The aim of this study was to determine the effect of 12 weeks of training on the critical velocity and maximal lactate steady state of elite swimmers. The tests to determine critical velocity and maximal lactate steady state were performed before and after 12 weeks of training. Critical velocity after 12 weeks of training was significantly higher than before training (1.4590.10 m × s (1 vs. 1.4190.11 m × s (1 ). In contrast, no significant differences in the velocity at maximal lactate steady state were observed before and after training (1.4190.10 m × s (1 vs. 1.4390.10 m × s (1 ). There was also a decrease in mean lactate concentration after 12 weeks of training. Before training, the velocity at maximal lactate steady state occurred at 100% of critical velocity, with a mean lactate concentration of 4.34 mmol × l (1 . After training, the velocity at maximal lactate steady state occurred at 98% of critical velocity, with a reduced mean lactate concentration of 3.69 mmol × l (1 . Based on these results, it would appear that 12 weeks of training was enough to promote an increase in critical velocity. Although no significant differences in the velocity at maximal lactate steady state were observed before and after training, the decrease in mean lactate concentration after training demonstrated greater efficiency of the aerobic system, leading to less wear during the tests.

We investigated the effects of hand paddles and parachute on the relative duration of stroke phases and index of coordination of competitive crawl-strokers. Eleven male-swimmers (age: 21.9 ± 4.5 years; 50-m best time: 24.23 ± 0.75 s) were evaluated in four maximal-intensity conditions: without equipment, with hand paddles, with parachute, and with both hand paddles and parachute. Relative stroke phase duration of each arm, swimming velocity, and stroke rate were analysed from video (60 Hz). The index of coordination was quantified based on the lag time between propulsive phases of each arm, which defined the coordination mode as catch-up, opposition or superposition. The stroke rate decreased in all conditions (P < 0.05) and swimming velocity decreased with parachute and with paddles + parachutes (P < 0.05). The coordination mode changed from catch-up in free swimming (-2.3 ± 5.0%) to opposition with paddles (-0.2 ± 3.8%), parachute (0.1 ± 3.1%), and paddles + parachute (0.0 ± 3.2%). Despite these variations, no significant differences were observed in relative duration of right and left arm-stroke phases, or in index of coordination. We conclude that the external resistances analysed do not significantly influence stroke phase organization, but, as a chronic effect, may lead to greater propulsive continuity.

This study investigated the acute effects of different sizes of paddles on the force-time curve during tethered swimming and swimming velocity in front-crawl stroke. Fourteen male swimmers (20.0 ± 3.7 years; 100-m best time: 53.70 ± 0.87 s) performed two 10-s maximal efforts in tethered swimming to obtain peak force, average force, impulse, rate of force development, stroke duration and time to peak force. Swimming velocity, stroke rate and stroke length were obtained from two 25-m maximal swims. Both tests were repeated in five conditions: free swimming, wearing small (280 cm (2) ), medium (352 cm (2) ), large (462 cm (2) ) and extra-large (552 cm (2) ) hand paddles. Compared to free swimming, paddles provided significant increases of peak force (medium: 11.5%, large: 16.7%, extra-large: 21.7%), impulse (medium: 15.2%, large: 22.4%, extra-large: 30.9%), average force (medium: 5.1%, large: 7.5%), rate of force development (extra-large: 11.3%), stroke duration (medium: 9.3%, large: 11.8%, extra-large: 18.5%), time to peak force (medium: 11.1%, large: 15.9%, extra-large: 22.1%), swimming velocity (medium: 2.2%, large: 3.2%, extra-large: 3.7%) and stroke length (medium: 9.0%, large: 9.0%, extra-large: 14.8%), while stroke rate decreased (medium: -6.2%, large: -5.5%, extra-large: -9.5%). It is concluded that medium, large and extra-large paddles influence the force-time curve and change swimming velocity, suggesting these sizes may be useful for force development in water.

O objetivo deste estudo foi analisar a reprodutibilidade dos parâmetros biomecânicos da curva força-tempo do estilo "Crawl" em um protocolo de 10 s no nado atado. Dezesseis nadadores do sexo masculino (idade: 20,4 ± 4,0 anos; tempo na prova de 100 m livre: 53,68 ± 0,99 s) realizaram dois esforços máximos de 10 s no nado atado. Os parâmetros força pico, força média, taxa de desenvolvimento de força, impulso, duração da braçada, tempo para atingir a força pico e força mínima foram representados pela média de oito braçadas consecutivas obtidas em cada tentativa. Utilizou-se o teste t para observar as diferenças entre os esforços para cada parâmetro. O nível de significância estabelecido foi de 5%. A reprodutibilidade relativa foi medida pelo coeficiente de correlação de Pearson e a consistência entre as duas tentativas pelo coeficiente de correlação intraclasse (CCI). A reprodutibilidade absoluta foi verificada pelo coeficiente de variação (CV). Não foi demonstrada diferença estatisticamente significante para nenhum parâmetro biomecânico quando comparados os dois esforços. Os elevados CCI e baixos CV indicaram alta consistência interna dos parâmetros analisados. Conclui-se que os parâmetros biomecânicos analisados a partir do nado atado são reprodutíveis quando empregado protocolo de curta duração o que demonstra a possibilidade de utilização do protocolo com alto grau de confiabilidade, por parte de treinadores e atletas.

This study investigated the effects of hand paddles, parachute and hand paddles plus parachute on the inter-limb coordination of butterfly swimming. Thirteen male swimmers were evaluated in four random maximal intensity conditions: without equipment, with hand paddles, with parachute and with hand paddles + parachute. Arm and leg stroke phases were identified by 2D video analysis to calculate the total time gap (T1: time between hands' entry in the water and high break-even point of the first undulation; T2: time between the beginning of the hand's backward movement and low break-even point of the first undulation; T3: time between the hand's arrival in a vertical plane to the shoulders and high break-even point of the second undulation; T4: time between the hand's release from the water and low break-even point of the second undulation). The swimming velocity was reduced and T1, T2 and T3 increased in parachute and hand paddles + parachute. No changes were observed in T4. Total time gap decreased in parachute and hand paddles + parachute. It is concluded that hand paddles do not influence the arm-to-leg coordination in butterfly, while parachute and hand paddles + parachute do change it, providing a greater propulsive continuity.

Rev Bras Cineantropom Desempenho Hum 2010, 12(1): [49][50][51][52][53][54] Resumo -O objetivo do presente estudo foi verificar o efeito da ingestão de cafeína sobre os parâmetros do modelo de potência crítica determinado em cicloergômetro. Participaram do estudo oito sujeitos do sexo masculino. A ingestão de cafeína pura (6 mg.kg -1 ) ou placebo (maltodextrina) foi realizada através de protocolo duplo-cego, 60 minutos antes dos testes. Para determinação da potência crítica, os sujeitos foram submetidos a quatro testes de cargas constantes em cicloergômetro, realizados aleatoriamente, nos momentos cafeína e placebo, nas intensidades de 80, 90, 100 e 110% da potência máxima, a uma cadência de 70 rpm até a exaustão. A potência crítica e a capacidade de trabalho anaeróbio foram obtidas através de regressão não linear e ajuste de curva para o modelo hiperbólico potência-tempo. Para o tratamento estatístico, utilizaram-se-se o teste de Shapiro Wilk e o teste t de Student pareado. Não foram encontradas diferenças significativas na potência crítica nas condições cafeína e placebo (192,9 ± 31,3 vs 197,7 ± 29,4 W, respectivamente). A capacidade de trabalho anaeróbio foi significativamente maior na condição cafeína (20,1 ± 5,2 vs 16,3 ± 4,2 W, p< 0,01). Foi, ainda, obtido um alto valor de associação (r 2 ) entre as condições cafeína e placebo (0,98± 0,02 e 0,99± 0,0). Através dos resultados obtidos, concluiu-se que a ingestão de cafeína não proporcionou melhorias no desempenho da potência crítica, entretanto, elevou os valores da capacidade de trabalho anaeróbio por influenciar o desempenho nas cargas de maior intensidade e menor duração. Palavras-chave: Potência Crítica; Cafeína; Ergogênico. (192.9 ± 31.3 vs 197.7 ± 29.4 W, respectively). The anaerobic work capacity was significantly higher in the caffeine group (20.1 ± 5.2 vs 16.3 ± 4.2 W, p<0.01). A high association (r 2 ) was observed between the caffeine and placebo conditions (0.98 ± 0.02 and 0.99 ± 0.0, respectively Abstract -

This study compared anthropometric parameters among different military sports. One hundred and seventy male cadets of the Brazilian Air Force Academy, who were participants of athletics (n= 33, 20.5±1.3 years), basketball (n= 11, 19.9±1.8 years), fencing (n= 10, 19.9±0.7 years), soccer (n= 21, 20.9±1.6 years), judo (n= 17, 20.7±1.0 years), swimming (n= 15, 20.4±1.2 years), orienteering (n= 10, 21.3±1.6 years), military pentathlon (n= 11, 20.7±1.2 years), water polo (n=10, 21.1±0.9 years), shooting (n= 18, 21.3±1.2 years) or volleyball (n= 14, 20.9±1.7 years) military competitive teams, participated in this study. Height, body mass, body mass index, fat percentage, lean body mass, fat mass, waist and hip perimeters, and waist-hip ratio were measured. Main effects were detected for height, body mass, body mass index, lean body mass, waist and hip perimeters. The only significant finding was that orienteers present lower lean body mass than volleyball and water polo players. These results point out the homogeneity of group anthropometric parameters (except lean body mass), suggesting that military coaches do not rely on the anthropometric parameters, but on specific skills demonstrated during initial period of practice to choose athletes for their teams.

Resumo -O objetivo do presente estudo foi verificar a influência da utilização de diferentes combinações de distâncias sobre os valores da Velocidade Crítica (VC) e Capacidade de Trabalho Anaeróbio (CTAn). Participaram do estudo dezenove nadadores com experiência em treinamento na modalidade. A VC foi determinada através do coeficiente angular da reta de regressão linear entre a distância e o tempo obtido em cada repetição. Para a determinação da VC, foram utilizadas cinco distâncias (50, 100, 200, 400 e 800m) com intervalo de 24 horas entre elas. Posteriormente, foram feitas quatro combinações entre as distâncias: VC1 (50, 100 e 200m), VC2 (100, 200 e 400m), VC3 (200, 400 e 800m) e VC4 (50, 100, 200, 400 e 800m). O teste de Shapiro-Wilk foi utilizado para determinar a normalidade das amostras. Para comparações entre a VC e as diferentes combinações de tiros, utilizou-se ANOVA one way (p<0,05). A combinação com distâncias menores (VC1) proporcionou maiores valores da VC (1,47 ± 0,13), causando com isso uma diminuição na CTAn (11,91 ± 2,61). A utilização de tiros de média e longa distância proporcionou um valor mais baixo para a VC (1,38 ± 0,10, 1,34 ± 0,09 e 1,36 ± 0,09) e maior para a CTAn (19,84 ± 6,74, 27,44 ± 6,91 e 18,43 ± 5,21) quando comparados com os tiros curtos, respectivamente para VC2, VC3 e VC4. Através dos dados obtidos, conclui-se que a distância dos tiros possui grande influência sobre os valores da VC e da CTAn, podendo com isso superestimar ou subestimar a velocidade correspondente à máxima fase estável do lactato. Palavras-chave: Velocidade Crítica; Limiar anaeróbio; Natação. (50, 100, 200, 400 and 800 m) performed at an interval of 24 hours were used for the determination of CV, followed by the following four combinations of distances: CV1 (50, 100 and 200 m), CV2 (100, 200 and 400 m), CV3 (200, 400 and 800 m), and CV4 (50, 100, 200, 400 and 800 m AWC (11.91 ± 2.61). The use of shots of medium and long distance resulted in a lower CV (1.38 ± 0.10, 1.34 ± 0.09 and 1.36 ± 0.09 for CV2, CV3 and CV4, respectively) and higher AWC (19.84 ± 6.74, 27.44 ± 6.91 and 18.43 ± 5.21) when compared to short shots. The results suggest that shot distance influences CV and AWC, overestimating or underestimating the speed corresponding to maximum lactate steady state. Abstract -The purpose of this study was to determine the influence of different distance combinations on critical velocity (CV) and anaerobic work capacity (AWC). Nineteen swimmers experienced in this training modality participated in the study. CV was calculated by the angular coefficient of the linear regression line between distance and time obtained for each repetition. Five distances