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- Exploratory study on maturation and competition level in young karate practitionersPublication . Branco, Marco A. C.; Brito, Antonio Vences; Seabra, Ana Paula; Mercê, Cristiana; Rodrigues Ferreira, Mário André; Milheiro, Vitor; Catela, DavidEmparelhar crianças propicia sucesso e reduz lesões no desporto. Apesar das diferenças de maturação entre crianças, a idade cronológica mantém-se o principal critério para equalizar os níveis de competição, mas com uma eficiência limitada. No entanto, no karaté, o peso também é considerado. Fomos verificar se existe associação entre a idade cronológica e os indicadores maturacionais e, encontrar modelos simples que permitam colocar em reflexão novas formas de avaliação da maturação. Foram recolhidos dados em 54 jovens praticantes de karaté (idade: 12,67 ± 2,49 anos; experiência: 4,99 ± 2,44 anos; altura: 150,45 ± 15,25cm; peso: 43,09 ± 14,17 kg, 20 raparigas). A idade correlacionou-se significativamente com auto-observação da maturação sexual (rho = 0,838; p < 0,01), e foi possível encontrar modelos de regressão simples que têm uma explicação moderada na maturação, apenas utilizando variáveis de medição simples, tal como a altura, o peso e o perímetro do braço. Estes resultados devem levar as entidades competentes a refletir acerca do modo de emparelhamento dos atletas nas competições de uma forma justa em termos de maturação.
- Desempenho anaeróbio em jovens praticantes federados de futebolPublication . Rodrigues Ferreira, Mário André; Noite, João; Fernandes, R.; Fernando, Catarina; Brito, António VencesUm bom desempenho anaeróbio é essencial para o sucesso desportivo no futebol. O objetivo do estudo foi verificar as diferenças entre o desempenho anaeróbio de jovens praticantes federados de futebol (n=10) e de jovens não praticantes federados em nenhuma modalidade desportiva (n=9). Os participantes realizam o teste anaeróbio Wingate, com uma resistência de 75g/kg (7,5% do peso corporal), tendo sido utilizado o cicloergómetro Monark 894E. As variáveis estudadas foram a potência anaeróbia máxima, a potência anaeróbia média e a perda de potência anaeróbia, sendo apresentada em termos absolutos (W) e em termos relativos (W/kg). Para comparação dos grupos em análise utilizámos a técnica estatística t de Student (bicaudal), com o programa SPSS (Statistical Package for Social Sciences) versão 17.0, adotando um nível de significância de p <0,05. Os resultados obtidos revelaram diferenças estatisticamente significativas na potência anaeróbia máxima relativa (9,83 vs. 8,59 W/kg; p =,011) e na potência anaeróbia média relativa (6,99 vs. 5,92 W/kg; p =,021), onde os jovens praticantes federados de futebol obtiveram um desempenho superior. Concluímos que os jovens praticantes federados de futebol apresentam uma maior capacidade para produzir potência anaeróbia máxima e para manter essa potência ao longo dos 30 segundos, provavelmente devido à prática desportiva.- A great anaerobic performance is essential for the sporting success in football. The aim of the study was to analyze the differences in anaerobic performance between young soccer players (n=10) and young non-practicing any sport (n=9). Participants performed the Wingate anaerobic test, with a resistance of 75g/kg (7.5% of body weight), and the ergometer used was the Monark 894E. The variables studied were the peak anaerobic power, average anaerobic power and anaerobic power drop, and it is presented in absolute terms (W) and relative to body weight (W/kg). To compare the groups, the Student’s t test (two-tailed) was used with the SPSS (Statistical Package for Social Sciences) version 17.0, adopting a significance level of p <0.05. The results showed statistically significant differences in relative peak anaerobic power (9.83 vs. 8.59 W/kg, p =.011) and relative mean anaerobic power (6.99 vs. 5.92 W/kg, p =.021), where young football players presented superior performance. We conclude that the young football players have a higher capacity to produce maximum anaerobic power and to maintain that power over the 30 seconds, probably due to sport practice.
- The influence of sport practices on body composition, maturation and maximum oxygen uptake in children and youthPublication . Mercê, Cristiana; Branco, Marco A. C.; Rodrigues Ferreira, Mário André; VencesBrito, Antonio; Catela, David; Seabra, Ana Paula; Milheiro, Vítor; Cynarski, WojciechSystematic sport practice at younger ages positively influences body composition and maximum oxygen uptake (VO2max). On the other hand, its influence on maturation is still not consensual, and some studies claim a negative effect. Few studies have approached the differences in this influence according to different sport practices. The present study aims to analyse and compare the influence of karate and swimming practices, and the non-practice of sports, on body composition, VO2max and maturation in children and youth. Data were collected in 126 youth, 54 karate athletes, 36 swimming athletes and 36 participants with no sport practice (M=11.56±2.06 years). The type of sport practice had a different influence on body composition and VO2max, no negative influence was verified on maturation. In general, the sport practices revealed a positive influence in children and youth’s body composition. The karate practice provided significant lower body fat mass and higher lean mass in males. Swimming athletes revealed a significant higher VO2max compared to all other groups, while karate didn´t differed from no-practice group. The different influence of sport practices verified highlighted the importance of a multilateral development of children and youth by practising several sports.
- Metabolic and energetics characterization and gender comparison in prepubertal karate practitionersPublication . VencesBrito, António M.; Rodrigues Ferreira, Mário André; Milheiro, Vitor; Branco, Marco A. C.; Mercê, Cristiana; Seabra, Ana Paula; Catela, DavidThe number of children practicing karate is constantly increasing. It is necessary to provide correct information to the karate masters/coaches about this specific population, so they can properly develop karate training processes without causing any harm to practitioners but, on the contrary, contribute to the harmonious development of children and youths. This study was carried out with twenty-one prepubertal karate practitioners, male and female. They were analyzed on their maturational development, metabolic and energetic behavior in an incremental test until exhaustion. Only the energetic variables presented significant differences between gender, so it seems that the karate practice has a similar metabolic impact in the development of the prepubertal karate practitioners of both genders
- Effect of Aging on the Lower Limb Kinematics in Karate Practitioners: Comparing Athletes and Their SenseisPublication . Branco, Marco A. C.; Brito, António Vences; Rodrigues-Ferreira, Mário André; Branco, Gonçalo A. C.; Polak, Ewa; Cynarski, Wojciech J.; Jacek, WąsikWith the life expectancy increasing, older adult population has gained the attention of many researchers. Aging is known to lead to a general decline in bodily functions, which affect the quality of life. The aim of this study was to analyze how the aging process affects veteran active karate practitioners, in the kinematic and temporal structure of the frontal kick. Nine black belt karate practitioners over 50 years old and 24 black belt karate practitioners, aged between 20 and 30 years old, all male, performed the frontal kick mae-geri. Results showed that knee is the structure that holds most differences between young and veterans, both for linear and for angular variables during the mae-geri performance. Statistical differences were found in linear velocity for the knee; linear acceleration of the knee, hip, and RASIS; maximum angular velocity for knee and hip; maximum angular acceleration for ankle and hip; and in the range of motion of knee. The temporal variables show differences, between groups, in maximum linear velocity, maximum linear acceleration, and maximum angular acceleration. However, no differences were found between groups for the time before contact in the maximum linear and angular acceleration, which allow us to remark both the effects of the aging process and the effect of training. This study corroborates the ability of older people to achieve benefits from sports practice, achieving higher efficiency than the younger adults in task execution, but using different motor control strategies.
- The effects of aging on electromechanical delay: a comparison between karate athletes and non-athletesPublication . Brito, António Vences; Rodrigues Ferreira, Mário André; Branco, Marco A. C.Normal aging in humans is associated with a progressive decline in biological functions that affect motor performance. This study intended to analyze the effects of aging on electromechanical delay during the mae-geri kick performance. Forty-six males were divided into three groups according to age and sports practice: 9 veteran karate practitioners aged between 50 and 63 years (VetK), 21 young karate practitioners (YgK) and 16 non-karate practitioners aged between 18 and 35 years old. Electromechanical delay was defined as the time interval between the onset of the electric activity of a muscle and the beginning of joint movement. The statistical analysis was performed with One-Way Analysis of Variance and Turkey HSD Post-Hoc (SPSS, version 17.0). Rectus femoris EMD was found to be signifi cantly longer in VetK, suggesting that aging has a negative impact on the neuromuscular activity and contractile capacity of this muscle.
- Athletes and their Sensei’s: did aging affect the lower limb kinematics in karate practitionersPublication . Branco, Marco A. C.; Brito, António Vences; Rodrigues-Ferreira, Mário André; Branco, Gonçalo A. C.Aging leads to a general decline in body functions that affects quality of life. Muscle function begins to slow the contraction from the 40 to 50 years and decreases muscle strength 1 to 1.5% per year after 60 years (Booth, Weeden, & Tseng, 1994; Vandervoort, 2002; Vandervoort & Mccomas, 1986). Older adults do less work for lower fast angular velocities (Power, et al., 2014), and less power for slow, moderate and fast angular velocities (Dalton, Power, Vandervoort, & Rice, 2012), than young adults. These losses increase as age increases. One factor that exacerbates these functional losses is the sedentary lifestyle, however, the physical exercise appears as an inversion factor, which cannot only reverse this decline but also promote an increase in functional capacity at the neuromuscular level. The athletic performance is seen as diminished in older adults, but in the case of martial arts, the karate Sensei’s are the technical execution model. This leads us to question if in karate young adults have better performance than older adults? Which in many cases are their Senseis’s. The aim of this study was to analyze the effects of the aging process in the kinematic and temporal structure of the frontal kick on veteran active karate practitioners.
- Exploratory study on maturation and competition level in young karate practitionersPublication . Branco, Marco A. C.; VencesBrito, António M.; Seabra, Ana Paula; Mercê, Cristiana; Rodrigues Ferreira, Mário André; Milheiro, Vítor; Catela, DavidParing children improve the chance for success and reduce injury in sport. Despite the maturity differences between children, chronological age remains the main criterion to equalize competition levels, but with limited efficiency. However, in Karate, weight is also considered. We went to investigate the association between chronological age and maturational indicators and find simple models to put on reflection new ways to assess the maturity. Data were collected in 54 young Karate practitioners (age: 12.67 ± 2.49 years, experience: 4.99 ± 2.44 years, height: 150.45 ± 15.25 cm, weight: 43.09 ± 14, 17 kg, 20 girls). Age correlated significantly with self-observation of sexual maturation (rho = 0.838; p < 0.01), and it was possible to find simple regression models that have a moderate explanation in maturation, using only simple measurable variables such as the height, weight and arm circumference. These results should lead the competent entities to reflect on the way of pairing of the athletes in the competitions, in a fair way in terms of maturation.