Evaluation of strength training effects on neuromuscular system in soccer players in pre-competitive period

The evaluation of training programs in soccer modality in various moments of periodization is important in the sports preparation control process. So in this way, this study aimed to investigate neuromuscular adaptations during strength training in professional soccer game in pre-competitive period. 15 professional soccer players, aged between 18 and 28 years participated of this study. Initially they were submitted to explosive strength test (Squat Jump), speed resistance (RAST) and displacement velocity (10 and 30m). Two evaluations were performed: one in the beginning of the study (M1), and the other (M2) after 12 weeks. In the first 6 weeks speed strength training, in the first 2 with 60% of Maximum Load (ML) and the other 4 weeks with 75% of ML was conducted. In the 6ª to 12ª weeks, the development turned to maximum strength (85% of ML). After collecting the data were kept in computational bank and then produced information in the descriptive way, by means of centrality and dispersion, and in the inferential, Student t test for paired data (p\u3c0.005). The main results point to improvement in all capacities with emphasis on explosive strength 41.49±0.04cm in M1 to 44.05±3.19 cm in M2, as well as the velocity of 10 meters, 5.22±0.33 m/s in M1 to 5.54±0.33 m/s in M2. There were positive neuromuscular adaptations after the proposed training, indicating that during the studied period, strength work improved athletic performance capacities

Characterization and reproducibility of canoe slalom simulated races: physiological, technical and performance analysis

The aims of this study were to characterise and test the reproducibility of canoe slalom race simulations performed on two different days, analysing the physiological, technical and performance responses characteristic of the sport. Six high-performance male canoe slalom K1 athletes (age 17±2yrs) underwent two race simulations with an interval of 72 hours. The artificial course consisted of twelve gates. Each simulation was analysed the runtime, distance travelled, mean velocity; images were captured by the digital camera (JVC) and determined quantitative variables. Heart monitors (Polar, RS800x model) were used to record heart rate during race simulations and recovery; data were stored every 5 s, to determine the blood lactate concentration ([Lac]), blood samples were collected from the earlobe at rest and after 1, 3, 5, 7 and 9 min of race simulation (recovery). Tests of normality (Shapiro Wilk) and variance (Levene) were applied. The variables were compared using paired t-tests. Intraclass coefficient correlation (ICC) and Pearson product moment were used for relationship. In all cases, the level of significance was pre-fixed at 5%. Differences between the first and second simulations could not be noticed. Another important indicator was the high correlation found between the runtime (ICC=0.71), distance travelled (ICC=0.77), mean velocity (ICC=0.80) and total number of paddles (ICC=0.79). The lactate levels on minutes 3, 5, 7 and 9 also pointed towards strong correlations (ICC=0.88, ICC=0.90, ICC=0.95 and ICC=0.90 respectively), which may indicate that the adopted simulation model seems to be practicable and of great value to canoe slalom evaluations.We would like to thank FAPESP and CNPq for providing financial support

Adaptation of invasive and non-invasive protocols to aerobic and anaerobic specific evaluation in female basketball players

OBJECTIVE: To adapted the critical velocity (CV), RAST test and lactate minimum (LM) to evaluation of female basketball players. METHODS: Twelve well-trained female basketball players (19 ± 1yrs) were submitted to four intensities running (10 - 14 km/h) at shuttle exercise until exhaustion, applied on alternate days. The linear model 'velocity vs. 1/tlim' was adopted to determine the aerobic (CV) and anaerobic (CCA) parameters. The lactate minimum test consisted of two phases: 1) hiperlactatemia induction using the RAST test and 2) incremental test composed by five shuttle run (20-m) at 7, 8, 9, 10, and 12 km/h. Blood samples were collected at the end of each stage. RESULTS: The velocity (vLM) and blood lactate concentration at LM were obtained by two polynomial adjustments: lactate vs. intensity (LM1) and lactate vs. time (LM2). ANOVA one-way, Student t-test and Pearson correlation were used for statistical analysis. The CV was obtained at 10.3 ± 0.2 km/h and the CCA estimated at 73.0 ± 3.4 m. The RAST was capable to induce the hiperlactatemia and to determine the Pmax (3.6 ± 0.2 W/kg), Pmed (2.8 ± 0.1 W/kg), Pmin (2.3 ± 0.1 W/kg) and FI (30 ± 3%). The vLM1 and vLM2 were obtained, respectively, at 9.47 ±0.13 km/h and 9.8 ± 0.13 km/h, and CV was higher than vLM1. CONCLUSION: The results suggest that the non-invasive model can be used to determine the aerobic and anaerobic parameters. Furthermore, the LM test adapted to basketball using RAST and progressive phase was effective to evaluate female athletes considering the specificity of modality, with high success rates observed in polynomial adjustment 'lactate vs. time' (LM2).OBJETIVO: Adaptar os protocolos de velocidade crítica (Vcrit), RAST Test e Lactato Mínimo (LM) à especificidade do basquetebol feminino. MÉTODOS: Doze basquetebolistas bem treinadas (19 ± 1 anos) foram avaliadas pelo modelo velocidade crítica, composto por quatro intensidades (10,8, 12,0, 13,0, 14,5 km/h) de corridas vai-vem até exaustão, aplicadas em dias alternados. O modelo linear 'velocidade versus 1/tlim' foi adotado para determinação de parâmetros aeróbio (Vcrit) e anaeróbio (CCA). O LM foi composto por duas fases: 1) indução hiperlactacidêmica, caracterizada pelo RAST adaptado, e 2) fase progressiva, composta por cinco estágios de 3 minutos em corridas vai-vem de 20 m (7 a 12km/h), com coletas de sangue ao final de cada estágio. RESULTADOS: A velocidade (vLM) e a concentração do lactato mínimo foram obtidas pelos ajustes polinomiais 'lactato versus intensidade' (LM1) e 'lactato versus tempo' (LM2). A ANOVA one-way, teste t-Student e correlação de Pearson foram utilizados na análise estatística. A Vcrit foi obtida a 10,3 ± 0,2 km/h e a CCA estimada em 73,0 ± 3,4 m. O RAST foi capaz de induzir a hiperlactacidemia e determinar potências máxima (3,6 ± 0,2 W/kg), média (2,8 ± 0,1 W/kg), mínima (2,3 ± 0,1W/kg) e o índice de fadiga (30 ± 3%). A vLM1 e vLM2 foram obtidas, respectivamente, a 9,47 ± 0,13 e 9,8 ± 0,13km/h, sendo a vLM1 menor que a Vcrit. CONCLUSÕES: Os resultados sugerem que o modelo específico não invasivo pode ser utilizado para determinar parâmetros aeróbios e anaeróbios de basquetebolistas e, assim como em outras modalidades, a Vcrit superestima as intensidades de LM. Além disso, a adaptação do LM ao basquetebol feminino utilizando o RAST e a fase progressiva em exercício vai-vem foi efetiva para avaliar as atletas respeitando a especificidade da modalidade, com elevado percentual de sucesso no ajuste polinomial 'lactato versus tempo'.17117

Changes in torque production and aerobic / anaerobic parameters during a futsal season

Orientador: Sergio Augusto CunhaTese (doutorado) - Universidade Estadual de Campinas, Faculdade de Educação FísicaResumo: O futsal é uma modalidade esportiva que apresenta alternância entre momentos de alta e baixa intensidade, além de apresentar diferentes ações como acelerações, desacelerações e mudanças de direções. O objetivo geral do presente estudo foi investigar as alterações na produção de torque, parâmetros fisiológicos, quantificação e intensidade do treino de atletas de futsal durante uma temporada de treinamento monitorado. Participaram do presente estudo oito atletas de uma equipe profissional de futsal masculino que disputa a primeira divisão do campeonato paulista. Ao longo de dezoitosemanas de treinamento, os atletas foram submetidos a três períodos de avaliações, iniciais (A1), após 6 semanas (A2) e após 18 semanas (A3). Foram realizadas 131 sessões de treinamento, e ao final de cada sessão foi apresentada a escala de percepção subjetiva de esforço (PSE) sendo possível, a partir da PSE, avaliar a intensidade de treinamento. Quantificou-se também o volume de treinamento (minutos) realizado em cada uma das sessões e o conteúdo de treinamento trabalhado. Em cada um dos períodos de avaliações foram realizadas coletas referentes ao lactato mínimo e à avaliação isocinética. O protocolo de lactato mínimo foi composto por duas fases, sendo a primeira chamada indução à hiperlactacidemia, na qual o RAST test foi executado, e a segunda chamada fase progressiva. Na fase progressiva os atletas executaram corridas "vai-e-vem" 20m, em intensidades progressivas (entre 8,5 e 14,5 Km/h) distribuídas em estágios, com duração de três minutos cada. A avaliação isocinética consistiu em 1 série de 5 repetições máximas de extensão/flexão do joelho unilateral de forma concêntrica, tanto com o membro dominante como não dominante, na velocidade angular de 60°¿s-1 através de um dinamômetro isocinético (Biodex System Pro4). Os parâmetros analisados:1.velocidade do lactato mínimo, 2.concentração do lactato na velocidade do lactato mínimo,3. tempo pós atingir a velocidade do lactato mínimo e 4.pico de torque, foram comparados nos diferentes períodos de avaliação através da ANOVA one-way de medidas repetidas e teste post hoc de Tukey. O nível de significância adotado foi p<0,05. Com relação a intensidade analisada pela PSE os escores permaneceram entre 3 e 5 durante as semanas avaliadas. O volume de treinamento, com exceção da primeira semana que apresentou valores próximos a 110 minutos, apontou valores oscilando de 50 a 75 minutos. O conteúdo de treinamento trabalhado constituiu-se de 67% do tempo caracterizado por atividades que envolveram componentes do futsal. A velocidade do lactato mínimo, a concentração do lactato na velocidade do lactato mínimo e o pico de torque de extensores e flexores não apresentaram diferenças estatísticas entre as avaliações. Já na concentração do lactato na velocidade do lactato mínimo, foi possível observar uma melhora estatística da A1 em relação a A2 e A3. Os processos de avaliações foram eficazes na quantificação dos parâmetros aeróbios e anaeróbios bem como na determinação da produção de torque. Porém, os baixos escores apresentados pela PSE e a manipulação dos métodos de treino não foram efetivos para que uma melhora significativa das capacidades avaliadas fossem encontradasAbstract: Futsal is a modality that has alternation between moments of high and low intensity, additionally presents different actions such as accelerations, decelerations and changes of directions. The aim of this study was to investigate the changes in torque production, physiological parameters, quantification and training intensity of futsal athletes during a monitored training season. Eight professional futsal athletes from the first league of Paulista¿s Championship team participated of this study. Throughout eighteen weeks of training, the athletes were evaluated in the initial week (A1), after 6 weeks (A2) and after 18 weeks (A3).131 training sessions were performed, at the end of each session the rating of perceived exertion (RPE) was presented, being possible to evaluate the intensity of training. It was also quantified the training volume (minutes) performed in each session and what kind of training content was carried. For each evaluation period the following measures were performed: (a) lactate minimum protocol composed of two phases: the first called inducing the hyperlactacidemia, in which the RAST test was performed, followed by the progressive phase after 8 minutes of passive recovery. In the progressive phase, athletes performed runs "back-and-forth" 20m in progressive intensities (between 8.5 and 14.5 km / h) distributed in stages, lasting three minutes each. (b) Isokinetic evaluation consisted of 1 serie of 5 maximum repetitions of extension/flexion of the unilateral knee in concentric mode, with both the dominant and non-dominant member at an angular velocity of 60°¿s-1 using an isokinetic dynamometer (Biodex System Pro4). The analyzed parameters as lactate minimum speed, lactate concentration at lactate minimum speed, time after reaches the lactate minimum speed and peak torque were compared in different evaluation periods by one-way ANOVA repeated measures and Tukey's post hoc. The level of significance adopted was ?<0.05.Regarding to intensity analyzed by RPE the scores remained between 3 and 5 during the evaluated weeks. The volume, except the first week that presents values close to 110 minutes, showed values ranging from 50 to 75 minutes. The training content carried presented in 67% of time as feature activities involving futsal components. The lactate minimum speed, lactate concentration in lactate minimum speed and peak torque of extensors and flexors showed no statistical differences between evaluations. While the lactate concentration in lactate minimum speed was possible to observe an improvement when compared A1 in relation to A2. The evaluations processes were effective in quantifying the aerobic and anaerobic parameters as well as the determination of torque production. However, the lower scores presented by RPE and manipulation of the training methods were not effective for a significant improvement of the capacities analyzedDoutoradoBiodinamica do Movimento e EsporteDoutora em Educação Física01-P-02195/2012CAPE

Modelo competitivo da distância percorrida por futebolistas na Uefa Euro 2008

O objetivo do presente estudo centra-se em conhecer o modelo competitivo da distância percorrida por futebolistas na Uefa Euro 2008, mediante as posições de jogo, os tempos e a distância total percorrida durante as partidas. Foram analisadas todas as partidas das 16 seleções, totalizando 31 jogos, dos quais participaram 460 futebolistas. Posteriormente, produziram-se informações descritivas e inferenciais. Os principais resultados apontam que: i) futebolistas da elite europeia percorreram 10232 ± 852m; ii) meio-campistas (10894 ± 648m) percorreram maior distância, seguidos pelos laterais (10274±694m), atacantes (10108 ± 624m), zagueiros (9498 ± 592m) e goleiros (4198 ± 610m); iii) a distância média percorrida no 1º tempo (4907 ± 201m) das partidas foi maior do que a do 2º tempo (4890 ± 238m)

Desequilibrio del torque isocinético de la rodilla en jugadoras de futsal femenino

Introduction: The specificity of sports training can lead to muscle specialization with a possible change in the natural hamstring/quadriceps torque ratio (HQ ratio), constituting a risk factor for muscle injury at the joint angles in which muscle imbalance may impair dynamic stability. Objective: The aim was to evaluate the torque distribution of the hamstrings and quadriceps and the HQ ratio throughout the range of motion in order to identify possible muscle imbalances at the knee of female futsal athletes. Methods: Nineteen amateur female futsal athletes had their dominant limb HQ ratio evaluated in a series of five maximum repetitions of flexion/extension of the knee at 180°/second in the total joint range of motion (30° to 80°). The peak flexor and extensor torque and the HQ ratio (%) were compared each 5° of knee motion using one-way repeated measures ANOVA and Tukey’s post hoc test (p<0.05) to determine the joint angles that present muscular imbalance. Results: Quadriceps torque was higher than 50° to 60° of knee flexion, while hamstrings torque was higher than 55° to 65°. The HQ ratio presented lower values than 30° to 45° of knee flexion and four athletes presented values lower than 60%, which may represent a risk of injury. However, the HQ ratio calculated by the peak torque showed only one athlete with less than 60%. Conclusion: The HQ ratio analyzed throughout the knee range of motion allowed identifying muscle imbalance at specific joint angles in female futsal players.Introdução: A especificidade do treinamento esportivo pode levar à especialização muscular, com possível alteração da razão do torque isquiotibiais/quadríceps (razão IQ) natural, constituindo um fator de risco de lesão muscular nos ângulos articulares em que o desequilíbrio muscular pode prejudicar a estabilidade dinâmica. Objetivo: O objetivo foi avaliar a distribuição do torque dos músculos isquiotibiais e quadríceps e da razão IQ ao longo de toda a amplitude de movimento, de modo a identificar possíveis desequilíbrios musculares no joelho de atletas de futsal feminino. Métodos: Dezenove atletas amadoras de futsal feminino tiveram a razão IQ do membro dominante avaliada em uma série de cinco repetições máximas de flexão/extensão do joelho a 180°/ segundo na amplitude de movimento total (30° a 80°). O pico de torque flexor e extensor e a razão IQ (%) foram comparados a cada 5° de movimento do joelho pela one-way ANOVA de medidas repetidas e do teste post hoc de Tukey (p < 0,05) para determinar os ângulos articulares que apresentam desequilíbrio muscular. Resultados: O torque do quadríceps foi maior que 50° a 60° de flexão do joelho, enquanto o torque dos isquiotibiais foi maior que 55° a 65°. A razão IQ apresentou menores valores que 30° a 45° de flexão do joelho e quatro atletas apresentaram valores abaixo de 60%, o que pode representar risco de lesão. No entanto, a razão IQ calculada pelo pico de torque mostrou apenas uma atleta com menos de 60%. Conclusão: A razão IQ analisada ao longo de toda a amplitude de movimento permitiu identificar desequilíbrio muscular em ângulos articulares específicos em atletas de futsal feminino.Introducción: La especificidad del entrenamiento deportivo puede llevar a la especialización muscular, con posible cambio de la razón de torque entre isquiotibiales/cuádriceps (razón IC) natural, constituyendo un factor de riesgo de lesión muscular en los ángulos de las articulaciones, en el que el desequilibrio muscular puede perjudicar la estabilidad dinámica. Objetivo; El objetivo fue evaluar la distribución del torque de los músculos isquiotibiales y cuádriceps y la razón IC a lo largo de todo el rango de movimiento para identificar posibles desequilibrios musculares en la rodilla en atletas de futsal femenino. Métodos: Diecinueve atletas amateurs de futsal femenino tuvieron la razón IC de la extremidad dominante evaluada en una serie de cinco repeticiones máximas de flexión/extensión de la rodilla a 180°/segundo en el rango de movimiento total (30° a 80°). El pico de torque flexor y extensor y la razón IC (%) fueron comparados a cada 5° de movimiento de la rodilla por el ANOVA one-way de medidas repetidas y de la prueba post hoc de Tukey (p < 0,05) para determinar los ángulos articulares que presentan desequilibrio muscular. Resultados: El torque del cuádriceps fue mayor que 50° a 60° de flexión de la rodilla, mientras que el torque de los isquiotibiales fue mayor que 55° a 65°. La razón IC presentó los valores más bajos que 30° a 45° de flexión de la rodilla y cuatro atletas presentaron valores inferiores al 60%, lo que puede representar riesgo de lesión. Sin embargo, la razón IC calculada por el pico de torque máximo, mostró sólo una atleta con menos del 60%. Conclusión. La razón IC analizada a lo largo de todo el rango de movimiento permitió identificar desequilibrio muscular en ángulos articulares específicos en atletas de futsal femenino

Analysis of soccer players’ positional variability during the 2012 uefa european championship : a case study

The purpose of this study was to analyse players’ positional variability during the 2012 UEFA European Championship by applying principal component analysis (PCA) to data gathered from heat maps posted on the UEFA website. We analysed the teams that reached the finals and semi-finals of the competition. The players’ 2D coordinates from each match were obtained by applying an image-processing algorithm to the heat maps. With all the players’ 2D coordinates for each match, we applied PCA to identify the directions of greatest variability. Then, two orthogonal segments were centred on each player’s mean position for all matches. The segments’ directions were driven by the eigenvectors of the PCA, and the length of each segment was defined as one standard deviation around the mean. Finally, an ellipse was circumscribed around both segments. To represent player variability, segment lengths and elliptical areas were analysed. The results demonstrate that Portugal exhibited the lowest variability, followed by Germany, Spain and Italy. Additionally, a graphical representation of every player’s ellipse provided insight into the teams’ organisational features throughout the competition. The presented study provides important information regarding soccer teams’ tactical strategy in high-level championships that allows coaches to better control team organisation on the pitch47