Efeito do aquecimento com corrida sobre a agilidade e a impulsão vertical em jogadores juvenis de futebol

The aim of this study was to evaluate the effect of warm-up on agility (AG) and on vertical jump (VJ) tests in youth soccer players. Sixteen players performed the AG and VJ tests without warm-up (NW) and with warm-up (WW) randomly, within two weeks, at least 48 h interval, during season. The warm-up was performed only a light running during 10 min. The paired t-test identified significant difference (p <0,05) between the NW and WW conditions in the tests of SR and CJ (9,14 +/- 0,28 vs 8,94 +/- 0,30 s e 51,4 +/- 4,2 vs 54,5 +/- 6,4 cm, respectively). The warm-up performed on light intensity running was effective to improve the AG and VJ tests performance in youth soccer players.

Desempenho tático de jogadores de futebol: comparação entre equipes vencedoras e perdedoras em jogo reduzido

The aim of study was to verify what tactical behaviors differ winner from loser teams in small sized games in youth soccer players. The tactical performance of winners and losers teams was compared through of System of Tactical Assessment in Soccer (FUT-SAT). Three thousand eight hundred and eight tactical actions were carried out by seventy-two youth soccer players from the under-11 (n=12), under-13 (n=12), under-15 (n=30) and under-17 (n=18) categories of Portuguese teams. Twenty four teams were composed to analyze, each team carried out one match (12 match analyzed). Each team was composed by three line players with goalkeeper which was not analyzed in test. The statistical analysis was performed thought the SPSS 17.0 software for Windows. A descriptive analyze and the KolmogorovSmirnov, Chi-square, Mann-Whitney U and T-Test tests to the independent samples was carried out, and the Cohen’s Kappa test to determining of the sample reability. Considering 76 variables analyzed, 12 presented significant differences among players of winners and loses teams. The players of the winner teams presented superiority in Macro-Category Action, in the Defensive tactical principles, Equilibrium and Defensive Unity. In the category Local of action in the Field, the winner teams presented superiority in the number of defensive actions performed in the defensive midfielder. In the category Result of the action, the variables Keep without the ball, Retrieving the ball possession and Shots on goal the winner teams presented higher results, while in variables Losing the ball possession and Suffering shot on goal the loser teams presented higher results. In the Performance Macro-Category, the superiority of the winners was showed by better Tactical Performance Index (TPI) in the Penetration principles, Offensive Unity, and in the Offensive phase of the game. The results demonstrated that the winner players presented superiority in both stages of the game.

Muscle lesion treatment in Brazilian soccer players: Theory vs. Practice

Background: In this study we evaluated the rehabilitation profile of Brazilian soccer players which underwent lower limb muscle lesions.Methods: This is a descriptive investigation. We evaluated 139 professional soccer players (1724 years old). We evaluated the following variables: muscle lesion diagnosis, symptoms, non steroidal anti-inflammatory used, physiotherapy treatment, which physiotherapy recourses was used if treated and train adaptation.Results: In great part of the athletes muscle lesion remained between 2 weeks and 1 month. Around 54% were diagnosed by a physician; the other part was diagnosed by a physical therapist. Non steroidal anti-inflammatory were prescribed by physicians in 42% of the cases; in 7% the physical therapist prescribed the medication while in 49% of the cases the masseur prescribed the drug. More than 1/4 of the athletes received physiotherapy treatement between 48 hours and 5 days. Isometric exercise therapy was applied in 15% of the cases. 63% were not accompanied by the physiotherapist on their return to the field. 48% received massages immediately after injury.Conclusion: We presented discrepancy between the recommended theory described by several researches and the practice. We indicate the necessity of recycling in a general context the rehabilitation of muscle injuries.

Effect of soccer training on the running speed and the blood lactate concentration at the lactate minimum test

Tegtbur et al. [23] devised a new method able to estimate the intensity at maximal lactate steady state termed lactate minimum test. According to Billat et al. [7], no studies have yet been published on the affect of training on highest blood lactate concentration that can be maintained over time without continual blood lactate accumulation. Therefore, the aim of the present study was to verify the effect of soccer training on the running speed and the blood lactate concentration (BLC) at the lactate minimum test (Lac(min)). Thirteen Brazilian male professional soccer players, all members of the same team playing at National level, volunteered for this study. Measurements were carried out before (pre) and after (post) eight weeks of soccer training. The Lac(min) test was adapted to the procedures reported by Tegtbur et al. [23]. The running speed at the Lac(min) test was taken when the gradient of the line was zero. Differences in running speed and blood lactate concentration at the Lac(min) test before (pre) and after (post) the training program were evaluated by Student's paired t-test. The training program increased the running speed at the Lac(min) test (14.94 +/- 0.21 vs. 15.44 +/- 0.42* km(.)h(-1)) and the blood lactate concentration (5.11 +/- 2.31 vs. 6.93 +/- 1.33* mmol(.)L(-1)). The enhance in the blood lactate concentration may be explained by an increase in the lactate/H+ transport capacity of human skeletal muscle verified by other authors.

Psychological, biochemical and physiological responses of Brazilian soccer players during a training program

Aims of the study. - The aim of this study is to investigate the behavior of the physiological, biochemical and psychological parameters in Brazilian soccer players during a training program.Materials. - Fifteen athletes were evaluated at the beginning (T1), in the middle (T2) and at the end (T3) of the training program. on the first day, at 7:30 am, before the blood collecting at rest for the determination of serum creatine kinase (CK), serum creatinine and serum urea, the athletes had their psychological parameters assessed by the profile of mood state questionnaire (POMS). After 90 min, they performed a 250-m sprint. on the second day at 8:30 am, the athletes had their alactic anaerobic performance measured and, after 40 min, they completed the aerobic test. Friedman test was used to verify the behavior of overtraining markers.Results. - There was a decrease in vigor score in T3 (p=0.01) compared with T1 and T2. In T3 (p=0.01), the athletes also showed an increase in serum creatinine levels compared to T1. Furthermore, in the same period, we verified a diminishing in the team performance.Conclusion. - The training program developed between T2 and T3 led to the fall of the vigor score, the increase in serum creatinine concentrations and the diminishing in team performance. (c) 2007 Elsevier Masson SAS. All rights reserved.

Does muscle imbalance affect fatigue after soccer specific intermittent protocol?

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Representation and analysis of soccer players' actions using principal components

This paper proposes the use of the Principal Components Analysis (PCA) method to represent and to analyse soccer players' actions distribution in the pitch. The seven games of the Brazilian National Team during the 2002 World Cup were analysed. The player's position actions were measured from videotapes in a computer interface. The results were: a) the graphical representation, given by two orthogonal segments in the two directions of maximal variability and centred at the mean of each player's actions position; b) the eccentricity measurement, given by the variability ratio and c) the actions zone area, given by variability product. The results showed that the individual characteristics of acting were well represented by the PCA, allowing comparisons among games and providing insights related to the tactical organisation of the team.

Serum and plasma hormonal concentrations are sensitive to periods of intensity and volume of soccer training

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Hematological parameters and anaerobic threshold in Brazilian soccer players throughout a training program

We assessed the responses of hematological parameters and their relationship to the anaerobic threshold of Brazilian soccer players during a training program. Twelve athletes were evaluated at the beginning (week 0, T1), in the middle (week 6, T2), and at the end (week 12, T3) of the soccer training program. on the first day at 7:30 AM, before collecting the blood sample at rest for the determination of the hematological parameters, the athletes were conducted to the anthropometric evaluation. on the second day at 8:30 AM, the athletes had their anaerobic threshold measured. Analysis of variance with Newman-Keuls'post hoc was used for statistical comparisons between the parameters measured during the soccer training program. Correlations between the parameters analyzed were determined using the Pearson's correlation coefficient. Erythrocytes concentration, hemoglobin, and hematocrit were significantly increased from T1 to T2. The specific soccer training program led to a rise in erythrocytes, hemoglobin, and hematocrit from T1 to T2. We assumed that these results occurred due to the plasma volume reduction and may be explained by the soccer training program characteristics. Furthermore, we did not observe any correlation between the anaerobic threshold and the hematological parameters.

Rapid hamstrings/quadriceps strength capacity in professional soccer players with different conventional isokinetic muscle strength ratios

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

The influence of fluid ingestion on performance of soccer players during a match

The purpose of this study was to verify the effects of a carbohydrate-electrolyte drink on soccer performance. Twenty soccer players volunteered to participate in the study. Players were allocated to two assigned trials according to their positional roles in the team: CHO group (ingesting a 6% carbohydrate-electrolyte solution at regular 15 minutes intervals) and NCHO (ingesting no fluid) during 75 min on-field soccer game. During the trials, body mass loss, heart rate, time spent running, number of sprints and core temperature were measured. There were statistically significant changes (p < 0.05) in body mass loss (CHO: 1.14 ± 0.37 kg vs. NCHO: 1.75 ± 0.47 kg) and number of sprints performed (CHO: 14.70 ± 4.38 vs. NCHO: 10.70 ± 5.80) between groups. The main finding of the present study indicates that supplementation with a carbohydrate-electrolyte drink during a soccer match is beneficial in helping to prevent deterioration in performance. © Journal of Sports Science and Medicine (2004).