Introduction Researchers have, for decades, contributed to an increased collective understanding of the physiological demands in cross-country skiing; however, almost all of these studies have used either non-elite subjects and/or performances that emulate cross-country skiing. To establish the physiological demands of cross-country skiing, it is important to relate the investigated physiological variables to the competitive performance of elite skiers. The overall aim of this doctoral thesis was, therefore, to investigate the external validity of physiological test variables to determine the physiological demands in competitive elite cross-country skiing. Methods The subjects in Study I – IV were elite male (I – III) and female (III – IV) cross-country skiers. In all studies, the relationship between test variables (general and ski-specific) and competitive performances (i.e. the results from competitions or the overall ski-ranking points of the International Ski Federation (FIS) for sprint (FISsprint) and distance (FISdist) races) were analysed. Test variables reflecting the subject’s general strength, upper-body and whole-body oxygen uptake, oxygen uptake and work intensity at the lactate threshold, mean upper-body power, lean mass, and maximal double-poling speed were investigated. Results The ability to maintain a high work rate without accumulating lactate is an indicator of distance performance, independent of sex (I, IV). Independent of sex, high oxygen uptake in whole-body and upper-body exercise was important for both sprint (II, IV) and distance (I, IV) performance. The maximal double-poling speed and 60-s double-poling mean power output were indicators of sprint (IV) and distance performance (I), respectively. Lean mass was correlated with distance performance for women (III), whereas correlations were found between lean mass and sprint performance among both male and female skiers (III). Moreover, no correlations between distance performance and test variables were derived from tests of knee-extension peak torque, vertical jumps, or double poling on a ski-ergometer with 20-s and 360-s durations (I), whereas gross efficiency while treadmill roller skiing showed no correlation with either distance or sprint performance in cross-country skiing (IV). Conclusion The results in this thesis show that, depending on discipline and sex, maximal and peak oxygen uptake, work intensity at the lactate threshold, lean mass, double-poling mean power output, and double-poling maximal speed are all externally valid physiological test variables for evaluation of performance capability among elite cross-country skiers; however, to optimally indicate performance capability different test-variable expressions should be used; in general, the absolute expression appears to be a better indicator of competitive sprint performance whereas the influence of body mass should be considered when evaluating competitive distance performance capability of elite cross-country skiers.

Le but de ce travail est de prouver la supériorité d’une technique alternative de propulsion manuelle non-conventionnelle basée sur le système à leviers. La faisabilité d’un prototype intégrant la technique non-conventionnelle ainsi que les avantages et les inconvénients sont également recherchés. Les évaluations objectives et subjectives en relation avec l’interface sujetprototype ainsi que les habiletés sur terrain et les paramètres physiologiques ont fait l’objet d’études expérimentales. Le prototype conçu pourrait constituer une tentative dans le domaine de l’handisport permettant aux sportifs handicapés de recourir à une stratégie de propulsion manuelle non-conventionnelle évitant les complications induites par la technique conventionnelle / Wheelchair propulsion has been reported to be responsible for musculoskeletal pain in the upper extremities. Epidemiological studies have shown a high prevalence of shoulder complaints in paraplegic and quadriplegic spinal cord injured (SCI) people. It has been argued that the high incidence of shoulder complaints in SCI was the result of the weightbearing or propulsion function of the upper extremity in those subjects. This work aimed at proposing an alternative wheelchair propulsion technique based on the levers’ system. The interface prototype-users, the wheelchair skills evaluation, the oxygen uptake and the cardiac frequency are investigated by an objective and subjective studies. Our prototype is designed to be an attempt in the field of disabled athletes having some advantages of a non-conventional manual wheelchair propulsion technique, avoiding complications induced by the conventional one

O objetivo geral do presente estudo foi analisar o comportamento dos valores do pico de consumo de oxigênio (VO2pico) e de lactato, em grupos de crianças e jovens não praticantes de natação e atletas de natação no período etário de sete a 17 anos de idade; e ainda, a) investigar as possíveis diferenças entre os valores de VO2pico dos grupos durante o período etário citado em relação ao gênero e ao treinamento sistemático, b) analisar a influência da massa corporal total na variação do VO2pico em função da idade, gênero e treinamento para o período etário citado, c) analisar a influência da massa corporal total na variação do VO2pico tendo como fator interveniente à gordura corporal, d) analisar as concentrações de lactato no sangue após esforço gradualmente crescente até a exaustão para o período etário citado. O delineamento utilizado foi transversal e contou com uma amostra de 145 crianças e jovens de sete a 17 anos de idade, com no mínimo três sujeitos de cada idade e gênero que foram subdivididos em dois grupos – controle (escolares) e experimental (nadadores).Cada grupo foi subdividido em três grupos etários (sete a 10, 11 a 14 e 15 a 17 anos) perfazendo 12 subgrupos (seis no feminino e seis no masculino). Após aprovação de Comissão de Ética Institucional e assinatura do termo de consentimento informado os voluntários realizaram uma anamnese para avaliar o histórico de saúde. Em laboratório, foram realizadas medidas antropométricas, eletrocardiograma de repouso e teste funcional em esteira para a avaliação da aptidão cardiorespiratória – VO2pico. Os resultados foram apresentados de forma descritia e inferencial como análise descritiva, diagramas box-plot, ANOVA e ANCOVA. O programa estatístico usado foi o SPSS versão 11.0. O nível de significância adotado foi 0,05. Os valores médios de VO2picoabs, VO2picorelcor e VO2picorelcor ajustado entre crianças e jovens de diferentes faixas etárias de escolares e nadadores em ambos os gêneros não são equivalentes, com exceção das meninas da faixa etária de sete a 10 anos. O delta de lactato (repouso e pós exercício) é dependente do gênero, faixa etária e grupo de treinamento. Os valores de VO2pico em escolares e nadadores sofrem influência da idade e do gênero. Os valores de VO2pico das crianças e jovens de sete a 17 anos de idade escolares e nadadores para diferentes faixas etárias sofrem influência da massa corporal total, em especial da somatória de dobras cutâneas periféricas, tendo como fator interveniente a gordura corporal. As variáveis de delta de lactato e somatória de dobras cutâneas consideradas como covariáveis levaram ao estabelecimento do modelo para VO2picorelcor (ml.kg-1.min-1) e VO2picorelcor ajustado (ml.kg-0,67.min-1) com R2 elevados, mas maiores no último caso. / The general aim of this study was to analyze the behavior of the peak oxygen uptake (VO2peak) values and lactate, in children and youths groups no swimming practitioner and swimming athletes from seven to 17 years age group; and even, a) to investigate the possible differences among VO2peak values of groups during this age group related to gender and systematic training, b) to analyze the influence of total body mass in VO2peak variation related to the age, gender and training for this age group, c) to analyze the influence of total body mass in VO2peak variation having as interventional factor the body fat, d) to analyze the blood lactate concentrations after growing gradually effort until exhaustion for this age group. The cross-sectional experimental design had a sample with 145 children and youths from seven to 17 years old, with three subjects at least of each age and gender subdivided in two groups – control (pupils) and experimental (swimmers). Every group was subdivided in three age groups (7-10, 11-14 and 15-17 years) making 12 sub-groups (6 female and 6 male). After approved Institutional Ethical Boarding and Informed Consent signed, the volunteers were submitted the anamnesis for participation health screening. In the lab, were performed anthropometrical measurements, rest electrocardiogram and functional test on a treadmill to asses the cardiorespiratory fitness – VO2peak. The results were presented on a descriptive and inferential way like descriptive analyses, diagrams box-plot, ANOVA e ANCOVA. The statistic program used was the SPSS version 11.0. The significance level adopted was 0,05. The VO2peakabs, VO2peakrelcor e VO2peakrelcor adjusted means values between children and youths of different age groups pupils and swimmers in both genders are not equivalent, with exception on the girls from seven to 10 years old age group. The lactate delta (rest and after exercise) is dependent of the gender, age group and training group. The VO2peak means values in pupils and swimmers suffer influence of the age and the gender. The VO2peak values of the children and youths from seven to 17 years old pupils and swimmers for different age groups suffer influence of the total body mass, in special of the peripheral skinfolds sum, having as interventional factor the body fat. The variables lactate delta and skinfolds sum here considered like covariate leaded to the establishment of the model for VO2peakrelcor (ml.kg-1.min-1) and VO2peakrelcor adjusted (ml.kg-0,67.min-1) with higher R2, but greater in the last case.

Biological wastewater treatment relies on the diverse and complex metabolic activities of bacteria to remove pollutants. Its success depends on the metabolic efficiency of the bacteria. Activated sludge models use parameters that attempt to depict bacterial growth and metabolic processes. However, current methods do not separate metabolic activity from growth and maintenance. As a result, activated sludge processes are misinterpreted or over-simplified. Alternative methods for gauging bacterial activity have been proposed and include the measurements of cellular derived compounds that relate specifically to energy cycling and include Nicotinamide Adenine Dinucleotide [NADH]. To date, NADH has been largely measured within activated sludge using commercial online fluorimeters with in situ probes. However, this current method provides a measure of the 'bulk' (raw) fluorescence within the system, resulting in difficulties when interpreting fluorescence data and poor sensitivity for detecting changes in intracellular [NADH]. This study has developed a more reliable method for estimating intracellular [NADH] and thus metabolic activity within activated sludge systems. Separating extracellular from intracellular [NADH] in samples was crucial because NADH was released and accumulates in the extracellular environment at a concentration of 200 ~M immediately following bacterial death or lysis. This concentration did not decline overtime. This not only caused high background fluorescence but also reduced the sensitivity of detection for changes in intracellular [NADH]. In particular, considerably higher [NADH] values to those from the extracellular suspensions were obtained following extraction of the intracellular material, suggesting that the cell membranes were not being penetrated by the excitable light source. Of the extraction procedures examined, filtration followed by extraction of the intracellular material with a hot Tris buffer was the most efficient and was recommended for accurate estimates of intracellular [NADH] in situ. In addition, standards were used to quantify NADH (moles per cell and/or unit volume) from unknown samples. The limits of detection were found to be 1.058 - 353 uM, whereas concentrations above 353 jAM self-quenched. Sample concentrations were always within these limits of detection. Hence, the sensitivity, reliability and experimental application of the original method was improved upon and able to be used for the direct measurement of microbial metabolic activity, something that has not been demonstrated before now. This study found that bacteria have between 106~ I 08 NADH molecules per cell depending on their metabolic state. A highly metabolically active bacterial cell had between 1O6~ tO7 NADH molecules, while a less active bacterial cell had between to7 -to8 NADH molecules. These measurements of metabolic activity were simultaneously monitored alongside other measures of bacterial growth, such as the incorporation of radiolabelled thymidine into DNA as a direct measure of DNA replication (new cell synthesis), the incorporation of radiolabelled leucine into protein as a direct measure of protein synthesis, oxygen uptake rates (OUR) as a direct measure of respiration, ATP as a measure of potential energy and dissolved organic carbon (DOC) as a measure of substrate assimilation. As OUR deceased, bacterial growth (using both the thymidine and leucine assays), specific [NADH] and specific [ATP] increased. High OUR and substrate oxidation rates simultaneous with low specific [NADH] indicated high rates of electron transport and thus efficient metabolic activity. Also, low OUR and substrate oxidation rates simultaneous with high specific [NADHI indicated inefficient rates of electron transport, therefore inhibiting oxidative phosphorylation (ATP production). A lack of oxygen as the terminal electron acceptor did not efficiently reoxidise NADH to NAD and resulted in an accumulation of NADH within the cell. Thus, a measure of low specific [NADHI was linked to the efficient rate of reoxidation of NADH to NAD* and reflects high metabolic efficiency. DNA and protein syntheses were coupled following substrate enrichment (glucose or acetate), indicating that bacteria were in balanced growth. However, DNA and protein syntheses became uncoupled once substrate was depleted, indicating unbalanced growth. An average Leu:TdR ratio of 7.4 was determined for activated sludge and was comparable to values published from marine systems. This ratio increased during log growth phase and decreased during stationary growth phases. Specific growth rates determined using the [3HITdR and [3H]Leu assay yielded values ranging from 2 - 10.5 d' and from 2.5 - 6 d1, respectively and were comparable to published values. Changes in OUR, NADH, ATE', DNA replication and protein synthesis were statistically ordinated using multidimensional scaling, and changes (in magnitude and direction) in bacterial metabolic activity were observed. Such methods enable the tracing of where bacteria divert their energies, such as to growth or maintenance and thus provide a greater understanding of bacterial behaviour in activated sludge. While studying anoxic and anaerobic conditions were beyond the scope of this work, the use of such methods to monitor bacterial metabolic activity under such conditions is warranted.

<p>This thesis evaluates the performance of a deammonification system designed as a two-step tech-nology consisting of an initial partial nitritation followed by an Anammox process. Operation of a technical-scale pilot plant at the Himmerfjärden Wastewater Treatment Plant (Grödinge, Swe-den) has been assessed. Oxygen Uptake Rate (OUR) to evaluate the respiration activity of nitrifi-ers in the system and batch tests to assess reaction rates have also been applied in the study. It was found that the total inorganic nitrogen elimination strongly depended on the nitrite-to-ammonium ratio in the influent to the Anammox reactor, which was correlated with the per-formance of the partial nitritation phase. Therefore, a control strategy for oxidation of ammo-nium to nitrite has been proposed. Controlled oxygen supply to the partial nitritation reactor is obligatory to obtain a proper pH drop indicating oxidation of ammonia to nitrite at the adequate ratio. A very high nitrogen removal efficiency (an average of 84%) and stable operation of the system have been reached. Conductivity measurements were also used to monitor the system influent nitrogen load and the nitrogen removal in the Anammox reactor. The data gathered from the operation of the pilot plant enabled the use of multivariate data analysis to model the process behaviour and the assessment of the covariances between the process parameters. The options for full-scale implementation of the Anammox systems have been proposed as a result of the study.</p>

Objectives To assess physical fitness in pregnancy and to evaluate its effect on perceived health, back pain, blood pressure and duration of gestation. Also, to evaluate the effect of serum relaxin levels on blood pressure and duration of gestation. Material and methods A prospective cohort of 520 pregnant women were examined in early pregnancy and five months postpartum with regard to socio-demographic characteristics and estimated peak oxygen uptake (V̇O2 peak, est.). Serum concentrations of relaxin were carried out in early pregnancy. Physical exercise, possible back pain and blood pressure were measured repeatedly throughout pregnancy. Results Absolute V̇O2 peak, est. in early pregnancy was positively correlated to perceived health, which was lower during than after pregnancy. The average absolute V̇O2 peak, est. in early pregnancy of 2.4 l/minute was 0.02 l/minute less than the V̇O2 peak, est. postpartum, while regular physical exercise decreased throughout pregnancy. Absolute V̇O2 peak, est. in early pregnancy was not associated to the incidence of any low back pain location in pregnancy or postpartum, but inversely to intensity of back pain and diastolic blood pressure and positively with duration of gestation. Elevated serum relaxin levels were associated with decreased diastolic blood pressure and higher duration of gestation among women with miscarriage. Conclusions Perceived health, diastolic blood pressure and duration of gestation were positively affected by physical fitness while no effect was shown on the incidence of back pain. The effect of physical fitness on duration of gestation and diastolic blood pressure might have clinical implications as well as the increased serum relaxin levels on miscarriages.

Falls in people aged over 65 years account for the largest proportion of all injury-related deaths and hospitalisations within Australia. Falls contributed to 1,000 deaths and 50,000 hospitalisations in older people during 1998 (Commonwealth Department of Health and Aged Care 2001). It has been predicted that by 2016, 16% of the Australian population will be aged over 65 years (Australian Bureau of Statistics 1999) placing considerable pressure on the health care system. Furthermore, prospective studies have shown that 30-50% of people aged 65 years and over, will experience a fall (Tinetti et al. 1988b; Campbell et al. 1989; Lord et al. 1994b; Hill 1999; Brauer et al. 2000; Stalenhoef et al. 2002) and this figure increases exponentially with age (Lord et al. 1994b). Many physiological falls risk factors have been established including reduced leg strength, poor balance, impaired vision, slowed reaction time and proprioception deficits. However, little research has been conducted to determine whether performance on aerobic fitness tasks is also a physiological falls risk factor. Aerobic fitness has previously been related to an individual's ability to perform activities of daily living, which in turn has been linked to falls. It was therefore proposed that aerobic fitness might also be a risk factor for falls among community dwelling older people. This research aimed to provide clinical evidence to inform public health practice. This thesis comprised of four objectives: the first to find suitable measures of aerobic fitness for older people; the second investigated relationships between existing clinical tests and future falls; the third explored relationships between aerobic fitness tests and future falls; the final objective was to examine the independent relationships between falls and clinical and physiological characteristics. The participants were recruited through a random sample from the local electoral roll, with an average age of 73 ±6 years. Of the 87 participants who completed the prospective component of the study, 37% were male and 63% were female. Sixty-three participants (65%) reported no previous falls, 19 (20%) reported a single fall, and 16 (15%) reported two or more falls in the previous 12 months. The first objective required participants recruited from the community to take part in submaximal and maximal fitness tests in order to find suitable measures of aerobic fitness. A further objective was to determine whether older people were able to fulfil the 'standard' criteria for completion of a maximum oxygen consumption test. The measures used in this research included: maximum oxygen consumption, peak oxygen consumption, ventilatory threshold, oxygen uptake kinetics, oxygen deficit, efficiencies, oxygen consumption at zero, 30 and 50 watts, predicted max and Six-Minute Walk Test distance. Only weak relationships were observed between submaximal aerobic measures and peak oxygen consumption. Furthermore, only 54% of participants were able to fulfil the criteria to complete a test of maximum oxygen consumption, indicating it was not a suitable measure for use among a sample of community dwelling older people. Therefore submaximal aerobic variables were used in the following chapters. The second objective investigated the relationship between clinical measures and falls among older people and was carried out to enable comparisons between the population in this study and those described in the literature. This research found that the Timed Up and Go (TUG) test was the most sensitive of all clinical tests (including the Berg Balance Scale, Function Reach, Performance Oriented Mobility Assessment and Physiological Profile Assessment) for the assessment of future falls. The TUG requires participants to stand up, walk 3m, turn, walk back, and sit down. Time taken to complete the test is the recorded value. For this study, a cut-off value of 7-seconds was established, above which individuals were at increased risk of falls. Previous research suggested cut-off times of over 10s were appropriate for older people. However, this is the first study to assess falls prospectively and definitively find that the TUG can discriminate between future fallers and non-fallers. This research also investigated the differences in falls risk factors for functionally different subsamples, as defined by their ability to undertake and complete the cycle test. The participants who could complete the test had significantly better balance ability and strength than those unable to undertake or complete the cycle test. However, this inability to undertake or complete the cycle test was not itself a predictor of future falls. These two groups also differed in the relationships between clinical test results and falls risk. Participants in the no-cycle group had very similar results to that of the entire cohort. Even after adjustment for age, the TUG, foot and hand reaction times and knee flexion strength were all performed better by non-fallers than fallers. However, none of these differed between fallers and non-fallers for participants in the cycle group. This group had better balance ability and strength than the no-cycle group. These results indicated that the cycle group differed from the no-cycle group and the entire sample, further indicating that factors other than the physiological variables measured in this research influence falls risk in strong participants with good balance ability. Similar results were reported when aerobic tests and falls were investigated in the third objective. In the whole sample, the fallers walked significantly less distance than non-fallers for the 6-MWT. Similar results were found for participants in the no-cycle group but not the cycle group. All participants were able to complete the Six-Minute Walk Test (6-MWT) although only 74% were able to undertake and complete the cycle test. The fourth objective was to consider all measures from the previous chapters as potential predictors of falls. The variables most predictive of future falls were the TUG and having experienced one or more falls in the previous 12 months. As a result they could be used as screening tools for the identification of high-risk fallers who require referral for further assessment. This could be completed by a General Practitioner or Practice Nurse, which would ensure that screening is being undertaken in the wider population. If the patient is at high risk they should be referred for falls risk factor assessment to determine an optimal tailored intervention to reduce future falls. Low risk patients should be referred for preventive evidence-based activities. These steps can potentially improve quality of life for individuals, and if effective in preventing future falls, will result in reduced costs to the individual and the Australian public. The results of this work demonstrate that the best screening tests are simple tasks like the TUG and asking an individual if they have experienced a fall in the last 12 months. This research also found that strong, mobile older people who could undertake and complete a submaximal cycle ergometer test, still experienced falls in the following 12 months, although the causes of this are currently unknown. This research showed that physiological falls risk factors are less relevant as these highly functional older people do not have physiological deficits. However, this research found that the 6-MWT showed promise as a predictor of falls in a group who could not complete a submaximal cycle ergometer test, who had lower strength, balance and functional fitness scores than a group who could complete this cycle test. The results showed that physiological falls risk factors are still very important for older people with lower physical abilities, and this is where aerobic fitness may still be related to falls. While the association between aerobic fitness and falls remains unclear, these are novel and provocative findings highlighting the need for future falls risk investigations to consider aerobic fitness as a contributing factor.

A prevalência de sobrepeso e obesidade entre crianças e adolescentes tem aumentado em países em desenvolvimento e desenvolvidos, ocasionando um sério problema de saúde pública. A obesidade na adolescência pode alterar o perfil lipídico, principalmente quando acompanhada de uma baixa aptidão cardiorrespiratória. A obesidade, bem como as dislipidemias são considerados importantes fatores de risco para a doença arterial coronariana. O presente estudo teve como objetivo avaliar a correlação entre o perfil lipídico, bem como outros marcadores de risco para doença arterial coronariana, e a aptidão cardiorrespiratória de crianças e adolescentes obesos, de ambos os gêneros. Um total de 63 crianças e adolescentes obesos, entre 11 e 17 anos, foi incluído em um estudo transversal, realizado na cidade de Porto Alegre. Foi utilizado o pacote estatístico SPSS, versão 10.0 para Windows. Foram aplicados o teste t para amostras independentes e o teste de Mann-Whitney para identificar diferenças entre gêneros e estágio maturacional quando a distribuição apresentava-se normal e não-normal, respectivamente. Utilizou-se a correlação de Pearson ou Spearman para dados paramétricos e não-paramétricos, respectivamente. Não encontramos correlação significativa entre o pic2 o V& O e os marcadores de risco para doença coronariana TG, CT, HDL-C, LDL-C, ApoA1, ApoB, Não-HDL-C, CT/HDL, LDL-C/HDL-C, insulina, glicose, índice HOMA-IR e PCRus. Do total de crianças e adolescentes avaliados, somente um indivíduo, do gênero masculino, não apresentava nenhum parâmetro metabólico alterado. Encontramos uma prevalência precoce importante de indivíduos com hipercolesterolemia (15,0%); hipertrigliceridemia (23,3%); hiperglicemia (35,6%); hiperinsulinemia (40,4%); valores altos de LDL-C (16,7%), PCRus (38,3%) e Não-HDL-C (26,7%); e valores baixos de HDL-C (21,7%) e do VO2pico (93,5% da meninas e 100% dos meninos). Concluindo, apesar de não encontrarmos correlação significativa entre o perfil lipídico e a aptidão cardiorrespiratória de crianças e adolescentes obesos neste estudo, uma prevalência alta de dislipidemias e outros marcadores de risco coronariano alterados foram encontrados. / The prevalence of overweight children and adolescents has been increasing in both developed and developing countries, creating a serious public health problem. Obesity in adolescence can alter the lipid profile mainly when accompanied by a low cardiorespiratory fitness. Obesity and dislipidemy are well-established risk factors for the coronary artery disease. The aim of the present study was to evaluate the correlation among the lipid profile, as well as other risk markers for the coronary artery disease, and the cardiorespiratory fitness of obese children and adolescents of both genders. A total of 63 children and adolescents between 11 and 17 years old were included in this cross-sectional study, developed in the city of Porto Alegre. Statistical analysis was performed by the software SPSS, version 10.0 for Windows. The T-test for independent samples and the Mann-Whitney test were applied to identify differences among gender and pubertal stage when the distribution was normal and abnormal, respectively. The Pearson’s or the Spearman’s correlation was used for parametric and nonparametric data, respectively. We did not find significant correlation between pea2 k V& O and the risk markers for the coronary disease TG, TC, HDL-C, LDL-C, non-HDL-C, TC/HDL, insulin, glucose, HOMA-IR values, and PCRus. Among all individuals evaluated, only one person – a male – did not show any altered metabolic parameter. We found an important precocious prevalence of individuals with hypercholesterolemia (15%); hypertriglyceridemia (23.3%); borderline hyperglycemia (35.6%); hyperinsulinemia (40.4%); high values of LDLC (16.7%), PCRus (38.3%), non-HDL-C (26.7%); and low values of HDL-C (21.7%) and 2 peak V& O (93.5% of the girls and 100% of the boys). In conclusion, although we did not find any significant correlation between lipid profile and cardiorespiratory fitness in obese children of both genders in this study, a high prevalence of undesirable lipid levels and other altered coronary risk markers were found.

A prevalência de sobrepeso e obesidade entre crianças e adolescentes tem aumentado em países em desenvolvimento e desenvolvidos, ocasionando um sério problema de saúde pública. A obesidade na adolescência pode alterar o perfil lipídico, principalmente quando acompanhada de uma baixa aptidão cardiorrespiratória. A obesidade, bem como as dislipidemias são considerados importantes fatores de risco para a doença arterial coronariana. O presente estudo teve como objetivo avaliar a correlação entre o perfil lipídico, bem como outros marcadores de risco para doença arterial coronariana, e a aptidão cardiorrespiratória de crianças e adolescentes obesos, de ambos os gêneros. Um total de 63 crianças e adolescentes obesos, entre 11 e 17 anos, foi incluído em um estudo transversal, realizado na cidade de Porto Alegre. Foi utilizado o pacote estatístico SPSS, versão 10.0 para Windows. Foram aplicados o teste t para amostras independentes e o teste de Mann-Whitney para identificar diferenças entre gêneros e estágio maturacional quando a distribuição apresentava-se normal e não-normal, respectivamente. Utilizou-se a correlação de Pearson ou Spearman para dados paramétricos e não-paramétricos, respectivamente. Não encontramos correlação significativa entre o pic2 o V& O e os marcadores de risco para doença coronariana TG, CT, HDL-C, LDL-C, ApoA1, ApoB, Não-HDL-C, CT/HDL, LDL-C/HDL-C, insulina, glicose, índice HOMA-IR e PCRus. Do total de crianças e adolescentes avaliados, somente um indivíduo, do gênero masculino, não apresentava nenhum parâmetro metabólico alterado. Encontramos uma prevalência precoce importante de indivíduos com hipercolesterolemia (15,0%); hipertrigliceridemia (23,3%); hiperglicemia (35,6%); hiperinsulinemia (40,4%); valores altos de LDL-C (16,7%), PCRus (38,3%) e Não-HDL-C (26,7%); e valores baixos de HDL-C (21,7%) e do VO2pico (93,5% da meninas e 100% dos meninos). Concluindo, apesar de não encontrarmos correlação significativa entre o perfil lipídico e a aptidão cardiorrespiratória de crianças e adolescentes obesos neste estudo, uma prevalência alta de dislipidemias e outros marcadores de risco coronariano alterados foram encontrados. / The prevalence of overweight children and adolescents has been increasing in both developed and developing countries, creating a serious public health problem. Obesity in adolescence can alter the lipid profile mainly when accompanied by a low cardiorespiratory fitness. Obesity and dislipidemy are well-established risk factors for the coronary artery disease. The aim of the present study was to evaluate the correlation among the lipid profile, as well as other risk markers for the coronary artery disease, and the cardiorespiratory fitness of obese children and adolescents of both genders. A total of 63 children and adolescents between 11 and 17 years old were included in this cross-sectional study, developed in the city of Porto Alegre. Statistical analysis was performed by the software SPSS, version 10.0 for Windows. The T-test for independent samples and the Mann-Whitney test were applied to identify differences among gender and pubertal stage when the distribution was normal and abnormal, respectively. The Pearson’s or the Spearman’s correlation was used for parametric and nonparametric data, respectively. We did not find significant correlation between pea2 k V& O and the risk markers for the coronary disease TG, TC, HDL-C, LDL-C, non-HDL-C, TC/HDL, insulin, glucose, HOMA-IR values, and PCRus. Among all individuals evaluated, only one person – a male – did not show any altered metabolic parameter. We found an important precocious prevalence of individuals with hypercholesterolemia (15%); hypertriglyceridemia (23.3%); borderline hyperglycemia (35.6%); hyperinsulinemia (40.4%); high values of LDLC (16.7%), PCRus (38.3%), non-HDL-C (26.7%); and low values of HDL-C (21.7%) and 2 peak V& O (93.5% of the girls and 100% of the boys). In conclusion, although we did not find any significant correlation between lipid profile and cardiorespiratory fitness in obese children of both genders in this study, a high prevalence of undesirable lipid levels and other altered coronary risk markers were found.

O objetivo do presente estudo foi analisar as respostas cardiorrespiratórias, cinemáticas e neuromusculares de mulheres jovens realizando o exercício de corrida estacionária em diferentes cadências nos meios aquático e terrestre. Doze mulheres jovens, experientes na prática de hidroginástica, foram amostras voluntárias do estudo. Cada uma participou de duas sessões experimentais: 1) coleta dos dados de caracterização da amostra e realização de um teste de esforço máximo; 2) coleta das variáveis cardiorrespiratórias (freqüência cardíaca (FC), consumo de oxigênio (VO2), percentual da FC máxima (%FCmáx) e percentual do VO2 máximo (%VO2máx)), cinemáticas (velocidade angular média (VAMQ) e de pico do quadril (VAPQ)) e neuromusculares (amplitude do sinal eletromiográfico (EMG) dos músculos vasto lateral (VL), bíceps femoral (BF), reto femoral (RF) e semitendinoso (ST)). Para a coleta de tais variáveis, dois protocolos de testes foram realizados, um no meio terrestre e outro no meio aquático, com um intervalo de duas horas entre eles. Para cada um dos meios, o exercício de corrida estacionária foi realizado durante 4 min em 3 cadências submáximas (60, 80 e 100 bpm) e durante 15 s no máximo esforço, com um intervalo de 5 min entre cada situação. Utilizamos análise de variância com bloqueamento, considerando o efeito do sujeito como mais uma fonte de variação para a análise estatística, com os dados processados nos programas SPSS versão 13.0 e R-project. Como resultados, as variáveis VAMQ e VAPQ foram significativamente mais elevadas quando o exercício foi executado no meio terrestre, e maiores quanto maior a cadência de execução, sugerindo um padrão cinemático distinto entre os meios. Da mesma forma, as respostas cardiorrespiratórias foram maiores para o exercício no meio terrestre e aumentaram significativamente com o aumento da cadência de execução. Já as respostas neuromusculares não apresentaram um comportamento semelhante, visto que o sinal EMG dos músculos VL, BF, RF e ST não aumentou significativamente com o incremento da cadência de execução, exceto das cadências submáximas para o máximo esforço. Na comparação entre os meios, o meio terrestre apresentou respostas significativamente maiores para o sinal EMG de todos os músculos nas cadências submáximas, exceto para o músculo ST que apresentou respostas semelhantes. Entretanto, no máximo esforço todos os grupos musculares analisados apresentaram respostas similares entre os meios. Em suma, a realização do exercício de corrida estacionária no meio aquático em cadências de execução submáximas apresenta respostas cardiorrespiratórias e neuromusculares menores do que o mesmo executado no meio terrestre, para as cadências fixas do presente estudo. Todavia, em intensidades máximas, a amplitude do sinal EMG pode apresentar padrões de ativação muscular semelhante entre os meios. / The aim of the present study was to analyze the cardiorespiratory, kinematic and neuromuscular response of young women performing stationary running exercise at different cadences in aquatic and terrestrial environments. The study sample consisted of twelve young women, experienced in hydrogymnastics. Each one took part in two experimental sessions: 1) collection of sample characterization data and the performance of a maximum effort test; 2) collection of the cardiorespiratory (heart rate, (HR), oxygen uptake (VO2), percentage of maximum HR (%HRmax) and percentage of maximum VO2 (%VO2max)), kinematic (mean hip angular velocity (MHAV) and peak hip angular velocity (PHAV)), and neuromusuclar variables (electromyographic signal amplitude (EMG) of the vastus lateralis (VL), biceps femoris (BF), rectus femoris (RF) and semitendinosus (ST) muscles). In order to collect these variables, two test protocols were carried out, one land-based and the other water-based, with a two-hour interval between them. The stationary running exercise was performed in each of these environments during 4 min at 3 submaximal cadences (60, 80, and 100 bpm) and during 15 s at maximum effort, with a 5 min-interval between each situation. We used blocked variance analysis, in which the effect of the subject was considered an additional source of variation for the statistical analysis. The data was processed using the SPSS (version 13.0) and R-project programs. The findings showed that the MHAV and PHAV were significantly higher when the exercise was performed on land, and higher the greater the cadence of execution, suggesting distinct kinematic patterns for the two environments. Similarly, the cardiorespiratory responses were higher with the land-based exercise and increased significantly with increased cadence. The neuromuscular responses, however, showed no such behavior, with the EMG signal from the VL, BF, RF and ST muscles showing no significant increase with greater cadence of execution, except from the sub-maximum cadences to the maximum effort. When comparing the environments, the terrestrial environment presented significantly greater EMG signal responses from all the muscles at the sub-maximum cadences, except for the ST muscle which presented similar responses in both environments. However, at the maximum effort, all the analyzed muscle groups showed similar responses in both environments. In summary, at the cadences used in the present study, the performance of the stationary running exercise in an aquatic environment at a sub-maximum cadences presents lower cardiorespiratory and neuromuscular responses than the same exercise performed on land. Yet, at maximum intensities, the amplitude of the EMG signal may present similar muscular activation patterns in the two environments.