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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