Francisco Zacaron Werneck

Morphological and maturational predictors of technical performance in young soccer players

The purpose of the present study is to describe the association between chronological age, morphology, biological maturation and sport experience in relation to technical performance in young Brazilian soccer players. Technical, maturation and anthropometric variables were assessed in 119 soccer players, 74 and 45 in the under-15 and under-17 categories, respectively. Data were analyzed using a multiple linear regression model. Adiposity was negatively associated with technical performance regardless the age-category. Weight was negatively associated with technical performance in under-15 and positively with the under-17 category, respectively. In under-17 biological maturation was negatively related to the dribbling test and positively associated with the ball control test. Years of experience proved to be positively associated with technique taught to soccer player in the under-17 category. The explained variance was different between categories. The technical performance of Bra- zilian soccer players aged 14-to-17 seems to be related to biological maturation, adiposity, weight and years of experience.

Pulmonary Oxygen Uptake Kinetics During Exercise in Subclinical Hypothyroidism

BACKGROUND Patients with subclinical hypothyroidism (SCH) have lower exercise tolerance, but the impact on oxygen uptake (VO2) kinetics is unknown. This study evaluated VO2 kinetics during and after a constant load submaximal exercise in SCH. METHODS The study included 19 women with SCH (thyrotropin (TSH)=6.87±2.88 μIU/mL, free thyroxine (fT4)=0.97±0.15 ng/dL) and 19 controls (TSH=2.29±0.86 μIU/mL, T4=0.99±0.11 ng/dL) aged between 20 and 55 years. Ergospirometry exercise testing was performed for six minutes with a constant load of 50 W, followed by six minutes of passive recovery. The VO2 kinetics was quantified by the mean response time (MRT), which is the exponential time constant and approximates the time needed to reach 63% of change in VO2 (ΔVO2). The O2 deficit-energy supplied by anaerobic metabolism at the onset of exercise-and O2 debit-extra energy demand during the recovery period-were calculated by the formula MRT×ΔVO2. Values are mean±standard deviation. RESULTS In the rest-exercise transition, patients with SCH showed slower VO2 kinetics (MRT=47±8 sec vs. 40±6 sec, p=0.004) and a higher oxygen deficit (580±102 mL vs. 477±95 mL, p=0.003) than controls respectively. In the exercise-recovery transition, patients with SCH also showed slower VO2 kinetics (MRT=54±6 sec vs. 44±6 sec, p=0.001) and a higher oxygen debit (679±105 mL vs. 572±104 mL, p=0.003). The VO2 kinetics showed a significant correlation with TSH (p<0.05). CONCLUSIONS This study demonstrates that women with SCH have the slowest VO2 kinetics in the onset and recovery of a constant-load submaximal exercise and highlights that this impairment is already manifest in the early stage of the disease.

Oxygen Uptake and Heart Rate Kinetics after Different Types of Resistance Exercise

Abstract Oxygen uptake (VO2) and heart rate (HR) kinetics after exercise are important indicators of fitness and cardiovascular health. However, these variables have been little investigated in resistance exercise (RE). The current study compared post-exercise kinetics of VO2 and the HR among different types of REs. The study included 14 males (age: 26.5±5.4 years, body mass: 80.1±11.4 kg, body height: 1.77±0.07 m, fat content: 11.3±4.6%) with RE experience. Dynamic muscle strength was measured using one repetition maximum (1RM) with regard to the half-squat, bench press, pull-down, and triceps pushdown exercises. The participants performed a maximum number of repetitions at 80% of 1RM for each exercise, separated by a recovery period of 60 minutes. VO2 was measured using ergospirometry. VO2 and HR kinetics were assessed using the time constant of the recovery curves, and excess oxygen consumption (EPOC) was calculated afterward. Significant differences were not observed across the exercises with regard to VO2 kinetics. However, the half-squat exercise elicited a greater EPOC than the bench press and triceps pushdown exercises (p<.05). HR kinetics was slower for the half-squat exercise than for the other exercises (p<.05). These findings confirm that the type of RE influences both the cardiac autonomic response post-exercise and EPOC, but not VO2 kinetics

INFLUÊNCIA DOS SALTOS VERTICAIS NA PERCEPÇÃO DA CARGA INTERNA DE TREINAMENTO NO VOLEIBOL

Introducao: No voleibol, o salto vertical e considerado um elemento de extrema importância no treinamento, pois e necessario durante as acoes de levantamento, saque, bloqueio e ataque, condicionando a obtencao de importantes vantagens nas acoes ofensivas (ataque) e defensivas (bloqueio), elementos fundamentais para a conquista dos pontos no jogo. Objetivo: Analisar a influencia do salto vertical na quantificacao da carga de treinamento no voleibol por meio do metodo da percepcao subjetiva do esforco (PSE) da sessao. Metodos: Participaram do estudo 15 atletas do sexo masculino de uma equipe de voleibol. Foi realizada a quantificacao dos saltos e da PSE de 30 sessoes de treinamento. Resultados: Na analise por posicao, a PSE apresentou correlacao positiva com o numero de saltos e se mostrou mais forte nos opostos (r = 0,44; p = 0,001; n = 57), seguida pelos ponteiros (r = 0,34; p < 0,001; n = 109) e centrais (r = 0,18; p = 0,03; n = 141). Conclusao: Conclui-se que o salto vertical de ataque exerce maior influencia no valor final de PSE apontado pelos atletas nas sessoes de treinamento.

Relationship Between Training Volume and Ratings of Perceived Exertion in Swimmers.

The markers of external training load (ETL), distance and intensity, do not take into account the athletes’ psychophysiological stress, i.e., internal training load (ITL). Thus, the aim of this study was to evaluate the relationship between ETL and ITL using the rating of perceived exertion (RPE) and session-RPE in swimmers. Seventeen young swimmers (10 male, 15.8 ± 0.87 yr and 7 female, 15.1 ± 0.46 yr) belonging to one national level youth team took part in this study over 4 wk. The external training load was planned using swimming distance (in meters) at seven different training intensities. Swimmers’ RPE was assessed 30 min after each training session. Session-RPE was calculated by multiplying RPE by session duration (min). The relationship between the variables was analyzed with Pearson correlations and a multiple linear regression was performed to predict the session-RPE as a function of the independent variables (aerobic and anaerobic volume). The swimming distance at different intensities correlated strongly with RPE and very largely with session-RPE (.64, p < .05 and .71, p < .05, respectively). Regression analysis indicated that the aerobic and anaerobic volumes together explained more than 50% of the ITL variability. In conclusion, the swimming distance in each training session was significantly associated with RPE and session-RPE in swimmers. In other words, based on these results, the use of high-volume training at lower intensities affects the RPE and Session-RPE more than the anaerobic volume.

Relative age effect on olympic triathlon athletes

INTRODUCAO: Nas competicoes esportivas disputadas por categorias de idade, acredita-se que jovens nascidos nos primeiros meses do ano tenham vantagens, por serem alguns meses mais maduros do que seus pares. Esta diferenca na idade relativa pode influenciar a selecao dos atletas pelos treinadores. Este fenomeno, comumente estudado em esportes coletivos, tem sido pouco investigado em esportes individuais.OBJETIVO: O presente estudo analisou o trimestre de nascimento dos atletas olimpicos de triatlo de ambos os sexos que participaram das Olimpiadas de Londres 2012.METODOS: Foi identificado o quartil (trimestre) de nascimento de 111 atletas (55 homens e 56 mulheres). Para a analise dos dados, empregou-se o teste qui-quadrado com nivel de significância de 5%.RESULTADOS: Nos homens, foi observada uma maior predominância de atletas nascidos no primeiro e segundo quartis (X2 = 11,545; gl= 3; p=0,01), enquanto que nas mulheres esta tendencia nao foi observada (X2=1,286; gl=3; p=0,73). Verificou-se ainda relacao significativa entre o semestre de nascimento e a conquista de medalhas.CONCLUSAO: O efeito da idade relativa foi observado nos triatletas das Olimpiadas de Londres 2012 do sexo masculino, sendo relacionado ao desempenho dos atletas. Isto sugere que a data de nascimento pode ter influenciado a selecao desses atletas nas etapas de formacao. Novos estudos ainda sao necessarios para confirmar o fenomeno da idade relativa no triatlo.ABSTRACT Introduction: In sports contested by age categories, it is believed that young people born in the first months of the year show advantages because they are a few months more mature than their peers. This difference in relative age may influence the selection of athletes by coaches. This phenomenon, commonly studied in team sports, has been little studied in individual sports. Objective: The present study examined the quarter of birth date of triathlon Olympic athletes of both genders, who participated in the London Olympics 2012. Methods: The quartile (quarter) of birth date of 111 athletes (55 men and 56 women) was identified. For data analysis, the chi-square test with a significance level of 5% was employed. Results: In men, there was a predominance of athletes born in the first and second quartiles (X 2 = 11,545; gl = 3; p=0,01), whereas in women this trend was not observed (X 2 = 1,286; gl = 3; p=0,73). There was also a significant relationship between the semester of birth and winning medals. Conclusion: We concluded that the relative age effect was observed in triathletes on the London Olympics 2012 and it is related to performance in men. This suggests that the birth date may have influenced the selection of these athletes in the formative years. Further studies are needed to confirm the relative age effect in triathlon.Keywords: athletes/classification, athletes/statistics & numerical data, age distribution.

Resistance properties of elastic tubing commonly used in rehabilitation and sports training and the effects of previous cyclic loading-unloading

Os tubos elasticos tem sido amplamente utilizados como resistencia externa variavel em protocolos de reabilitacao e treinamento desportivo. O objetivo deste estudo foi avaliar a resistencia e feito da fadiga (reducao da rigidez) apos estiramentos repetidos de tubos elasticos de latex (TEL) e tubos elasticos de borracha natural (TEBN). As amostras foram submetidas a testes de tracao axial em 0, 1000 e 3000 ciclos de carga – descarga. Cada respectivo valor de ciclagem consistiu de 6 amostras. Os ciclos de carga – descarga alcancaram uma deformacao maxima de 100% do comprimento inicial e taxa de deslocamento de 1800 mm/min; apos cada teste, as amostras foram carregadas monotonicamente (500 mm/min) ate 300% de deformacao e registrada a resposta de forca. Os resultados obtidos neste estudo sao similares aos valores de resistencia obtidos a 0 ciclos reportados pelo fabricante TEBN (84N vs. 80N), mas eles nao confirmacao a informacao de que os tubos “prata” mantem a capacidade de oferecer resistencia apos o ciclagem dos tubos elasticos para as deformacoes de 100% (p = 0.001), 200% (p = 0.021), e 250% (p = 0.002) do comprimento inicial. Os TEL e TEBN mostraram uma perda da capacidade em oferecer resistencia semelhante (9.5 – 15.5% vs. 9.9 – 15.2%, respectivamente).

The relative age effect in olympic swimmers

O objetivo foi investigar o efeito da idade relativa (EIR) em nadadores nos Jogos Olimpicos de 2012, analisando as diferencas entre os continentes, sexos e a relacao com a conquista ou nao de medalhas. Novecentos e setenta e oito atletas (507 homens e 471 mulheres) foram estratificados a partir do seu quartil de nascimento. Na distribuicao dos quartis, foi observado um maior percentual de atletas nascidos no 1o e 3o quartil. Ja na distribuicao por sexo, o EIR foi verificado para feminino (χ2 = 12.304; gl = 3; p = .01), mas nao para o masculino (χ2 = 1.426; gl = 3; p = .70). Quanto a analise do efeito da idade relativa pelo desempenho e por continente, nao houve relacao significativa entre o quartil de nascimento e a conquista de medalha e o continente asiatico foi o unico em que foi verificado o efeito da idade relativa, respectivamente. Concluiu-se que o efeito da idade relativa esta presente em nadadores de Londres 2012. Alem disso foi representativo em relacao as mulheres, nao esta relacionado a conquista de medalhas olimpicas e esta presente apenas no continente asiatico.

ADAPTAÇÃO TRANSCULTURAL DO QUESTIONÁRIO THREE DAY PHYSICAL ACTIVITY RECALL

Introduction: There are several tools that measure physical activity in Brazil. One of them is the Three Day Physical Activity Recall; however, until now, no tool was subjected to cross-cultural adaptation. Objective: To describe the procedures and criteria for selecting the Three Day Physical Activity Recall on the conceptual, semantic and items equivalence, which resulted in the Brazilian version for adolescents from 10 to 12 years. Methods: Articles have been compiled containing the self-report instrument that had as variables of interest the level of physical activity and energy cost. A survey was conducted in the following databases: BIREME, LILACS, MEDLINE, PubMed, SciELO, Web of Science, and SPORTDiscus. The steps of cultural adaptation came next: 10 doctors and 30 members of the target population participated of the evaluation and adjustment of the construct to the Brazilian culture (conceptual and item equivalence) and the Portuguese version of the instrument followed all recommendations for semantic equivalence. Results: Here we present the evaluations of doctors on the Portuguese version of the instrument, involving questions about regionality of activities, cognitive impairment to self-report, instructions, ability to measure physical activity and their domains. The different versions of the translation and retranslation of the tool, highlighting on the changes requested as well as the final version are presented. Conclusions: Since the prerequisites of cultural adaptation have been met, it was concluded that the tool is adapted for the target population and culture; nevertheless, the psychometric qualities, reproducibility and validity, construct and criterion must be tested.

Heart rate kinetics during exercise in patients with subclinical hypothyroidism

Studies suggest that patients with subclinical hypothyroidism (SH) have sympathovagal imbalance, which could lead to a slower heart rate (HR) response in the transition from rest to exercise. Thus the objective of this study was to investigate the behavior of the HR kinetics in patients with SH during the transition from rest to exercise. The study included 18 SH women [thyroid stimulating hormone (TSH) = 6.95 ± 2.94 μIU/ml and free thyroxine (FT4) = 0.96 ± 0.15 ng/dl] and 17 euthyroid women (TSH = 2.28 ± 0.84 μIU/ml and FT4 = 0.98 ± 0.07 ng/dl). Both groups were matched for physical activity, menopausal status, and age. The HR kinetics was obtained during the course of a constant-load exercise (50 W), for 6 min, in a cycle ergometer, and quantified from the mean response time (MRT), which is equivalent to the time taken to reach 63% of the HR at steady state. SH patients showed slower HR kinetics than the control group (MRT = 48.5 ± 17.6 vs. 36.0 ± 10.3 s, P = 0.015). The MRT has been shown to correlate with the level of physical activity (r = -0.361; P = 0.033) and with the subjective perception of exertion at the end of the exercise (r = 0.365; P = 0.031). It is concluded that SH patients have slower HR kinetics in the transition from rest to exercise compared with euthyroid women, with this impairment being associated with lower levels of physical activity.NEW & NOTEWORTHY Subclinical hypothyroidism patients have slower heart rate kinetics in the transition from rest to exercise when performing a constant-load exercise at 50 W.