ESE - Artigos em Revistas Indexados à WoS/Scopus
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- Contextos familiares e aproveitamento na aula de ciências: estudo de características específicas dos processos de socialização primáriaPublication . Pires, Delmina; Morais, Ana MariaEste trabalho insere-se na linha de investigação desenvolvida pelo projecto ESSA (Estudos Sociológicos da Sala de Aula). Um dos objectivos fundamentais desta linha de investigação é compreender a influência das componentes sociológicas da família e da escola no aproveitamento diferencial dos alunos provenientes de grupos sócio-culturais distintos, principalmente no que diz respeito a competências de elevado nível de abstracção, procurando, à medida que determina as causas e soluções desse aproveitamento diferencial, encontrar práticas pedagógicas que melhorem o aproveitamento das crianças de grupos sócio-culturais mais desfavorecidos. Enquanto parte da referida linha de investigação, este estudo centra-se na análise do contexto de socialização familiar, nomeadamente a nível das condições do espaço pedagógico familiar, do grau de embebimento do discurso pedagógico oficial no discurso pedagógico familiar, do tipo de orientação de codificação dos pais e da prática pedagógica que os alunos aprendem a valorizar na família, e tenta compreender a relação entre os factores sociológicos desse contexto de socialização e o (in)sucesso dos alunos, medido em função do seu aproveitamento cognitivo nas competências de elevado nível de abstracção em ciências da Natureza.
- Aprendizagem científica e contextos de socialização familiar: um estudo com crianças dos estratos sociais mais baixosPublication . Pires, Delmina; Morais, Ana MariaO estudo foi desenvolvido no âmbito da teoria de Bernstein e fundamenta-se em trabalhos anteriores (Morais et al, 1993) que têm mostrado a influência da socialização da criança na família na resposta dos alunos à escola. Esses trabalhos evidenciaram que no interior da classe trabalhadora, há padrões diferentes de socialização familiar que originam um aproveitamento escolar diferencial e sugeriram a necessidade de outros estudos. Neste estudo, pretendia-se, por um lado, estudar a influência de factores sociológicos dos contextos pedagógicos familiares dos alunos da classe trabalhadora no seu aproveitamento em ciências, e por outro lado comparar em função desses factores e do aproveitamento em ciências, na escola, os alunos da classe trabalhadora urbana e rural. A amostra era constituída por 85 alunos e respectivos pais, do 6° ano de escolaridade de uma escola preparatória de uma cidade de província do norte de Portugal. Esta amostra era constituída por duas sub-amostras, uma urbana e outra rural. Os resultados obtidos permitem concluir que existe uma relação significativa entre os factores sociológicos do contexto pedagógico familiar dos alunos e o seu sucesso escolar. Os factores mais relevantes parecem ser o nível profissional e académico dos pais, a sua participação em agências de oposição ou reprodução cultural e as características do espaço pedagógico familiar. Os resultados mostraram também que há diferenças fundamentais no interior da classe trabalhadora que podem explicar o aproveitamento diferencial dos alunos deste estrato social. Desta forma, o estudo dá um contributo para a compreensão da relação entre a família e a escola.
- Fatores cineantropométricos determinantes em natação pura desportivaPublication . Fernandes, Ricardo J.; Barbosa, Tiago M.; Vilas-Boas, João PauloO objetivo deste trabalho é apresentar uma revisão bibliográfica das principais características cineantropométricas do nadador e a forma como estas influenciam a sua prestação na modalidade. As principais conclusões obtidas foram as seguintes: (i) os nadadores são mais altos e pesados do que a população em geral; (ii) os nadadores apresentam um elevado índice envergadura/altura, explicitando valores elevados do diâmetro biacromial e do comprimento dos MS; (iii) verifica-se uma elevada razão entre os diâmetros biacromial e bicristal, traduzindo um fator decisivo na modalidade: a promoção de um coeficiente de arrasto inferior; (iv) foram observados elevados valores de comprimento e superfície dos membros dos nadadores (afetando positivamente a sua capacidade propulsiva); (v) os nadadores de elite apresentam um somatótipo médio ecto-mesomorfo e as nadadoras são centrais ou mesomorfas equilibradas; (vi) como grupo, os nadadores apresentam um maior percentual de massa gorda do que outros desportistas, fator este que poderá beneficiários relativamente à sua flutuabilidade.
- Energy cost and intracyclic variation of the velocity of the centre of mass in butterfly strokePublication . Barbosa, Tiago M.; Keskinen, Kari L.; Fernandes, Ricardo J.; Colaço, Paulo; Lima, António B.; Vilas-Boas, João PauloThe purpose of this study was to examine the relationship between the intra-cycle variation of the horizontal velocity of displacement (dV) and the energy cost (EC) in butterfly stroke. Five Portuguese national level swimmers performed one maximal and two submaximal 200-m butterfly swims. The oxygen consumption was measured breath-by-breath by portable metabolic cart. A respiratory snorkel and valve system with low hydrodynamic resistance was used to measure pulmonary ventilation and to collect breathing air samples. Blood samples from the ear lobe were collected before and after each swim to analyse blood lactate concentration. Total energy expenditure (Etot) and EC were calculated for each swim. The swims were videotaped in the sagittal plane with a set of two cameras providing dual projection from both underwater and above the water surface. The APAS system was used to analyse dV for the centre of mass. The Etot increased linearly with the increasing V, presenting a significant correlation coefficient between these parameters (r=0.827, P<0.001). The increase in EC was significantly associated with the increase in the dV (r=0.807, P<0.001). All data were presented as the mean value and the standard deviation. It is concluded that high intra-cycle variation of the velocity of the centre of mass was related to less efficient swimming and vice versa for the butterfly stroke.
- Relationships between energetic, stroke determinants, and velocity in butterflyPublication . Barbosa, Tiago M.; Keskinen, Kari L.; Fernandes, Ricardo J.; Colaço, Paulo; Carmo, Carla; Vilas-Boas, João PauloThe purpose of this study was to identify the relationship between the bioenergetical and the biomechanical variables (stroke parameters), through a range of swimming velocities, in butterfly stroke. Three male and one female butterflier of international level were submitted to an incremental set of 200-m butterfly swims. The starting velocity was 1.18 m(.)s(-1) for the males and 1.03 m(.)s(-1) for the female swimmer. Thereafter, the velocity was increased by 0.05 m(.)s(-1) after each swim until exhaustion. Cardio-pulmonary and gas exchange parameters were measured breath by breath for each swim to analyze oxygen consumption and other energetic parameters by portable metabolic cart (K4b(2), Cosmed, Rome, Italy). A respiratory snorkel and valve system with low hydrodynamic resistance was used to measure pulmonary ventilation and to collect breathing air samples. Blood samples from the ear lobe were collected before and after each swim to analyze blood lactate concentration (YSI 1500 L, Yellow Springs, US). Total energy expenditure energetic cost (E-tot), stroke frequency (SF), stroke length (SL), mean swimming velocity (V), and stroke index (SI) were Calculated for each lap and average for each 200-m stage. Correlation coefficients between E-tot and V, EC, and SF, as well as between EC and SI were statistically significant. For the relation between EC and SL, only one regression equation presented a correlation coefficient with statistical significance. Relations between SF and V, as well as between SI and V were significant in all of the swimmers. Only two individual regression equations presented statistically significant correlation coefficient values for the relation established between V and the SL. As a conclusion, the present sample of swims demonstrated large inter individual variations concerning the relationships between bioenergetic and biomechanical variables in butterfly stroke. Practitioners should be encouraged to analyze the relationships between V, SF, and SL individually to detect the deflection point in SL in function of swimming velocity to further determine appropriate training intensities when trying to improve EC.
- Semelhança somatotipológica entre irmãosPublication . Vasques, Catarina; Lopes, Vitor P.; Seabra, André; Silva, Simonete; Maia, José A.R.O presente estudo visou averiguar a semelhança somatotipológica entre irmãos. A amostra foi constituída por 366 pares de irmãos de ambos os sexos com idades compreendidas entre os 10 e os 18 anos. Foram efectuadas medições de altura; peso; três pregas de adiposidade subcutânea (tricipital, subescapular e supraíliaca); dois perímetros (braquial e geminal) e dois diâmetros (bicôndilo-umeral e bicôndilo-fémural), sendo o somatótipo calculado de acordo com o procedimento de Heath-Carter. Os procedimentos estatísticos utilizados foram os seguintes: coeficiente de correlação de Pearson e correlação canónica, calculados no software SYSTAT 11.0. Os principais resultados foram: (1) os valores de correlação entre irmãs são superiores na endomorfia (r=0,46) e ectomorfia (r=0,40); (2) os rapazes entre si apresentam maior semelhança na componente ectomórfica (r=0,44); (3) na mesomorfia os valores de correlação são moderados tanto para pares de irmãs como para os pares de irmãos rapazes; (4) nos pares de irmãos de sexo oposto os valores de correlação são muito baixos em qualquer uma das componentes do somatótipo (0,07 a 0,27); (5) de acordo com o conceito tridimensional do somatótipo, os resultados da análise canónica (Rc=0,51) indicam uma semelhança somatotipológica superior nos irmãos do sexo masculino. De uma forma geral, os valores de correlação entre os pares de irmãos sugerem uma semelhança somatotipológica moderada.
- Is time limit at the minimum swimming velocity of VO2 max influenced by stroking parameters?Publication . Fernandes, Ricardo J.; Marinho, D.A.; Barbosa, Tiago M.; Vilas-Boas, João PauloThe aim of this study was to observe the relationship between time limit at the minimum velocity that elicits maximal oxygen consumption (TLim-VO2max) and stroke rate, stroke length, and stroke index. 13 men and 10 women, highly trained swimmers, performed an intermittent incremental test for v V02 max assessment and an all-out swim to estimate TLim-v V02 max. The mean ± SD TLim-v V02max, v V02 max, stroke rate, stroke length, and stroke index values were 233.36 ± 53.92 sec., 1.40 ± .06 meter/sec., 35.58 ± 2.89 cycles/min., 2.39 ±.22 meter/cycle, and 3.36 ±.41 meter2/(cycle• sec.), respectively. The correlation between TLim-v V02 max and stroke rate was -.51 (p<0.1), and values for TLim•v V02 max with stroke length (r = 52, p< 0.1 and stroke index (r = .45, p< .05). These results seem to suggest that technical skill is a key factor in typical efforts requiring prolonged aerobic power.
- Evaluation of the energy expenditure in competitive swimming strokesPublication . Barbosa, Tiago M.; Fernandes, Ricardo J.; Keskinen, Kari L.; Colaço, Paulo; Cardoso, Carla; Silva, José; Vilas-Boas, João PauloThe purpose of this study was to measure and compare the total energy expenditure of the four competitive swimming strokes. Twenty-six swimmers of international level were submitted to an incremental set of 200-m swims (5 swimmers at Breaststroke, 5 swimmers at Backstroke, 4 swimmers at Butterfly and 12 swimmers at Front Crawl). The starting velocity was approximately 0.3m· s–1 less than a swimmer’s best performance and thereafter increased by 0.05m· s–1 after each swim until exhaustion. Cardio-pulmonary and gas exchange parameters were measured breath-by-breath (BxB) for each swim to analyze oxygen consumption (V˙ O2) and other energetic parameters by portable metabolic cart (K4b2, Cosmed, Rome, Italy). A respiratory snorkel and valve system with low hydrodynamic resistance was used to measure pulmonary ventilation and to collect breathing air samples. Blood samples from the ear lobe were collected before and after each swim to analyze blood lactate concentration (YSI 1500 L, Yellow Springs, Ohio, USA). Total energy expenditure (E˙ tot), was calculated for each 200-m stage.E˙ tot differed significantly between the strokes at all selected velocities. At the velocity of 1.0m· s–1 and of 1.2m· s–1 the E˙ tot was significantly higher in Breaststroke than in Backstroke, in Breaststroke than in Freestyle and in Butterfly than in Freestyle. At the velocity of 1.4m· s–1, the E˙ tot was significantly higher in Breaststroke than in Backstroke, in Backstroke than in Freestyle, in Breaststroke than in Freestyle and in Butterfly than in Freestyle. At the velocity of 1.6m· s–1, the E˙ tot was significantly higher in Breaststroke and in Butterfly than in Freestyle. As a conclusion, E˙ tot of well-trained competitive swimmers was measured over a large range of velocities utilising a new BxB technique. Freestyle was shown to be the most economic among the competitive swimming strokes, followed by the Backstroke, the Butterfly and the Breaststroke.
- Habitual physical activity levels in childhood and adolescence assessed with accelerometryPublication . Lopes, Vitor P.; Vasques, Catarina; Maia, José A.R.; Ferreira, João V.Aim. The purposes of this study were: (1) to evaluate age and gender differences in PA of children and adolescents; (2) to find out if children and adolescents fulfill the PA recommendations. Methods. PA was assessed in 265 female and 238 male subjects, ranging from 6 to 18 years of age, with MTI actigraph model 7164, during 7 consecutive days, grouped in 4 age groups. The MTI actigraph data was reduced to bouts (30-, 20-, 10-, and 5-min) and minutes spent in moderate PA (MPA), vigorous PA (VPA), and very vigorous PA (VVPA). Results. The oldest boys and girls revealed a lower number of PA bouts. Significant gender differences were found in daily VPA, F(1, 492) = 37.67, p<0.001; and VVPA F(1, 494) = 24.11, p<0.001. Boys were more active than girls. Significant age group differences were also found in MPA, F(3, 494) = 87.40, p<0.001; VPA, F(3, 492) = 78.15, p<0.001; and VVPA, F(3, 454) = 54.89, p<0.001. In both genders MPA, VPA and VVPA decreased with age. Till the age of 14, children had means between 79.6±30.6 and 144.1±76.9 min*day-1 of PA. After this age there was a decrease to 44.1±19.9 min*day-1 in girls and to 56.3±31.9 min*day-1 in boys. Conclusions. Boys had more minutes a day of vigorous and very vigorous PA than girls. PA decreased with age. The children from 6 to 15 of this fulfilled the recommendations of 60 min*day-1 of moderate to vigorous PA.
- Physiological adaptations to head-out aquatic exercises with different levels of body immersionPublication . Barbosa, Tiago M.; Garrido, Maria F.; Bragada, JoséThe purpose of this study was to compare the physiological adaptations to basic head-out aquatic exercises with different levels of body immersion. Sixteen young and clinically healthy subjects (9 women and 7 men) volunteered to participate in this study. Each subject performed 3 repetitions (on land, immersed to the hip, and immersed to the breast) of the aquatic exercise ‘‘rocking horse’’ for 6 minutes. The rating of perceived effort (RPE), the maximal heart rate achieved during the exercitation (HRmax), the percentage of the maximal theoretical heart rate estimated (%HRmax), the peak of oxygen uptake during the exercise (V˙ O2peak), and the energy expenditure (EE) were evaluated. The RPE was significantly higher when exercising immersed to the hip than on land ( p 0.01) and immersed to the breast ( p 0.03). The HRmax and %HRmax were significantly lower when exercising with immersion to the breast than on land ( p 0.01) and with immersion to the hip ( p 0.01). The V˙ O2peak was significantly different between all conditions. The lower mean value was verified when exercising immersed to the breast, followed by immersion to the hip and on land. The EE was significantly higher when performing aquatic exercises on land than when immersed to the hip ( p 0.02) and the breast ( p 0.01). So, physiological responses when exercising immersed to the hip are higher than when immersed to the breast. The physiological responses when exercising on land are higher than when exercising with immersion to the hip and to the breast.