Publications

2023
Giatsis, G., Lola, A., Drikos, S., Lopez-Martinez, A. B., & Turpin, J. A. P. (2023). Beach volleyball set and technical performance indicators for elite women’s teams. Journal of Human Sport and Exercise, 18. Universidad de Alicante Servicio de Publicaciones.
Tsakiri, M., Drikos, S., Sotiropoulos, K., Skordilis, E., & Barzouka, K. (2023). Separating winning and losing teams in sitting volleyball: the role of skills and differences across gender. International Journal of Performance Analysis in Sport. Routledge.Abstract
Sitting volleyball (SV) is a dynamic with short actions sport in the paralympic programme. The purpose of the study was to identify the volleyball skills that best discriminate between winning and losing an SV set, for both the genders. The data were collected from all sets played (N = 224) on the 2019 European men and women SV Championship. Cluster analysis established three types of sets according to the final score difference: 2–4 points (balanced), 5–11 points (semi-balanced) and over 11 points (unbalanced). Three-way MANOVAs were conducted to analyse gender, type of set and type of result differences for selected performance indicators. The analyses revealed significant multivariate differences across gender (p <.001), types of set (p =.014) and result (p <.001) and significant interaction effect of result with gender (p =.025) and type of set (p <.001). A follow-up discriminant analysis showed that setting and attacking were the most important skills for all sets. The results showed that in SV the attack is the most important factor, which determines winners and losers, even in balanced sets. In SV, the importance of skills across gender was similar to volleyball, while there were differences in the structure of the game compared to the sequential order of skills in volleyball.
Drikos, S., Sotiropoulos, K., & Barzouka, K. (2023). Game-Related Skills that Influence Success in Elite Men’s Volleyball. (A. Baca & Exel, J., Eds.)13th World Congress of Performance Analysis of Sport and 13th International Symposium on Computer Science in Sport. SpingerLInk. Website
Drikos, S., Sotiropoulos, K., Oikonomopoulou, A., Michalopoulos, G., & Barzouka, K. (2023). Predictive factors of the setting performance and distribution per game complex in junior female volleyball. Motricidade. WebsiteAbstract
The present study aimed to analyse the associations between spatiotemporal characteristics of the setting and the origin of the ball in terms of the game complexes for junior female volleyball teams. Multinomial logistic regression and multiple correspondence analysis were applied to analyse 3.675 setting actions (Complex I = 1.593, Complex II = 2.082) in the final phase of the Greek Junior Championship. Results showed that the origin of the ball from the left lane of the court eases the setter for an accurate setting during CI while passing from the right lane incommodes the setter during CII. Regarding setting zone, for accurate setting, odds are increased by 3.2 for zone 4 during CI while decreased by 23.8 for zone 3 during CII. The junior setters' distribution of setting is predictable and creates favourable conditions for the opponent to deal with it. The improvement of junior female setters' ability to follow the team's offensive tactic regardless of the ball's origin, to manipulate passes received from the right lane of the court during CII and the acceleration of setting tempo for the wing hitters could be training goals for coaches.
2022
Drikos, S., Sotiropoulos, K., Gkreka, S., Tsakiri, M., & Barzouka, K. (2022). Variations in Attack Patterns between Female and Male outside hitters in top-level Volleyball. International Journal of Sports Science and Coaching. presented at the 2, SAGE PublicationsSage UK: London, England.Abstract
In volleyball outside hitters have wide participation in the offensive game. This study aims to analyze the variables that predict attack effectiveness in top-level volleyball depending on gender. ...
Fatahi, A., Molla, R. Y., Drikos, S., Alriyami, S. A., & Jadidoleslam, S. (2022). A Comprehensive Analysis of the Serve Reception Zone, Set Zone and Attack Quality of the Top-Level Volleyball Players. European Journal of Human Movement, 48, 54-63.Abstract
The game analysis is known as a useful tool for understanding the level of technical-tactical performance of volleyball. As one of the main characteristics of volleyball is defined as the intense relationship between its skills and concluded performance, the present study aimed to perform a comprehensive analysis of the serve reception zone, set zone and attack quality of the top-level volleyball players. The analysis process included reviewing the videos of the games by an experienced scout man who was an expert analyst and specialist in the knowledge of volleyball skills. Initially, during each game video checking, data were collected, and irrelevant/invalid outputs were deleted. Data were exported to the Data Volley special volleyball analysis software. Bivariate associations were assessed for pairs of variables with Pearson’s chi-squared tests. Statistical significance was set at p<0.05. Moreover, the effect size was calculated in terms of Crammer’s V, with values of <0.1, 0.1-0.3 and > 0.5 for small, medium, and large effects respectively. The results showed that there were significant relationships between reception zone with setting zone, setting zone with attack quality as well as reception zone with attack quality. Coaches may consider the relationship between critical skills of volleyball to promote their team performance.
Achilleopoulos, I., Sotiropoulos, K., Tsakiri, M., Drikos, S., Zacharakis, E., & Barzouka, K. (2022). The effect of a proprioception and balance training program on balance and technical skills in youth female volleyball players. Journal of Physical Education and Sport, 22, 840-847.Abstract
{A skilled control of postural stability is fundamental in many of the actions performed by volleyball athletes. The effectiveness in serving, forearm passing or setting the ball is affected by the athlete’s ability to control their dynamic balance. When referring to team sports, earlier studies have shown that balance and proprioception training have the potential to induce performance enhancement in selected components of physical fitness and some technical skills but only few of them focus on the field of volleyball. Therefore, the purpose of this study is to investigate the effect of a balance and proprioception training program on dynamic balance and volleyball skills of female volleyball players aged 13-15 years. The sample is consisted by 18 participants who were divided into an experimental group (EG
Balasas, D. G., Mandroukas, A., Michailidis, Y., Drikos, S., Sotiropoulos, Κ., Christoulas, K., Metaxas, T. I., et al. (2022). Muscle fibre type, size and satellite cell pool in male volleyball players. Trends in Sport Sciences, 29, 45-50. University School of Physical Education.Abstract
Introduction. Longitudinal volleyball training stimuli can cause an increase in muscle strength that is brought about by neurological and morphological adaptations, such as changes in muscle fibre composition percentage and cross-sectional area (CSA). Aim of Study. The aim of this study was to examine the biological adaptations of volleyball-players in terms of muscle fiber type composition, cross-sectional area, myonuclei and satellite cell pool in comparison to physically active controls. Material and Methods. Ten professional volleyball-players (VG) and five physically active-persons (CG) participated in this study. Muscle biopsies were obtained from the vastus-lateralis of the dominant leg. Results. Immunohistochemical analysis revealed that although MHC I and MHC IIC muscle fibre distribution was not different between the groups, MHC IIX and MHC IIAX were totally absent in VG and appeared only in the CG. The cross-sectional area revealed a slightly different pattern as both MHC I and IIA were larger for the volleyball players. In accordance, MHC II myonuclei number was moderately larger in the volleyball players, while the satellite cells and their ratio to number of fibres had a large and very large difference, respectively. Conclusions. In conclusion, our study reveals that volleyball training-induced hypertrophy for both type I and II muscle fibres in the vastus lateralis of volleyball players and resulted in a specific shift in muscle fibres containing MHC II isoforms. This hypertrophy of the muscle fibres is associated with an increase in the myonuclear number and satellite cells.
Oikonomopoulou, A., Barzouka, K., Sotiropoulos, K., Drikos, S., & Noutsos, K. (2022). Spatiotemporal analysis of setting per game complex and origin of the ball in junior female volleyball players. Journal of Physical Education and Sport, 22, 652-660.Abstract
In volleyball, the performance in the passing affects the setter’s strategy and the effectiveness of the attack after the reception or defense. This study aims to assess the spatial and temporal characteristics of the setting choices made by junior female volleyball setters and their performance concerning the origin of the ball and the game complex. The sample for this analysis consists of 3728 setting actions (Complex I = 1.616, Complex II = 1.212). A three-member group of experienced coaches assessed the setting zones’ choices as well as the setting tempo and the performance of junior female setters from 20 volleyball games of teams competing in the final phase of the Greek Junior Championship. The variables under consideration were complex of the game (C1 & CII), origin of the ball (left/middle/right lane for the vertical and front/centre/back lane for the horizontal axis of the court), setting zone (six zones of the court), setting tempo (1st, 2nd & 3rd tempo) and setting performance in a five-level ordinal scale. Inter-rater and intra-rater reliability coefficients were estimated using Cohen’s kappa coefficient with acceptable values. The test of independence for the categorical variables was carried out using the chisquare test. Following the overall independence test, the difference in proportions among all levels of variables was tested. Results showed that junior female setters regardless of the complex and the origin of the ball choose zone 4 in a 3rd tempo, performed in a moderate and good setting. However, the origin of the ball was an important variable for the subsequent setting. The most preferable route of the ball was from a pass in the left lane of the court to an attack in zone 4 regardless of the game complex. Additionally, setters when receiving the ball from the left and middle lane of the court prefer more often zone 3 in 1st tempo, during CI than CII. The results of the study will give useful directions to the coaches of the specific age category regarding the creation of appropriate training programs for the individual improvement of the setters and teams.
2021
Drikos, S., Barzouka, K., Balasas, D. G., & Sotiropoulos, K. (2021). Effect of quality of opposition on game performance indicators in elite male volleyball. International Journal of Sports Science & Coaching. presented at the 5, SAGE PublicationsSage UK: London, England.Abstract
Performance in a volleyball match is the result of a dynamic and interactive process between two teams. The current study aimed to investigate the influence of the quality of opposition on skill performance indicators. A total of 550 teams’ performances (N¼550) from 275 sets of men’s European Championship 2019 was recorded and the effectiveness of 12 parameters from 5 basic volleyball skills was analyzed. A two-step cluster analysis was performed to divide 24 teams into three quality groups (upper, middle, lower) and 6 types of match status were created according to the quality of the opponents. Binomial logistic regression showed that for each type of match, the key performance factors that discrim- inate win and loss are differentiated, while the efficacy of attack win is associated with the success almost with all contexts studied. Other significant parameters were serve aces for matches between upper-quality teams, opponent’s errors for matches between teams of different quality and avoidance of blocked attacks for balanced matches. The findings emphasize the need for coaches to plan strategies that allow players with special serving abilities to risk for an ace, to enhance the side-out skills of their team and to work detailed on attack coverage systems
Ntzoufras, I., Palaskas, V., & Drikos, S. (2021). Bayesian models for prediction of the set-difference in volleyball. IMA Journal Of Management Mathematics, 2.Abstract
We study and develop Bayesian models for the analysis of volleyball match outcomes as recorded by the set-difference. Due to the peculiarity of the outcome variable (set-difference) which takes discrete values from −3 to 3, we cannot consider standard models based on the usual Poisson or binomial assumptions used for other sports such as football/soccer. Hence, the first and foremost challenge was to build models appropriate for the set-difference of each volleyball match. Here we consider two major approaches: (a) an ordered multinomial logistic regression model and (b) a model based on a truncated version of the Skellam distribution. For the first model, we consider the set-difference as an ordinal response variable within the framework ofmultinomial logistic regression models. Concerning the second model, we adjust the Skellam distribution to account for the volleyball rules. We fit and compare both models with the same covariate structure as in Karlis & Ntzoufras (2003). Both models are fitted, illustrated and compared within Bayesian framework using data from both the regular season and the play-offs of the season 2016/17 of the Greek national men’s volleyball league A1.
Gkreka, S., Barzouka, K., Drikos, S., & Sotiropoulos, K. (2021). Performance of Male and Female Top-level Outside Hitters Regarding the Spatiotemporal Characteristics of the Volleyball Spike. Inquiries in Sport & Physical Education, 19, 30-45.Abstract
The present study aimed to analyze the attack effectiveness of top-level outside hitters regarding spatiotem- poral parameters, such as the volleyball complex, the position of the setter, the type of opponent block, the tempo and the zone of attack. A three-member team of experienced coaches recorded and assessed 1968 attacks of male (N=800) and female (N=1168) outside hitters from 20 volleyball matches (M=10; W=10) of the six top-ranked teams in Men and Women 2018 World Championships. The assessment was based on a five-level ordinal tactical scale. The test of independence for categorical variables was carried out using χ2 test and Fisher’s exact test. A follow- up correspondence analysis was applied to visualize the entries in the table of relative frequencies. The analysis revealed that male outside hitters were more effective than female in a) the complexes I and II, b) the offensive actions from zones 4 and 6, c) the 2nd fast attack tempo, d) either the setter was in the offensive or defensive line, e) when facing single or double block. Nevertheless, female outside hitters performed fewer unforced errors than male in a) the complex I, b) spikes from zone 4, c) 3rd attack tempo, d) when the setter was on the defensive line and d) the offensive actions facing double block. Finally, the male outside hitters who played according to line-up positions either near the setter (OH1), neither the away from the setter (OH2) were more effective than the female outside hitters but OH1 performed more frequent unforced errors. These findings can lead volleyball coaches to develop specified training plans to improve the performance of outside hitters of both genders.
Sotiropoulos, K., Drikos, S., & Barzouka, K. (2021). Variations in attack patterns between female and male opposite players in top-level volleyball. International Journal of Sports Science and Coaching.Abstract
In volleyball, the opposite player is the most requested hitter since she/he is the player with a higher probability of successfully carrying out attacks. The main objective of this study was to analyze variables that predicted attack effectiveness, in top-level teams depending on gender. Inferential analysis and multinomial logistic regression were applied to analyze 1512 attacks of men and women opposite players from 79 sets of the six top-ranked teams in the Men and Women 2018 World Championships. The analysis revealed that in female volleyball to increase the odds for a winning attack from the opposite player, teams have to pass the ball more accurately, setters have to set in a faster tempo and opposites avoid off-speed attack and spike in a diagonal direction from position 2. On the contrary, in male volleyball the odds for a winning attack from the opposite player are increased when male setters set accurate to the pre-agreement point on the net independent of the quality of the previous pass, opposite players hit in parallel and volleyball coaches select proper line-up and process tactical substitutions to increase the number of rotations with an opposite player in the offensive zone.
Tsakiri, M., Drikos, S., Sotiropoulos, K., & Barzouka, K. (2021). Active and non-active time during elite men and women sitting volleyball matches. Journal of Physical Education and Sport, 21, 1715-1721. presented at the 6, Editura Universitatii din Pitesti.Abstract
This paper aims to determine and sort the rally and break-time duration (including the rest time) in elite men’s and women’s Sitting Volleyball matches. The sample of study comprises 9195 rallies were retrieved from 68 (34 men and 34 women) Sitting Volleyball matches (corresponding to 224 sets) of the 2019 European Sitting Volleyball championship which monitored and recorded. Inter-rater and intra-rater reliability coefficients were estimated using Cohen’s kappa coefficient. The results of the study showed that the total average attempts in the block of serve, setting, attack, block and defence are higher in men compared to women (p≤.001). Also, the duration of the rally was longer in men, 5.98s, compared to 4.98s of women (p≤.001). The non-parametric Kruskal-Wallis test demonstrated that in both genders the highest average rally length was recorded in the 5th set (7.42s for men and 5.4s for women, respectively) and in the 3rd period of that set for men (6.22s) and the 1st period for women (5.06s). For both genders, the highest average break-times were recorded in the 5th set (28.23s for men and 27.73s for women) and, in particular, the 3rd period of that set (23.75s for men and 25.14s for women). According to the study result, one of the reasons contributing to the higher rally length in men’s matches is the higher number of attempts for all Sitting Volleyball skills that men performed comparing to women. The results of this study can be used by players, coaching staff, teams and federations for the organization, design, planning and managing of workouts and matches.
Sotiropoulos, K., Drikos, S., Papadopoulou, S. D., & Barzouka, K. (2021). Characterizing adaptations of serve indicators in top-level male volleyball among seasons. International Journal of Sports Science and Coaching, 16, 784-792.Abstract
{The purpose of this study was to analyse selected serve characteristics in top-level male volleyball, with a special focus on detecting adaptations of the serve skill among seasons. The indicators examined were type, position, direction and quality of serve. The sample consisted of 5482 serves from three final phases of different top-level tournaments (Olympic Games 2012
Drikos, S., Nikolaidou, M. E., Sotiropoulos, K., & Barzouka, K. (2021). Inquiry of discriminant variables to predict success in balanced sets and performance level in elite men's volleyball. In 29th International Conference of Physical Eduaction and Sports (pp. 429-432). WebsiteAbstract
{Effectiveness in the volleyball players' ability to control their postural sway during the game's actions involving contact with the floor (i.e. passing, digging) contributes to the final score. The purpose of this study was to investigate the postural stability performance of female veteran volleyball players (VVP). Sixty nine top-level female VVP were assigned to an active (N=29) and a non-active group (N=40). Due to the age range (43.7-66.7 years) of participants, they were further assigned to a younger (<51 years) and older (≥51 years) age group (Active: Younger=14
M.E., N., Schroll, A., Sotiropoulos, K., Drikos, S., Barzouka, K., & Arampatzis, A. (2021). Postural stability performance in female veteran volleyball players. In 29th International Conference of Physical Education and Sports (pp. 87-91). WebsiteAbstract
{Effectiveness in the volleyball players' ability to control their postural sway during the game's actions involving contact with the floor (i.e. passing, digging) contributes to the final score. The purpose of this study was to investigate the postural stability performance of female veteran volleyball players (VVP). Sixty nine top-level female VVP were assigned to an active (N=29) and a non-active group (N=40). Due to the age range (43.7-66.7 years) of participants, they were further assigned to a younger (<51 years) and older (≥51 years) age group (Active: Younger=14
2020
Drikos, S., Sotiropoulos, K., Barzouka, K., & Angelonidis, Y. (2020). The contribution of skills in the interpretation of a volleyball set result with minimum score difference across genders. International Journal of Sports Science & Coaching, 15, 542-551. presented at the 8, SAGE Publications Inc.Abstract
The aim of the present study was to identify volleyball skills that best discriminate between winning and losing in a set with the minimum score difference of men’s and women’s volleyball. The data have been collected for men from 140 and for women from 98 teams’ performances in all sets finished with 2 points difference between the top four teams in the final ranking during the men’s and women’s Greek Volleyball League for five seasons (2013–2014 until 2017–2018). The primary recorded and evaluated skills from 119 sets for men and women respectively are: 3422 and 2419 serves, 2916 and 2120 passes, 2566 and 1656 attacks after serve’s pass, 1518 and 1804 counter-attacks (after defense) and 1595 and 818 blocks. For the evaluation scale of each skill, a six-level ordinal scale was employed, with the value of “one” indicating a poorly executed skill and the value of “six” an excellent executed skill. The analysis revealed significant multivariate differences in gender and in the type of result and not in their interaction. A follow-up discriminant analysis showed that attack 1 is the most important performance indicator for male teams. Meanwhile, for female teams, the most important performance indicators are winning attack after serve’s pass but also counter-attack. The discriminant function classified correctly 67% and 58%, for men and women respectively, allowing space for further improving the critical performance indicators for both genders.
Frousiou, K., Drikos, S., Sotiropoulos, K., & Barzouka, K. (2020). Comparison of spatiotemporal characteristics and offensive performance of top- level male and female opposite volleyball players per game complex. Exercise & Society, 31-44.Abstract
In volleyball, the opposite player is the most requested hitter since she/he is the player with a higher probability of successfully carrying out attacks. Thus, the main objective of this study was to analyze and compare the spatiotemporal parameters and the effectiveness of attack for opposite players in top-level teams depending on gender. Inferential analysis was applied to analyze 1523 attacks coming from the opposite player (W=910and M=613) from 79 sets (W=42 and M=37) of the top-ranked teams in Women and Men 2018 World Championships. The analysis revealed that in complexes I and II male opposite players attacked more often from zone 1, using 2nd fast attack tempo, against a single or triple block, more effectively in complex I but with more errors in complex II than women. In female volleyball, opposites attacked more often from zones 2 and 6, in 2nd slow and 3rd tempo of attack while they faced up more often than men double or open block. In complex III women opposite players attacked from zone 2, using 2nd slow and 3rd tempo against double block more frequently than men who attacked from zone 1, in 2nd fast tempo against a single or triple block.
Michalopoulos, G., Sotiropoulos, K., Drikos, S., Barzouka, K., & Angelonidis, Y. (2020). Spatiotemporal analysis of setting per game complex and team rotation in junior volleyball. Trends in Sport Sciences, 27, 141-148.Abstract
Introduction. In volleyball, setting is a critical skill from a technical and tactical point of view, as it affects attack directly: the better the quality of the setter’s performance, the more excellent attack actions are carried out by men and women attackers. Aim of Study. This study aimed to assess the spatial and temporal characteristics of the setting choices made by junior male volleyball setters and their performance concerning the game complex per match rotation. Material and Methods. A three-member group of experienced coaches assessed the setting zones choices, the setting tempo, and the performance of junior male setters from 20 volleyball games of teams competing in the final phase of the 2016 Greek Junior Championship. A five-level ordinal scale was used to evaluate the setting. The test of independence for the categorical variables was carried out using the chi-square test (χ2 ). Following the overall independence test, the difference in proportions among all levels of variables was tested. Results. Results showed that zone 4 was the junior setters’ first choice irrespective of the game complex. More detailed, in Complex II, the most preferable setting zones were 4 and 6, while zone 3 was the primary selection in Complex I. The setting in the first tempo was the most favorite option in Complex I, although second slow tempo was the most frequently used setting option in Complex II. As for the quality of the setting, the dominant value for both complexes was quality level 2. Conclusions. In conclusion, the junior male setters directed the ball mainly to position 4 by using the slow 2nd tempo settings irrespective of the game rotation. Moreover, they showed a higher proportion of excellent setting actions and used fast settings (first tempo) more frequently in Complex I than in Complex II. KEYWORDS:
Barzouka, K., Sotiropoulos, K., Drikos, S., Kitsiou, A., & Angelonidis, Y. (2020). Current trends of the serve skill in relation to the in-game roles of the elite volleyball players: Comparison between genders. Journal of Human Sport and Exercise, 16. presented at the 2, Universidad de Alicante Servicio de Publicaciones.Abstract
{The aim of this study was to investigate the current trends of the serve skill for each one of the in-game roles of the players for both genders in high-level volleyball. The serve actions of male (M) and female (F) elite players from 20 volleyball games (M = 10
Kitsiou, A., Sotiropoulos, K., Drikos, S., Barzouka, K., & Malousaris, G. (2020). Tendencies of the volleyball serving skill with respect to the serve type across genders. Journal of Physical Education and Sport ® (JPES), 20, 564-570. WebsiteAbstract
{The purpose of this study was to investigate the areas from which the serves performed by elite volleyball players were carried out, the zones into where they were directed and their performance in respect to the serve type used per gender. A three-member group of coaches assessed the serve actions of male (M) and female (F) elite players from 20 volleyball games (M=10
2019
Drikos, S. (2019). Complex 1 in Male Volleyball as a Markov Chain.. In D. Karlis, Ntzoufras, I., & Drikos, S. (Eds.), MATHSPORT INTERNATIONAL 2019 CONFERENCE (pp. 80-85). Athens University Economics and Business.Abstract
In Volleyball, complex 1 consists of the serve’s pass (reception) - setting - attack skills in this specified order. This sequence is a stable pattern to win a point. Furthermore, it is important for the teams’ success. Taking into account that this pattern is a first-order Markov chain, the creation of a probability transition matrix is feasible. Assuming multinomial likelihood with a Dirichlet prior on the transition probabilities a Markovian transition matrix can be constructed and the calculation of conditional success probabilities is, thus, achievable. Data from the performance analysis of the winning team from recent world championships in three age categories (U19, U21, Men) of male Volleyball is used. The findings lead to redefining target pass area and to shrinking the evaluation scale at least for the teams under study. Moreover, pass accuracy is necessary because it must give at least two options for attack, but not sufficient condition for the success of attack in all age categories for male Volleyball. In the U19 age category, there is a lack of stabilization in the complex 1 sequence after pass against jump spin serve.
Drikos, S., & Tsoukos, A. (2019). Teaching offence system 5:1 and evaluating performance in volleyball based on a spreadsheet.. In 11th Conference on Informatics in Education 2019 (pp. 362-373). University of Piraeus.Abstract
Information and Communication Technologies can have a positive impact on the learning environment by providing Physical Education teachers with a tool-kit for a complementary, alternative form of teaching knowledge objects in the Physical Education area. In volleyball teaching the system 5: 1 (5 hitters-1 setter) is difficult due to the complexity of the rotation rules. An interdisciplinary micro scenario, which includes monitoring of a multimedia application, practicing the team’s rotations by completing a relevant spreadsheet, applying a training protocol with evaluation of volleyball skills accompanied by quantification and visualization of positive, negative or neutral probability in a rally helps students both understand both the 5: 1 volleyball system and elements of Statistics.
2018
Drikos, S., Angelonidis, Y., & Sobonis, G. (2018). The role of skills in winning in different types of set in women’s volleyball. International Journal of Performance Analysis in Sport, 18, 950-960. presented at the 11, Routledge.
Drikos, S. (2018). A longitudinal study of the success factors in high-level male Volleyball. Journal of physical Activity Nutrition and Rehabilitation, 439-449. WebsiteAbstract
n Volleyball a team’s performance in skills is connected to the game result and to the team’s success in a championship. In order to identify the determinant parameters for the success in male volleyball, performance data for all teams of 12 Greek Volleyball championships from 2005-06 until 2016-17 (n=143) was used. The effectiveness of fourteen (14) parameters from 5 basic volleyball skills: serve, attack after passing, attack after defence, block and reception was examined. The findings lead to the conclusion that the best predictors of a team’s success in final ranking are serve aces, passing errors, precise pass and attack after pas sing or after defence. The relevant discriminant function has classified correctly 77.6% of the teams in positions 1-4, 5-8 and 9-12. Furthermore, among teams in positions 1-2 and 3-4 (n=48) the variables attack win and attack error, after reception and de fence have significantly higher scores and are able to discriminate correctly 83,3% of the original cases.
Drikos, S. (2018). Pass level and the outcome of attack for age categories in male Volleyball. Journal of Physical Activity, Nutrition and Rehabilitation, 3, 428-438. WebsiteAbstract
In Volleyball, complex 1 consists of pass-set-attack skills in this specified order. This sequence is a stable pattern to win a point. Furthermore, it is important for teams' success. Taking into account that this pattern is a first-order Markov chain, the creation of a probability transition matrix is feasible. Assuming multinomial likelihood with a Dirichlet prior on the transition probabilities a Markovian transition matrix can be constructed, and the calculation of conditional success probabilities is, thus, achievable. Data from the performance analysis of the winning team from recent world championships in three age categories (U19, U21, Men) of male Volleyball is used. Evaluation of the pass through a six-level ordinal scale is possible after the validation of the entire scale. The findings lead to redefining target pass area and to shrinking the evaluation scale at least for the teams under study. Moreover, pass accuracy is necessary because it must give at least two options for attack, but not sufficient condition for the success of attack in all age categories for male Volleyball. In U19 age category, there is a lack of stabilization in the complex 1 sequence after pass against jump spin serve.
Tsoukos, A., Drikos, S., Brown, L. E., Sotiropoulos, K., Veligekas, P., & Bogdanis, G. C. (2018). Upper and Lower Body Power are Strong Predictors for Selection of Male Junior National Volleyball Team Players. Journal of Strength and Conditioning Research, 1. presented at the 1, Ovid Technologies (Wolters Kluwer Health).Abstract
{The purpose of the present study was to determine whether a battery of anthropometric and lower and upper body strength, speed and power tests predicted selection of young volleyball players for a Junior National Team by expert coaches. Fifty-two male junior volleyball players (14.8±0.5 yrs, height: 1.84±0.05 m, body mass: 72.5±7.1 kg) took part in a training camp and underwent a selection procedure by expert coaches' of the junior national team. Anthropometric data and fitness tests results were obtained and players were graded on a scale from 0 to 100 on the basis of their performance in a volleyball tournament. Selected players were superior in the majority of measured variables (p≤0.017) and had higher grading scores compared with non-selected players (85.3±4.1 vs. 70.5±5.6, respectively, p<0.01). The combination of spike jump and reach test (SJR) and 3 kg medicine ball throw velocity (MB3) explained 63.5% of the variance in expert coaches' grading (p<0.001). A multivariate discriminant analysis yielded a significant discriminant function (Wilk's lambda= 0.55, χ= 29.324, p<0.001, η=0.82). SJR and MB3 were the only variables that contributed to the discriminant function (standardized function coefficients: SJR = 0.68
Drikos, S., & Tsoukos, A. (2018). Data benchmarking through a longitudinal study in high-level men’s volleyball. International Journal of Performance Analysis in Sport, 18, 1-11. Routledge.Abstract
A benchmark is a reference point for comparisons established from the value of a performance indicator. In order to create benchmarks for volleyball, we used performance data from each team of the Greek Volley League from the season 2005-2006 until the season 2016-2017 (N = 143). We considered the effectiveness of 14 parameters from five skills: serve, attack after passing, attack after defence, block and pass. The results showed that high-level teams of the Greek championship, which finished in positions 1-4, had as benchmarks: (a) in serve, two aces every five serve errors, while teams 9-12 had two aces every six errors, (b) in attack after passing one error or one passive block every four kills, while teams 9-12 had one every five kills, (c) in attack after defence one error or one passive block every three kills versus every two kills for 9-12 and (d) one error every nine passes on the target against every seven passes for 9-12. Overall, the results of this study indicate that success in volleyball can be explained with skill performance indicators, expressed as the ratio of successful to unsuccessful attempts, or with a ratio of successful attempts per set, in case of block skill. ABSTRACT FROM AUTHOR
2017
Kountouris, P., Aggelonidis, I., & Drikos, S. (2017). Time characteristics of four consecutive Olympic Volleyball Games after the implementation of the new regulations. Journal of Physical Activity Nutrition and Rehabilitation, 190-198.Abstract
The purpose of the present study was to investigate the time characteristics four consecutive Olympic Games after the implementation of the new regulations, both in men and women. Data concerns the points and the duration of the set and the match as well and the total match duration, from Olympic volleyball games (Sidney 2000, Athens 2004, Beijing 2008 and London 2012). In total 312 matches were analyzed. Results indicated a continuous significant increase in the set and accordingly match durations, both in men and women. Overall the mean set duration for each of the first four sets increased from around 22 minutes in Sydney to 26 minutes in London and the fifth sets increased from around 15 minutes to 17.5 minutes respectively. This may be is a consequence of the teams' primary commitment to performance improvement in the defense tactics and the special attention given to the avoidance of faults. In conclusion, the implementation of the new rules since 2000, especially those related with the change to the rally point system, with each set played to 25 points and the introduction of rule for libero player have forced volleyball coaches and players to reevaluate their strategies and tactics in the goal of winning a rally, a set and a game. The collateral prolongation of the rallies and the increased uncertainty of the outcome have undeniably made the game more spectacular and intriguing to watch.
2015
Kountouris, P., Drikos, S., Aggelonidis, I., Laios, A., & Kyprianou, M. (2015). Evidence for Differences in Men's and Women's Volleyball Games Based on Skills Effectiveness in Four Consecutive Olympic Tournaments. Comprehensive Psychology, 4, 1-7.Abstract
This study compares the differences in effectiveness of the five volleyball skills (serve, reception, attack, block, and dig) between men and women in high- level tournament games played at the last four consecutive Olympics. Results showed that men's and women's volleyball games are completely differentiated by two outcome measures. The first one is the higher proportion of faulty serves performed by men which is essentially attributable to the 19 cm difference in net height, while the second one derives from the fact that men outperform women at the execution of the attack.
2014
Drikos, S., & Kountouris, P. (2014). The Importance of Certain Performance Indicators on Specific Set Types in Volleyball. Inquiries in Sport & Physical Education, 12, 17-25. WebsiteAbstract
The aim of this study was to identify volleyball performance indicators that best discriminate between winning and losing teams in a set according to set final score differences. The data were collected from teams’ performances (N=175) in all sets played during the 2009 Men’s European Volleyball Championship in Turkey. Clusters analysis established three different groups of sets according to set final score difference: 2 points (ambivalent), 3-5 points (safe), >5 points (unbalanced). A Wilcoxon signed rank test was performed on 10 performance indicators and 4 match indicators. The analysis revealed 11 important indicators for all sets have been played and for unbalanced set too, 7 important indicators for safe sets and 1 indicator for a m-bivalent sets. The analysis of ambivalent sets showed that the winning teams had a statistically significant (p <0.001) percentage of points from direct attack compared to the defeated teams. The resu lts confirm that coaches of men’s volleyball team should attach importance to improving offensive capacities of athletes
Bakodimos, G., Kasampalis, A., Drikos, S., & Dimitriadis, J. (2014). The correlation between the type of pass after float serve and the efficiency of attack in men’s elite volleyball. In 22nd International Congress of Physical Education & Sport (pp. 206-211). Democritus University of Thrace,.Abstract
The changes of regulations affect the development of all sports. In volleyball one of the key changes in the 1998 regulations was that players were allowed to pass the float serve with upper head pass technique. The outcome of this change was the use of this as main technique by numerous players mostly in float serve. At the last congress of the FIVB proposed repealing regulation, ' as in volleyball on sand, but was not accepted. Reception serve is part of the syndrome 1 Volleyball and important to the success of attack, but also for the game success, while the speed of the attack in Volleyball Men is a predictor for the final result of the game.The purpose of this research is to highlight the differences in the effectiveness of the attack syndrome1 Volleyball depending on the type of pass to the float serve or jump from the ground. The data comes from recording the technical skill of the pass after float serve (N >15.500) of 176 games performance teams (88 races for 2 groups) of the season 2012‐13 A1 National Men category . The technical skills are assessed (dropping to 5‐level ordinal scale) the type of pass used (with U.h or L.h) , the zone in which the passer is located (in nominal scale six levels) , the zone of which the attack took place (in nominal range 5 levels) ,and the efficiency of theattack (on regular 3‐level scale) . The interatomic control of reliability was tested with the log Cohen K coefficient and weighted Coehn K.For the statistical processing of data applied logistic regression by the method of maximum probabilities. Results showed that all the passes with L.h technique were more than the total passes with UH technique and efficacy of attack after the L.h is better, than the effectiveness of the attack after the UH pass technique.
2011
Drikos, S., & VAGENAS, G. E. O. R. G. E. (2011). Multivariate assessment of selected performance indicators in relation to the type and result of a typical set in men’s elite volleyball. International Journal of Performance Analysis in Sport, 11, 85-95.Abstract
The aim of this study was to identify volleyball performance indicators that best discriminate between winning and losing teams in a set according to set final score differences. The data were collected from teams’ performances (N=350) in all sets played during the 2009 Men’s European Volleyball Championship in Turkey. Clusters analysis established three different groups of sets according to set final score difference: 2 points (ambivalent), 3-5 points (safe), >5 points (unbalanced). A 3x2 MANOVA (type of set x type of result) was then performed on 9 performance indicators reflecting % expressions of four basic skills of the game (serve, pass, attack, block). The analysis revealed significant multivariate differences in type of set, in type of results, and in their interaction. A follow-up Discriminant Analysis showed that effectiveness of attack is the most important performance indicator for all types of sets, far more for the ambivalent ones. The discriminant function correctly classified increasing % of cases with increase in score difference. Especially for ambivalent sets 67.3% were correctly classified, letting some space for further improving the critical performance indicators. The results suggest that training of a men’s volleyball team should emphasize more to improve offensive abilities.
2009
Drikos, S., Kountouris, P., Laios, A., & Laios, Y. (2009). Correlates of Team Performance in Volleyball. International Journal of Performance Analysis in Sport, 9, 149-156.Abstract
The overall performance of a Volleyball team depends on many factors, from which decisive are considered to be the execution of skills that lead immediately to winning or losing the rally. These are lost serves, aces, kill- attacks, attack errors and kill-blocks. The analysis of these skills in relation to team performance, as expressed by the ratio of sets won to the total number of sets, lead to the formation of two new correlates. These are the serving efficiency ratio (SER), defined as the ratio of lost serves to aces, and the attack efficiency ratio (AER), defined as the number of kill attacks divided by the sum of attack errors and kill-blocks. Analysis of the data collected from all the matches of the male A1 volleyball professional league of 2005-2006 in Greece proved that the two efficiency ratios were better predictors of the teams overall performance than the five original variables. The findings lead to clear-cut definitions of norms both for the serving and attack efficiency ratio. The leading teams had a SER of around two and an AER of around three. These criteria are valuable tools especially for Volleyball coaches in deciding for the appropriate tactics of their teams.
2008
Drikos, S., & Kountouris, P. (2008). The relationship between volleyball skills and final ranking in high level men’s Volleyball.. In A. Hökelmann & Brummund, M. (Eds.), World Congress of Performance Analysis of Sport VIII (pp. 284-289). Otto-von-Guericke-Universität Magdeburg. Website