5 km front crawl in pool and open water swimming: breath-by-breath energy expenditure and kinematic analysis.

PURPOSE: Breath-by-breath energy expenditure during open water swimming has not yet been explored in an ecological environment. This study aimed to investigate and compare energetics and kinematics of 5 km swimming, in both swimming pool and open water conditions. METHODS: Through four independent studies, oxygen uptake ([Formula: see text]2) kinetics, heart rate (HR), blood lactate concentration ([La-]) and glucose level (BGL), metabolic power ([Formula: see text]), energy cost (C) and kinematics were assessed during 5 km front crawl trials in a swimming pool and open water conditions. A total of 38 competitive open water swimmers aged 16-27 years volunteered for this four part investigation: Study A (pool, ten females, 11 males), Study B (pool, four females, six males), Study C (pool case study, one female) and Study D (open water, three females, four males). RESULTS: In the swimming pool, swimmers started with an above average swimming speed (v), losing efficiency along the 5 km, despite apparent homeostasis for [La-], BGL, [Formula: see text]2, [Formula: see text] and C. In open water, swimmers started the 5 km with a below average v, increasing the stroke rate (SR) in the last 1000 m. In open water, [Formula: see text]2 kinetics parameters, HR, [La-], BGL, respiratory exchange ratio and C were affected by the v and SR fluctuations along the 5 km. CONCLUSIONS: Small fluctuations were observed for energetic variables in both conditions, but changes in C were lower in swimming pool than in open water. Coaches should adjust the training plan accordingly to the specificity of open water swimming.

STATIC STRETCHING DOES NOT REDUCE VARIABILITY, JUMP AND SPEED PERFORMANCE.

BACKGROUND: Stretching is often part of the warm-up routine prior to athletic participation; however, controversial evidence exists on the effects of stretching on countermovement jump (CMJ) and sprint performance. Additionally, analysis of variability between repeated tasks is useful for monitoring players, to analyze factors that could affect the performance, and to guide clinical decisions for training strategies. PURPOSE: The purpose of this study was to examine whether static stretching (SS) prior to CMJ and 20-meter (20-m) sprint would affect performance, and to investigate whether SS affects an athlete's ability to perform these tasks consistently. METHODS: Twenty-two trained healthy athletes (23.2 ± 5.0 years) attended, randomly, two testing sessions, separated by 48 hours. At session one, all participants underwent 10 minutes of dynamic running warm-up followed by the experimental tasks (three CMJ and three 20-m sprint), whereas five minutes of stretching was added after the warm-up routine at session two. All participants performed the same experimental tasks in both sessions. The stretching protocol consisted of five stretching exercises for each lower limb. RESULTS: The paired-samples t-test revealed no significant differences between the stretching protocol condition and no stretching condition for the 20-m sprint (t(21)=.920; p=.368) and CMJ (t(21)=.709; p=.486). There were no significant differences in trial-by-trial variability on 20-m sprint (t(21)=1.934; p=.067) and CMJ scores (t(21)=.793; p=.437) as result of SS. CONCLUSION: The SS protocol did not modify jumping and running ability in trained healthy athletes. The SS prior to training or competition may not cause detrimental effects to athletic performance. LEVEL OF EVIDENCE: Level III, Nonrandomized controlled trial.

Comportamento da pressão arterial em homens pré-hipertensos participantes em um programa regular de natação / Blood pressure behaviour in pre-hypertensive men engaged in a regular swimming program / Comportamiento de la presión arterial después de la práctica de natación en hombres pre-hipertensos

INTRODUÇÃO: A natação tem sido recomendada como tipo de atividade física para a prevenção, tratamento e controle da hipertensão arterial. OBJETIVO: Analisar os efeitos da prática regular de natação sobre a pressão arterial de adultos pré-hipertensos. MÉTODOS: A amostra foi composta por 36 homens pré-hipertensos divididos em dois grupos: Experimental - GE (n=24, 40,60±9,36 anos) e Controle - GC (n=12, 40,57±8,05 anos). O GE realizou um programa regular de natação, com três sessões semanais de 45 min, durante 12 semanas, enquanto o GC não alterou seus hábitos alimentares e permaneceu sem praticar atividade física no período. O procedimento estatístico utilizado para verificar as diferenças entre as médias antes e depois de 12 semanas do programa regular de natação foi o teste-t de Student. O estudo admitiu o nível de p < 0.05 para a significância estatística. RESULTADOS: O grupo GE apresentou diferenças estatisticamente significativas nas variáveis analisadas quando comparadas com o GC, tanto na pressão arterial sistólica, PAS (Δ = - 5,89 mmHg, p = 0,00), como na pressão arterial diastólica, PAD (Δ = - 5,15mmHg, p = 0,00). CONCLUSÃO: Os resultados mostram que um programa regular de natação provoca reduções significativas na pressão arterial em repouso em homens pré-hipertensos. .

INTRODUCTION: Swimming as a modality of physical activity that has been recommended for preventing, controlling and treating arterial hypertension. OBJECTIVE: To verify the persistent effects of a regular swimming program on pre-hypertensive adults on arterial pressure levels. METHODS: The sample was constituted of 36 pre-hypertense individuals who were divided into two groups: experimental - GE (n=24, 40.60 ± 9.36 years old) and control - GC (n=12, 40.57 ± 8.05 years old. GE individuals took part in a regular swimming programme consisting of three forty-five training sessions weekly (ST) for 12 weeks, whereas GC individuals were instructed not to alter their nutritional habits and did not practice any physical activity during the experiment. The Student t-test was used as statistical procedure to analyze the differences between the average indexes recorded before and after the 12-weeks regular swimming program. The study admitted a level statistical significance at p < 0.05 for. RESULTS: The results led to the conclusion that experimental group presented a statistically significant difference for the analyzed variables when compared to Control group. There was an important reduction of systolic blood pressure, SBP(Δ = - 5,89 mmHg, p = 0,00), and also of diastolic blood pressure, DBP (Δ = - 5,15mmHg, p = 0,00). CONCLUSION: The results showed that a regular swimming program leads to a significant decrease in resting blood pressure values of pre-hypertensive men. .

INTRODUCCIÓN: La natación ha sido recomendada como un tipo de actividad física para la prevención, tratamiento y control la de hipertensión arterial. OBJETIVO: Analizar los efectos de la práctica regular de natación sobre la presión arterial de adultos prehipertensos. MÉTODOS: La muestra se ha compuesto por 36 hombres con prehipertensión delineados en dos grupos: experimental - GE (n=24, 40,60±9,36 años) y Control - GC (n=12, 40,57±8,05 años). El GE realizó un programa regular de natación, con tres sesiones semanales, duración de 45 minutos, durante 12 semanas, mientras que el GC no cambió los hábitos alimenticios y permaneció sin realizar actividad física en el período. El procedimiento estadístico utilizado para averiguar las diferencias entre los promedios antes y después de 12 semanas del programa regular de natación fue el test t de Student. El estudio admitió el nivel de p< 0.05 para la significancia estadística. RESULTADOS: El grupo GE presentó diferencias estadísticamente significativas en las variables analizadas, cuando comparadas con el GC, tanto en la presión arterial sistólica, PAS (Δ = - 5,89 mmHg, p = 0,00) como en la presión arterial diastólica, PAD (Δ = - 5,15mmHg, p = 0,00). CONCLUSIÓN: Los resultados muestran que un programa regular de natación provoca reducciones significativas en la presión arterial en reposo en hombres prehipertensos. .

Haematological changes in elite kayakers during a training season.

This study monitored haematological markers in response to training load in elite kayakers during a training season. The sample comprised eight elite kayakers aged 22 ± 4.2 years with a 77.2 ± 6.7 kg body mass and a 177.5 ± 5.6 cm stature. The initial [Formula: see text]O(2max) was 61.2 ± 5.5 mL·kg(-1)·min(-1). The control group consisted of six healthy males, aged 18.6 ± 1.1 years, with an 81.3 ± 13.8 kg body mass and a 171.9 ± 4.5 cm stature. Blood samples were collected at the beginning of the training season after an off-training period of six weeks (t(0)), at the 11th week after the application of high training volumes (t(1)), at the 26th week after an intense training cycle (t(2)), and at the 31st week at the end of a tapering phase (t(3)). Differences between time points were detected using ANOVA and the Bonferroni post hoc test. Significant changes were found after the intense training cycle (t(2)), lymphocytes decreased while haemoglobin, mean corpuscular volume, mean corposcular haemoglobin, mean concentration of corpuscular hemoglobin concentration, platelets distribution width, and red blood cell distribution width values increased when compared with baseline values. At t(3), a reduction in monocyte numbers and an increase in mean platelet volume compared with baseline values were seen. By reducing the volume and intensity of training, many variables returned to values close to those at baseline. Although many athletes had accumulated responses over time due to training, they still suffered transient changes that appear to be influenced by training load. Haemorheology monitoring may help detect health risks, especially during times of intensified training.

Resposta da frequência cardíaca e da concentração de lactato após cada segmento do triathlon olímpico / Heart rate and blood lactate concentration response after each segment of the Olympic Triathlon event

INTRODUÇÃO: As respostas fisiológicas de cada uma das modalidades envolvidas no triathlon são diferentes. Cargas de treino poderiam ser melhores prescritas se consideradas as individualidades fisiológicas de cada segmento para cada atleta. OBJETIVO: Observar o comportamento das variáveis fisiológicas, frequência cardíaca (FC) e concentração de lactato sanguíneo, antes e depois de cada segmento do triathlon: natação, ciclismo e corrida. MÉTODOS: Doze atletas do sexo masculino cumpriram uma prova de triathlon com distância olímpica. Coletas de sangue da polpa digital foram feitas antes do início da prova, após a natação, após o ciclismo, após a corrida e, ainda, uma hora após a prova. Cada atleta foi monitorizado com frequencímetro (Polar® S610) durante toda a prova. Análises estatísticas foram realizadas através da correlação de Spearman e teste de Wilcoxon para amostras não paramétricas (p<0,05). RESULTADOS: Nesta pesquisa, a maior intensidade foi registrada, em ambos os parâmetros fisiológicos, durante o ciclismo (86,3% da frequencia cardíaca máxima (FCmáx); 6,98mmol), seguida pela natação (85,2% FCmáx; 5,75mmol) e corrida (83,6% FCmáx; 4,47mmol), respectivamente. CONCLUSÃO: Conclui-se que a prescrição da carga de treino para o triathlon será mais eficiente se baseada nas respostas fisiológicas (FC e o lactato sanguíneo) individuais de cada modalidade.

INTRODUCTION: The physiological responses of each part of Triathlon are different; better training loads could be prescribed for athletes considering each segment of this sport. OBJECTIVE: The purpose of this study was to investigate the behavior of physiological variables - heart rate and blood lactate concentration - before the event, after each segment of an Olympic Triathlon: swimming, cycling and running, and after recovery time. METHODS: The sample included twelve male triathletes who participated in a triathlon event with Olympic distance. Capillary blood samples were taken from the fingertip in the beginning of the event (pre-event), after each segment (swimming, cycling, running) and after 1 hour of recovery. Each athlete was monitored during the entire event by a heart rate monitor (Polar® S610). Statistical procedures included: Spearman correlations and Wilcoxon non parametric tests (p<0.05). RESULTS: The study results showed that the highest intensity was reached during cycling (HRmax: 86.3%; Lac: 6.98 mmol/L) in both physiological parameters, followed by swimming (HRmax: 85.2%, Lac: 5.75 mmol/L) and running (HRmax: 83.6%, lac: 4.47mmol), respectively. CONCLUSIONS: Training load prescription based on different physiological markers responses - such as heart rate and blood lactate concentration - of each triathlon segment will be more efficient for the Olympic triathlon demands.