Kinematical changes in swimming front crawl and breaststroke with the AquaTrainer® snorkel

The aim of the present study was to assess the kinematical changes when swimming maximal bouts in Front Crawl and Breaststroke with the AquaTrainer® snorkel. Thirteen male swimmers (7 at Breaststroke and 6 at Front Crawl) of national level performed randomly two maximal bouts of 100-m swims: one bout using the Aqua- Trainer® snorkel (snorkel swim) and another one without the snorkel (free swim). The swims were videotaped in sagital plane with a pair of cameras providing 2D kinematics evaluation. The following measures were assessed: swimming performance (T100), stroke cycle period (P), stroke rate (SR), stroke length (SL), swimming velocity (v), swimming eYciency as estimated by the stroke index (SI), speed Xuctuation (dv) and the mathematical characterisation of dv. T100 was signiWcantly higher when swimming with the snorkel than in free swimming at Breaststroke (= 6.26%) and at Front Crawl (= 4.75%). P, SR and SL, as well as SI and dv did not present signiWcant diVerences. The main Wnding of the study was that changes in the swimming velocity imposed by the use of the Aquatrainer® do not seem due to changes in general kinematics or swimming eYcienc

Physiological assessment of head-out aquatic exercises in healthy subjects: a qualitative review

In the last decades head-out aquatic exercises became one of the most important physical activities within the health system. Massive research has been produced throughout these decades in order to better understand the role of head-out aquatic exercises in populations’ health. Such studies aimed to obtain comprehensive knowledge about the acute and chronic response of subjects performing head-out aquatic exercises. For that, it is assumed that chronic adaptations represent the accumulation of acute responses during each aquatic session. The purpose of this study was to describe the “state of the art” about physiological assessment of head-out aquatic exercises based on acute and chronic adaptations in healthy subjects based on a qualitative review. The main findings about acute response of head-out aquatic exercise according to water temperature, water depth, type of exercise, additional equipment used, body segments exercising and music cadence will be described. In what concerns chronic adaptations, the main results related to cardiovascular and metabolic adaptations, muscular strength, flexibility and body composition improvements will be reported

THE DETERMINATION OF DRAG IN THE GLIDING PHASE IN SWIMMING

The hydrodynamic drag forces produced by the swimmer during the sub aquatic gliding have been analyzed appealing to experimental investigation methods (e.g., Lyttle et al., 2000). However, the obtained results varied, which can translate some of the main inherent difficulties involved in the experimental studies. Thus, through application of a numerical method of Computational Fluid Dynamics (CFD), we intended to study the hydrodynamic drag forces, created during the displacement of the swimmer in different gliding positions, attempting to address some practical concerns to swimmers and coaches

Longitudinal assessment of elite swimmers performance leading to 2008 Beijing Olympic Games

The aim of this research was to track and analyze the stability of 400-m freestyle performance throughout elite swimmers preparation to the 2008 Beijing Olympic Game

Effects of musical cadence in the acute physiologic adaptations to head-out aquatic exercises

The purpose of this study was to analyze the relationships between musical cadence and the physiologic adaptations to basic head-out aquatic exercises. Fifteen young and clinically healthy women performed, immersed to the breast, a cardiovascular aquatic exercise called the ‘‘rocking horse.’’ The study design included an intermittent and progressive protocol starting at a 90 b min21 rhythm and increasing every 6 minutes, by 15 b min21, up to 195 b min21 or exhaustion. The rating of perceived effort (RPE) at the maximal heart rate achieved during each bout (HRmax), the percentage of the maximal theoretical heart rate estimated (%HRmax), and the blood lactate concentration ([La-]) were evaluated. The musical cadence was also calculated at 4 mmol L21 of blood lactate (R4), the RPE at R4 (RPE@R4), the HR at R4 (HR@R4), and the %HRmax at R4 (%HRmax@R4). Strong relationships were verified between the musical cadence and the RPE (R2 = 0.85; p , 0.01), the HRmax (R2 = 0.66; p , 0.01), the %HRmax (R2 = 0.61; p , 0.01), and the [La-] (R2 = 0.54; p , 0.01). The R4 was 148.13 6 17.53 b min21, the RPE@R4 was 14.53 6 2.53, the HR@R4 was 169.33 6 12.06 b min21, and the %HRmax@R4 was 85.53 6 5.72%. The main conclusion is that increasing musical cadence created an increase in the physiologic response. Therefore, instructors must choose musical cadences according to the goals of the session they are conducting to achieve the desired intensity

Longitudinal assessment of swimming performance in the 200 m freestyle event

Several studies have been carried out in order to identify the factors that can predict swimming performance. However, all these studies only analyzed determinant factors in a single moment. It was not taken into account the longitudinal stability and changes, as a result of individual development, new training methods and technological sophistication

Análise longitudinal da performance em natação pura desportiva: abordagem exploratória

O estudo teve como objectivo analisar a estabilidade da performance na prova de 400m livres ao longo da carreira desportiva. Foram analisados 45 nadadores masculinos, durante sete épocas consecutivas (desde a categoria de Infantil B até Sénior). A performance foi analisada com recurso ao melhor tempo em cada categoria na prova de 400m Livres em piscina curta. Foi efectuada a análise da estabilidade das médias, pela observação dos quartis ao longo da carreira desportiva, assim como a tendência central (média) e respectiva dispersão (um desvio-padrão). Foi ainda analisada a variação entre valores médios com recurso à ANOVA medidas repetidas e respectivo post-hoc teste (Bonferroni). Analisou-se ainda a estabilidade normativa pela auto-correlação entre as sete categorias (Pearson). Foi calculado o Kappa de Cohen (K) com um intervalo de confiança de 95%. Para todos os procedimentos estatísticos foi utilizado o programa informático SPSS 13,0 à excepção do K, o qual foi calculado através do programa estatístico Longitudinal Data Analysis. Foram verificadas diferenças significativas entre os valores médios de performance entre todas as categorias. Os valores de auto-correlação variaram entre o moderado e o elevado ao longo da carreira desportiva. Constata-se que na passagem de Juvenil B para A, a estabilidade torna-se elevada (>0,60). O valor de K, expressando a estabilidade ao longo de toda a carreira desportiva, é baixo (K = 0.327 ± 0,046). Em síntese, a predição do nível competitivo na categoria sénior com base na performance nas categorias de formação é reduzido. Todavia, a passagem de Juvenil B para A parece ser um momento marcante, onde a capacidade preditiva aumenta de forma acentuada

Tracking the 2004-2008 Olympic cycle performance in long distance freestyle events

Swimming seems to be one of the most studied sport among Sport Sciences community. Researchers are constantly attempting to identify and understand the factors that can predict swimming performance with a higher accuracy (e.g., Silva et al., 2007)

Comparação dos procedimentos metodológicos de reconstrução cinemática 2d na técnica de bruços – Duplo meio / planos seprados

O presente estudo teve como propósito principal o de averiguar os procedimentos bem como o grau de concordância das reconstruções dos parâmetros cinemáticos de execução na técnica de bruços com recurso a duas metodologias distintas de captura e reconstrução cinemétrica, duplo meio (DM) e planos separados (PS). A amostra foi constituída por 7 nadadores do sexo masculino especialistas na técnica de bruços (19.1 ± 4,3 anos de idade; 1.78 ± 0.62 m de estatura; 70.4 ± 8.0 kg de massa corporal; 69.10 ± 4.16 s de recorde pessoal aos 100 m Bruços em piscina longa). O protocolo consistiu na realização de um percurso de 100 m na técnica de bruços à máxima velocidade possível (prova maximal), em piscina de 50 metros. Os registos de imagem para posterior tratamento foram recolhidos por um sistema constituído por um par de câmaras de vídeo (uma subaquática - inclusa numa caixa estanque e uma de superfície). Assim, foram recolhidas as imagens da prova utilizando as duas metodologias, o DM e os PS. Duas câmaras registaram respectivamente imagens aéreas (GR-SX1 SVHS, JVC, Yokoama, Japão) e subaquáticas (GR-SXM25 SVHS, JVC, Yokoama, Japão) no plano sagital, a 25 metros da parede testa de partida. Foi efectuada a análise cinemática (Ariel Performance Analysis System, Ariel Dynamics Inc., Califórnia, EUA) de um ciclo gestual completo, através de um leitor de vídeo a 50 Hz (Panasonic, AG 7355, Japão). Recorreu-se ao método de digitalização em planos separados (aéreo e subaquático) e subsequente reconstrução pela aplicação do algoritmo2D-DLT [1]. Foi adoptado o modelo antropométrico de Zatsiorsky, adaptado por de Leva [6],, incluindo a divisão do tronco em 2 partes articuladas. Os sinais foram filtrados com uma frequência de corte de 5 Hz, como sugerido por Winter [15], com recurso a dupla-passagem. A fiabilidade do processo de digitalização-redigitalização para os dois métodos foi muito elevada (R = 0.97; ICR = .87; 0.95). Determinouse a duração absoluta do teste (T100, s), a duração absoluta do ciclo gestual (Durciclo), a frequência ciclo (FC, Hz), a distância de ciclo (DC, m), a velocidade de nado (v, m.s-1), o índice de nado (IN, m2.c-1.s-1), a flutuação intra-cíclica da velocidade horizontal do centro de massa (dv, %) e o deslocamento vertical do centro de massa corporal (Dy, m). Foi efectuada a comparação entre as duas situações com recurso a estatística não paramétrica (Teste de Wilcoxon) para P £ 0.05. O resultados sugerem-nos a ideia de que o padrão biomecânico de execução técnica dos nadadores na técnica de bruços parece ter características diferentes quando comparados os dados dos dois métodos de reconstrução cinemática (DP e PS)

Stability and prediction of 100-m breaststroke performance during the careers of elite swimmers

The aim of this study was to track and analyze the 100-m Breaststroke performance stability throughout elite swimmer’s career. 35 Portuguese male top-50 were analyzed for seven consecutive seasons between 12 and 18 years old. Best performances were collected from ranking tables. Longitudinal assessment was performed based on two approaches: (i) mean stability was analyzed by descriptive statistics and ANOVA repeated measures for each season followed by a post-hoc test (Bonferroni test), (ii) normative stability was analyzed with self-correlation (Malina, 2001) and the Cohen’s Kappa tracking index (Landis and Koch, 1977). There was a 100-m Breaststroke performance enhancement from children to adult age. The overall career performance prediction was low. The change from 13 to 14 years can be a milestone, where the ability to predict the final swimmer’s performance level strongly increases