Search

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 fîndings 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.

This article reviews the state of art of the research concerning the biomechanics of blocking in volleyball. Since it is fundamental to link the “reality of the game” (what happens in the field) with laboratory simulations, the logic procedure to investigate this skill followed this progression: 1) the importance of block in the game was analyzed in terms of relationships with the match results. 2) Blocking footwork techniques were classified and data relative to the frequency of blocking to stop the opponents attack were collected and analysed. 3) Kinematical analyses of blocking techniques were performed in the laboratory of the Faculty of Exercise and Sport Science at the University of Bologna, Italy. These results allow coaches to adjust the tactic in the game, to differentiate the type of drills and to develop some special exercises to train players for the improvement of their blocking technique.

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 ± 5 years), 15 naïve 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.

Introduction and Aim of the study: Table tennis literature displays many efforts about the study of both the development of the game technique and the match and notational analysis. However those works were principally based on the observation and survey of some of the most important aspects: the strokes, the direction of the movements and the efficacy (won, lose, mistakes, etc.). This study aims to elaborate another kind of analysis including the footwork technique (different kind of steps). The most important thing, considering the best player technique, is the best execution of the movement and steps, for reaching in the shortest time the right position, and playing the best stroke. Methods: 1. Environment: 29th Olympic Games in China - Man’s table tennis singles final 2. Population: the n°1 (W. H.) and the n°2 (M. L.) in the world ranking 3. Data collected: footwork technique (different kind of steps), strokes and efficacy. 4. Analysis: it has been analysed the contingency table about Footwork/Strokes and Footwork/Efficacy. Results: The two considered players use mainly the One step (30% and 29%) to return the services, W.H. uses very often the Turn step (17%) to hit the ball with Topspin or Counter topspin. On the other side M.L. prefers to use a more balanced footwork technique, using a combination of Chassè and Turn step (14% and 14%). W.H. uses more frequently the topspin (14%)and the Counter topspin (15%), M.L. prefers the Counter topspin (17%) followed by Topspin (13%). It is possible to notice that the players do not use one step (13%-11%) during the game phases and W.H. does not use one step in particular to hit the ball with a forehand Topspin (10%). The players use in particular the One step in a neutral way (without efficacy, 63% and 72%), W.H. uses the Turn step with good results (25%) but also in a negative way (21%). During the match M.L. is able to use with more positive results every different kind of steps. He shows negative performances using the Chassè (25%) and the Crossover (23%).

Knee injuries such as anterior cruciate ligament lesions and patellar tendonitis are very frequent in volleyball, and are often attributed to micro traumas that occur during the landing phase of airborne actions. The aim of the present study was to compare different jumping activities during official men's and women's volleyball games. Twelve top-level matches from the Italian men's and women's professional leagues were analysed. The jumps performed during the games were classified according to the landing technique used by the player (left or right foot or both feet together), court position, and ball trajectory. Chi-square analyses were performed to detect differences in landing techniques between the sexes, court positions, and trajectories when serving, attacking, blocking, and setting. Significant differences (P < 0.05) were found between the sexes for block, set, and spike but not for the jump serve. The frequency of landings on one foot was related to court position and the trajectory of the sets: when spiking faster sets, the players were more likely to use a one-footed landing. The present results should help coaches and physiotherapists to devise appropriate training and prevention programmes, and reveal the need for further detailed biomechanical investigations of the relationships between landings and knee injuries.

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., Ureña 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’Donoghue P. (eds). pp.481-490

INTRODUCTION – AIM OF THE STUDY: Blocking is an indispensable feature of winning volleyball teams. Among the fundamental components of efficient block execution the reaction time is especially important (Vint1). There is a large body of research in the sphere of experimental psychology (Pesce Anzeneder e.g2), but less in applied situation (Dorfhman3, Westphal4). Biomechanical analysis of the block in volleyball was not presented data relative to this important aspect (Quade5 and Lobietti6 e.g). The aim of this study was to collect data on block reaction time by means of stereo-photogrammetry and to compare tendencies from the different type of block. METHODS: This study analysed block techniques used by 10 male volleyball players (age 26.7, height 192.4 m, weight 86.7 kg) of B1 Italian League. 3D kinematics were estimated by means of stereo-photogrammetry (Vicon Motion Systems, Oxford, UK). Six infrared cameras (max resolution 300.000 pixel, frequency 100 Hertz) filmed markers (diameter 14 mm) attached to the body (45), the net (4) and the stick (2). Players had to carry out block exercises as answer to a stimulus: an operator on the other side of the net moved the stick up, right or left in order to simulate the possible sets in zone 2, 3 or 4. Players had to jump vertically or after a lateral move (slide or cross step). The reaction time was calculated as the difference between the frame of the first movement of the COMr (Centre of mass of trunk and lower body) and the frame of the first movement of the stick. Obtained results were further analysed to allow the comparison depending on the block technique used. Statistical Analysis: The T-Test (α=0.05) was performed to analyse differences between the vertical jump and block with lateral move. RESULTS: The subjects were fastest to react when they executed the slide towards right (254±27 msec), while they were slowest when they had to execute a vertical Jump (343±54 msec). T-tests showed significant differences between vertical jump and the jump with right movement using both techniques: slide (t=0.0009) and cross (t=0.007). To the left significant differences were not found (t=0.15 comparing with the slide and t=0.14 with the cross). The reaction time was faster moving to the right (t=0.006) than the left. CONCLUSIONS: Examined players were faster to react in lateral moves than in vertical jumps. We can suppose that the reason for this is that in the real game ouside blockers are ready to move laterally instead of jumping vertically. REFERENCES: 1. VINT, P., (1997). “Qualitative Analysis of a volleyball Blocking Performance”. University of North Carolina at Greensboro. 2. PESCE ANZENEDER, C. et al. (1997). “Attività cerebrale e prestazione attentiva nel pallavolista”, Sds/Rivista di cultura sportiva, Anno XVI, n. 39, 53-62 3. DORFMAN, P. W., (1977). “Timing and anticipation: a developmental perspective”, Journal of Motor Behaviour, Vol. 9 No. 1, 67-79 4. WESTPHAL, G. et al. (1985). “ Zur Antizipationsfähigkeit des Blockspielers im Volleyball“, Leistungssport 6/85 5. QUADE, K. (1993) “Zur Funktion und Belastung der unteren Extremitäten bei volleyballspezifischen Sprüngen”, SFT-Verlag Erlensee. 6. LOBIETTI, R. et al. (2006). “Blocking the quick attack in volleyball: a 3D kinematical analysis”, Department of Sport Science and Kinesiology University of Salzburg 14-18 July 2006 (eds.), Salzburg

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.

The aim of this study is to investigate the environmental sustainability of a golf course in Reggio Emilia, established over a dumping ground, with a residential and tourist complex, in comparison with some Scottish glof courses.

Landing from blocking jumps in women’s volleyball Introduction The frequency of knee injuries (e.g. ACL lesions and patellar tendonitis) in volleyball is very high: the causes of these injuries have often been hypothesized due to the landing phases in airborne actions such as spike and block. Watkins & Green3, stated that 15% of accidents occurred in the landing phase, and Cassel1 noted that 60% of the acute injuries happened landing from block and attack with or without contact with other player. The purpose of this study was to determine tendencies in landing from blocking activities. Methods 8 female teams of the Italian Professional Leagues were analysed and the landing phase of the jumps were classified by type of technique (left foot, right foot or two feet together) and court positions. Chi-square analyses were performed with the level of significance set at 0.05 to detect differences among positions when blocking. Results Table 1: Comparison between Blocking positions Number of jumps Percentage Both Left Right Both Left Right Pos. 4 201 52 46 67.2 17.4 15.4 Pos. 2 370 34 4 90.7 8.3 1.0 Pos. 3 217 174 244 34.2 27.4 38.4 Total 788 260 294 58.7 19.4 21.9 In females a significant difference was found (χ2 (4) = 353.70; p< 0.001) but while outside blockers landed bilaterally 67% of 299 in position 4 and 91% of 408 in position 2), in the middle players landed more with the right foot (38%), then with either feet (34%) and less with the left foot (27%). Discussion Middle blockers land more often with only one foot as they have to move quicker in both directions. Blockers’ landings in positions 2 and 4 were expected to be similar as equal numbers of blocks are made in these two positions. Conclusion The type of landing techniques were already analysed but the reliability of the data presented in this report is higher because higher number of match analysed and subjects are top level players. The present study allows previous biomechanical research that considered bilateral landings to be compared with the reality of the game situation: previous laboratory findings could be considered for outside blockers. To complete the analysis further investigations relative to the middle blockers should be designed with players moving laterally before the jump and landing with only one foot. References 1. Cassel E, Cassel E. (2001) Monash University Accident Research Centre. 2. Tillman MD, Hass CJ, Brunt D, Bennet GR. (2004) Journal of sports science and medicine, 3, 30-36 3. Watkins J, Green BN. (1992) British Journal Sports Medicine, 26(2), 135-137.

A kinematical study of Read and Commit block in Volleyball Introduction Two tactic systems are used for blocking in volleyball: the Read Block System (RBS) or the Commit-Option Block System (CBS). In the RBS, the blocker starts close to the net looking to the opponent’s setter, ready to react to different types of set. In the CBS, the blockers has to follow the approach of the specific opposite hitter without worrying about the set. In both cases the key point for the effectiveness of the block is the lateral movement before the jump. Two types of footwork techniques are normally used: the Cross-over (CO) and the Slide Step (SS) 1,2. Previous studies jumping vertically showed significant differences between systems3. It’s the same after a lateral movement? Methods Subjects: 4 males elite level players were acquired by means of stereo-photogrammetry (6 cameras, 100 Hz frequency 16 markers). Simulating the RBS, players had to carry out block exercises as answer to a stimulus: an operator on the other side of the net moved a 2 markers stick up, right or left in order to simulate the possible sets in zone 2, 3 or 4. The player was prompt to react, reading the coach miming of the opponent set in all the three possible directions (left, right, or up) and then moved or jumped consequently. In the CBS, the player decided by himself when start. Three trials for each type of block were acquired. The best trials were identified from the maximum jump height reached. The following variables were selected: temporal phases of steps, elevation, knee flexion angles (at the countermovement). The non-parametric Wilcoxon test was performed to compare the two type of blocking techniques (α=0.05). Results No significant differences were found between the two tactic systems. Discussion/Conclusion Footwork techniques can be trained at the same time in order to be applied in both tactics. Thus, the difference in blocking performance seems to depend mostly by the decision making process and in the control of arms and hands when contacting the ball. References 1. Cox R. H., Noble, L., & Johnson, R. E. (1982). RQES, 53 (2), pp. 101-107. 2. Buekers, M. J. (1991). RQES, 62 (2), 232-2 3. Lobietti R., Fantozzi S., Merni F. (2006) In: XXIV ISBS Congress Vol.1 pp. 151-154

The physical effort in the defensive phase of volleyball games: comparison among positional roles Introduction The number of jumps performed by players during a game is a commonly used parameter when defining the physical loading in volleyball1,2. The aim of this study is to compare the jumping performance in volleyball players of different roles, focusing the analysis on the defensive phase of the game, characterized by jumps aimed to serve, block and eventually counterattack. A similar number of jumps is hypothesized to be between opposite-role players due to similarities in their technical characteristics. Methods 3 volleyball games (15 sets) of a top level male team were considered. Data were collected with the Data Video system (Dataproject s.r.l., Bologna, Italy). The jumps were subdivided in serving, blocking and counterattacking (spiking) jumps. The mean jump number for game of each category was analysed with Chi-square tests with the level of significance set at 0.05. Comparisons were made respectively between the setter (P) vs. the opposite (O), the two hitters (S1 - S2) and the two middle blockers (C1 - C2). Results Table 1: Comparison between role and position in the defensive phase Position SERVE BLOCK SPIKE Mean ± S.D. % Mean ± S.D.. % Mean ± S.D. % C1 15.0±1.0 24.5 12.0±2.6 69.0 4.0±2.6 6.5 C2 14.7±0.6 23.0 12.0±1.0 71.1 3.3±3.5 5.2 S1 24.0±0.6 43.6 8.0±4.0 48.5 4.3±0.6 7.9 S2 20.0±11.1 38.5 5.7±3.1 48.7 6.7±1.5 12.8 P 18.3±6.5 35.3 9.0±1.0 42.3 1.0±0.0 1.1 O 21.0±3.0 43.8 8.0±2.6 44.0 5.7±5.0 11.8 Discussion Chi-square tests showed a significant difference between the number of jumps performed by the setter (P) and the opposite (O) when spiking and setting. Discussion/Conclusion The innovation of this pilot study is to analyze the jumping performance specifically in the defensive phase of the volleyball game. The difference shown between the setter and the opposite may be due to the different task they have to perform in the transition from defense to counterattack. Using the most popular line-up system, called the 5-1, the setter is the responsible of every second touch, then his aim is to transform the defence into counterattack. Indeed, the opposite in many teams is the primary hitter, attacking equally from the front and the back row. References 1. Fontani, G., Ciccarone, G. et al. (2000) SDS-Rivista di cultura sportiva. 50:14-20. 2. Tillman, M.D., Hass, C.J. et al. (2004) Journal of sports science and medicine. 3:30-36.

Footwork and steps (one step, side to side, slide step, “turn” step, cross step, and combinations of these steps are fundamental in table tennis. Players should use the best technique for guarantying the shortest time to arrive in the right position, that gives possibility to play the best shot. AIM OF THE STUDY This study aims to define the different footwork techniques used by table tennis players. To compare different footwork techniques for giving useful suggestions to coaches and implementing better training for players, from a technical and physical point of view. METHODS 1. Analysis of 2 matches of 4 male players from 2006 World Team Table Tennis Championships (videos recorded from television). The players were at the moment of competition the n° 1, 2, 3 and 50 of the world ranking. The matches analysed were between the n° 1 vs n° 50 and n° 2 vs n° 3. 2. To record the 5 different types of steps defined and the 16 types of shot (8 of drive and 8 of back) was used a 16 x 5 table. The last step before the shot or the attempt to hit the ball was selected for this analysis. 3. The analysis of the frequencies of the use of different types of step were performed and percentage calculated 4. The non-parametric Chi Square test were performed to identify significant differences (α=0.01) between in the use of footwork techniques by the 4 players. RESULTS The results allow a qualitative description of the various step movements. The one step resulted as the preferred type of movement used in the 43% of the time; the “turn” step was used the 24%; the “chasse” 17%; the slide 9% and the cross 7%. Chi Square analyses comparing the use of different types of steps by the players shows significant differences (χ² (15) = 35.35, p

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 “naturally” 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.

Statistics in volleyball are very important at professional level, enabling an analysis of team’s and players’ 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’ 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® (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’s 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 –0,53 in M and –0,45 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’s 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.

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 “frontality” 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 “frontality at the net”. 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...