Players In Different Positions Research Articles

Differences in Physical Indexes between Football Players of Different Playing Positions and Correlation to the Weekly Training Load

The aim of this study was twofold: (a) to examine the differences on physical indexes between players of different playing positions and (b) to reveal the correlations between their physical parameters and the running profile within the weekly microcycles. The subjects (n = 44) were separated into five positions: central defenders (n = 7), wide defenders (n = 9), midfielders (n = 13), wingers (n = 8) and strikers (n = 7), and all of them belonged to a professional 1st division European team during the 2020–21 and 2021–22 seasons. An incremental treadmill protocol was used to assess the VO2max, vVO2max and the vRER in the last week before the regular season. Then, during the first semesters, external load data were collected for two consecutive seasons to analyze the running profiles of the different positions. There were no differences on physical parameters between the players of various positions, but interestingly there were different correlations with the external load during the microcycles. Central defenders did not show any correlation. For the other positions, correlations were found between respiratory exchange ratio (vRER) and metabolic power efforts (MPWEF) (p = 0.028, r = 0.721) for wide defenders, between vRER and medium intensity accelerations (ACC2) (p = 0.004, r = 0.741) for midfielders, medium intensity decelerations (DEC2) (p = 0.01, r = 0.685), metabolic power zone 5 (MPW5) (p = 0.016, r = 0.652), MPWEF (p = 0.005, r = 0.725), and also between maximal rate of oxygen consumption (VO2max) and high intensity decelerations (DEC3) (p = 0.045, r = 0.564), metabolic power zone 4 (MPW4) (p = 0.026, r = 0.614), MPW5 (p = 0.017, r = 0.646), MPWEF (p = 0.01, r = 0.685). A correlation between velocity on VO2max (vVO2max) and ACC2 (p = 0.038, r = 0.733), MPW5 (p = 0.005, r = 0.873), and MPWEF (p = 0.009, r = 0.84) was found for the wingers. Finally, there was a correlation between vRER and MPWEF (p = 0.026, r = 0.866), and between vVO2max and high intensity accelerations (ACC3) (p = 0.03, r = 0.801) for the strikers. Our study supports that the external load of players in different positions during the training sessions is correlated with their physical indexes. These correlations are determined mostly by their tactical role, but not from their physical level, as there were no differences.

Intensity Thresholds for External Workload Demands in Basketball: Is Individualization Based on Playing Positions Necessary?

Currently, basketball teams use inertial devices for monitoring external and internal workload demands during training and competitions. However, the intensity thresholds preset by device manufacturers are generic and not adapted for specific sports (e.g., basketball) and players' positions (e.g., guards, forwards, and centers). Using universal intensity thresholds may lead to failure in accurately capturing the true external load faced by players in different positions. Therefore, the present study aimed to identify external load demands based on playing positions and establish different intensity thresholds based on match demands in order to have specific reference values for teams belonging to the highest competitive level of Spanish basketball. Professional male players (n = 68) from the Spanish ACB league were monitored during preseason official games. Three specific positions were used to group the players: guards, forwards, and centers. Speed, accelerations, decelerations, impacts/min, and player load/min were collected via inertial devices. Two-step clustering and k-means clustering categorized load metrics into intensity zones for guards, forwards, and centers. Guards covered more distance at high speeds (12.72-17.50 km/h) than forwards and centers (p < 0.001). Centers experienced the most impacts/min (p < 0.001). Guards exhibited greater accelerations/decelerations, albeit mostly low magnitude (p < 0.001). K-means clustering allowed the setting of five zones revealing additional thresholds. All positions showed differences in threshold values (p < 0.001). The findings provide insights into potential disparities in the external load during competition and help establish position-specific intensity thresholds for optimal monitoring in basketball. These data are highly applicable to the design of training tasks at the highest competitive level.

What is the visual behaviour and attentional effort of football players in different positions during a real 11v11 game? A pilot study.

Visual perception has been defined as the first step to a football player's decision-making process and it plays an important role in performance in sport. The skill of focussing to prioritize relevant cues has been also considered crucial in sport. This pilot study aims to explore the visual behaviour and attentional effort of three football players (mean age 19 ± 0 years old) in specific-role positions; Right-winger (RW), Centre-Midfielder (CM) and Left-Back (LB), in the five seconds before receiving the ball from their teammate. Twenty-two male football players performed an 11v11 game, where 24 game sequences (trials) from which 166 fixations were recorded and analysed via the Tobii Pro eye-movement registration glasses and software. The gaze behaviour dependent variables were the mean of fixation duration (FD), time to first fixation (TTF), both measured in milliseconds (ms), and the number of fixations (NF) on eight areas of interest (AOIs). AOIs include teammate with and without the ball, opponent without the ball, space around teammate with and without the ball, space around opponent without the ball, ball and undefined. The mean pupil diameter (PD) correlates to the attentional effort and was measured in millimetres (mm). Descriptive statistics showed nonregular search rate data between the participants in FD, TTF, NF on the AOIs. Mean FD on the ball: (CM, 270 ms), (RW, 570 ms), (CM, 380 ms). They also presented differences in the mean PD during play; (CM: 2.90 mm ± 0.26), (RW: 2.74 mm ± 0.30), (LB 2.77mm ± 0.27). Albeit the sample size was small, the findings demonstrated a promising way to measure the on-field perceptual-cognitive abilities of football players according to their specific positions, since different playing roles revealed to present distinctive visual and attentional patterns. This could potentially assist in tailoring players 'visual and focus training.

What is the visual behaviour and attentional effort of football players in different positions during a real 11v11 game? A pilot study

Background Visual perception has been defined as the first step to a football player’s decision-making process and it plays an important role in performance in sport. The skill of focussing to prioritize relevant cues has been also considered crucial in sport. This pilot study aims to explore the visual behaviour and attentional effort of three football players (mean age 19 ± 0 years old) in specific-role positions; Right-winger (RW), Centre-Midfielder (CM) and Left-Back (LB), in the five seconds before receiving the ball from their teammate. Methods Twenty-two male football players performed an 11v11 game, where 24 game sequences (trials) from which 166 fixations were recorded and analysed via the Tobii Pro eye-movement registration glasses and software. The gaze behaviour dependent variables were the mean of fixation duration (FD), time to first fixation (TTF), both measured in milliseconds (ms), and the number of fixations (NF) on eight areas of interest (AOIs). AOIs include teammate with and without the ball, opponent without the ball, space around teammate with and without the ball, space around opponent without the ball, ball and undefined. The mean pupil diameter (PD) correlates to the attentional effort and was measured in millimetres (mm). Results Descriptive statistics showed nonregular search rate data between the participants in FD, TTF, NF on the AOIs. Mean FD on the ball: (CM, 270 ms), (RW, 570 ms), (CM, 380 ms). They also presented differences in the mean PD during play; (CM: 2.90 mm ± 0.26), (RW: 2.74 mm ± 0.30), (LB 2.77mm ± 0.27). Conclusions Albeit the sample size was small, the findings demonstrated a promising way to measure the on-field perceptual-cognitive abilities of football players according to their specific positions, since different playing roles revealed to present distinctive visual and attentional patterns.

Children's Physiological and Perceptual Responses to Sports Exergames When Played in Different Positions.

Today's children are prone to becoming involved in exergames, but their positions during play have not been sufficiently investigated to determine whether the positions they adopt result in equal responses. The design of this study involved the collection of physiological and perceptual responses (i.e., heart rate (HR), rating of perceived exertion, and enjoyment score) during exergames in three different sports (bowling, tennis, and boxing) with players in different positions (sitting and standing). The participants played each game for 10 min while their HR was recorded. After the gameplay, each perceptual response was retrieved. The results revealed a significant increase in HR above rest during exergaming overall (p < 0.001). Standing gameplay resulted in a significantly higher HR (p < 0.001) than seated gameplay. Compared to tennis and bowling, boxing produced the highest physiological response (p < 0.001) and perceived exertion (p < 0.05) in both positions. The participants perceived all the sports exergames to be enjoyable, as their enjoyment scores did not significantly differ for each game (p > 0.5). For all the variables, no statistically significant differences between genders were identified (p > 0.5). This home-based intervention demonstrated that sports exergames are not only enjoyable; overall, they can provide at least moderately intense physical activity, whether played seated or standing.

Comparison of dynamic and static balance among professional male soccer players by position

PurposeBalance is an important performance aspect of all athletes. The aim of this study was to compare static and dynamic balance in soccer players in different positions. MethodsForty youth and young adult professional soccer players were divided into four groups according to their playing positions: goalkeepers (GK), defenders (DF), midfielders (MF) and forwards (FW) (10 per position). Static and dynamic balance assessed on the dominant and non-dominant legs were measured using a force platform for 30s (static one-leg stand), and “Y Balance Test” (dynamic balance). ResultsGK exhibited greater ML static balance (less ML sway) compared with other players (p < 0.02–0.001). Moreover, results demonstrated better GK dynamic balance compared to DF and FW (p < 0.04–0.006). MF showed better dynamic balance than DF and FW (p < 0.019–0.007) and lower dynamic balance scores were found among DF and FW (p < 0.05). ConclusionIn conclusion, these results affirm position-specific balance performance with greater static and dynamic balance of GK and dynamic balance with MF. It is suggested that evaluation of balance and postural control performance should be considered a relevant part of the position-specific functional evaluation of soccer players.

What is the visual behaviour and attentional effort of football players in different positions during a real 11v11 game? A pilot study

Background: Visual perception has been defined as the first step to a football player’s decision-making process and it plays an important role in performance in sport. The skill of focussing to prioritize relevant cues has been also considered crucial in sport. This pilot study aims to explore the visual behaviour and attentional effort of three football players (mean age 19 ± 0 years old) in specific-role positions; Right-winger (RW), Centre-Midfielder (CM) and Left-Back (LB), in the five seconds before receiving the ball from their teammate. Methods: Twenty-two male football players performed an 11v11 game, where 24 game sequences (trials) from which 166 fixations were recorded and analysed via the Tobii Pro eye-movement registration glasses and software. The gaze behaviour dependent variables were the mean of fixation duration (FD), time to first fixation (TTF), both measured in milliseconds (ms), and the number of fixations (NF) on eight areas of interest (AOIs). AOIs include teammate with and without the ball, opponent without the ball, space around teammate with and without the ball, space around opponent without the ball, ball and undefined. The mean pupil diameter (PD) correlates to the attentional effort and was measured in millimetres (mm). Results: Descriptive statistics showed nonregular search rate data between the participants in FD, TTF, NF on the AOIs. Mean FD on the ball: (CM, 270 ms), (RW, 570 ms), (CM, 380 ms). They also presented differences in the mean PD during play; (CM: 2.90 mm ± 0.26), (RW: 2.74 mm ± 0.30), (LB 2.77mm ± 0.27). Conclusions: Albeit the sample size was small, the findings demonstrated a promising way to measure the on-field perceptual-cognitive abilities of football players according to their specific positions, since different playing roles revealed to present distinctive visual and attentional patterns.

Aerobic power across positions - an investigation into women's soccer performance.

The aim of the study was to discern the disparities in the aerobic capacity of female athletes occupying various positions within a soccer team, and to understand the physical characteristics of the athletes in different positions. It is critical to understand that the physical demands for players vary depending on their positions on the field, a factor that greatly influences their training and gameplay. The study engaged a sample of 25 female soccer players, average age of 22.72 (±2.69 SD), all of whom were active participants in the Chinese Women's Super League. The sample was distributed across several playing positions, including forwards, midfielders, and defenders. To gather pertinent data on oxygen uptake, a progressive load test was administered on a treadmill, coupled with a gas analyzer to amass respiratory indices (JAEGER, Germany). The study revealed that there was a notable variance in the maximum oxygen uptake among players in different positions. The midfielders exhibited the highest VO2 max at 63.24±7.04 ml/kg/min, followed by the forwards who averaged at 58.92±7.70 ml/kg/min, and finally the defenders who recorded the smallest average at 55.73±4.40 ml/kg/min. The outcomes of this study indicate that the positional role of a player in a team correlates with their aerobic capacity. Therefore, the positional demands significantly shape the player's physical characteristics, influencing their training and gameplay. This understanding is vital for the optimal conditioning of athletes in different positions in the sport of soccer.

What is the visual behaviour and attentional effort of football players in different positions during a real 11v11 game? A pilot study

Background: Visual perception has been defined as the first step to a football player’s decision-making process and it plays an important role in performance in sport. The skill of focussing to prioritize relevant cues has been also considered crucial in sport. This pilot study aims to explore the visual behaviour and attentional effort of three football players (mean age 19 ± 0 years old) in specific-role positions; Right-winger (RW), Centre-Midfielder (CM) and Left-Back (LB), in the five seconds before receiving the ball from their teammate. Methods: Twenty-two male football players performed an 11v11 game, where 24 game sequences (trials) from which 166 fixations were recorded and analysed via the Tobii Pro eye-movement registration glasses and software. The gaze behaviour dependent variables were the mean of fixation duration (FD), time to first fixation (TTF), both measured in milliseconds (ms), and the number of fixations (NF) on eight areas of interest (AOIs). AOIs include teammate with and without the ball, opponent without the ball, space around teammate with and without the ball, space around opponent without the ball, ball and undefined. The mean pupil diameter (PD) correlates to the attentional effort and was measured in millimetres (mm). Results: Descriptive statistics showed nonregular search rate data between the participants in FD, TTF, NF on the AOIs. Mean FD on the ball: (CM, 270 ms), (RW, 570 ms), (CM, 380 ms). They also presented differences in the mean PD during play; (CM: 2.90 mm ± 0.26), (RW: 2.74 mm ± 0.30), (LB 2.77mm ± 0.27). Conclusions: Albeit the sample size was small, the findings demonstrated a promising way to measure the on-field perceptual-cognitive abilities of football players according to their specific positions, since different playing roles revealed to present distinctive visual and attentional patterns.

Peak Running, Mechanical, and Physiological Demands of Professional Men's Field Hockey Matches.

The aim of this study was to investigate the peak running, mechanical, and physiological demands of players of different positions in professional men's field hockey matches. Eighteen professional male field hockey players participated in the study, and data were collected in eleven official matches. Players wore GPS units (Vector S7, Catapult Sports) and heart rate (HR) monitors (Polar H1, Polar Electros) to collect physical and physiological data. Physical and physiological output of forwards, midfielders, and defenders in full matches and during 1-min peak periods was analysed. For all metrics and positions, the values identified for the 1-min peak periods were greater than the average values of match play (p < 0.05). In terms of 1-min peak period Player Load, all three positions were significantly different from each other. Forwards achieved the highest Player Load per minute, while defenders the lowest. The distance per minute, high-speed distance per minute, and the relative average heart rate of defenders were significantly lower than of midfielders and forwards (p < 0.05). The current study revealed the peak running, mechanical, and physiological demands of professional men's field hockey matches. It is recommended when prescribing training programmes, to consider not only match average demands, but also peak demands. Forwards and midfielders displayed similar peak demands, while defenders had the lowest demands in all metrics except the number of accelerations and decelerations per minute. Player Load per minute can be used to identify the differences in peak mechanical demands between forwards and midfielders.

Metabolic power in the men’s European handball championship 2020

ABSTRACT Purpose To ascertain the typical metabolic power characteristics of elite handball players of different positions, and whether changes occur within matches. Methods 414 elite male handball players were included. During all 65 matches of the EURO 2020, local positioning system data were collected, yielding 1853 datasets. Field players were categorised into six positional groups: centre backs (CB), left/right wings (LW/RW), left/right backs (LB/RB) and pivots (P). Metabolic power, total energy expenditure, high-power energy, and the equivalent distance index were calculated. We used linear mixed models with players as random and positions as fixed effects models. Intensity models adjusted for time-dependency by incorporating the duration of play. Results LW/RW spent most time on the court, expanded most total energy, and most relative energy per kg body weight in the high-intensity categories. CB played at the highest mean metabolic power (7.85 W/kg; CI95% [7.67, 8.03]). Playing intensity decreased by 2.5% (0.2 kJ/kg/s; CI95% [0.17, 0.23]) per 10 min played. Conclusion Positional differences in metabolic power parameters exist. In general, wing players had the highest volume and CB the highest intensity of match-play. Analysis of metabolic intensity in handball should take position and players’ time on the court into account.

MÉTODOS DE TREINAMENTO FUNCIONAL PARA JOGADORES DE BASQUETEBOL

ABSTRACT Introduction: Although exercise development has shown great theoretical progress, there are still many problems regarding the current sports teaching process in physical fitness training dedicated to basketball. One of the current needs is the evaluation of the current training methods of its players and the functional introduction method in this scenario. Objective: Explore the physical characteristics and functional training methods in different positions of basketball players. Methods: A literature search was conducted to survey the current scientific practices and the athletes of the second national men's and women's basketball team who participated in a winter training from January 10 to March 10, 2019 were taken as the objects of study, also considering the different positions of the active athletes of the CBA, WCBA, NBA and WNBA. Results: The results showed that the average blood lactate level of the second national women's basketball team was 11.19mmol/L, slightly lower than the national women's team (11.8±1.2mmol/L), indicating that the athletes’ anaerobic capacity reached a high level. Conclusion: Basketball players in different positions have different demands regarding physical characteristics and training methods. Level of evidence II; Therapeutic studies - investigation of treatment outcomes.

Survey of Differences In Endurance Levels of Soccer Players with Various Positions

This study aims to determine the level of endurance of players in different positions in soccer games. The research method used in this study is a survey method with testing and measurement techniques. The population in this study is the SSB Macan Tutul players in 2021, as many as 22 players, using total sampling by making the population a sample. The results of the study are calculated based on the player's position and criteria in the SSB Macan Tutul group in 2021. The results of the study based on the position of the players showed that the goalkeeper position got an average score of 41, the defender 42.7, the midfielder 44, and the attacker 42.3, and none of them met the VO2max standard. Based on the criteria for the 2021 SSB Macan Tutul group, it shows that in the very good category (4.5%) or as many as 1 person, good (27.3%) or as many as 6 people, moderate (40.9%) or as many as 9 people, bad (27.3%) or as many as 6 people, and very bad (0%) or not at all. The player who has the highest VO2max is the midfield player, with a value of 48.8 ml/kg/min. The player with the lowest VO2max is the goalkeeper, with a value of 40.8 ml/kg/min, compared to an average player’s VO2max of 43 ml/kg/min. Keywords: Endurance Level, Player Position, VO2max

Return to Play and Performance After Anterior Cruciate Ligament Reconstruction in National Football League Players.

Background:Considerable variability exists in return-to-play rates after anterior cruciate ligament (ACL) injury and reconstruction (ACLR) among National Football League (NFL) players of different positions.Purpose/Hypothesis:The purpose of this study was to compare return-to-play and performance levels by position in NFL players after ACLR. It was hypothesized that (1) ACL injuries have significant effects on the careers of NFL players, including return to play and performance, and (2) players of certain positions that involve relatively less pivoting and cutting perform better after ACLR.Study Design:Descriptive epidemiology study.Methods:All NFL players who underwent ACLR between 2013 and 2018 were identified using the FantasyData injury database. Player characteristics, snap count, games played, games started, and performance metrics were collected for 3 years before and after injury using the Pro Football Reference database. Performance was measured using an approximate value (AV) algorithm to compare performance across positions and over time. Nonparametric tests were used to compare the pre- and postinjury data and the percentage change in performance between different positions.Results:Overall, 312 NFL players were included in this study, and 174 (55.8%) returned to play. Of the eligible players, only 28.5% (n = 59/207) remained in the league 3 years postinjury. Within the first 3 years postinjury, players played in fewer games (8.7 vs 13.7; P < .0001), started in fewer games (3.0 vs 8.3; P < .0001), had lower AVs (1.5 vs 4.3; P < .0001), and had decreased snap counts (259.0 vs 619.0; P < .0001) compared with preinjury. Quarterbacks were most likely to return to play (92.9% vs 53.7%; P = .0040) and to return to performance (2% vs 50% decrease in AV; P = .0165) compared with the other positions. Running backs had the largest decrease in AV (90.5%), followed by defensive linemen (76.2%) and linebackers (62.5%).Conclusion:The study findings indicated that NFL players are severely affected by ACL injury, with only 28.5% still active in the league 3 years after the injury. Running backs, defensive linemen, and linebackers performed the worst after injury. Quarterbacks were most likely to return to play and had superior postinjury performance compared with the other positions.

Evaluation of Cardiorespiratory Fitness and Its Correlation with Team Performance, Player Position and Physical Characteristics in the Soccer Premium League of Iran

Background: This study is one of the first to specifically analyze cardiorespiratory fitness and its association with age, weight, height, body fat percentage (BFP), body mass index (BMI), team performance, and player position for a large number of soccer players in an Asian top league. Methods: 213 players (age = 25 ± 5 years, height = 181.2 ± 6.8 cm, weight = 76.1 ± 8.1 kg, BFP = 11.3 ± 3.1) affiliated with 16 soccer clubs from Iran’s Premier League (i.e., the highest level of club football in Iran), were tested for maximal aerobic power (VO2 max), first and second ventilatory thresholds (VT1 and VT2), and ventilatory efficiency at rest (VO2 rest). The nonparametric Spearman's correlation test was performed to check for correlations, and the resulting rank correlation coefficients (rs) and probability value (P) are presented. Results: In terms of mean ± standard deviation, the 213 male players participating in this study have VO2max = 55.3 ± 5.4 mL.kg-1.min-1, VT1 = 57.3 ± 4.2 (% max), VT2 = 92.6 ± 3.4 (% max) and VO2rest = 7.1 ± 1.4 mL.kg-1.min-1. No correlation between VO2max and team performance or BFP was observed. The correlations between VO2max and age (rs= -0.23, P = 10-3), height (rs = -0.34, P ≅ 0), weight (rs = -0.42, P ≅ 0) and BMI (rs = -0.30, P = 10-5) were considered statistically significant. The difference between VO2max of players in different positions was also statistically significant. Goalkeepers possessed the lowest VO2max, with a mean value of 49.8 mL.kg-1.min-1. Defenders had the lowest mean VO2max value players (equal to 54.7 mL.kg-1.min-1) amongst outfield players, and midfielders had the highest mean VO2max (= 56.9 mL.kg-1.min-1). The other indices of cardiorespiratory fitness (VT1, VT2 and VO2rest) had no statistically significant correlation with the physical characteristics of the soccer players, team performance and player position. Conclusions: The study demonstrates that VT1, VT2, and VO2rest are not distinguishing factors amongst different categories of age, weight, height, team performance, and player position, but VO2max varies with age, weight, height, and BMI. The study also shows that there is a high correlation between the physical demands of player positions during a game and the aerobic capacity of players in those positions, and this must be taken into account in soccer training.

Comparison of oxygen consumption of football players in different positions of the game

Background: Football players have different structural and physiological characteristics due to the variety of tasks that lie in this field. The main purpose of this research was to compare oxygen consumption of football players in different positions of the game. Materials and methods: The research method was causal or post-occurrence. So nine halfbacks, seven attackers, three goalkeepers and six defenders were chosen to participate in this research. The Chinese bicycle was used to measure Vo2max. The heart rate was determined by the electronic heart rate. Nolan Margaria-Kalamen test machine was used to measure the anaerobic power of players. Analysis of variance and F test were used to compare the mean of differences. All steps were performed using SPSS 21 at the level of 0.05. Results: There is a significant difference between Vo2max of goalkeepers and halfbacks; between goalkeepers and attacking players; between defenders and attackers. There was a significant difference between the anaerobic capacity of halfbacks and goalkeepers; between attackers and goalkeepers. Conclusion: The position and the duration of activity has a great effect on Vo2max and anaerobic of players. So to increase both characteristics of the players depends on the position of the game. Key words: oxygen consumption, anaerobic consumption, football, positions of the game

PHYSICAL DEMAND IN SOCCER SMALL-SIDED GAMES: INFLUENCE OF TEAM COMPOSITION

ABSTRACT Introduction Small-sided games (SSG) are used as training tools for physical conditioning in soccer. To date, however, it is unknown whether team composition affects athletes’ physical performance. Specifically, based on the differences presented by players of different positions, it is expected that the use of positional status as a criterion for team composition will affect players’ physical performance. Objective To compare the physical demands of SSG in teams composed of young soccer players in the same position or different positions. Methods 12 U-15 soccer players participated in the study. The athletes performed 3v3 SSGs under two conditions: teams in which the athletes played in the same position (i.e. three defenders), and teams in which the players took up different positions (i.e. defender, midfielder and attacker). Data were obtained on total distance traveled, distance in speed zones, and accelerations, using GPS devices. The data were analyzed using the paired t-test, comparing the two experimental conditions. Results There was higher physical demand among defenders and midfielders when the SSG was performed with athletes playing in the same position, in terms of distances covered in different speed zones. However, there were no differences in relation to acceleration actions. Conclusion Team composition affects the physical performance of soccer athletes during 3v3 SSG. Level of evidence IV; Case series.

MCDA based approach to sports players’ evaluation under incomplete knowledge

Abstract Basketball is a constantly developing sport due to the dynamics of changes in the significant characteristics of a basketball player. The acquisition of new basketball players’ skills strongly influences the development of new technologies, as well as the game itself. In addition, it plays an important role in the personal development of young people seeking new achievements. However, it is difficult to determine which basketball player is the best. Creating a proper ranking of the best basketball players in the NBA league is extremely important. There are many rankings of players in the NBA league, but it is difficult to determine if they are correct due to lack of relevant data in the assessment process. The NBA has many talented basketball players in different positions. Their different predispositions make the correct ranking very difficult. Using only one attribute of a given basketball player may prove to be wrong when assessing basketball players playing on different positions. In addition, some basketball players may be missing data, because it was not collected during the player’s playing time. Therefore, the survey was carried out in the absence of some statistics in several basketball players. The aim of such a survey is to prove that creating the correct ranking is possible for incomplete data. For the evaluation of selected basketball players from the NBA league a technique from the family of multi-criteria decision making methods (MCDA) called COMET was used. The COMET method works on the basis of fuzzy logic, and its distinguishing feature compared to other methods is its resistance to the paradox of reversal of rankings. Resistance to the paradox of reversal of rankings is ensured by the fact that the assessment of alternatives does not take place on their own, but on characteristic objects. An expert has been involved in their proper evaluation. This article presents research against NBA basketball players, which shows that correct ranking of basketball players even with partial lack of data for them is possible.

THE PECULIARITIES OF THE BODY’S EXTERNAL STRUCTURE AND INDICATORS OF CENTRAL HEMODYNAMICS OF VOLLEYBALL PLAYERS OF DIFFERENT POSITIONS

The aim was to determine the main differences in the external structure of the body and the of central hemodynamics parameters in of high-level sports skills volleyball players of the juvenile age with the role of libero, hitters and setters. Materials and methods: 116 volleyball players of high level athletic skill of the youth age from 16 to 20 years old. The control group included 140 practically healthy girls who were not engaged in sports of the corresponding age. Anthropometric investigation was performed according to Bunak's V.V. and Martirosov's E.G. method, rheographic - according to the method of Ronkin M.A. and Ivanov L.B. The reliability of the difference between independent quantitative values was determined using Mann-Whitney U-test. Results: It was established that volleyball players have significantly higher total, longitudinal, circumferential dimensions of the body, width of distal epiphyses, transverse diameters of the chest and pelvis in comparison with girls, who are not involved in sport. According to the most parameters of the body external structure the hitters are predominate than setters and libero. In hitters and setters, most anthropo-somatotypological parameters are larger than in nonathletes. The stroke and minute volumes, the impact index, the volume velocity of the blood and the capacity of the left ventricle in volleyball players are significantly higher. Specific peripheral resistance is significantly lower than that of girls who are not involved in sports. Between the volleyball players of different positions in the value of the central hemodynamics parameters, there were no significant differences, except for the impact index, which is significantly higher in libero than in the hitters. Conclusions: The external structure of the body, anthropometric parameters and indicators of central hemodynamics depend of volleyball player's position and have some peculiarities.

Pacing characteristics of whole and part-game players in professional rugby union

Contemporary theories on players’ intensity distribution in team sports suggest that they regulate their outputs using pacing strategies. There is currently limited information on how movement patterns and pacing strategies of rugby union players in different position groups (forwards and backs) vary when exposed to different bout types (whole game, starter or finisher). Global positioning system (GPS) and accelerometer data were collected from 100 professional match participations to determine temporal effects on movement patterns. For forwards, finishers (players who entered the game as substitutes) demonstrated significantly greater high-speed running distance (% difference, ± 90%CI; magnitude-based inference and effect size) (↑ 55, ±17%; very likely large) and acceleration frequency (↑ 78, ±59%; very likely large) than whole game players. For backs, starters (players who started the game and were later substituted) displayed greater high-speed running distance than whole game players (↑ 27, ±21%; ES = likely medium) but this difference did not achieve statistical significance (p = .07). Forwards displayed “slow-positive” pacing strategies regardless of bout type, while backs displayed “flat” pacing strategies. Forwards and backs adopt different pacing strategies regardless of bout type, with forwards demonstrating progressively greater performance decrements over the course of the match. These findings reflect differing physical demands, notably contact and running loads, of players in different positions.