ranges (175.10 km2 ± 55.37 km2). However, annual home ranges for both sexes were larger than those during hyperphagia (p = 0.003) or mating (p = 0.004) seasonal home ranges, between which there was no difference (p = 0.451). Individual home ranges overlapped for most bears, consistent with their non-territorial nature. I found that bears avoided roads and lower elevations, while showing a preference for sloping terrain throughout the non-denning period. Paunsaugunt black bear home ranges are larger than any other black bear home ranges reported in literature. We determined weekly average distances and directions for all bears. For two bears, one male and one female, we determined daily averages and directions. Nine bears provided daily averages for 12 seasonal units across all four years. Activity patterns indicate the typical crepuscular pattern noted in normal bear populations that lack human habituation. Identifying areas core use areas and potential den sites is helpful to understanding black bear ecology and useful when making decisions about how to plan infrastructure and educate the public. This research indicates that Paunsaugunt black bears avoid human activity; however, we need continued research to help determine specific interactions between bears and anthropomorphic influences.

Previous research has shown that with advancing age, there are increasing incidences of slip and fall injuries. Understanding mechanisms associated with gait adjustments across a known slippery surface may help in proactively avoiding slips and falls. The primary goal of this study involved examination of gait parameters and muscle activity characteristics of the lower extremities during two different walking conditions. Research has shown that both physical and mental changes accompany the aging process in humans. Moreover, research has shown that emotions and physiological responses are related. A secondary goal of this study was to examine the relationships of fear of falling with gait parameters and muscle activity. This study consisted of exposing 14 younger and 14 older participants to controlled slippery conditions safely, while studying normal and adjusted gait characteristics (friction requirement, heel contact velocity, and step length) and muscle activity characteristics (Integrated EMG). First, a baseline measure was done to study normal gait prior to any exposure to slipping. A second measure was done following a slip from a contaminated floor surface, but before the initiation of a second slip. The results indicate that there were significant gait parameter differences between younger and older participants for both walking conditions. Results also indicate that there were differences in muscle activity between to the two age groups for the adjusted condition. Findings suggest that older individuals require an additional step to properly adjust gait for a contaminated walking surface. / Master of Science

Submitted by Renata Lopes (renatasil82@gmail.com) on 2016-06-17T14:40:24Z No. of bitstreams: 1 giovanneambrosioferreira.pdf: 4854968 bytes, checksum: 69664974d5a598bcb10de741b98887d4 (MD5) / Approved for entry into archive by Adriana Oliveira (adriana.oliveira@ufjf.edu.br) on 2016-07-13T14:39:11Z (GMT) No. of bitstreams: 1 giovanneambrosioferreira.pdf: 4854968 bytes, checksum: 69664974d5a598bcb10de741b98887d4 (MD5) / Made available in DSpace on 2016-07-13T14:39:11Z (GMT). No. of bitstreams: 1 giovanneambrosioferreira.pdf: 4854968 bytes, checksum: 69664974d5a598bcb10de741b98887d4 (MD5) Previous issue date: 2016-03-31 / Alterações antrópicas na paisagem proporcionam potenciais ameaças para diversas espécies de mamíferos. A introdução de espécies domésticas representa uma forte pressão, seja pela predação, competição, ou na veiculação de doenças domésticas para vida silvestres. O gato doméstico possui características biológicas e comportamentais que permitem uma grande adaptabilidade às áreas naturais, propiciando assim a exploração e ocupação destes ambientes, potencializando riscos às espécies nativas. Por essa razão, sua ação é apontada como um dos principais motivos da perda de espécies, principalmente em ilhas. Torna-se assim imprescindível a necessidade da verificação destas potenciais ameaças e da avaliação de estratégias voltadas para amenizá-las. Neste estudo, observamos a interferência da presença de fêmeas como um fator importante para a determinação do tamanho da área de vida dos machos. Foi constatada a predação sobre todas as espécies de pequenos mamíferos não voadores, amostradas em campanhas de capturas, em uma Área de Proteção Ambiental insular de Mata Atlântica. Entretanto, foram detectados valores opostos ao esperado para riqueza, abundância e diversidade de espécies entre diferentes áreas, considerando-se a presença ou ausência e a densidade destes felinos. Verificou-se também que para os gatos semidomiciliados, a disponibilidade de presas não foi determinante para o consumo destas espécies, o que reforça seu comportamento generalista e oportunista de predação. Observou-se ainda a sobreposição entre quatro espécies de felinos neotropicais em relação às áreas utilizadas pelos gatos domésticos vivendo nesta Unidade de Conservação. No que diz respeito às estratégias para amenizar os impactos pela presença dos gatos, foi demonstrado que o procedimento de intervenção pela castração dos machos, reduz significativamente, tanto a área de vida (75,89%), quanto o padrão de atividade (73,59%) destes gatos em condições semidomiciliares. Todavia, mesmo com a redução desta área de atividade após o procedimento de castração, esperava-se o mesmo efeito para o consumo de presas, mas verificou-se que a castração não interferiu nem no consumo destas, nem nas estimativas de populações de pequenos mamíferos não voadores, amostradas em áreas naturais onde ocorrem em simpatria com gatos. A presença de espécies de pequenos mamíferos exóticas com estreita associação com ambientes antropizados, registradas apenas nas amostras fecais analisadas, tanto no período anterior, quanto no período pós-castração, e a pouca variação no número de presas consumidas, indicam que esta predação possivelmente ocorra nas imediações das propriedades onde residem estes gatos. Os resultados indicam que, embora deva ser incentivada a fim de evitar um crescimento desordenado da população de gatos nestas áreas, a castração não deve ser a única estratégia utilizada para minimizar possíveis impactos causados pela presença destes felinos em áreas naturais. / Anthropic changes in the landscape provide potential threats to several mammal species. The introduction of domestic species is a strong pressure, by either the predation, competition, or placement of domestic diseases to wild lives. The domestic cat has biological and behavioral characteristics that allow to it a great adaptability to natural areas, promoting thus the exploitation and occupation of these environments, increasing risks to native species. Because of this, its action is one of the main reasons for the loss of species, especially on islands. It is therefore imperative the need to verify these potential threats and the evaluation of strategies aimed to mitigate them. In this study, the interference of female presence was observed as an important factor for determining the dimensions of the males home range. It has been found the predation on all kinds of small non-flying mammals, sampled on collection campaigns in an Islander Atlantic Environmental Protection Area. However, it was possible to detect opposite values expected for wealth, abundance and species diversity among different areas, considering the presence or absence and the density of these felines. It was also found that for semi-domiciled cats, the availability of preys was not decisive for the consumption of these species, which reinforces its generalist and opportunistic behavior of predation. In addition to this, there was a superimposition among four species of Neotropical felines in relation to areas used by domestic cats living in this Protection Area. In regards to the strategies to mitigate the impacts by the presence of cats, the intervention through castration of males significantly reduces both the home range (75.89%), and the pattern of activity (73.59%) of these cats under semi-domiciled conditions. However, even with the reduction of this activity area after the castration procedure, it was expected the same effect for the prey consumption of, but it was found that castration did not interfere on the consumption nor on the estimates of small non-flying mammals, sampled in natural areas where there is sympathy with cats. The presence of exotic species of small mammals with close association with anthropic environments, registered only in fecal samples analyzed both in the previous period and the post-castration period, and the small variation in the number of preys consumed indicate that this predation possibly occurs in the vicinity of the properties where these cats reside. The results indicate that, although it should be encouraged in order to avoid a disorderly growth of the cat population in these areas, castration should not be the only strategy used to minimize possible impacts caused by the presence of these felines in natural areas.

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No. of bitstreams: 1 giovanneambrosioferreira.pdf: 11308277 bytes, checksum: 29c09d7d3d127c6be8192883098b796f (MD5) Previous issue date: 2011-02-25 / CAPES - Coordenação de Aperfeiçoamento de Pessoal de Nível Superior / O livre acesso de gatos (Felis silvestris catus) a áreas externas da residência de seus proprietários (chamados semi-domiciliados), quando em ambientes naturais pode ocasionar predação sobre animais silvestres, competição alimentar com carnívoros nativos, e ainda potencializara veiculação de zoonoses. Informações a respeito do comportamento destes animais em fragmentos de mata atlântica são raros, desta forma, este estudo objetivou avaliar: a) os itens encontrados na dieta e sua variação sazonal através da análise de amostras fecais; b) a área de vida e os padrões de atividade por meio de rádio telemetria; c) as diferenças individuais na dieta e a disposição das fezes nos territórios por meio do método da marcação de isca de gatos semi-domiciliados encontrados em um fragmento remanescente de Mata Atlântica localizado ao sul do município de Ilha Comprida – SP. Resultados coletados entre setembro de 2009 e setembro de 2010 demonstram que mesmo recebendo alimentos dos proprietários, a espécie apresentou uma dieta oportunista e generalista, com pouca variação sazonal (X2 = 6,754; p = 0,4549). As presas mais consumidas foram insetos (21,26%), seguidos por mamíferos (14,24%) e aves (4,11%). Machos residentes em propriedades ausentes de fêmeas demonstraram maiores área de vida e sobreposições sobre as áreas dos demais gatos, que apresentaram valores semelhantes entre si. Os horários de maior atividade ocorreram no período crepuscular noturno, principalmente nos horários de 20-22h e 02-04h; enquanto o período entre 14-16h apresentou menor registro. Maiores atividades registradas durante a estação seca, todavia, machos demonstraram maior atividade noturna, em ambas as estações, enquanto fêmeas maiores atividades diurna, principalmente durante a estação seca. As amostras fecais encontradas próximas ao centro de atividade, geralmente estavam enterradas, enquanto à medida que se distanciavam, podiam ou não estar enterradas. Ocorreram poucas variações na dieta entre os sexos. Entretanto, fêmeas mais novas predaram animais menores (insetos); fêmeas mais velhas predaram também vertebrados maiores; enquanto para os machos observou-se o inverso. A diversidade de itens de presas nativas encontrados na dieta demonstra a capacidade adaptativa e o comportamento inato de predação da espécie. A pequena diferença encontrada entre as estações reflete na pequena variação sazonal encontrada no período amostrado. Os resultados indicam que a disponibilidade e abundância de recursos (alimento e abrigo) foram os fatores mais importantes na determinação das áreas de vida de fêmeas, enquanto a disponibilidade e acesso a estas, seriam os determinantes para os machos. Sugere-se que o padrão de atividade sofra influência das variações sazonais. A maneira como as fezes são encontradas no ambiente estão relacionadas ao status hierárquico ou questões comportamentais e ecológicas de seu produtor. Sendo assim, informações importantes sobre a dieta e comportamento de caça individuais foram obtidas por meio da identificação individual de suas fezes. Os resultados obtidos por este estudo contribuem para pesquisas que visem à preservação de espécies vulneráveis às influencias causadas pela presença desta espécie em ambientes naturais, ou ainda que busquem obter esclarecimentos sobre a saúde e o bem estar destes animais, espécies nativas e seus proprietários. / Free access for cats (Felis silvestris catus) to areas outside the residence of its owners (called semi-resident), when in natural environments may cause predation on wildlife, food competition with native carnivores and more, increase the zoonoses placement. Information about the behavior of these animals in the Atlantic forest fragments are rare, thus this study aimed to assess: a) the items found on diet and its seasonal variation by analyzing fecal samples; b) the home range and patterns of activity by radio telemetry; c) individual differences in diet and feces disposal in the territories by the method of marking bait semidomiciled cats found in an Atlantic forest fragment located south of the city of Ilha Comprida – SP. The results collected between September 2009 and September 2010 show that even getting food from the owners, the species had a generalist and opportunistic diet, with little seasonal variation (X2 = 6,754, p = 0,4549). The most consumed preys were insects (21,26%), followed by mammals (14,24%) and poultry (4,11%). Males residing in properties absent from females had larger home ranges and overlap the areas of other cats, which showed similar values. The time of greatest activity occurred in the evening twilight period, mainly during 20-22h and 02-04h, while the period between 14-16h showed the lowest record. Major activities recorded during the dry season, however, males showed greater nocturnal activity in both seasons, while females more daytime activities, especially during the dry season. The fecal samples found near the center of activity usually were buried, and as much as they distanced from the center they could be buried or not. There were few variations in diet between the sexes. However, younger females preyed on smaller animals (insects); older females also ate higher vertebrates, whereas for males the opposite was observed. The diversity of prey items found in the native diet demonstrates the adaptiveness in innate behavior and predation of the species. The small difference found between the seasons reflected in the low seasonal variation found in the sample period. The results indicate that the availability and abundance of resources (food and shelter) were the most important factors in determining the home range of females, while the availability and access to them, and are the determinants for males. It is suggested that the activity pattern is influenced by seasonal variations. How feces are found in the environment are related to the hierarchical status or behavioral and ecological issues of its producer. Thus, important information about diet and individual hunting behavior were obtained through individual identification of feces. The results of this study contribute to research aimed at the preservation of species vulnerable to influences caused by the presence of this species in natural environments, or even seek clarification about the health and wellness of these animals, native species and their owners.

Orientadora: Eleonore Zulnara Freire Setz / Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Biologia / Made available in DSpace on 2018-08-20T18:03:19Z (GMT). No. of bitstreams: 1 Gestich_CarlaCristina_M.pdf: 2412818 bytes, checksum: 3850c0adff0e3465f46c136d4a4903b3 (MD5) Previous issue date: 2012 / Resumo: A alteração das necessidades energéticas dos endotérmicos pela variação da temperatura ambiental devido aos custos da termorregulação pode influenciar seu comportamento. O objetivo desse estudo foi investigar a influência da temperatura nos comportamentos de sauás (Callicebus nigrifrons) na Serra do Japi, região com marcada sazonalidade e temperatura reduzida pela altitude. Para isso, relacionamos com a temperatura: o padrão de atividade, os itens alimentares e os comportamentos termorregulatórios durante o descanso (seleção de micro-hábitat, contato entre os indivíduos e postura corporal). Quanto menores as temperaturas mínimas noturnas, o que pode representar estresse térmico, os sauás iniciaram suas atividades mais tardiamente, no momento em que a temperatura ambiental já estava elevada. A distância percorrida diariamente não variou com a temperatura, mas os sauás locomoveram mais no início do dia, horário mais frio, coincidindo com o início das atividades. Entre os meses, a locomoção foi menor nos mais frios, possivelmente resultando em economia de energia. Não houve seleção por itens alimentares mais calóricos em temperaturas baixas. Entretanto, houve aumento no forrageio nos meses mais frios (não relacionado com a disponibilidade de frutos), compatível com a ideia de que os custos da termorregulação podem influenciar a ingestão de alimentos. A seleção de locais ao sol foi maior em temperaturas baixas, e tal comportamento pode estar reduzindo os custos da termorregulação com o aumento da absorção de calor da radiação solar. O contato entre os indivíduos ao longo do dia não teve relação com a temperatura e pode ter sido influenciado somente pelas interações sociais. A postura não variou em função da temperatura e aquelas que resultavam em menor perda de calor para o meio foram predominantemente adotadas. Isso, provavelmente, devido ao porte pequeno da espécie (elevada razão superfície/volume) que contribui para maior perda de calor nas baixas temperaturas registradas. Conclui-se que os sauás apresentam variação comportamental em função da temperatura ambiental quanto à escolha de micro-hábitats e padrão de locomoção e forrageio / Abstract: Variations in ambient temperature can change the energy requirements of endothermics due to costs of thermoregulation. So, ambient temperature can influence animal's behavior. The aim of this work was to investigate ambient temperature influence on wild black-fronted titi monkeys (Callicebus nigrifrons) behavior. We conducted this study in Serra do Japi, region with marked seasonality and temperature reduced due to high altitude. We analyzed the relation between temperature and the following variables: activity pattern, types of food consumed and thermoregulatory behaviors observed during resting (microhabitat selection, contact between individuals and body posture). In lower night minimum temperatures, which may represent thermal stress to titi monkey, they started their activities later in the day, after ambient temperature increase. There was no correlation between path length and ambient temperature, but titis moved more at beginning of the day (at the coldest hours), when they were starting these activities. During the coldest months, titis moved less, which could be a strategy to save energy. During this period, they did not select higher-calorie food items, but there was an increase in foraging behavior (not related to fruit availability), which is consistent with the idea that the energy costs of thermoregulation can influence food intake. The sunny resting places were selected at low temperatures. This behavior could be used to reduce thermoregulation costs, allowing the increase of heat absorption from solar radiation. The contact between individuals throughout the day was not related to the temperature and may be influenced only by social interactions. Body postures were not influenced by ambient temperature and postures that avoid heat loss were predominantly adopted. This is probably due to the small size of the species (considering the high surface/volume ratio) which contributes to greater heat loss at low temperatures. We concluded that titi monkey's behaviors vary in function of ambient temperature, such as microhabitat choice and pattern of moving and foraging / Mestrado / Ecologia / Mestre em Ecologia

The conducted study on the southern river otter Lontra provocax presents for the first time substantial data and analyses on preferred habitat components, activity pattern, prey availability, diet composition and potential food competitors, as well as a first attempt in age determination. Three southern river otter (1,2) were successfully equipped with radio transmitter. Both females were classified as resident whereas the male southern river otter was classified as temporary resident. Home range (FK 95) was 14358 m and 17675 m respectively. As only one home range was accessible for habitat analysis, the preferred habitat structures were analysed. Thus the plant Chusquea quila is most important for den sites in anthropogenic modified areas. In natural habitat dens were encountered under big trees and overhanging roots. Hunting areas in anthropogenic modified regions show considerably more woody debris than non-hunting areas, as the main prey the crayfish Samastacus spinifrons hides in this substrate. Most of their time southern river otter spent in their dens (60 %). Lontra provocax show cathemeral behaviour and when being active, the time bouts of movement behaviour averaged 2:18 hours.The crustacean species Samastacus spinifrons was the most encountered aquatic prey species in abundance and in total biomass in the river Queule and in the diet of Lontra provocax. Likewise fish may play an important role to meet the southern river otter s daily metabolic requirements. Monthly collected water samples even close to villages, had physico-chemical parameter values well below critical or toxic levels on aquatic species. Age determination was conducted on four male skulls of southern river otter. Tooth wears; tooth abrasions; dental pulp; relative width of dental pulp, incremental cementum lines and sutures of the skull were used for age determination. The animals were classified as juvenile (1), subadult-adult (1) and senior (2).

No description available.

Consistently, reports in the literature have identified that a sedentary lifestyle contributes to the progression of a range of chronic degenerative diseases. The measurement of energy expenditure and physical activity pattern in children is a challenge for all professionals interested in paediatric health and from a broader perspective, the public health fraternity charged with considering longer term health consequences of physical inactivity. The primary objective of this thesis was to identify a suitable indirect and objective measurement technique for the assessment of energy expenditure and physical activity pattern in children. The ideal characteristics of such a technique are that it should be reproducible and have been validated against a criterion reference method. To achieve this goal, a series of methodological studies were undertaken (Chapters II and III). This work was essential to increase accuracy during the individualised laboratory calibration process and further minimise prediction errors when analysing data from 7 days of monitoring under free-living conditions in the second part of the study (Chapters IV and V). In the first study to verify the combined effect of body position, apparatus and distraction on children's resting metabolic rate (RMR), experiments were carried out on 14 children aged 8-12 (mean age = 10.1 years ± 1.4). Each participant underwent 2 test sessions, one week apart under three different situations: a) using mouthpiece and nose-clip (MN) or facemask (FM); b) sitting (SEAT) or lying (LY) and c) TV viewing (TV) or no TV viewing. In the first session, following 20 min rest and watching TV, the following protocol was used: LY: 20 min - stabilisation; 10 min using MN and 10 min using FM. Body position was then changed to seated: 20 min stabilisation; 10 min using FM; 10 min using MN. In the second session, FM and MN order was changed and participants did not watch TV. Data were analysed according to the eight combinations among the three studied parameters. Repeated measures ANOVA indicated statistically significant differences for &VO2 (p=0.01) and RMR (p=0.02), with TVMNSEAT showing higher values than TVFMLY. Bland-Altman analysis showed a bias for &VO2, &VCO2, RQ and RMR between TVFMLY and TVMNSEAT of -17.8±14.5 ml.min-1, -8.8±14.5 ml. min-1, 0.03±0.05 and -115.2±101.9 kcal.d-1, respectively. There were no differences in RMR measurements due to body position and apparatus when each variable was isolated. Analyses of distraction in three of four combinations indicated no difference between TV and no TV. In summary, different parameter combinations can result in increased bias and variability and thereby reported differences among children's RMR measurement. The second study dealt with treadmill adaptation and determination of self-selected (SS) walking speed. Assessment of individual and group differences in metabolic energy expenditure using oxygen uptake requires that individuals are comfortable with, and can accommodate to, the equipment being utilised. In this study, a detailed proposal for an adaptation protocol based on the SS was developed. Experiments were carried out on 27 children aged 8-12 (mean age = 10.3±1.2 yr). Results from three treadmill tests following the adaptation protocol showed similar results for step length with no significant differences among tests and lower and no statistically significant variability within- and between-days. Additionally, no statistically significant differences between SS determined over-ground and on a treadmill were verified. These results suggest that SS speed determined over-ground is reproducible on a treadmill and the 10 min familiarisation protocol based on this speed provided sufficient exposure to achieve accommodation to the treadmill. The purpose of the third study was to verify within- and between-day repeatability and variability in children's oxygen uptake ( &VO2), gross economy (GE) [ &VO2 divided by speed] and heart rate (HR) during treadmill walking based on SS. 14 children (mean age = 10.2±1.4 yr) undertook 3 testing sessions over 2 days in which four walking speeds, including SS, were tested. Within- and between-day repeatability was assessed using the Bland and Altman method and coefficients of variability (CV) were determined for each child across exercise bouts and averaged to obtain a mean group CV value for &VO2, GE and HR per speed. Repeated measures ANOVA showed no statistically significant differences in within- or between-day CV for &VO2, GE or HR at any speed. Repeatability within and between-day for &VO2, GE and HR for all speeds was verified. These results suggest that submaximal &V O2 during treadmill walking is stable and reproducible at a range of speeds based on children's SS. In the fourth study, the objective was to establish the effect of walking speed on substrate oxidation during a treadmill protocol based on SS. Experiments were carried out on 12 girls aged 8-12 (mean age = 9.9±1.4 yr). Each participant underwent 2 test sessions, one week apart. Workloads on the treadmill included 2 speeds slower than SS (1.6 [V1] and 0.8 km.h-1 [V2] slower than SS), SS (V3), and a speed 0.8 km.h-1 faster than SS (V4). Indirect calorimetry from respired gas measurements enabled total fat (FO) and carbohydrate (CHO) oxidation rates to be calculated according to the non-protein respiratory quotient (Peronnet and Massicote, 1991) and percentage of CHO and FO calculations using equations from McGilvery and Goldstein (1983). Repeated measures ANOVA followed by a Tukey Post Hoc test (p< 0.05) was used to verify differences in CHO and FO rates among speeds. Paired T-test was used to verify differences in CHO and FO rates between tests per velocity. The reliability between-day was assessed using intraclass correlation coefficient (ICC). Results showed significant differences for CHO among all speeds, as well as significant differences for FO between V1 and V2 against V3 and V4 in both tests. Analyses between trials per velocity showed no significant substrate use differences as well as acceptable reliability. At the self-selected speed (V3) there was an accentuation in FO reduction as well as an increase in CHO oxidation. The purpose of the fifth study was to determine whether there were differences in substrate oxidation between girls (G) and women (W) during a treadmill protocol based on SS. Experiments were carried out on 12 G aged 8-12 (mean age = 9.9±1.4 yr) and 12 W aged 25-38 (mean age = 32.3±3.8 yr). The treadmill protocol included 6 min workloads followed by 5 min rest periods. Workloads included 2 speeds slower than SS (1.6 (V1) and 0.8 km.h-1 (V2) slower than SS), SS (V3), and a speed 0.8 km.h-1 faster than SS (V4). Total fat and carbohydrate (CHO) oxidation rates were calculated from indirect calorimetry according to the non-protein respiratory quotient. Repeated measures ANOVA followed by a Tukey Post Hoc test was used to verify intra-test differences in CHO and fat oxidation rates among speeds. Intergroup differences were analysed using paired T-test. Fat utilisation in W achieved a plateau at a relative velocity 0.8 km.h-1 slower than SS, but for G, fat utilisation increased until SS, and then stabilised upon reaching the higher velocity. CHO oxidation curves rose abruptly above V2 for W, while for G the acute increase occurred after SS (V3). Collectively, these results indicate that as walking intensity increases G are able to meet the energy demands of the work by increasing fat oxidation together with the increased CHO oxidation up to SS. In contrast for W, increasing CHO oxidation is associated with an early decrease in fat utilisation at a velocity slower than the self-selected speed. The sixth study dealt with validation of indirect techniques for the measurement of energy expenditure in free-living conditions against the DLW technique. Experiments were carried out on 19 children aged 8-12 (mean age = 10.3±1.0 yr). To indirectly predict energy expenditure 12 different procedures were used. Only one procedure, combining activity and heart rate (AHbranched), was based on a group equation, the others were based on individualised regression. Three of the individually-based techniques were able to accurately predict energy expenditure in free-living conditions. These tecniques were HRPAnetRMR using HRnet [HR exercise minus sleep HR (SHR)] against PAnet (measured PA exercise minus measured RMR) and upper and lower body equations corrected by RMR; HRPAnet4act using the same procedure but corrected by the mean resting &VO2 for 4 resting activities [(4act) = supine watching TV, sitting watching TV, sitting playing computer games and standing], and HRPALBnet4act using only lower body activities and corrected by 4act. HRPAnetRMR was only slightly more accurate than HRPAnet4act and HRPALBnet4act, but this technique is only adjusted by RMR whereas the other two are heavily dependent on more complex laboratory calibration. Bland and Altman (1986) analyses showed no significant differences between AHbranched predicted and measured TEE using the DLW technique. A SEE of 79 kcal.d-1 and a mean difference of 72 kcal.d-1, with a 95% CI ranging from -238 to 93.9 kcal.d-1 was found. In addition, no significant differences between predicted HRPAnetRMR and measured TEE using DLW were found, showing an SEE of 99 kcal.d-1 and a mean difference of -67 kcal.d-1, and a 95% CI ranging from -276.6 to 141.9 kcal.d-1. AHbranched and HRPAnetRMR were both valid and similarly suitable for the prediction of energy expenditure in children under free-living conditions. Significant associations between DLWAEE and the after-school time window indicated that this time window as an important discretionary period representative of children physical activity. However, the duration of the after-school time windows should be more carefully considered. Accelerometer data showed a better association between the largest after-school time window (3.5 hr) and measured TEE. The final study, completed with 19 children aged 8-12 (10.3±1.0 yr) highlighted, under laboratory conditions across a range of walking and running speeds, the inadequacy of the use of the standard MET in children. This traditional approach overestimates energy expenditure with an increased difference linearly related to speed increments. Minute-by-minute analyses of 7 days of free-living monitoring showed an average overestimation of 64 minutes per day for moderate-to-vigorousphysical- activity (MVPA) using the standard MET compared with the individually measured MET. For all intensities, these differences were statistically significant (p< 0.001). The second part of this study showed a variability of 20% in the average time spent at MVPA when comparing HR I 140 bpm and HR > 50%P &VO2 (P &VO2 = the highest &VO2 observed during an exercise test to exhaustion). Results of the current study compared to observations in the literature showed that HR I 140 bpm consistently estimates lower MVPA time than HR > 50%P &VO2. When these two PA indices were compared with individual and standard MET measured minute-byminute, statistically significant differences were verified among all of them at MPA, but no differences were verified at VPA, except between individual and standard METs. However, whether each one of the PA indices used are under- or overestimating time at MVPA is still debatable due to the lack of a gold standard. Finally, each index used in this study classified different numbers of participants as achieving the PA target of 60 min.d-1. The wide variability between indices when attempting to classify children who are achieving the recommended target is cause for great concern because habitually these indices are utilised as screening tools in paediatric and public health settings and used to guide behavioural interventions.