José Afonso

The weight of terminal actions in Volleyball. Contributions of the spike, serve and block for the teams’ rankings in the World League 2005

The purpose of this paper was to study performance levels in scoring skills in the Volleyball World League 2005, and to relate the results to the teams’ final ranking in the tournament. The sample consisted in 33745 actions, distributed by serve (n=12434), block (n=7200), and spike (n=14111), having been recorded during 72 World League 2005 matches. Both absolute (number of successful and unsuccessful executions) and relative (coefficient of performance, percentage of successful executions and percentage of unsuccessful executions) variables have been considered for the three dimensions (spike, serve, and block). Team ranking has been calculated for each variable. Also, each team’s final ranking in the tournament has been considered. The results permit us to conclude that the spike is the best indicator of success in high level volleyball, but only when considering relative measures. Simultaneously, the number of block points per game proved to be a good indicator of success in volleyball. Finally, the number of serve errors and the percentage of serve points are associated with the team’s tournament ranking. That is, the best teams fail a higher number of serves, but also win more points with this action.

Determinants of block cohesiveness and attack efficacy in high-level women's volleyball

Abstract Analysing the performance of a team is important for optimizing the training process, thus improving the quality of practice. The interactions between the two opposing teams generate specific dynamical interactions, leading to the emergence of unique game patterns, which are of interest in such analyses. Hence, the purpose of the present study is to analyse probabilistic relationships that might predict certain outcomes relating to block cohesiveness and attack efficacy in elite-level womens volleyball. Six volleyball matches from the 2006 FIVB Womens World Championships were analysed, producing a total of 650 sequences. A multinomial logistic regression was applied, with the level of significance determined at α = 0.05. The results clearly suggest that one of the most important cues for the blockers to analyse is the availability of the opponents middle-attacker for quick attacks. This emphasizes the notion of availability, a functional concept of the greatest importance. Regarding anticipation strategies from the block, they are justifiable when the opponent pulls a quick one-foot attack behind the setter, since it diminishes the probability of an attack point or positive attack. In conclusion, it is the effective availability of a player to execute a certain action, and the type of that availability, that will induce different types of response strategies, whether wait and react, or a multitude of specific anticipation movements. Research should take this into consideration, exploring new and particular forms of availability and of anticipation movements, providing a higher in-depth view of game dynamics.

Determinants of attack tactics in Youth male elite volleyball

The aim of this study was to identify determinants of the attack tactics’ effectiveness in Elite Youth Men’s Volleyball. Eleven matches of the 2007 World Youth Championship were analyzed, totalling 863 actions of reception, 1191 actions of attack and 435 actions of defence. Multinomial logistic regression was applied in order to analyze the association of reception effect, defence effect, attack tempo and attack type, with the attack effectiveness. The reliability of the observation was calculated through Cohen’s Kappa, with values being above 0.81. This study showed that the powerful attack increased the chances of scoring in both side-out and transition. Regarding the timing of the attack, 1st tempo increased the chances of scoring in transition. These results show that the Elite Youth male’s game claims a more offensive game through powerful and quick attacks.

Procedural knowledge, decision-making and game performance analysis in Female Volleyball’s attack according to the player’s experience and competitive success

The purpose of this study was to analyse procedural knowledge, decision-making and game performance of the zone 4 attackers in Volleyball, according to the players’ experience and competitive performance. A verbal interview protocol was implemented immediately after randomly chosen live game actions to analyze procedural knowledge. Decision-making and players’ performance were analyzed by video images. Oneway Anova, Independent Samples t-Test, and Pearson Chi-Square were applied to data analysis. The results showed that more experienced and more successful players play more under goal concepts than condition concepts and concern more often with the opponent. Specifically, more experienced players mentioned more goal concepts and less sophisticated conditions, as more successful players mentioned more action concepts. More experienced players also presented fewer condition concepts than the less experienced ones. Successful players tended to make more appropriate decisions. However, as player’s experience and competitive success are multidimensional variables they might not be fully well characterized by the number of years of practice and competitive results. Therefore, future research is required, and it should include other criteria to characterize both variables. Moreover, qualitative analysis is needed, since it will allow a deeper understanding of the tactical development of the players according to the specific nature of the training process, and also considering the competitive success and the player’s experience as multidimensional variables.

Relationship between the use of commit-block and the numbers of blockers and block effectiveness.

The purpose of this paper is to find out the effect of the use of the commit block on the number of players in the block and block effectiveness in the side-out phase and counter-attack phase, and give reference values on the utilization of the commit and reading block. The sample was made up of four male national teams (Portugal, Japan, Cuba and Yugoslavia). The actions of the teams where analyzed in 549 sequences corresponding to 25 sets of the World League 2001. The variables studied were: game phase, usage of the commit block against first tempo, block effectiveness, and spike opponent’s error. The results show that the use of the commit block difficult the formation of double and triple blocks in the wings and does not increase the block effectiveness or the opponent’s error in spike.

Visual search behaviours and verbal reports during film-based and in situ representative tasks in volleyball

Abstract Several researchers have explored the processes underlying perceptual-cognitive expertise, mainly using film-based studies. However, few have compared the extent to which data from film-based settings differ from those obtained through in situ collection. This gap in the literature is a relevant concern, since scientific research is used to provide guidance for designing training programmes. In this paper, eye movement recording and verbal reports of thinking were combined to explore the processes underpinning skilled performance in a representative volleyball task involving both film-based and in situ data collection. Nine volleyball players performed as backcourt defenders while wearing an eye-tracking device and providing verbal reports of thinking after each sequence. A number of significant differences were observed between the data gathered under film-based and in situ conditions. Namely, in the in situ condition participants employed longer fixations (728.11±129.27 ms) than in the film condition (659.57±178.06 ms), and there were differences in the nature of the fixation locations. With respect to verbal reports, participants exhibited superior level of sophistication in the in situ condition (2.57±0.50 vs. 2.30±0.84 in the film condition), while denoting a greater concern with the opponents under this condition (1.00±0.73) than in the film condition (0.59±0.60). These differences emerged despite task design and constraints being highly similar. No differences were apparent in the number of gaze fixations and fixation locations across conditions or in the number of verbalised condition concepts. Although exploratory, our data suggest that the mechanisms underpinning skilled decision-making in sports differ between film-based and in situ conditions.

Attack Coverage in High-Level Men's Volleyball: Organization on the Edge of Chaos?

Abstract Change is pervasive, but emerging patterns are occasionally detectable through analysis of systemic behaviors. Match analysis uses these patterns in order to reduce the degree of improvisation and to optimize the training process. However, it is possible that certain game phases elude systematic patterning. In this vein, our aim was to analyze the case of attack coverage in men’s volleyball, as we suspected it would elude systematic patterning and has received negligible attention in scientific research. We analyzed the occurrence of attack coverage in 4544 plays of the 2011 Volleyball World League. A Chi-square test with residual adjusted values was applied to explore significant associations between variables. A Monte Carlo correction was applied, as some cells had n<5. Effect sizes were determined using Cramer’s V. Overall, attack coverage occurred in 3.89% of ball possessions, and 23 distinct structures emerged. These structures lacked significant associations with the game complex, setting zone, and effect of attack coverage. Conversely, attack coverage structures showed significant associations with the attack zone and tempo, with very strong effect sizes (V=0.472 and V=0.521, respectively). As certain attack zones are deeply associated with attack tempo, it is apparent that quicker attack plays affect attack coverage structuring, promoting the formation of less complex structures. Ultimately, attack coverage structures seem to depend on momentary constraints, thereby rendering rigid systematization impracticable. Still, we contended that a principle-based approach might be suitable. This invites researchers to rethink how to interpret game regularities.

Skill-Based Differences In Visual Search Behaviours And Verbal Reports In A Representative Film-Based Task In Volleyball

A desire to increase understanding of the mechanisms underpinning expert performance has motivated a large body of research. We examined the processes supporting skilled performance in a complex film-based volleyball task using a representative simulated environment. Participants were presented a complex, game-like volleyball task. We combined eye movement recording with immediate retrospective verbal reports of thinking in fifteen elite female volleyball players, ranked into skilled and less skilled groups. Skilled players employed longer fixations than their less skilled counterparts, and spent a greater amount of time fixating the receiver and functional spaces between two or more players. Skilled participants generated significantly more condition concepts, and presented a superior level of sophistication in their verbal reports. Data suggests that it is relevant to use tasks that simulate real-life environments. The definition of functional spaces, aiming for locations that stimulate retrieving information from more than one cue at a time, affords researchers to use eye-tracking devices to analyze peripheral vision. Based on collection of verbal reports researchers could assess if those functional spaces were relevant for the subjects. Researchers need to be thoughtful when designing representative tasks in order to accurately simulate competitive contexts.

Systemic Mapping of High-Level Women’s Volleyball using Social Network Analysis: The Case of Serve (K0), Side-out (KI), Side-out Transition (KII) and Transition (KIII)

Competitive sports are growing in popularity at an exponential rate, with training becoming an almost overwhelming process, demanding an understanding and awareness of the effects of a great number of variables on sport performance. Thus, systemic approaches have emerged as essential for understanding the complex dynamics of performance. In this vein, Social Network Analysis (SNA) acquires particular relevance in comprehending the relationships established between different nodes. Therefore, the purpose of the present study was to analyze performance in high-level women’s volleyball using SNA. A systematic mapping of four game complexes of the volleyball game was carried out using Gephi©. The analyzed complexes were: serve (K0), side-out (KI), side-out transition (KII) and transition (KIII). A total of 8 matches from the first Group Stage of the Women’s World Grand Prix 2015 were viewed (1,264 rallies), and eigenvector centrality values were calculated. Results showed that most variables presented categories with relatively close eigenvector values, pointing to a diversified distribution of events. However, some categories did exhibit substantially distinct eigenvector centralities. Based on the findings of the present study, it was concluded that it was crucial to develop ways to enhance teams’ abilities to play off-system, as it was the most common situation in female high-level volleyball. It was also shown that this enhancement should be carried out by providing diversity to the teams’ options, as this diversity would create more uncertainty in the opponent and therefore, a higher chance of success.

The Effect of Body Mass Index on Acute Cardiometabolic Responses to Graded Exercise Testing in Children: A Narrative Review

Although the beneficial role of exercise for health is widely recognized, it is not clear to what extent the acute physiological responses (e.g., heart rate (HR) and oxygen uptake (VO2)) to a graded exercise test are influenced by nutritional status (i.e., overweight vs. normal-weight). Therefore, the main objectives of the present narrative review were to examine the effect of nutritional status on acute HR, and VO2 responses of children to exercise testing. For this purpose, we examined existing literature using PubMed, ISI, Scopus, and Google Scholar search engines. Compared with their normal-body mass index (BMI) peers, a trend of higher HRrest, higher HR during submaximal exercise testing, and lower HRmax was observed among overweight and obese children (according to BMI). Independent from exercise mode (walking, running, cycling, or stepping), exercise testing was metabolically more demanding (i.e., higher VO2) for obese and overweight children than for their normal-weight peers. Considering these cardiometabolic differences according to BMI in children might help exercise specialists to evaluate the outcome of a graded exercise test (GXT) (e.g., VO2max, HRmax) and to prescribe optimal exercise intensity in the context of development of exercise programs for the management of body mass.