Offensive Players Research Articles

A deep dive into the use of local positioning system in professional handball: Automatic detection of players' orientation, position and game phases to analyse specific physical demands.

The objective of this study is to automate and analyse the quantification of external load during an elite men's handball match. This study was carried out using data from a local positioning system and inertial measurement units. The literature review leads us to assume that physical demands are different depending on position, player specialty and phases of the game. In order to do this analysis, raw data was used from professional competitors of a Spanish club during National and European competition matches. First, a game phase algorithm was designed to automate phase recognition. Then, a descriptive evaluation of the means and standard deviation was performed with the following variables: total distance, total time, total Accel'Rate, the percentages of distance and time per speed and displacement direction. A Kruskal Wallis test was applied to normalized distance and normalized Accel'Rate. Defensive play showed the highest values on covered distance (930.6 ± 395.0 m). However, normalized distance showed significant differences (p<0.05) across all phases with defensive play (558.8 ± 53.9 m/10min) lower than offensive play (870.3 ± 145.7 m/10min), offensive transition (1671.3 ± 242.0 m/10min) or defensive transition (1604.5 ± 242.0 m/10min). Regarding position, wing players covered the most distance (2925.8 ± 998.8 m) at the second highest intensity (911.4 ± 63.3 m/10min) after offensive back players (1105.0 ± 84.9 m/10min). Significant difference in normalized requirements were found between each playing position: goalkeepers, wings, versatile backs, versatile line players, offensive backs and defensive backs (p<0.05), so a separation between offensive or defensive specialists is plausible and necessary. In conclusion, as physical demands differ for each game phase, activity profile among players is modulated by their playing position and their specialty (offense, defense or none). This study may help to create individual training programs according to precise on-court demands.

Is ball-possession style more physically demanding than counter-attacking? The influence of playing style on match performance in professional soccer.

In soccer, the offensive style of play describes characteristic behavioral features of the players at team level during the offensive phase of matches. This study aimed to investigate the effect of offensive playing style (i.e., while in ball possession) on physical and technical match performance during offensive play as well as success-related factors. The sample consisted of official tracking and event data of 153 matches of the 2020/21 German Bundesliga season. For every team in every match an offensive playing style coefficient was calculated to locate teams on a continuum between ball possession and counter-attacking style. This calculation contains 11 technical and physical performance parameters and has already been validated. In addition, dependent physical (e.g., sprinting distance), technical (e.g., passes), and success-related (e.g., goals) variables were examined. A separate linear mixed model was calculated for each dependent variable. While teams with lower playing style coefficient values (= counter-attacking style) covered more high-intensity (p ≤ 0.01; R2 = 0.13) and sprinting distances per second in possession (p ≤ 0.01; R2 = 0.14), teams with higher playing style coefficient values (= ball possession style) were physically more demanded over a whole match (e.g., more accelerations (p ≤ 0.01; R2 = 0.69), decelerations (p ≤ 0.01; R2 = 0.69), high-intensity (p ≤ 0.01; R2 = 0.36), sprint distance (p = 0.03; R2 = 0.08)). Furthermore, teams with higher playing style coefficient values played more horizontal passes (p ≤ 0.01; R2 = 0.73) and revealed better passing success rates (p ≤ 0.01; R2 = 0.17). In contrast, teams with lower playing style coefficient values played more long passes (p < 0.01; R2 = 0.58). The influence of the playing style coefficient on success-related variables was smaller (p ≤ 0.36; R2 = 0.10-0.13). Concluding, offensive playing style affects physical and technical match performance, but has limited influence on success. Hence, coaches can use the findings to optimize training contents to prepare players for the physical demands of a match.

Three-defender versus two-defender systems in football: A comparison of offensive play

Scientific research on tactical formations in football is scarce and the studies that do exist focus on aspects linked to physical conditioning. Therefore, the objective of this work was to analyse offensive play differences between three-centre-back (3CB) and two-centre-back (2CB) formations. A total of 72 matches played by eight LaLiga teams (Spain) during the 2018–19 season were analysed. Four teams used a 3CB system and four teams a 2CB system. Data were obtained from the Opta sports company, and the reports were generated using Mediacoach. Three groups of variables were analysed (passes, possession and finishing). The results showed that both the number of team passes (‘passes received’, ‘passes attempted’) and their effectiveness (‘number’ and % of ‘completed’ passes) were significantly greater ( p &lt; 0.001) in 3CB systems. As far as possession was concerned, 3CB systems obtained a higher percentage ( p = 0.004, ES = 0.45), time average ( p = 0.001, ES = 0.57) and possessions with more than nine passes ( p = 0.000). Finally, regarding the variables relating to attack finishing, the values attained significantly higher levels in the 3CB teams in ‘expected goals’ ( p = 0.020), ‘goals scored’ ( p = 0.030) and ‘probability of a shot being a goal’ ( p = 0.046). It could be concluded that 3CB teams presented greater rates of ball possession and attack finishing.

Differences between Elite and Professional Male Handball Players in Kinematic Parameters of Single Fake Movement

Feint movement is an important factor for offensive players to outplay their guard, and score. So far, there is no evidence of feint biomechanical analysis on a sample of elite players in handball or other team sports. Therefore, this study aimed to investigate kinematic parameters of single side fake movement between elite and professional level handball players. The sample of participants consisted of 10 handball players divided into two subsamples: elite handball players (100.00 ± 8.00 kg; 196.00 ± 4.64 cm) and professional handball players (91.20 ± 3.42 kg; 192.4 ± 7.30 cm). The kinematic analysis was conducted using a GAIT-LaBACS software system. Variables consisted of two phases (fake phase and actual phase) of feint single change of direction. Both phases included seven kinematic parameters that were observed. Statistical analysis included descriptive statistic parameters. The differences between elite and professional handball players were analyzed by multivariate and univariate variance analysis. Results showed significant differences between elite and professional players (λ = 0.44, p = 0.00), in fake phase (i.e., 1. Phase). The results also indicate that in there is no statistically significant difference between both groups (λ = 0.64, p = 0.22). Two variables had significant differences between elite and professional players (i.e., step length of the stride leg (p = 0.02) and moving the leg opposite the throwing arm in space (p = 0.00)). To conclude, the article examines specific movement patterns of single side fake movement in elite players and the confirmed importance of efficient skill execution in top level handball. On the contrary, less skilled players use more space for the same technical element.

Exploring the Effects of Tasks with Different Decision-Making Levels on Ball Control, Passing Performance, and External Load in Youth Football.

This study aimed to understand how the design of decision-making tasks affects youth football players' ball control, passing performance, and external load. A total of 16 male youth football players (age: 12.94 ± 0.25 years) competed in various tasks based on the following levels of decision-making: (i) low decision-making (Low DM), which consisted of a predefined ball control and passing sequence; (ii) moderate decision-making (Mod DM), which consisted of maintaining possession in a square with four players and two balls while maintaining the same position; and (iii) high decision-making (High DM), which consisted of a 3 vs. 3 + 2 neutral players ball possession game. The study design consisted of a pre-post design (a 6 min pre-test game, a 6 min intervention, and a 6 min post-test game). The players' ball control and passing performance were measured using the game performance evaluation tool and notational analysis, while GPS data were used to determine their physical performance. The pre-post test analysis revealed decrements in players' ability to identify more offensive players after the Mod DM task (W = 9.50, p = 0.016), while there was an increase in their ability to receive the ball towards the space following the High DM task (t = -2.40, p = 0.016). Analysis between groups showed lower values in most ball control variables for the Low DM task compared to the Mod DM task (ball control execution, p = 0.030; appropriateness, p = 0.031; motor space, p = 0.025), while there were also lower values in the distance covered while sprinting (p = 0.042). Overall, prescriptive tasks (Low DM) that are repetitive in nature may affect players' perceptual attunement, whereas static tasks (e.g., Mod DM) may limit their ability to locate players in more offensive positions. Moreover, game-based situations (High DM) seem to acutely enhance players' performance, possibly due to contextual dependency. Overall, coaches should carefully consider the type of practice structure when designing tasks that aim to improve players' technical skills in youth football.

Using machine learning pipeline to predict entry into the attack zone in football.

Sports sciences are increasingly data-intensive nowadays since computational tools can extract information from large amounts of data and derive insights from athlete performances during the competition. This paper addresses a performance prediction problem in soccer, a popular collective sport modality played by two teams competing against each other in the same field. In a soccer game, teams score points by placing the ball into the opponent's goal and the winner is the team with the highest count of goals. Retaining possession of the ball is one key to success, but it is not enough since a team needs to score to achieve victory, which requires an offensive toward the opponent's goal. The focus of this work is to determine if analyzing the first five seconds after the control of the ball is taken by one of the teams provides enough information to determine whether the ball will reach the final quarter of the soccer field, therefore creating a goal-scoring chance. By doing so, we can further investigate which conditions increase strategic leverage. Our approach comprises modeling players' interactions as graph structures and extracting metrics from these structures. These metrics, when combined, form time series that we encode in two-dimensional representations of visual rhythms, allowing feature extraction through deep convolutional networks, coupled with a classifier to predict the outcome (whether the final quarter of the field is reached). The results indicate that offensive play near the adversary penalty area can be predicted by looking at the first five seconds. Finally, the explainability of our models reveals the main metrics along with its contributions for the final inference result, which corroborates other studies found in the literature for soccer match analysis.

A Visible Analysis Approach for Table Tennis Tactical Benefit.

Tactics are one of the winning factors in table tennis matches because they can reflect the technical strength and strategies of players. However, the current evaluation method of tactics is relatively simple, and it can be difficult to distinguish the pros and cons of different tactics. To solve these issues, this study used information from 60 matches played by top-25 men's right-handed shake-hand offensive players as samples and proposed a tactical benefit algorithm and a visible evaluation model to analyse tactical performance. The model could help coaches and players find meaningful tactics quickly and easily and make reasonable comparisons between them. The results showed that 1) the numbers of tactics based on the tactical association-mining model and the L-shaped curve were 37 in the first six strokes. Among them, there were 9 selected tactics in the first to third strokes, the third to fifth strokes, and the second to fourth strokes, respectively, and 10 selected tactics in the fourth to sixth strokes. 2) The visible evaluation model of tactical benefit can determine the difference between the frequency, scoring rate, and benefit of different tactics as mapped into the model as well as quickly and effectively discover the distribution of tactics and measure the advantages and disadvantages of tactics from multiple dimensions.

Functional Performance Tests, On-Ice Testing and Game Performance in Elite Junior Ice Hockey Players.

This study aimed to explore relationships between fitness, on-ice physical abilities and game performance among elite junior male ice hockey players. Twenty-one major junior ice hockey players (18.9 ± 1.4 years old) participated in the study. Measures including five fitness tests (anthropometric measures, pull up test, bench press test, broad jump, vertical jump) and three on-ice skating tests (multi-stage aerobic skating test, 44-m sprint test, and backward skating test) were assessed during their pre-season training camp. Game performance metrics (collected during the regular season) were collected using InStat software. Results of the (on-ice and off-ice) functional performance test protocol and on-ice tests were analyzed by evaluating correlation coefficients in multiple areas of game performance: 1) physical implication (body checks), 2) offensive contribution (expected goals for, types of zone entries), and 3) defensive actions (blocked shots, expected goals against). They revealed that performance in the broad jump test was associated with skating speed. Some significant correlations were also observed between on-ice test performance indicators such as received body checks, expected goals and blocked shots. In summary, results indicate that on-ice test protocols were associated with players’ performance in multiple aspects of the game. Partial correlation analyses revealed that some of these relationships were specific to the player's position. Forward skating was associated with forwards’ offensive play, and backward skating was specifically related with defensemen’s performance (offense and defense). The addition of on-ice physical tests appears essential for interpreting the results of ice hockey players' physical tests and integrating these results into players’ physical preparation and the in-season follow-up.

Examining the game-specific practice behaviors of professional and semi-professional esports players: A 52-week longitudinal study

This study followed a longitudinal design to objectively monitor practice behaviors of professional and semi-professional esports players over a year. Publicly available data were collected from 30 male Counter-Strike: Global Offensive players (age: 23.76 ± 2.88y). Players were classified into two groups: professional (n = 18) or semi-professional (n = 12). The total hours of practice (all game-specific practice) and the competitive hours of practice (time spent in competitive modes only) were collected weekly. Generalised Estimating Equations were used to compare the practice behaviors of the two groups. Professional and semi-professional esports players completed an average of 30.9 ± 8.2 h and 24.7 ± 3.6 h per week of total game-specific practice, respectively, and 19.6 ± 6.9 and 15.0 ± 2.7 h of competitive practice, respectively. A significant week∗group interaction was observed for total practice time (Wald χ2 = 9.48, p = 0.002) and total competition practice time (Wald χ2 = 7.54, p = 0.006). Specifically, professional esports players completed 6.6 (SE = 2.2) hr per week more of total practice hours than semi-professional players, of which 4.8 (SE = 1.8) hr were competitive practice. This sample of expert esports performers complete high volumes of practice which can be monitored via publicly accessible repositories.

Substitutions in football – what coaches think and what coaches do

ABSTRACT Substitutions are probably the most important opportunity for football coaches to actively influence a match in progress. The present article presents two studies investigating substitutions in football from two different methodological perspectives: Study I, a survey reporting the opinions of 73 licensed coaches, and Study II, data-based analysis of a total of 41,301 substitutions from 7,230 matches in seasons 2014/15 to 2018/19 of the top four European football leagues. The coaches stated to prefer offensive substitutions over defensive substitutions and additionally indicated that changing the current score was more likely to be a reason for substitution than keeping the score. The analysis of the data revealed that not offensive, but neutral substitutions, where the player is replaced by a player of the same playing position, were most frequent. However, offensive players participated significantly more frequently in substitutions. In addition, a high level of score dependence was found, as more than half of the defensive substitutions were made while winning and more than half of the offensive substitutions were made while losing. The present study sheds light on the substitution behaviour of coaches in football and intends to stimulate discussion on the optimal timing and the type of substitutions.

GIRD syndrome in male handball and volleyball players: Is the decrease of total range of motion the turning point to pathology?

Adaptations in glenohumeral range of motion may affect overhead athletes and lead to shoulder pathologies. The purpose of this study was to evaluate glenohumeral internal rotation deficit (GIRD) and postero-superior impingement among male handball and volleyball players and the relationship between these pathologies and training level (amateur vs. professional), position (attack vs. no attack), experience (> 5 years vs. < 5 years) and sports. Sixty-seven handball players and 67 volleyball players with a mean age of 25 [± 5] years were included. The range of motion including external and internal rotation in 90∘ abduction of the dominant and non-dominant shoulder was measured of each examined athlete. Visual analogue scale, disabilities of the shoulder and hand score, constant score and subjective shoulder value were recorded. The athletes were examined for postero-superior impingement and abduction force was measured with an isokinetic dynamometer. Internal rotation was significantly lower and external rotation was significantly greater in the dominant arm for both sports. 72% presented with GIRD. GIRD was more prevalent in athletes active for > 5 years (odds ratio (OR) 3), in those training > 3 times per week (OR 1.4) and in handball players (OR 2.7). 24% presented with postero-superior impingement. Players active for > 5 years (OR 1.22), professionals (OR 1.14), volleyball players (OR 1.19), offensive players (OR 2.2) and athletes with GIRD > 10∘ (OR 1.5) showed a higher prevalence of postero-superior impingement. GIRD is a common phenomenon in handball and volleyball players. Offensive players are frequently suffering from postero-superior impingement. GIRD > 10∘ leads in nearly 75% of the athletes to a decrease of total range of motion and a high rate of postero-superior impingement. Thus, a decreased range of motion seems to be the turning point from adaptation to pathology. Therefore, regular controls of range of motion and countermeasures by means of stretching the posterior shoulder joint should be integrated in the training content.

Exploration of the moderator effect of cultural diversity on team performance across 45 professional football leagues: An ecological dynamics perspective on cross-cultural research

ObjectiveTo investigate the moderating effect of cultural diversity on team performance in professional football worldwide through the lens of ecological dynamics and cross-cultural psychology. Designand Method: Based a sample of 23,186 matches played by 728 teams across 45 leagues during the 2020/21 season, two sets of moderated regression analyses were conducted to examine the effect on sporting results of the interaction between teams’ cultural diversity, their dominant playing style and market value. In addition to bivariate correlations, a total of 16 ordinary least squares (OLS) regression models were designed to test 5 hypotheses. A new theoretical model, the Integrative Categorization-Intentionality Model (ICIM), was proposed to explain four key findings. FindingsCDI’s role as a statistically significant cross-cultural moderator was confirmed in relation to all three styles of play: possession-based (ß = −0.08, p < 0.05), constructive attacking (ß = −0.30, p < 0.01), and defensive (ß = 0.28, p < 0.05), the respective models explaining 35.6%, 34% and 35% of the variance. Results showed that cultural heterogeneity contributes to goal scoring in teams reliant on the first two styles, whilst defensively-oriented teams were more likely to improve performance with increasing cultural homogeneity. Moreover, the positive effect of cultural heterogeneity on sporting outcomes was more likely in less affluent teams. Finally, empirical evidence revealed a link between enhanced performance and a higher proportion of domestic defensive players in defensively oriented teams (ß = −0.11, p < 0.05), and, similarly, between a higher proportion of foreign offensive players in offensively-oriented teams (ß = −0.27, p < 0.01). ConclusionsThe study has practical implications for scouting/recruitment of players when strategizing on team cultural and functional composition, as well as for coaches in terms of designing suitable training practices gauged to match and develop multicultural teams’ diverse skill set, or more generally, in relation to managing multicultural teams.

External training load by accelerometery analysis during pick and roll in male amateur basketball

Accelerations and decelerations appear continuously in basketball. Limit and control how and when they occur and the relation with external load can be very useful.The objective of this study is to determine the type of accelerations and decelerations produced by the offensive players during screens situations. Secondly to determine if there are any relationships between players.389 screens situations (n = 389) were recorded using WIMU PRO® technology and a video camera. Each screen was classified according to six criteria. The following variables were analysed: accelerations 1 m / s² and 2 m / s² (Accel LOW), decelerations -1 m / s² -2 m / s² (Decel LOW), accelerations +2 m / s² (Accel HI), decelerations -2 m / s² (Decel HI), ∑ Accel and Decel LOW (Total LOW), ∑ Accel and Decel HI (Total HI), ∑ Accel and decel LOW and HI (Totals). Subsequently, a normality test and the Krurskal-Wallis non-parametric test was performed.Significant differences (p &lt;0.05) were obtained in all the variables analysed from the position, screen and player criteria. No differences were observed in any of the variables in the exercise, continuation and defense criteria.

Optimizing the best play in basketball using deep learning

In a close game of basketball, victory or defeat can depend on a single shot. Being able to identify the best player and play scenario for a given opponent’s defense can increase the likelihood of victory. Progress in technology has resulted in an increase in the popularity of sports analytics over the last two decades, where data can be used by teams and individuals to their advantage. A popular data analytic technique in sports is deep learning. Deep learning is a branch of machine learning that finds patterns within big data and can predict future decisions. The process relies on a raw dataset for training purposes. It can be utilized in sports by using deep learning to read the data and provide a better understanding of where players can be the most successful. In this study the data used were on division I women’s basketball games of a private university in a conference featuring top 25 teams. Deep learning was applied to optimize the best offensive play in a game scenario for a given set of features. The system is used to predict the play that would lead to the highest probability of a made shot.

The use of player tracking data to analyze defensive play in professional soccer - A scoping review

The analysis of tracking data in tactical game analysis is a topic of rising interest, as more detailed insights into performance structure in soccer can be obtained compared to traditional (e.g. notational) analyzes. Compared to the variety and detailed analyzes of offensive play, the number of studies analyzing the defensive play is low. However, in recent years, an increasing number of studies investigating defensive play have been published, so it seems useful to provide an overview of the current state of research in this area. Therefore, this study aims to identify the approaches that have been used to analyze the defensive play in professional soccer using player tracking data and to reveal the findings on successful defensive play. A systematic literature search of electronic databases (PubMed ( n = 604), Web of Science ( n = 593), and SPORTDiscuss ( n = 872)) was conducted according to the PRISMA extension for Scoping Reviews (PRISMA-ScR). Studies that were included used tracking data of professional adult male soccer and analyzed defensive play. The result is a total of 23 studies that were analyzed in detail using the standardized quality assessment checklist for systematic reviews in sports science. The synthesis of results was carried out descriptively by organizing the results into different levels of tactical play (individual level, group level, team level). All included studies were of good methodological quality. The approaches to investigate defensive play using tracking data are highly heterogeneous (e.g. analysis of defensive pressure, analysis of synchronization, behavioral analyzes, ball recoveries). Successful defensive play is characterized by high pressure at the individual level, by high inter-team and intra-team synchronization and balanced defense at the group level, and by a compact coordinated organization at the team level. By summarizing the state of research on defensive play in soccer using sophisticated analysis approaches that showcase the possibilities of tracking data, this study provides an important foundation for future research in this area.

Mechanism for shoulder pain and injury in elite badminton players

Purpose: to detect the mechanisms for shoulder pain and injury during forehand overhead stroke using the questionnaire and 2D video analysis. Methods and Materials: Participants were 48 university badminton players (aged 18-22) with national tournament level who had no current shoulder injuries. A questionnaire investigation and a forehand overhead clear test were performed. The angle of arm slot at the moment of hit was calculated from 2D videos analysis using Image J software. Data were compared between badminton players with shoulder problems and those without. Results: There were 6 badminton players reported a history of shoulder injury that all of them were offensive players. 11 badminton players (8 offensive players and 3 defensive players) reported present shoulder pain that offensive players showed 7.33 times more likely to sustain present shoulder pain than defensive players (OR = 7.33, 95%CI: 1.55-34.70, p = 0.007; Fisher’s Exact test: p = 0.012). Moreover, offensive players with present shoulder pain had significantly greater score of VAS (visual analog scale) than defensive players (74.0 mm ± 14.2 mm vs 44.6 mm ± 24.4 mm, p = 0.04). Significant differences of arm slot angle were found among badminton players with shoulder pain free, history of shoulder injury and present shoulder pain (35.74o ± 4.85o vs 42.90o ± 11.89 o vs 37.81o ± 6.40o, F = 3.27, p = 0.047). Conclusion: Offensive badminton players are more likely to suffer from shoulder injury and strong intensity of shoulder pain. Greater arm slot angle of hit phase might be the mechanism leading to shoulder problems in badminton players. For improving shoulder re-injury prevention and rehabilitation protocols, our findings should be taken into consideration by physiotherapists, physicians and coaches.

Epidemiology of Traumatic Posterior Hip Instability in the National Football League.

Background:There is a paucity of literature regarding injury incidence, mechanism, and return to play in National Football League (NFL) players who have sustained traumatic posterior hip instability.Purpose:To describe the incidence of traumatic posterior hip instability and the rate of return to play in NFL players across 18 seasons.Study Design:Descriptive epidemiology study.Methods:We retrospectively assessed all traumatic posterior hip dislocations/subluxations that occurred during football-related activities in the NFL seasons from 2000 through 2017. Player demographics and injury data (injury mechanism, season of injury, treatment, days missed, and return to play time) were collected from all 32 NFL teams prospectively through a leaguewide electronic health record system. Descriptive statistics are presented.Results:Across the 18 NFL seasons, 16 posterior hip instability injuries in 14 players were reported, with a maximum incidence of 4 (25%) in 2013. Posterior hip instability was predominantly sustained by offensive players (64.3%), with tight ends being the most affected (31.3%). Half of the injuries occurred during the regular season, 43.8% in the preseason, and 6.2% in the offseason. Of all injuries, 37.5% were noncontact, while 56.3% involved contact (direct or indirect), and 6.2% were of unknown mechanism. Among noncontact injuries, 66.7% occurred during cutting and change of direction while sprinting. The time of return to full participation was documented for 11 of the 16 reported injuries (68.8%); among them, the mean time loss was 136.7 ± 83.8 days—143.3 ± 99.6 days if the player underwent surgery (n = 4) and 116.7 ± 76.2 days missed by players without surgery (n = 6)—the treatment modality was unknown in 1 player.Conclusion:Although the incidence of traumatic posterior hip instability during the study period was low, all injured athletes missed time from football activities and competitions. Injuries that required surgery led to more missed time than those that did not. Ongoing research to understand risk factors and mechanisms of this injury, in conjunction with improvements to prevention and rehabilitation protocols, is necessary to ensure the safety of professional American football players.

Volleyball fight trajectory aerodynamic characteristics

When In volleyball, the air flow around the ball causes the ball to change direction. Comparing various balls, the ball bends, shakes, and falls differently. This is because the surface finish of the ball, the groove depth of the panel, and the panel shape change not only the surface flow but also the AC pattern, resulting in different aerodynamic characteristics for each ball. Therefore, ball performance research can lead to the development of the game, as knowledge of the ball's characteristics can give rise to new tactics. The serve is said to be the most offensive play because the player can raise the toss at his or her own timing. In this study, we focused on the jump serve, which has a high scoring rate on the serve, and obtained data on the flight trajectory, differences in aerodynamic characteristics, and force applied to the ball from groove measurements, ejection experiments, and fluid force measurements to obtain data for improving technique and coaching ability. In addition, to clarify the air flow around the ball, the separation point was visualized by 2D-PIV measurement. From the results obtained, it was confirmed that the ball lands in front of the surface as the number of rotations increases, but that it does not land in the court unless more rotations are applied depending on the ball, indicating that the surface and panel shapes have a significant impact on the flying trajectory.

Feasibility Study on Using AI and VR for Decision-Making Training of Basketball Players

Decision-making plays an essential role in basketball offense. Offensive players must make effective decisions to score a basket in various defensive situations. Virtual reality (VR) has been widely used in the training of athletes to strengthen their ability to make optimal decisions by creating controllable repeatable training scenarios. In this article, an action-aware offensive decision-making training system for basketball using VR and artificial intelligence is proposed. The proposed system is composed of different virtual defensive scenarios and an offensive action recognition framework. Trainees wearing head-mounted display and a motion capture suit are trained by intuitively interacting with the VR system and receive decision suggestions when a bad one is made. This study changes the training media and methods to create an immersive training environment during the training phase and evaluates the training effectiveness. These training scenarios are a conventional tactics board, the proposed VR system with a prerecorded <inline-formula><tex-math notation="LaTeX">$360^\circ$</tex-math></inline-formula> panorama video, and the VR system with computer-simulated virtual content. Results indicate that the training scenario affects the training in terms of decision time.

Return to Play After Arthroscopic Management of Rotator Cuff Tears in Professional Contact Athletes (245)

Objectives:Rotator cuff tears are rare injuries in professional contact athletes and there is limited data to help guide players and team physicians regarding outcomes after surgical management. The purpose of this study was to report on the clinical outcomes and return to play rates of professional contact athletes that underwent arthroscopic management of rotator cuff tears at our institution.Methods:A retrospective review was performed on 10 rotator cuff tears in 9 professional contact athletes that underwent arthroscopic management of a rotator cuff tear from 2002-2019 at our institution. 8 tears occurred in elite American football players, 7 from the NFL and 1 from the CFL. The remaining 2 rotator cuff tears were identified in professional hockey players from the NHL. The average age of the players was 28.7 ± 4.8 years. Patient information included age, sport, position played, date of injury, date of surgery and length of time from surgery to return to play. Surgical data included tear size, acuity and pattern as well as procedure performed (debridement vs repair). Both intra and post-operative complications were documented.The primary outcome measure was the ability to return to play and the number of games played after surgery was documented. As in other similar studies, return to play was defined as the ability to participate in at least 1 full regular-season game after surgery. Return to play and career length data were collected through publicly available internet sources (NFL, CFL and NHL statistical websites) as well as from the team’s medical staff.Results:80% of the professional contact athletes that underwent arthroscopic management of a rotator cuff tear in this study were able to return to play at the same professional. The average age of the players that returned to play was 27.3 ± 4.2 years and the average time to return to play was 7.9 ± 1.9 months. 8 of the 10 tears occurred in professional football players and the majority of these injuries (6 of 8) occurred in defensive players. 2 of the 10 tears occurred in professional hockey players from the NHL and both were offensive players. All of these players regained sufficient range of motion, strength and function to pass a pre-participation physical performed by their team’s medical staff and all participated in at least one regular season game. For the football players, the average playing experience after surgery was 32 ± 25 games played. For the hockey players, the average playing experience after surgery was 22 ± 11games played.9 of the 10 tears were full thickness tears that underwent arthroscopic single row repair while 1 was a partial tear that was debrided. The average tear size was 1.95 ±0.9 cm. The average number of suture anchors used was 1.35 ± 0.7. All tears involved the supraspinatus rotator cuff tendon and 4 were classified as small tears (<1cm), 3 as medium tears (1-3cm) and 2 as large tears (3-5cm). 7 of the 10 tears underwent acute surgical repair (<2 weeks from date of injury), while 3 players underwent delayed surgical intervention at the end of the season. The delay in surgical intervention did not appear to negatively impact healing rates or the ability to return to play. Other factors that did not appear to influence return to play included type of sport, position, type of procedure (debridement vs repair) or the number of suture anchors used in the repair. Post-operative imaging was available in 8 of the 10 tears and 7 of 8 (88%) demonstrated a healed repair. No intra-operative complications were noted.2 veteran players with large (3-5cm) full thickness tears did not return to play. The average age of these players was 34.5 years and both had > 10 years of professional playing experience. One of these players was an NFL player that demonstrated a repair failure at 6 months on post-operative imaging and elected to retire rather than undergo revision surgery. The second was an NHL player that retired for reasons unrelated to his shoulder, despite a good clinical outcome and a healed repair on post-operative imaging. To our knowledge, none of the remaining players have undergone subsequent surgical intervention or revision surgery on their injured shoulder.Conclusions:This is one of only a few studies since 1996 to report on the clinical outcomes after operative management of rotator cuff tears in elite professional contact athletes. The majority (80%) of the professional contact athletes in this series were able to return to play at the same professional level after arthroscopic management of a symptomatic rotator cuff tear. Older players with > 10 years of professional experience and large rotator cuff tears were less likely to return to play after surgical intervention.