The Cellular Composition of the Innate and Adaptive Immune System Is Changed in Blood in Response to Long-Term Swimming Training.

Competitive swimming requires high training load cycles including consecutive sessions with little recovery in between which may contribute to the onset of fatigue and eventually illness. We aimed to investigate immune changes over a 7-month swimming season. Fifty-four national and international level swimmers (25 females, 29 males), ranging from 13 to 20 years of age, were evaluated at rest at: M1 (beginning of the season), M2 (after the 1st macrocycle's main competition), M3 (highest training load phase of the 2nd macrocycle) and M4 (after the 2nd macrocycle's main competition) and grouped according to sex, competitive age-groups, or pubertal Tanner stages. Hemogram and the lymphocytes subsets were assessed by automatic cell counting and by flow cytometry, respectively. Self-reported Upper Respiratory Symptoms (URS) and training load were quantified. Although the values remained within the normal range reference, at M2, CD8+ decreased (M1 = 703 ± 245 vs. M2 = 665 ± 278 cell µL-1; p = 0.032) and total lymphocytes (TL, M1 = 2831 ± 734 vs. M2 = 2417 ± 714 cell µL-1; p = 0.007), CD3+ (M1 = 1974 ± 581 vs. M2 = 1672 ± 603 cell µL-1; p = 0.003), and CD4+ (M1 = 1102 ± 353 vs. M2 = 929 ± 329 cell µL-1; p = 0.002) decreased in youth. At M3, CD8+ remained below baseline (M3 = 622 ± 245 cell µL-1; p = 0.008), eosinophils (M1 = 0.30 ± 0.04 vs. M3 = 0.25 ± 0.03 109 L-1; p = 0.003) and CD16+56+ (M1 = 403 ± 184 vs. M3 = 339 ± 135 cell µL-1; p = 0.019) decreased, and TL, CD3+, and CD4+ recovered in youth. At M4, CD19+ were elevated (M1 = 403 ± 170 vs. M4 = 473 ± 151 cell µL-1; p = 0.022), CD16+56+ continued to decrease (M4 = 284 ± 131 cell µL-1; p < 0.001), eosinophils remained below baseline (M4 = 0.29 ± 0.05 109 L-1; p = 0.002) and CD8+ recovered; monocytes were also decreased in male seniors (M1 = 0.77 ± 0.22 vs. M4 = 0.57 ± 0.16 109 L-1; p = 0.031). The heaviest training load and higher frequency of URS episodes happened at M3. The swimming season induced a cumulative effect toward a decrease of the number of innate immune cells, while acquired immunity appeared to be more affected at the most intense period, recovering after tapering. Younger athletes were more susceptible at the beginning of the training season than older ones.

The impact of triathlon training and racing on athletes' general health.

Although the sport of triathlon provides an opportunity to research the effect of multi-disciplinary exercise on health across the lifespan, much remains to be done. The literature has failed to consistently or adequately report subject age group, sex, ability level, and/or event-distance specialization. The demands of training and racing are relatively unquantified. Multiple definitions and reporting methods for injury and illness have been implemented. In general, risk factors for maladaptation have not been well-described. The data thus far collected indicate that the sport of triathlon is relatively safe for the well-prepared, well-supplied athlete. Most injuries 'causing cessation or reduction of training or seeking of medical aid' are not serious. However, as the extent to which they recur may be high and is undocumented, injury outcome is unclear. The sudden death rate for competition is 1.5 (0.9-2.5) [mostly swim-related] occurrences for every 100,000 participations. The sudden death rate is unknown for training, although stroke risk may be increased, in the long-term, in genetically susceptible athletes. During heavy training and up to 5 days post-competition, host protection against pathogens may also be compromised. The incidence of illness seems low, but its outcome is unclear. More prospective investigation of the immunological, oxidative stress-related and cardiovascular effects of triathlon training and competition is warranted. Training diaries may prove to be a promising method of monitoring negative adaptation and its potential risk factors. More longitudinal, medical-tent-based studies of the aetiology and treatment demands of race-related injury and illness are needed.

Diferenças em populações de células exterminadoras naturais (Natural Killers-NK) sanguíneas periféricas entre atletas de caiaque e não atletas / Differences in peripheral blood Natural Killer cell populations between elite kayakers and non-athletes

INTRODUÇÃO: O exercício estressante prolongado tem sido associado a uma depressão transitória da função imune, com rotinas de treinamento e competição intensas e prolongadas capazes de levar os atletas a uma deficiência imune. OBJETIVO: O objetivo deste estudo foi observar se o treinamento cr ônico foi capaz de produzir diferenças sustentáveis no sangue periférico (SP) subpopulações de leucócitos (LEU, granulócitos, monócitos, linfócitos totais, linfócitos B e T, e células CD4+ e CD8+T e células natural killers) de atletas de caiaque de elite quando comparados com não atletas. MÉTODOS: A amostra incluiu 13 homens atletas de caiaque de elite, 20 ± 3 anos, 75,0kg ± 7,9 peso e 177,3 ± 7,1 cm estatura. O VO2max foi 58,3 ± 7,8mL.kg.min-1. O grupo de não atletas incluiu sete homens saudáveis, idade 18 ± 1 ano de idade, 81,3 ± 13,8Kg de peso corporal e 171,9 ± 4,5cm de estatura. As amostras de sangue dos atletas foram coletadas no início da temporada de treinamento, após um período fora do treinamento de seis semanas. Populações de células sanguíneas periféricas foram identificadas por análise de citometria de fluxo. Para identificar as diferenças entre os grupos de atletas e não atletas, o teste U de Mann-Whitney foi utilizado. RESULTADOS: N ão foram identificadas diferenças entre os atletas de caiaque treinados e não atletas em repouso, exceto para células natural killers (CD3-CD56+) e os valores da subpopulação CD3-CD56+CD8+ os quais foram mais baixos nos atletas. CONCLUSÃO: Nosso estudo encontrou que, após um período prolongado sem treinamento (seis semanas), somente a população de NK CD3-CD56+ e, em especial, a subpopulação de altamente citotóxica CD3-CD56+CD8+ apresentou níveis mais baixos nos atletas de elite quando comparados com os homens destreinados.

INTRODUCTION: Prolonged strenuous exercise has been associated with a transient depression of immune function, with prolonged intense training schedules and competition able to lead to immune impairment in athletes. OBJETIVE: The objective of this study was to see if chronic training was able to produce sustained differences in the peripheral blood (PB) leukocyte subpopulations (WBC, granulocytes, monocytes, total lymphocytes, B and T lymphocytes, CD4+ and CD8+ T cells and Natural Killer cells) of elite kayakers when compared to non-athletes. METHODS: The sample comprised 13 elite male kayakers, 20 ± 3 years old, 75.0 kg ±7.9 weight and 177.3±7.1 cm stature. The VO2max was 58.3±7.8 mL.kg.min-1. The Non-athlete group comprised 7 health males, aged 18±1 years old, 81.3±13.8 kg of weight and 171.9±4.5cm stature. The athlete's blood samples were collected at the beginning of the training season, after an off period of six weeks of training. Peripheral blood cell populations were identified by flow cytometry analysis. To verify the differences between the athlete and non-athlete groups the Mann-Whitney U Test was used. RESULTS: No differences between the trained kayakers and the non-athletes were found at rest except for Natural Killer cells (CD3-CD56+) and the CD3-CD56+CD8+ subset values that were lower in the athletes. CONCLUSION: Our study found that after a prolonged time without training (six weeks) only the NK CD3-CD56+ population and particularly the highly cytotoxic CD3-CD56+CD8+ subpopulation had lower levels in the elite athletes when compared to the untrained men.

Reliability and validity of physiological data obtained within a cycle-run transition test in age-group triathletes.

This study examined the validity and reliability of a sequential "Run-Bike-Run" test (RBR) in age-group triathletes. Eight Olympic distance (OD) specialists (age 30.0 ± 2.0 years, mass 75.6 ± 1.6 kg, run VO2max 63.8 ± 1.9 ml· kg(-1)· min(-1), cycle VO2peak 56.7 ± 5.1 ml· kg(-1)· min(-1)) performed four trials over 10 days. Trial 1 (TRVO2max) was an incremental treadmill running test. Trials 2 and 3 (RBR1 and RBR2) involved: 1) a 7-min run at 15 km· h(-1) (R1) plus a 1-min transition to 2) cycling to fatigue (2 W· kg(-1) body mass then 30 W each 3 min); 3) 10-min cycling at 3 W· kg(-1) (Bsubmax); another 1-min transition and 4) a second 7-min run at 15 km· h(-1) (R2). Trial 4 (TT) was a 30-min cycle - 20-min run time trial. No significant differences in absolute oxygen uptake (VO2), heart rate (HR), or blood lactate concentration ([BLA]) were evidenced between RBR1 and RBR2. For all measured physiological variables, the limits of agreement were similar, and the mean differences were physiologically unimportant, between trials. Low levels of test-retest error (i.e. ICC <0.8, CV<10%) were observed for most (logged) measurements. However [BLA] post R1 (ICC 0.87, CV 25.1%), [BLA] post Bsubmax (ICC 0.99, CV 16.31) and [BLA] post R2 (ICC 0.51, CV 22.9%) were least reliable. These error ranges may help coaches detect real changes in training status over time. Moreover, RBR test variables can be used to predict discipline specific and overall TT performance. Cycle VO2peak, cycle peak power output, and the change between R1 and R2 (deltaR1R2) in [BLA] were most highly related to overall TT distance (r = 0.89, p < 0. 01; r = 0.94, p < 0.02; r = 0.86, p < 0.05, respectively). The percentage of TR VO2max at 15 km· h(-1), and deltaR1R2 HR, were also related to run TT distance (r = -0.83 and 0.86, both p < 0.05).

Design of a three-dimensional hand/forearm model to apply computational fluid dynamics

The purpose of this study was to develop a three-dimensional digital model of a human hand and forearm to apply Computational Fluid Dynamics to propulsion analysis in swimming. Computer tomography scans of the hand and forearm of an Olympic swimmer were applied. The data were converted, using image processing techniques, into relevant coordinate input, which could be used in Computational Fluid Dynamics software. From that analysis, it was possible to verify an almost perfect agreement between the true human segment and the digital model. This technique could be used as a means to overcome the difficulties in developing a true three-dimensional model of a specific segment of the human body. Additionally, it could be used to improve the use of Computational Fluid Dynamics generally in sports and specifically in swimming studies, decreasing the gap between the experimental and the computational data.

O objetivo do presente estudo foi desenvolver um modelo digital tridimensional de uma mão e um antebraço humano para aplicar a Dinâmica Computacional de Fluidos ao estudo da propulsão em natação. Foram aplicados procedimentos computorizados de tomografia axial na mão e antebraço de um nadador Olímpico. Através de técnicas de processamento de imagem, os dados foram convertidos em coordenadas tridimensionais, que podem ser utilizadas em programas de simulação computacional. Através dos resultados encontrados, foi possível verificar uma semelhança quase perfeita entre o segmento humano e o modelo digital. Esta técnica pode ser utilizada como uma forma de ultrapassar as dificuldades em desenvolver um modelo digital tridimensional de um segmento específico do corpo humano. Complementarmente, pode ser bastante útil na melhoria da utilização da Dinâmica Computacional de Fluidos no Desporto, de uma forma geral, e, mais especificamente, nos estudos em natação, diminuindo a diferença entre a investigação experimental e a investigação computacional.