Top-level Players Research Articles

ESPORT: Electronic Sports Professionals Observations and Reflections on Training

Abstract Esports and high-performance human-computer interaction are at the forefront of implementing new hardware and software technologies Despite that, there is a paucity of research on how championship-level esports professionals approach aspects of their preparation. To begin addressing this gap, we conducted, transcribed, and analyzed interviews with top-level tournament players, coaches, and managers in the period 2015–2019. The interviews focused on mental, physical, and nutritional aspects of esports preparation. Initial processing included transcription and manual verification. Furthermore, where applicable, interview responses were rated and quantified by a panel of experts. Physical training was most often mentioned as a relevant or consistent activity, while nutrition was indicated as relatively unimportant. Qualitative analysis indicated that consistency and resilience are key factors for upcoming esports competitors to focus on. Interviewees also emphasized balancing their gameplay time with other activities. Lastly, we identified important areas critical for a deeper understanding of the mental and physical demands of professional esports players.

Effects of the Surface Type on the Sprint Force–Velocity–Power Profile of Female Beach Handball Top-Level Players

Beach handball (BH) is characterized by high-intensity actions, such as accelerations and short rest times, in combination with long periods of low-intensity activity during a match. The purpose of this study was to establish a comparative analysis between the effect of a hard surface vs. sandy surface on the properties of the sprint Force–Velocity–Power Profile (FVP) of female beach handball top-level players. Fourteen female BH players participated in this research. A cross-sectional investigation was performed in order to evaluate the determining variables of the FVP profile for different surfaces. After a specific warm-up, two maximal 20–30 m sprints (4 min resting between trials) were performed in two conditions (hard surface and sand) within 10 min. The female BH players showed higher mean values for all the FVP profile variables (p < 0.001) on the hard surface compared to sand, in addition to lower values for the 5 m (ES = 2.29 to 3.89) and 20 m sprinting times (ES = 2.39 to 3.99) (p < 0.001). However, the decrease in the ratio of force over acceleration was not discriminant between the surfaces. Positive correlations were found for the speed variables (0.691–0.807, p < 0.01), as well as the Pmax (0.520, p = 0.035), between the surfaces. A prior knowledge of the FVP profile for hard–sandy surfaces could offer an important reference value about the sprint properties of this population, and be useful for evaluating the efficiency, as well as the effect on the sprint and gaming performance, of specifically oriented training programs based on those reference values.

ACTN3 XX Genotype Negatively Affects Running Performance and Increases Muscle Injury Incidence in LaLiga Football Players.

The aim of this study was to investigate the association of the ACTN3 rs1815739 polymorphism with match running performance and injury incidence in top-level professional football players. A total of 315 top-level professional football players from the first division of Spanish football (i.e., LaLiga) participated in this prospective and descriptive study. The ACTN3 rs1815739 genotype was identified for each player using genomic DNA samples. During LaLiga 2021-2022, players' performance was obtained through a validated camera system in all official matches. Additionally, the incidence of non-contact injuries was obtained by each team's medical staff according to the International Olympic Committee (IOC) statement. From the study sample, 116 (36.8%) players had the RR genotype, 156 (49.5%) had the RX genotype, and 43 (13.7%) had the XX genotype. The anthropometric characteristics of the players were similar across genotypes. However, the total running distance (p = 0.046), the distance at 21.0-23.9 km/h (p = 0.042), and the number of sprints (p = 0.042) were associated with the ACTN3 genotype. In all these variables, XX players had lower match performance values than RR players. Additionally, total and match injury incidences were higher in XX players than in RR players (p = 0.026 and 0.009, respectively). The rate of muscle injuries was also higher in XX players (p = 0.016). LaLiga football players with the ACTN3 XX genotype had lower match running performance and a higher incidence of non-contact injuries over the season.

Multiple regression analysis for competitive performance assessment of professional soccer players.

Being in peak physical condition and having specific motor abilities are necessity for every top-level soccer player in order to achieve success in competition. In order to correctly assess soccer players' performance, this research uses laboratory and field measurements, as well as results of competitive performance obtained by direct software measurements of players' movement during the actual soccer game. The main goal of this research is to give insight into the key abilities that soccer players need to have in order to perform in competitive tournaments. Besides training adjustments, this research also gives insight into what variables need to be tracked in order to accurately assess the efficiency and functionality of the players. The collected data need to be analyzed using descriptive statistics. Collected data is also used as input for multiple regression models that can predict certain key measurements: total distance covered, percent of effective movements and high index of effective performance movements. Most of the calculated regression models have high predictability level with statistically significant variables. Based on the results of regression analysis it can be deduced that motor abilities are important factor in measuring soccer player's competitive performance and team's success in the match.

Association Between Total Genotype Score and Muscle Injuries in Top-Level Football Players: a Pilot Study

BackgroundRecently, genetic predisposition to injury has become a popular area of research and the association between a few single nucleotide polymorphisms (SNPs) and the susceptibility to develop musculoskeletal injuries has been shown. This pilot study aimed to investigate the combined effect of common gene polymorphisms previously associated with muscle injuries in Italian soccer players.ResultsA total of 64 Italian male top football players (age 23.1 ± 5.5 years; stature 180.2 ± 7.4 cm; weight 73.0 ± 7.9 kg) were genotyped for four gene polymorphisms [ACE I/D (rs4341), ACTN3 c.1729C > T (rs1815739), COL5A1 C > T (rs2722) and MCT1 c.1470A > T (rs1049434)].Muscle injuries were gathered for 10 years (2009–2019). Buccal swabs were used to obtain genomic DNA, and the PCR method was used to genotype the samples. The combined influence of the four polymorphisms studied was calculated using a total genotype score (TGS: from 0 to 100 arbitrary units; a.u.). A genotype score (GS) of 2 was assigned to the “protective” genotype for injuries, a GS of 1 was assigned to the heterozygous genotype while a GS of 0 was assigned to the “worst” genotype.The distribution of genotype frequencies in the ACE I/D (rs4341), ACTN3 c.1729C > T (rs1815739) and MCT1 c.1470A > T (rs1049434) polymorphisms was different between non-injured and injured football players (p = 0.001; p = 0.016 and p = 0.005, respectively). The incidence of muscle injuries was significantly different among the ACE I/D (rs4341), ACTN3 c.1729C > T (rs1815739) and COL5A1 C > T (rs2722) genotype groups, showing a lower incidence of injuries in the “protective” genotype than “worse” genotype (ACE, p < 0.001; ACTN3, p = 0.005) or intermediate genotype (COL5A1, p = 0.029).The mean TGS in non-injured football players (63.7 ± 13.0 a.u.) was different from that of injured football players (42.5 ± 12.5 a.u., p < 0.001). There was a TGS cut-off point (56.2 a.u.) to discriminate non-injured from injured football players. Players with a TGS beyond this cut-off had an odds ratio of 3.5 (95%CI 1.8–6.8; p < 0.001) to suffer an injury when compared with players with lower TGS.ConclusionsThese preliminary data suggest that carrying a high number of "protective" gene variants could influence an individual's susceptibility to developing muscle injuries in football. Adapting the training load parameters to the athletes’ genetic profile represents today the new frontier of the methodology of training.

Prevalence of hip femoroacetabular impingement deformities in high-level (La Liga) male professional football players.

Femoroacetabular impingement (FAI) is considered one of the main causes of hip osteoarthritis in young adults, especially in athletes. In recent years, morphological changes in FAI in the hip have been linked to early and intense sports participation, but studying top-level athlete samples is not easy. This paper presents the prevalence of FAI radiological markers in 120 active white male professional football players in the Spanish First Division League (La Liga) and compares the morphological changes with those of a control group of healthy individuals without significant sport activity. The precontract medical evaluation hip X-rays of 120 white male professional football players from four different First Division Spanish football teams were prospectively filed and retrospectively reviewed by a dedicated skeletal radiologist. The footballers' hip X-rays were compared with those of a control group of 80 healthy individuals (age-sex matched) without significant sport activity (obtained from routine work medical checks). The femoral head-neck deformity associated with the Cam type of femoroacetabular impingement was observed in 61.6% of professional football players and only in 11.6% of the control group (p <0.01). The presence of "herniation pit" (11.6%) and os acetabuli (13.3%) also reached statistical significance in the professional football players group. In the other analyzed parameters, no statistically significant differences between the groups were observed. White professional top-level football players have an increased incidence of abnormal lateral epiphyseal extension ("pistol grip deformity"), os acetabuli and herniation pits.

Prognostic Power of Foot Mobility in Identifying the Risk of Musculoskeletal Injuries: A Cross-Sectional Study of Male Volleyball Players at Different Competitive Levels.

(1) Background: The arch structure and mobility of the foot are considered injury risk factors in volleyball. However, there are limited studies presenting differences in injury prevalence and the risk of lower limb injuries in relation to the competitive level in male volleyball. Therefore, the main aim of the current study was to evaluate foot mobility (through navicular drop test) as an injury risk factor in volleyball players from different competitive levels. (2) Methods: The reliability and usefulness of navicular drop testing were initially assessed in test-retest procedures (based on a sample of eight participants and 16 feet measurements), with primary analyses conducted using foot measurements of the twelve top-level volleyball players (24 feet) and eighteen academic-level volleyball players (36 feet). The modified navicular drop test was conducted, and the feet were classified based on arch height, and injury prevalence was retrospectively assessed with a previously validated questionnaire. Chi-squared tests, receiver operating curves, and logistic regression were used as statistical methods. The navicular drop test was verified as a reliable tool by intraclass correlation coefficient (ICC) (3.1) analysis. (3) Results: There were no significant differences in injury prevalence between academic- and top-level volleyball players, though there was a significant relationship between pronated foot and injury risk independent of competitive level. Generally, for both groups, thresholds above 10 mm of the navicular drop were predictors of lower limb injuries. The risk of injury if the foot was pronated ranged from 70% (academic level) to over 90% (top-level players). However, no statistically significant effect of competitive level on the chance of injury was observed. (4) Conclusions: Our study found a high prevalence of foot injuries independently of competitive level. There was a relationship between pronation of the foot and the risk of injury. However, the risk of lower limb injury was higher in pronated top-level players. Also, a navicular drop greater than 10 mm was an excellent predictor of injuries at both competitive levels.

A model of a two-level hierarchical system with cooperative behavior of lower-level elements

One of the possible generalizations to the case of many persons of the classical hierarchical Germeier game is investigated. It is assumed that the lower level players choose one of the weakly efficient points. The maximal guaranteed result of the top-level player is calculated. Two variants of formulation of the problems are considered: games with and ithoutfeedback.

Are the somatotype still a useful method for selection in volleyball?

The goal of this research was to determine whether the somatotype is still a useful method that can be used to confirm the selection of young and promising volleyball players. For this purpose, groups of volleyball players of different age (U16 and U18) and status affiliation (starters and substitutes) were compared by means of calculated somatotypes. The sample of examinees was formed by top-level young Croatian female volleyball players (n=28, age=15.7±1.0 years, body height=179.6±7.2 cm body weight=64.8±7.0 kg), which was further then divided into subsamples regarding age category (U16 and U18) and team status (starters, non-starters). Players’ somatotype was calculated according to the Heath-Carter method, whereas the significance of differences between the groups was determined with the t-test for independent samples. The average somatotype of all players was calculated as a balanced ectomorph, and accordingly also for subsamples U16 balanced ectomorph and U18 endomorphic-ectomorph, while for starters endomorphicectomorph and for non-starters central somatotype. In addition, upon analysis of the somatotype of all players, it was determined there was a total of 10 categories out of the possible 13 somatotypes, and that among those the most represented were endomorphic-ectomorphs (39.3%) and central somatotypes (17.9%). Among players in the U16 and U18 age categories there were no differences determined in none of the somatotype components, whereas among starters and non-starters differences occurred only in the ectomorph somatotype component.

Kinematic and Neuromuscular Ranges of External Loading in Professional Basketball Players during Competition

Personalization of workloads is essential for optimizing training processes and minimizing the risk of injuries in sports. Precise knowledge of the external load demands borne by basketball players during competition is necessary for this purpose. The objective of this research was to determine the objective external load demands of five variables during a basketball competition, three kinematic (speed, accelerations, and decelerations) and two neuromuscular variables (impacts/min and Player Load/min), and subsequently establish workload ranges. Six official matches from preparatory tournaments involving professional basketball players from the Spanish first division, Liga ACB, were analyzed. Inertial devices and an UWB system were used for variable localization and recording within indoor spaces. Two methods, two-step and k-means clustering, were employed for workload range classification. The results revealed different workload thresholds clusters based on the data analysis technique used. The following speed ranges were identified in professional basketball players: Standing, &lt;2.95 km/h; Walking, 2.96 to 7.58 km/h; Jogging, 7.59 to 12.71 km/h; Running, 12.72 to 17.50 km/h; and Sprinting, &gt;17.51 km/h. The center of cluster 5 was found to determine the concept of a sprint (&gt;19 km/h) as well as high-speed running (&gt;17.50 km/h). Acceleration and deceleration ranges displayed few cases but with considerably high values, which must be considered when designing injury prevention tasks. The distribution of impacts showed a normal pattern, with identified periods during which players withstood significant G-forces (14%). Finally, the Player Load value at which an activity is considered to be very high, 1.95 au/min, was identified. Considering the obtained results, basketball is proposed as a sport with a high neuromuscular load. Coaches should choose the classification method that best suits their needs. These reference values are the first of their kind for this population of top-level professional players and should aid in adjusting training processes to match competition demands.

Effects of the New COVID-19-Induced Rule on Substitutions and Performance in Italian Elite Soccer.

COVID-19 has resulted in widespread changes, including within the realm of sports. Professional soccer has adapted by allowing more substitutions, leading to tactical adjustments and potential physical benefits. Accordingly, this study analyzed the impact of the new rule in Italian top-level soccer, focusing on substitution patterns and performance differences between the pre-COVID (2017-2018, 2018-2019 seasons) and post COVID (2020-2021, 2021-2022 seasons) eras. As such, publicly available data from 1520 matches (760 matches per era) were recorded. The sample included matches played from 40 Italian top division teams in both the pre- and post-COVID eras. Analyses confirmed substitutions follow a consistent temporal pattern throughout the match in both eras, highlighting a slight difference in second-half management, and showed the new rule is still not used to its full potential, thus raising concerns about teams' financial strength, as not all managers possess "deep benches" (i.e., a large number of top-level players available to play). Further analyses revealed a statistically significant increment (p = 0.002) in the quantity of collectively produced sprints in the post-COVID era compared to the pre-COVID one. The results from this study emphasize the need to carefully address sprint preparation and repeated sprint abilities, also considering factors such as the number of substitutes and their skill level.

Physical-Performance Changes Over the Season: Are They Related to Game-Performance Indicators in Elite Men Volleyball Players?

The development and influence of physical capabilities and game action performance over the course of the season are a big challenge for coaches and players. The aims of the present study were to examine (1)the seasonal changes in the physical capabilities (mechanical and kinematic) and game-performance indicators in top-level men volleyball players and (2)the relationship between these physical capabilities and game-performance indicators in official matches. Eleven top-level players participated. Players were physically tested 3 times during the season. Before each test, players' match performance (11 sets) was analyzed according to the level of opposition and match location. The percentage of change, statistical differences over the season (Friedman and Wilcoxon tests), and associations between variables (Spearman r) were calculated (P < .05) among mechanical (force-velocity profile during vertical jump and bench press), kinematic (jump height and spike ball speed), and game action performance features (coefficient, efficacy, and percentage of errors in serve, attack, and block). The theoretical maximal force and velocity during vertical jump and bench press, respectively; the peak spike ball speed; and the serve efficacy significantly increased over the season. Moreover, there was a significant reduction in serve errors as the jump height increased (r = -.44; P = .026), as well as a significant increase in serve errors as the peak spike ball speed increased (r = -.62; P = .001). These findings reveal how the physical and game action performance variables evolve and interact during the season. This may help coaches and trainers to monitor and analyze the most relevant volleyball performance factors.

Somatotypes of Top Croatian Male Volleyball Players

Situational efficiency of volleyball players depends on many factors, including specific ones in the area of morphology. The specialization of playing roles implies the performance of specific motor tasks, and therefore a specific combination of morphological factors necessary for the player’s efficiency. This study aimed to determine the somatotypes of groups of top-level volleyball players divided according to their playing role. The research was conducted on 40 (body height 192.22±8.58 cm, body weight 86.93±11.22 kg, age 24.18±4.97 years) male volleyball players from the Croatian A1 volleyball league. According to the playing role, 10 setters (body height 191.21±6.39 cm, body weight 84.12±8.76 kg, age 24.12±6.77 years), 10 middle blockers (body height 199.97±4.41 cm, body weight 94.82±6.67 kg, age 26.05±26.05 years), 10 liberos (body height 181.71±5.71 cm, body weight 74.97.21±5.59 kg, age 22.67±2.88 years) and 10 outside hitters (body height 196.06±4.34 cm, body weight 93.80±10.29 kg, age 23.89±5.53 years). Heath-Carter method was used for the somatotype determination. A statistically significant difference between the groups was detected in Body height, Body weight, Flexed arm girth circumference, Flexed calf girth circumference and Calf skinfold. The determined somatotypes for setters (2.8 - 3.8 - 3.4) and middle blockers (2.3 - 3.8 - 3.6) are mesomorph-ectomorph, and liberos (2.4 - 4.6 - 3.0) and outside hitters (2.5 - 4.3 - 3.1) are ecto-mesomorph. The results are in line with previous research. This confirms the importance of the longitudinal dimensionality of the skeleton in volleyball. In the future, we can expect the growth of the ectomorph component, with a stagnation or slight increase in the mesomorph component of the somatotype in top level volleyball.

The Role of the Specific Strength Test in Handball Performance: Exploring Differences across Competitive Levels and Age Groups.

The aim of this study was to determine if specific physical tests are sufficiently discriminant to differentiate players of similar anthropometric characteristics, but of different playing levels. Physical tests were conducted analyzing specific strength, throwing velocity, and running speed tests. Thirty-six male junior handball players (n = 36; age 19.7 ± 1.8 years; 185.6 ± 6.9 cm; 83.1 ± 10.3 kg; 10.6 ± 3.2 years of experience) from two different levels of competition participated in the study: NT = 18 were world top-level elite players, belonging to the Spanish junior men's national team (National Team = NT) and A = 18 players of the same age and anthropometric conditions, who were selected from Spanish third league men's teams (Amateur = A). The results showed significant differences (p < 0.05) between the two groups in all physical tests, except for two-step-test velocity and shoulder internal rotation. We conclude that a battery combining the Specific Performance Test and the Force Development Standing Test is useful in identifying talent and differentiating between elite and sub-elite players. The current findings suggest that running speed tests and throwing tests are essential in selecting players, regardless of age, sex, or type of competition. The results shed light on the factors that differentiate players of different levels and can help coaches in selecting players.

Muscle Contractile Properties Measured by the Tensiomyography (TMG) Method in Top-Level Football Players of Different Playing Positions: The Case of Serbian Super League.

The aim of this study is to investigate the differences in muscle contractile properties measured by the TMG method between top-level football players of different playing positions. The sample consisted of 57 football players from the Serbian Super League, divided into three groups: defenders-DF, midfielders-MF, and forwards-FW. Muscles included in the study were the Rectus Femoris (RF), Vastus Medialis (VM), Vastus Lateralis (VL), Biceps Femoris (BF), and Semitendinosus (ST) of the right (R) and left (L) leg. The TMG parameters used in this study were contraction time (Tc), delay time (Td), relaxation time (Tr), maximal displacement (Dm), and sustain time (Ts). The ANOVA results showed that differences in TMG parameters between top-level football players of different playing positions are small and exist only in the Tr of RF (F = 4.658, p = 0.014), BF (F = 4.433, p = 0.016), and ST muscle (F = 3.808, p = 0.028), and the Tc (F = 3.214, p = 0.048) and Td (F = 3.705, p = 0.031) of the VM muscle. All differences were detected between DF and FW players, and all differences were in the left (non-dominant) leg. The results obtained in this study indicate that the training and selection process in football, from the aspect of functional and mechanical muscle properties, should be similar for all players, regardless of playing position. It has been shown that TMG has relatively low sensitive strength for detecting differences between football players of different playing positions.

Within-season Adaptations in Physical, Physiological and Technical-tactical Performance of Experimented Futsal Players

This study analysed the seasonal variations in futsal players’ physical, physiological, and technical–tactical performance. Eight senior futsal players from the same team were monitored at three time points in the season (beginning of the preseason, middle of the first half of the season, and middle of the second half of the season). A progressive and intermittent shuttle-running test (the futsal intermittent endurance test) was applied to collect the following variables: maximum velocity, distance covered, total distance covered, test duration, initial heart rate, peak heart rate, peak blood lactate concentration, and rating of perceived exertion. In addition, different match-performance variables were assessed during a simulated futsal match (goals scored, shots on goal, successful passes, balls lost, balls recovered, and goals conceded). Results indicated that the physiological variables of initial heart rate (p&lt;.001, η2=.862) and peak blood lactate concentration (p=.001, η2=.640) significantly varied over the course of the season. However, no significant differences were found in the physical and technical–tactical variables. This study has implications for sport practitioners; specifically, it emphasizes that preseason and in-season training load periodization enhances the physiological fitness of top-level futsal players, although their physical and technical–tactical performance remained relatively stable.

Reducing Big Data to Principal Components for Position-Specific Futsal Training.

Since training/competition loads must be quickly assessed and interpreted to inform exercise prescription, big data should be simplified through multivariate data analysis. Our aim in the present research was to highlight which variables from big data analyses provided the most relevant information for describing the behavior of top-level futsal players in their different playing positions (i.e., goalkeeper, defenders, wingers, and forwards). We collected data from four top-level Spanish teams that participated in the final rounds of a national tournament. Through principal component analysis (PCA) we grouped 6-9 variables in 3-4 PCs that explained 62-81% of total variance, depending on playing positions. The most relevant variables explaining goalkeepers' performance were accelerations per minute, maximum acceleration (m/s2), 5-8 impacts per minute, and < 3 takeoffs per minute. Defenders' behavior was best explained by absolute distance covered from 6-12km/h (m/min) and from 18-21km/h (m/min), from 5-8 landings per minute, and > 8 landings per minute. Wingers' and pivots' performances were mainly explained by accelerations and decelerations, together with a high level of aerobic endurance (especially for wingers). These findings allow for individualized training and game analysis.

Temporal and Spatial Structure of Collective Pass-Chaining Action Performed by Japanese Top-Level Field Hockey Players.

In real hockey or soccer games, scoring opportunities usually occur quite rarely, and thus, for most of the duration of a game, the ball is drifting between the two goals. This pass-chaining situation can be regarded as the stable state of the offense–defense interaction. In the current study, temporal and spatial structure of this dynamical state was unveiled via quantification of the “defensive pressure distribution” on the pass trajectory, which was modeled as a non-linear function of the distance between the defender(s) and a given position on the pitch. Two groups, i.e., a top-level group and a less-skilled group, of Japanese collegiate hockey players were asked to play in 3-on-3 small-sided games between players of the same skill levels. When both the top-level and less-skilled players succeeded in passing the ball, there were no skill-level differences observed in the defensive pressure distribution on the pass trajectory. In these cases, the defenders put a certain level of pressure on the middle of the pass trajectory when the passer received a previously released pass, and later, when he released the ball to a teammate, the defenders approached the position at which the passer released the ball to intensively press on the passer. However, in the cases wherein they failed to thread the ball, clear differences were observed between the groups in terms of the defensive pressure distribution on the pass trajectory. In particular, for the less-skilled group, extremely intensive defensive pressure was put on the overall regions of the pass trajectory heavily concentrated on the timing at which the passer released the pass. This unique pressure distribution emerged for the less-skilled group because of their long ball-keeping duration (longer than 1 s and also longer than that for the top-level group), i.e., from the moment the passer received the ball, to the moment he released it to the next attacker. Thus, for top-level hockey players, a short time constant (less than 1 s) for the passing action will enable the passers to avoid extremely intensive defensive pressure, and enable the emergence of a dynamically stable attack–defense deadlock state through continuous chaining of the pass.

Validity of the Swimming Capacities and Anthropometric Indices in Predicting the Long-Term Success of Male Water Polo Players: A Position-Specific Prospective Analysis over a Ten-Year Period.

Long-term predictors of success in water polo are rarely reported. This study aimed to evaluate the position-specific validity of the swimming and anthropometric/body build tests on the prediction of the long-term success of male water polo players. The participants were 85 top-level players observed at baseline (junior level, when they were 17–18 years of age; 35 centers and 50 perimeter players) in tests of swimming capacities (15 m water polo sprint, 25 m sprint, and 100 and 400 m freestyle swimming) and anthropometric/body build indices (body mass, body height, arm span, body mass index, and body fat percentage). Over a period of 10 years, participants’ senior-level success was prospectively observed. Multinomial logistic regression with three levels of criteria (high achievement, medium achievement, and low achievement at the senior level) was applied to identify the predictive validity of the swimming and anthropometric/body build indices. For the total sample (not dividing perimeter from center players), all observed swimming capacities, body height, and arm span were significantly associated with success, with more successful players being taller, with a longer arm span, and superior swimming capacities. Body height and 100 m freestyle swimming were significant predictors of success among centers. Achievement in 100 and 400 m freestyle swimming, body height, and a lower percentage of body fat were correlated with higher senior-level performance in perimeter players. The results showed better validity of the anaerobic-lactate and aerobic swimming tests than sprint swimming in predicting the long-term achievement of male water polo players. Differences in the influence of swimming capacities and body-build indices on senior-level success between observed playing positions are related to differences in game duties, playing time, and consequent metabolic demands.

A Comprehensive Analysis of the Serve Reception Zone, Set Zone and Attack Quality of the Top-Level Volleyball Players

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 inthe 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&lt;0.05. Moreover, the effect size was calculated in terms of Crammer’s V, with values of&lt;0.1,0.1-0.3 and &gt;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.