A BIOMECHANICAL COMPARISON OF JUMPING TECHNIQUES IN THE VOLLEYBALL BLOCK AND SPIKE

The present case study kinematically analysed the spike and the block movements of a single volleyball player. The aim was to verify the hypothesis that for a right handed player the spike approach and the cross-over step in blocking after a move to the left are similar in coordination, whereas moving to the right before blocking requires a different movement pattern. The spatial and temporal variables of the jumps and the joint angles of the lower limbs during the countermovement were analysed. The results showed a high repeatability of the collected data. The similarity between the spike and the block when moving to the left confirmed the hypothesis. These results from a single subject should be extended by further studies of more athletes of varying skill levels

BLOCKING FOOTWORK TECHNIQUE OF DIFFERENT LEVEL AND GENDER

The purpose of this study was to determine tendencies in lateral footwork techniques used by volleyball players when blocking comparing gender and levels. Videos of matches of the Italian Professional Leagues were analysed: A1/M (15), A1/W (16), B1/M (4) and B1/W (4). The seven techniques identified (slide step, cross-over, vertical jump, repeated slides, jab-cross over, slide-cross-slide and running steps) were classified by front row position and type of set. The non-parametric chi-square analysis was performed to detect differences among genders and levels (α=0.05). The results have shown significant differences. The reasons for these differences were discussed. Some special exercises have been selected and suggested to better train players in blocking movements. Learning objectives for coaches: match analysis, block training

Blocking footwork techniques used by male and female volleyball players are different.

The purpose of this study was to determine tendencies in lateral footwork techniques used by volleyball players when blocking. Videos of 16 female and 15 male matches from the 2004-2005 season of the Italian Professional Leagues were analysed and the blockers\u2019 movements were classified. The seven techniques identified (slide step, cross-over, vertical jump, repeated slides, slide-cross, slide-cross-slide and running steps) were classified by front row position and type of set. The non-parametric chi-square analysis was performed to detect differences among genders, outside blocker positions and direction of movement. The results have shown significant differences (p<0.001). Moving laterally as middle blockers, women use more steps than men; female outside blockers frequently use the slide step while men use the cross step as principal footwork technique. The reasons for these differences are discussed in the article. In male volleyball, sets to outside hitters are faster: a smaller number of steps can be made by blockers. Female volleyball has the same trend: the use of cross techniques will increase in the future among women too. Some special exercises have been selected and suggested to better train players in blocking movements

A study of saccadic eye movement dynamics in volleyball: comparison between athletes and non-athletes

Airz. Visual search strategy in sports may influence performance. Thus it is interesting to investigate oculo-motor behavior of athletes and its possible impingement upon sport training and coaching. The differences in fixations and saccadic eye movements between expert volleyball players and novice subjects was studied, by carrying out a precise analysis of gaze shifts during the observation of a standard game situation. Methods. Fifteen professional athletes and fifteen non athletes watched at a volleyball filmed sequence in which a setter receives a pass tossed from the coach and sets it forward or backward. Then, the number and duration of fixations to specific interest areas (IAs) were counted. In addition, the sequences of saccades from each IA to the others were analyzed. Results, The results showed that expert players performed fewer fixations of longer duration and spent more time looking first at the initial pass trajectory and then at the setter's hands, disregarding the ball trajectory. The non athletes, instead, followed the whole course of the ball, before and after the hands touch. Conclusion. These f\ueendings support the interpretation that experts volleyball players extract more task-relevant information from each fixation than do less skilled athletes, and that player's proficiency influences the strategy used in the treatment of visual information

Reaction time and ocular movements in volleyball

Aim. This research aimed at better understanding the relationship between gaze strategy and anticipation skills of expert vs. nonathlete volleyball players. Methods. Thirty participants (26 \ub1 5 years), 15 na\uefve and 15 expert volleyball players, watched several film sequences where a professional volleyball setter tossed a ball. Movies were stopped at hand-ball contact then subjects had to respond, pressing game pad buttons, as quickly and accurately as possible whether the ball would have been tossed to the right or to the left of the net. Eye position was recorded using a wearable video based eye tracker. The scene was divided into six interest areas in order to analyse gaze strategy and reaction time. Results. Expert group were more accurate in predicting the side of the setting and faster than control group, showing a shorter key-press RT (see table 1). They exhibited more fixations of shorter duration in comparison to nonathletes and significantly they preferred coach, trunk and hands interest areas. A further analysis was done within expert group to see the differences between correct and incorrect responses. Wrong answers were associated with longer periods of time fixating on coach and setter hands areas in comparison to successful ones. All preferred areas were equally fixated for correct responses both in left and right settings, while there was a greater occurrence of wrong responses in left settings. Conclusion. Successful expert tries to extract information as long as possible, but not too long, before pushing the button, than unsuccessful experts

Blocking the quick attack in Volleyball: a 3D kinematic analysis

The importance of the volleyball block against the quick attack is more important in the modern volleyball with new scoring system. Two types of tactics are used normally: the Read Block System (RBS) and the Commit Block System (CBS). A preliminary study was conducted to identify variables that quantified the differences between these two techniques. Four young players performing the RBS and the CBS were acquired by means of stereo-photogrammetry and kinematic variables were identified. The quantified analysis confirm coaches experience: in the RBS the hands arrive over the net in a shorter time, the feet starts \u201cnaturally\u201d wider but the jump performed has a lower height with respect to the CBS. Further longitudinal and transversal studies will be conducted with more subjects of different level and gender

The side-out complex in volleyball: the effect of reception and attack performance with the final score.

INTRODUCTION Statistics in volleyball are a powerful tool to analyse teams and players performances in different skills. Team performance in passing has been traditionally considered very important according to many coaches. This skill was previously investigated in the two Italian professional leagues, by analysing passing performance through the collection of the number of perfect passes (Lobietti, 2006). Those authors concluded that to win the game it is important to avoid passing errors. In another study relative to the Olympic Games in Sidney it was observed that the manner of spike execution is affected by the performance of reception in terms of time and results (Palao, 2006). Since these results seem to be in contrast, a deeper analysis of the relationship between pass and first attack could be decisive to identify team performance tendencies and targets to reach in the first (side-out) complex of the game. METHODS Four seasons (2003-2007) of the Italian B1 male championship were considered. 257 matches were analysed with the Data Volley software (Dataproject, Bologna, Italy) with the contribution of an expert scoutman. Data relative to 4 teams of the B1 male League were further analysed. A 5 levels scale was used to assess the quality of the different skills according with the criteria normally used at international level (Lobietti, 2006). The percent results obtained for each set were classified in six categories depending on the difference between teams in the final score of each single set: 2, 3-5 and more than 6 points (plus or minus). Anova with Tukey post-hoc test (α=0.05) was performed to assess the differences between the six categories for each performance index . RESULTS Statistical analyses for each category allowed to identify the limit index between victory and defeat. Passing error showed significant difference: when passing errors are over the 5% the possibility to lose is very high and over 7% the difference in the final score becomes higher than 3 points. Attack points under 51% and attack errors over 10% predict a defeat; when attack points are over the 58% and attack blocked under the 7% the possibilities to win are very high. DISCUSSION The evaluation of passing confirmed the importance to avoid passing errors. After perfect passes, more than 31% of kills and less than 2.5% spike stuffed could be enough to win. Instead, after a bad pass attack, errors and undergoing blocks over the 5% conduct to a defeat. REFERENCES Palao J.M., Santos J.A., Ure\uf1a A. (2006), Effect of reception and dig efficacy on spike performance and manner of execution in volleyball. JHMS 51, pp. 221-238 Lobietti R., Di Michele R., Merni F. (2006). Relationships between performance parameters and final ranking in professional volleyball. Book of Proceedings of the 7th Word Congress of Performance Analysis of Sport, Szombathely, Hungary, 23-26 August 2006. Dancs H., Hughes M., O\u2019Donoghue P. (eds). pp.481-49

Relationships between performance parameters and final ranking in professional volleyball

Statistics in volleyball are very important at professional level, enabling an analysis of team\u2019s and players\u2019 performances in different skills. Many authors already investigated volleyball performance through statistical data but previous studies considered few parameters or included few games in their analysis. Aims is to detect the importance of eight selected parameters on the determination of the ranking at the end of the regular season in the Italian professional leagues. We tested especially the hypothesis that teams\u2019 performance in passing, traditionally considered very important by many coaches, is not so different between successful and unsuccessful teams. All the matches of the Italian Professional Leagues are recorded through the software Data Volley\uae (Dataproject s.r.l., Bologna, Italy) by scoutmen registering each touch of the ball during the game. These data are available online at the websites www.legavolley.it and www.legavolleyfemminile.it. We downloaded and analyzed the data relative to all games (M:182 and W:132) of the entire male (M) and female (W) A1 regular season 2004-2005. For each team (M:14; W:12) we considered the mean game value of the following parameters per set: Aces (B#), Attack Points (S#), Attack Errors (S=), Attack Stuffed (S/), Blocks (M#), Serve mistakes (B=), Perfect Passes (R#), Pass Errors (R=). A Pearson r correlation coefficient was computed between these variables and team\u2019s points in the final ranking (FP). A hierarchical and non-hierarchical cluster analysis has been carried out to detect the relationships between parameters in the determination of the success of volleyball teams in the entire championship. Final ranking (FP) are very correlated to S# for both W (r=0,93) and M (r=0,82) and also to M# strongly in M (r=0,74), but weakly in W (0,30). FP and B# are more correlated in W than in M (0,79 vs 0,51) and also FP has a negative high correlation with S/, similar in both leagues (W=-0,82; M:-0,78). FP and R= have inverse correlation (r=-0,79 in case of W and r=-0,41 in M), while for R# it is \u20130,53 in M and \u20130,45 in W. FP and B= correlations are weak for both the leagues. In hierarchical cluster analysis M shows two initial clusters: S/ and M# is the first one, FP and S# is the second. At a weaker correlation-level, anyway very high, these two clusters are reciprocally linked. B# and R# make a cluster with medium correlation. In W: FP, B# and S# are strongly linked in the same cluster. R= and S/ are linked with the first cluster at a weaker level. The parameter with the highest correlation with final ranking\u2019s points is, for both the leagues, the number of attack points per set. So attack may be considered the most important skill of volleyball. Passing performance does not appear fundamental, but it is important avoiding passing errors. Teams have to train pass receptions to save the ball and to take attacking chances. This numerical analysis can help coaches to better understand the game and to plan their program of training

Statistics in volleyball: the Italian Professionals Leagues

A 3D Biomechanical Analysis of Volleyball Block R. LOBIETTI, F. MERNI, S. CIACCI Faculty of Exercise and Sport Science, University of Bologna, Italy INTRODUCTION: Blocking is an indispensable feature of winning teams in volleyball. Key points for the effectiveness of the block are anticipation, decision-making, movement speed and jumping ability. Players should use a technique that guarantees the shortest time, the longest movement and a vertical jump close to the net. Coaches regard also very important the \u201cfrontality\u201d of the body to the net: pelvis and shoulders have to be parallel to the net as much as possible. Hands have to form an efficient surface over the net and control the rebound of the ball to score direct point or to touch the ball, deflect the hard shot and help the floor defence. Biomechanical studies are important to help coaches to teach players the best techniques. Researchers have generally two aims: the description of different footwork techniques and jumps, and the description of the move of the arms at the net. This study focuses on the differences in the lower limbs movement sequences in various step techniques and their modifications. We used four types of techniques as described by Lobietti (4). The movements to the right side we analyzed are: -Slide (SS): the right foot moves laterally and the left foot follows close to the lead foot, than the feet push up for the jump -Cross (CS): the left foot crosses over the right passing closer to the net and the right foot closes the move crossing back, than the feet push up for the jump Slide steps and Cross steps and combinations of these steps like Double Slide (DSS) and Slide-Cross (SCS) are basic frameworks of footwork in blocking. There are few published studies to determine the best footwork technique for the lateral movement sequence in volleyball blocking. Cox et al. (2) demonstrated that the cross-over (CS) and jab cross-over (SCS) techniques were the better in terms of getting the blocker off the ground and into the proper blocking position quickly. Buekers (1) stated that the optimal step technique should vary as a function of the lateral distance that must be travelled by the blocker. Lehnert et al. (3) stated that dropping hands during lateral displacement positively affects kinematics characteristics of movement and block jump height and that it is necessary to investigate further modifications of the middle blockers footwork used in top level volleyball. AIM OF THE STUDY To build and test a system for a quantitative description to establish different footwork techniques and to indicate to coaches tendencies to follow in training. METHODS A system for three-dimensional analysis of motion, VICON (Vicon Motion Systems, Oxford, UK), has been used filming six (4 hitters, 1 middle blocker, 1 setter) male volleyball players (age 25.1 y, height 188.8 m, weight 83.5 Kg) of B1 Italian League. Six infra-red video cameras (max resolution 300.000 pixel, frequency 100 Hertz) filmed passive markers fixed in different repere points of joints during blocking exercises. The system uses the stereophotogrammetry procedures to create a 3-D image. The procedures started with the cameras placement in relation with movement, very wide in space development, either in length (4m) than height (> 3m). Second step is the static and dynamic calibrations of the workspace. According with Tokuyama (6) we used 16 markers (diameter 14 mm) in pelvis and legs and instead of the centre of mass (COM) we analysed the kinematics data of the centre of the Pelvis (MEDH). Two additional markers where fixed to the net to calculate the angle between pelvis and net in the different phases of the move, to have data about the \u201cfrontality at the net\u201d. Then the subject is calibrated using the Helen Hayes marker-set (5). Each player executed 4 trials for each type of movement in both directions. The players were required to reach the best speed, the longest distance..