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This study aimed to identify the game-related statistics that discriminated between Euroleague basketball players and European basketball players playing in the NBA, when competing in the same event (EuroBasket 2015). There was a total of 78 matches played by 24 teams in two groups of analysis: NBA, participants in the European Championship who played in the NBA season of 2014-2015 (n = 26); Euroleague, participants in the European Championship who played in the Euroleague season of 2014-2015 (n = 82). The players’ performance variables were normalized to the time they spent on the court. To identify which variables best discriminated between the NBA and the Euroleague performance profiles, a descriptive discriminant analysis was conducted. Structure coefficients (SC) from the matrix greater than |0.30| were interpreted as meaningful contributors to discriminating between the groups. The results revealed a significant function (p = 0.008, canonical correlation of 0.51, Λ = 0.74, reclassification = 84.2%) and substantial performance differences in game-related statistics much related to the influence of body size (body height and mass), such as two-point field goals made (SC = 0.42) and missed (SC = 0.40), free-throws made (SC = 0.55), defensive rebounds (SC = 0.62), blocks (SC = 0.48) and suffered fouls (SC = 0.34). No differences were found at the level of game-related statistics indirectly related to perception, such as assists, turnovers or steals. Also, the greater body size in NBA players was likely related to higher variability in performance, thus, being an important topic for coaches and recruiters to analyse.

Objectives This study described the variability in acceleration during a resistance training task, performed in horizontal inertial flywheels without (NOBALL) or with the constraint of catching and throwing a rugby ball (BALL). Design and methods Twelve elite rugby players (mean ± SD: age 25.6 ± 3.0 years, height 1.82 ± 0.07 m, weight 94.0 ± 9.9 kg) performed a resistance training task in both conditions (NOBALL AND BALL). Players had five minutes of a standardized warm-up, followed by two series of six repetitions of both conditions: at the first three repetitions the intensity was progressively increased while the last three were performed at maximal voluntary effort. Thereafter, the participants performed two series of eight repetitions from each condition for two days and in a random order, with a minimum of 10 min between series. The structure of variability was analysed using non-linear measures of entropy. Results Mean changes (%; ±90% CL) of 4.64; ±3.1 g for mean acceleration and 39.48; ±36.63 a.u. for sample entropy indicated likely and very likely increase when in BALL condition. Multiscale entropy also showed higher unpredictability of acceleration under the BALL condition, especially at higher time scales. Conclusions The application of match specific constraints in resistance training for rugby players elicit different amount of variability of body acceleration across multiple physiological time scales. Understanding the non-linear process inherent to the manipulation of resistance training variables with constraints and its motor adaptations may help coaches and trainers to enhance the effectiveness of physical training and, ultimately, better understand and maximize sports performance.

This study aimed to compare youth football players' performance during two small-sided games with different pitch orientation: i) 40x30m and ii) 30x40m formats. Twenty under-15 players (age = 14.1 ± 0.5 years) participated in nine GK+4vs4+GK situations in each format, with the duration of six minutes each. Positional data were collected using individual GPS units, and computed for tactical and physical performance indicators. The SSG were video recorded, using notational analysis for collecting technical indicators. A novel method that incorporates time dependent notational information with spatiotemporal data was used to compute multidimensional parameters. Standardised effect sizes and non-clinical magnitude-based inferences were used to compare formats. Results showed that players covered more distance at higher intensities, presented more passes and dribbles and were more synchronised in the longitudinal axis while playing in the 40x30m pitch. In the 30x40m pitch, results showed a lower distance between team centroids, higher number of shots, more lateral passes and a wider team positioning. Multidimensional indicators, as players position and distance to the closest defender while shooting, revealed a more constant distance between attacker and defender in the 40x30m pitch. These results highlight the importance of integrating information from different indicators for a contextually valid information.

The purpose of this study was to describe the dynamics of a repeated sprint ability (RSA) cycling protocol in young elite basketball players. Twenty-two elite male basketball players (aged 18.3±0.6 years; training years 9.1±1.3 years) performed 3 bouts of a repeated sprint ability (RSA) protocols, consisting of 5 x 6-s cycling sprints with a 24-s rest interval between sprints. The work decrement during the first trial was high (14.1±4.8%) and after 5-minute rest did not change significantly. The total work decreased by 5.5% in the second work interval and by 2.9% in the third interval. During the 5-minute passive rest, young basketball players’ peak power recovered about 90% of the initial levels. It is suggested that rest intervals are sufficient to continue the game with adequate performance potential. A reduction in work decrement, while maintaining the capacity of all sprints, is needed to achieve a higher repeated sprint ability. Resumen El propósito de este estudio fue describir la dinámica de un protocolo de esprines repetidos en jóvenes jugadores de baloncesto. Veintidós jugadores de baloncesto masculino (con edades comprendidas entre 18,3 ± 0,6 años, años de entrenamiento de 9,1 ± 1,3 años) realizaron 3 series de un protocolo de esprín repetido, consistiendo en 5 esprines en cicloergometro de 6-s con de descanso de 24-s entre esprints. La disminución del trabajo durante la primera serie fue alta (14.1 ± 4.8%) y después de 5 minutos de descanso no cambió significativamente. El trabajo total disminuyó en un 5.5% en la segunda serie y en un 2.9% en la tercera. Durante el descanso pasivo de 5 minutos, la potencia máxima de los jóvenes jugadores de baloncesto recuperó aproximadamente hasta un 90% de los niveles iniciales. Se sugiere que los intervalos de descanso sean suficientes para continuar el juego con un potencial de rendimiento adecuado. Se necesita una reducción en el decremento del trabajo, mientras se mantiene la capacidad de todos los esprines, para optimizar esta capacidad de rendimiento tan importante en baloncesto.

Performance in team sports is the expression of complex, dynamic, interactive, and multidimensional processes. It is now well-established that optimum recovery after practice or match is a key factor of team sport performance. During season and tournaments, improving recovery could offer an advantage for following performance. As a consequence of the professionalization of different roles in staffs, new particular roles have been developed within the team sports physician core in order to improve recovery protocols. Presently, scientific literature presents a big amount of methods used to enhance recovery based on the type of practice, time between session or competitions and equipment and/or staff accessible. These practices, usually used by teams are related to: ergonutritional, water therapy, massages techniques, stretching compression garments, sleep strategies and psychological implements. Besides, travel fatigue has been recognized by athletes and coaches as a challenging problem that could benefit from practical solutions. Nowadays, players have to play a lot of matches without enough time to recover among them, therefore the use of well-managed recovery can lead to a competitive advantage. Although the main purpose of applied sport sciences investigation is to categorize the protocols as well as providing approaches for individual recovery, the stages to recognize the most appropriate recovery plans in the field of team sports come from the analysis of the individual parameters. Sin financiación No data JCR 2018 0.313 SJR (2018) Q3, 107/209 Physical Therapy, Sports Therapy and Rehabilitation, 171/289 Orthopedics and Sports Medicine No data IDR 2018 UEM

The aim of this study was: (i) to group basketball players into similar clusters based on a combination of anthropometric characteristics and playing experience; and (ii) explore the distribution of players (included starters and non-starters) from different levels of teams within the obtained clusters. The game-related statistics from 699 regular season balanced games were analyzed using a two-step cluster model and a discriminant analysis. The clustering process allowed identifying five different player profiles: Top height and weight (HW) with low experience, TopHW-LowE; Middle HW with middle experience, MiddleHW-MiddleE; Middle HW with top experience, MiddleHW-TopE; Low HW with low experience, LowHW-LowE; Low HW with middle experience, LowHW-MiddleE. Discriminant analysis showed that TopHW-LowE group was highlighted by two-point field goals made and missed, offensive and defensive rebounds, blocks, and personal fouls; whereas the LowHW-LowE group made fewest passes and touches. The players from weaker teams were mostly distributed in LowHW-LowE group, whereas players from stronger teams were mainly grouped in LowHW-MiddleE group; and players that participated in the finals were allocated in the MiddleHW-MiddleE group. These results provide alternative references for basketball staff concerning the process of evaluating performance.

Purpose: This study aimed to explore whether the outcome of professional football matches is affected by changes in intra-team movement synchronization. Methods: Positional data from 77 players wer...

This study aimed to assess the effects of the total quality of recovery and well-being indices (self-ratings of sleep during the preceding night, stress, fatigue and delayed onset muscle soreness) on rating of perceived exertion (RPE) and physical enjoyment (PE) during small-sided games. A total of 20 professional soccer players (25 ± 0.8 years) completed four 5-a-side game sessions of 25-min duration each (4 × 4 min work with 3-min passive recovery in-between). All variables were collected before each game session with the exception of RPE and Physical Activity Enjoyment Scale that were collected after. The results demonstrate that recovery state and pre-fatigue states were not contributing signals of affected internal intensity and enjoyment of players. The study established the objectivity and utility of RPE as a useful tool for determining internal intensity during soccer-specific training as well as PE for assessing emotional response during exercise or training session.

The aim of this study was to identify the effects of a differential-learning program, embedded in small-sided games, on the creative and tactical behavior of youth soccer players. Forty players from under-13 (U13) and under-15 (U15) were allocated into control and experimental groups and were tested using a randomized pretest to posttest design using small-sided games situations.The experimental group participated in a 5-month differential-learning program embodied in small-sided games situations, while the control group participated in a typical small-sided games training program. In-game creativity was assessed through notational analyses of the creative components, and the players' positional data were used to compute tactical-derived variables.The findings suggested that differential learning facilitated the development of creative components, mainly concerning attempts (U13, small; U15, small), versatility (U13, moderate; U15, small), and originality (U13, unclear; U15, small) of players' actions. Likewise, the differential-learning approach provided a decrease in fails during the game in both experimental groups (moderate). Moreover, differential learning seemed to favor regularity in pitch-positioning behavior for the distance between players' dyads (U13, small; U15, small), the distance to the team target (U13, moderate; U15, small), and the distance to the opponent target (U13, moderate; U15, small).The differential-learning program stressed creative and positional behavior in both age groups with a distinct magnitude of effects, with the U13 players demonstrating higher improvements over the U15 players. Overall, these findings confirmed that the technical variability promoted by differential learning nurtures regularity of positioning behavior.

espanolEl objetivo del presente estudio fue describir las respuestas fisiologicas y tecnico-tacticas en mujeres jovenes durante juegos reducidos (SSG) de baloncesto 3 contra 3 con y sin el estimulo verbal del entrenador y el bote. Seis jugadoras de baloncesto (edad: 14.3 ± 0.5 anos; altura: 167.8 ± 0.8 cm; peso: 56.5 ± 5.7 kg) tomaron parte del estudio piloto. Los juegos fueron grabados en video y despues las demandas tecnicas fueron registradas con software ad hoc de observacion. El pico de frecuencia cardiaca maxima se incremento de la serie 1 a la 3 durante el SSG con bote y estimulo del entrenador, asi como en el SSG sin bote y presencia del entrenador. Con el estimulo del entrenador se produjo mayores respuestas de frecuencia cardiaca y esfuerzo percivido que sin bote y estimulo del entrenador. No hubo diferencias en las acciones tecnicas, excepto en el numero de rebotes ofensivos que fue mayor en la tarea con estimulo del entrenador. En conclusion, el SSG con estimulo verbal deberia elegirse para centrarse en la carga fisiologica, mientras que el que se realiza sin el, puede ser util para mejorar el comportamiento colectivo, sin limitaciones en la carga fisiologica. EnglishThe aim of the present study was to describe the physiological and technical responses in young female during a basketball 3 vs. 3 small-sided games (SSG) with and without verbal coach encouragement and dribbling. Six young female basketball players (age: 14.3 ± 0.5 years; height: 167.8 ± 0.8 cm; body mass: 56.5 ± 5.7 kg) were recruited to participate in the present pilot study. The games were video recorded and afterwards the technical demands were notated with observational ad hoc software. The peak of maximum heart rate was increased from set 1 to set 3 during both the SSG with dribble and coach encouragement, as well as in the SSG without dribble and coach presence. With coach encouragement caused greater responses of heart rate and rate of perceived exertion than without both dribble and coach encouragement. There were no differences in technical actions, exception of the number of offensive rebounds showing a higher number in the coach encouragement task. In conclusion, the SSG with verbal encouragement should be selected to focus in physiological load, and SSG without might be useful to enhance collective behavior, without limitations in physiological load.

This study aimed to identify changes in tactical, physical and physiological performances in large-sided games during the preseason of elite footballers. Thirty professional football players participated in several GK+8vs.8+GK large-sided games across the first four weeks of the season. Players were monitored by GPS units and heart rate monitors to quantify physical, physiological and tactical performances. The variables were compared according to the preseason period, players' positioning and professional experience. The training situation promoted similar physiological responses during the first and the last training period. However, players were revealed to have higher levels of positional synchronization during the last preseason period, indicating an improved tactical performance. Tactical variables seem to reflect the improvement of players' performance during the preseason, measured in large-sided games situation, while affecting both physical and physiological demands. These results highlight the potential of positioning derived variables, concurrently to physical and physiological variables, for football training optimization.

The aim of this study was to compare heart rate (HR), rating of perceived exertion (RPE), and technical-tactical actions during small-sided games (SSGs) played without (CTR), with internal (IW), and with IW and external (IEW) wildcard players. A total of 22 young male soccer players (age 17.2 ± 0.9 years) randomly completed six 4vs4 SSG situations. The control conditions occurred with goals scored without goalkeeper (4vs4-NO) and with goalkeeper (4vs4-GK). During the experimental conditions, the situations incorporated 2 IW (4vs4+2IW-NO, 4vs4+2IW-GK) and 2 IEW (4vs4+2IW+2IEW-NO, 4vs4+2IW+2IEW-GK). Processed results did not include data from goalkeepers, IW, and IEW players. The HR was divided in intensity-zones (Z1, Z2, and Z3, for80%, 80-90%, and90% of maximal HR, respectively) and the analyzed technical-tactical actions were the pass, dribbling, collective success, and pause. The effects of IW and IEW were analyzed through repeated measures analysis of variance. During 4vs4+2IW+2IEW-NO, greater time was recorded in Z1 (p ≤ 0.05) compared with 4vs4-NO and 4s4+2IW-NO. During 4vs4+2IW+2IEW-GK, greater time was recorded in Z1 and less in Z3 (p ≤ 0.05) compared with 4vs4-GK. Greater RPE was reported in 4vs4-NO (p0.01) and 4vs4+2IW-NO (p0.01) compared with 4vs4+2IW+2IEW-NO, and during 4vs4-GK (p0.01) than 4vs4+2IW+2IEW-GK. Greater number of dribbling situations were recorded during 4vs4-NO (p ≤ 0.05) compared with 4vs4+2IW+2IEW-NO. In conclusion, compared with the control condition of 4vs4, the incorporation of IEW reduced HR, RPE, and dribbling actions.

The aim of this study was to explore the differences in technical, tactical and movement performance of professional male tennis players in Grand Slams, according to player's experience and relative quality. Match data of 1188 players competing in 2015–2017 Grand Slam tournaments were collected. Experience and relative quality (RQ) were used to classify players via cluster analysis, based on Cubic Clustering Criterion. Afterwards, a descriptive discriminant analysis was performed to identify the most important variables that best predict player clusters in each Grand Slam, and two discriminant functions were generated (p < 0.01). High-experienced Higher RQ Players (n = 337) outperformed other players in serve and return (fewer double faults, more second serve and return points won), rally winners and breaking opportunities while covering longer distance. Experienced Higher RQ Players (n = 267) hit faster serves and more aces, played more aggressively when returning (more return winners and unforce...

Objectives: This study aimed to identify whether the structure underlying the on-field interpersonal positioning tendencies of soccer players might discriminate the length of ball possession sequences.Methods: Data were gathered using GPS during 5-a-side games performed by under-19 elite soccer players.Results: The results revealed significant differences between clusters in almost all the variables, assuring that the regularity of the distance to centroid accurately discriminated the short from the long sequences of play. Also, the analyses revealed moderate significant interaction between Type of Relation (intra-team vs. inter-team) Sequences of Play (short vs. long) independently of the variable taken as criterion to divide the clusters.Conclusions: Regularity of intra- and inter-team interpersonal coordination is able to discriminate short and long sequences of play during SSG. Generally, short sequences of play displayed higher irregularity than the longer sequences. In the long sequence, int...

The aim of this study was to (i) identify technical and physical performances of basketballers according to playing position in strong and weak teams, and (ii) describe variability in game-togame performance according to game outcome, location, quality of teams and opposition. Performance-related variables of all the 699 matches of regular season 2015–2016 in the National Basketball Association were analysed. All the comparisons were performed using magnitude-based inferences. As could be expected, results showed that technical and physical performances differed between players of strong and weak teams. In technical aspect, forwards and centres from strong teams made more three-point field goals, but fewer two-point field goals, than their counterparts from weak teams. Interestingly, forwards and guards from strong teams covered shorter distances and lower speeds than their peers from weak teams. In addition, the threepoint field goals made and attempted presented high variability. Game location generally had no significant impact on the variability of players’ performance. Guards exhibited relatively lower variability in technical and physical variables in comparison with players from other positions. Exploring the difference and variability of technical and physical performances of basketballers allows fine-tuning of practice and game plans in order to build up optimal winning strategies.

The purpose of this study was two-step: (1) classify ball possession (BP) according to the duration and number of passes and (2) identify which tactical variables most discriminate the different BP. We obtained 527 BPs from four official matches of the Brazilian Soccer Championship 2016. Forty-one "notational", "space occupation", and "displacement synchronization" predictor variables were used. The BPs were classified into three groups: short (11.07 ± 4.49 s, 1.93 ± 0.99 passes), medium (26.83 ± 7.33 s, 5.41 ± 1.84 passes), long (55.50 ± 14.97 s, 12.11 ± 4.61 passes). Discriminant analysis identified the five most relevant variables to describe each group: coefficient of variation (CV) of the defensive team's synchronization-Y, CV defensive team´s synchronization-X, successful pass last third, CV distance between offensive team's centroid and target, mean of the offensive team's width. The approach highlights important variables and could benefit the description of offensive and defensive game sequences to provide precise knowledge on the process.

Facial expression analysis is a widespread technology applied in various research areas, including sports science. In the last few decades, facial expression analysis has become a key technology for monitoring physical exercise. In this paper, a deep neural network is proposed to recognize seven basic emotions and their corresponding probability values (scores). The score of the neutral emotion was tracked throughout the exercise and related with heart rate and power generation by a stationary bicycle. It was found that in a certain power range, a participant changes his/her expression drastically. Twelve university students participated in the sub-maximal physical exercise in stationary bicycles. A facial video, heart rate,and power generation were recorded throughout the exercise. All the experiments, including the facial expression analysis, were carried out offline. The score of the neutral emotion and its derivative was plotted against maxHR% and maxPower%. The threshold point was determined by calculating the local minima, with the threshold power for all the participants being within 80% to 90% of its maximum value. From the results, it is concluded that the facial expression was different from one individual to another, but it was more consistant with power generation. The threshold point can be a useful cue for various purposes, such as: physiological parameter prediction and automatic load control in the exercise equipment, such as treadmill and stationary bicycle.

Baptista, J, Travassos, B, Gonçalves, B, Mourão, P, Viana, JL, and Sampaio, J. Exploring the effects of playing formations on tactical behavior and external workload during football small-sided games. J Strength Cond Res 34(7): 2024-2030, 2020-This study aimed to identify the effects of playing formations on tactical behavior and external workload during football small-sided games. Twenty-three semiprofessional footballers integrated 3 different playing formations in a 7-a-side small-sided game, according to their specific player positions: team 4:3:0 (4 defenders and 3 midfielders); team 4:1:2 (4 defenders, 1 midfielder, and 2 forwards); and team 0:4:3 (4 midfielders and 3 forwards). Based on players' movement trajectories, the following individual and collective tactical variables were calculated: total distance covered and distance covered while walking, jogging, running, and sprinting, distance from each player to both own-team centroid and opponent-team centroid, individual area, team length, team width, and surface area. Approximate entropy was computed to identify the regularity of each variable. The team 4:3:0 promoted players' space exploration with moderate physical efforts. The team 4:1:2 promoted compactness and regularity of the team with increase in the physical efforts. The team 0:4:3 promoted team balance and adaptability on space coverage with increase in physical efforts. Concluding, different playing formations support different game dynamics, and variations on external load were directly linked with the variations on tactical behavior. The analysis of tactical behavior through quantification of variability of patterns of play and quantification of distance covered at different velocities were the most useful information for the analysis of the effects of practice task manipulations. Therefore, in a practical sense, strength and conditioning coaches should plan and monitor these tasks in interaction with the head coaches. info:eu-repo/semantics/publishedVersion

This study aimed to identify short-term effects on basketball players’ physical responses, technical performance, and tactical behaviour when the court dimension is increased 1-m wide to each side. Fourteen youth players participated in 5 vs. 5 simulated basketball games, under two different conditions: regular court (28x15m) and wider court (28x17m, 1-m wider for each side). Besides the assessment of physical and technical indicators, positional data were also used to compute the following variables: distance to the nearest opponent, distance to the nearest teammate, stretch-index and distance between centroids. Results indicated that in the wider court condition, the dispersion of player’s displacement trajectories duringthe offensive phase increased, which had slight repercussions on their physical responses and in the teams’ playing patterns. Conversely, during the defensive phase, players tended to move within the regular spatial references, regardless of court width manipulation. Overall, this study emphasizes that short-term effects of changing the court dimensions are relatively negligible, suggesting that informational constraints might require longer time-scales to yield robust changes in players’ performance. RESUMEN: El propósito de este estudio fue identificar los efectos a corto plazo en las respuestas físicas, técnicas y tácticas de jóvenes jugadores de baloncesto cuando la dimensiónde la cancha aumenta 1-m de ancho en cada lado. Catorce jugadores jóvenes participaron en juegos simulados de baloncesto de 5 vs. 5, en dos condiciones diferentes: cancha regular (28x15m) y cancha más amplia (28x17m, 1-m de ancho a cada lado). Además de la evaluación de los indicadores físicos y técnicos, también se utilizaron datos de posición para calcular las siguientes variables: distancia al oponente más cercano, distancia al compañero de equipo más cercano, coeficiente de dispersión del equipo y distancia entre los centroides de los equipos. Los resultados indicaron que, en la condición de cancha más amplia, la dispersión de las trayectorias de movimiento de los jugadores durante la fase ofensiva aumentó, lo que tuvo ligeras repercusiones en sus respuestas físicas y en los patrones de juego de los equipos. En contrapartida, durante la fase defensiva, los jugadores tienden a moverse dentro de las referencias espaciales regulares, independientemente de la manipulación del ancho de la cancha. En general, este estudio enfatiza que los efectos a corto plazo de cambiar las dimensiones de la cancha son relativamente ligeros, lo que sugiere que las restricciones informativas pueden requerir bastante más tiempo para producir cambios concretos en el rendimiento de los jugadores. RESUMO: Este estudo teve como objetivo identificar os efeitos a curto prazo na performance física, técnica e tática de jovens jogadores de basquetebol, quando a largura do campo é aumentada 1-m para cada lado. Catorze jovens jogadores participaram em jogos simulados de 5 vs. 5, em dois contextos distintos: campo regular (28x17m) e campo amplo (28x17m, 1-m mais largo para ambos oslados). Paralelamente à avaliação de indicadores físicos e técnicos, foram também recolhidos dados posicionais, com o intuito de calcular as seguintes variáveis: distância ao oponente mais próximo, distância ao companheiro de equipa mais próximo, coeficiente de dispersão da equipa e distancia entre os centroides das equipas. Os resultados demonstraram que no contexto de campo amplo, a dispersão das trajetórias de movimento dos jogadores aumentou durante a fase ofensiva, o que acarretou ligeiras repercussões nos perfis físicos e nos padrões de jogo das equipas. Em contrapartida, durante a fase defensiva, os jogadores tendem a mover-se dentro dos referenciais espaciais, independentemente da manipulação do tamanho do campo. No geral, este estudo realçou que osefeitos a curto prazo de alterar as dimensões do campo são pouco expressivos, o que sugere que os constrangimentos de informação podem requerer substancialmente mais tempo para produzir alterações concretas no rendimento dos jogadores.

Performance analysis research in association football has recently cusped a paradigmatic shift in the way tactical behaviours are studied. Based on insights from system complexity research, a growing number of studies now analyse tactical behaviours in football based on the collective movements of team players. The aim of this systematic review is to provide a summary of empirical research on collective tactical behaviours in football, with a particular focus on organising the methods used and their key findings. A systematic search of relevant English-language articles was performed on one database (Web of Science Core Collection) and one search engine (PubMed), based on PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. The keywords ‘football’ and ‘soccer’ were each paired with all possible combinations of the following keywords: ‘collective movement behaviour’, ‘collective behaviour’, ‘tactical behaviour’, ‘interpersonal coordination’, ‘space’, ‘Voronoi’, ‘synchronisation’, ‘tactical analysis’, ‘constraints’, ‘ecological dynamics’, and ‘dynamic positioning’. Empirical studies that were related to tactical analyses of footballers’ positional data were sought for inclusion and analysis. Full-text articles of 77 studies were reviewed. A total of 27 tactical variables were identified, which were subsequently organised into 6 categories. In addition to conventional methods of linear analysis, 11 methods of nonlinear analysis were also used, which can be organised into measures of predictability (4 methods) and synchronisation (7 methods). The key findings of the reviewed studies were organised into two themes: levels of analysis, and levels of expertise. Some trends in key findings revealed the following collective behaviours as possible indicators of better tactical expertise: higher movement regularity; wider dispersion in youth players and shorter readjustment delay between teammates and opponents. Characteristic behaviours were also observed as an effect of playing position, numerical inequality, and task constraints. Future research should focus on contextualising positional data, incorporating the needs of coaching staff, to better bridge the research-practice gap.

Quantifying game and training demands in basketball allows to determine player’s readiness and optimizes preparation to perform and reduce injury risks. Available research is using tracking technology to perform general descriptions of the game activities at professional levels, but somehow, is not exploring the possibilities of gathering data from new variables that can contribute with complementary information for the coaching staffs. The aim of this study was to identify changes in locomotor ratio, at higher and lower speeds, during the game quarters from elite under-18 basketball teams. Ninety-four male players participated in the study (age: 17.4 ± 0.74 years; height: 199.0 ± 0.1 cm; body mass: 87.1 ± 13.1 kg) from different playing positions, Guards (n = 35), Forwards (n = 42), and Centers (n = 17). Data were gathered from an international tournament and players’ movements were measured using a portable ultra-wide band position-tracking system (WIMU PRO®, Realtrack Systems, Almeria, Spain). The following variables were measured: (1) relative distance in different speed zones: walking (24.1 km·h−1); and (2) player load, vector magnitude expressed as the square root of the sum of the squared instantaneous rates of change in acceleration in each of the three planes divided by 100. Afterward, these variables were used to calculate players’ locomotor ratio (player load per meter covered) at higher (running, high-intensity running, and sprinting) and lower speeds (walking and jogging). Results from the locomotor ratio at both lower and higher speeds presented a significant effect for the quarter (F = 7.3, p < 0.001 and F = 7.1, p < 0.001, respectively) and player position (F = 3.1, p = 0.04, F = 9.2, p < 0.001, respectively). There was an increase in the locomotor ratio from game quarter (Q) Q1 to Q4 at lower speeds, but contrary trends at higher speeds, i.e., the values have decreased from Q1 to Q4. Also, forwards and centers of the best teams presented lower values at higher speeds. Altogether, the findings may be used by coaching staffs as a first baseline to elaborate normative behavior models from the players’ performance and also to induce variability and adaptation in specific practice planning.

Purpose: This study aimed to compare players' performances when manipulating the external markings of the pitch during football small-sided games. Methods: Ten under-15 players performed a 5-a-side (plus goalkeepers) under three conditions: (i) Lines, the game was played in a pitch in which the external boundaries were painted with full lines; (ii) Dashed, the game was played in a pitch in which the external boundaries were painted with dashed lines; (iii) Corners, the game was played in a pitch were the external boundaries were delimited by one marker at each pitch corner. Players' positional data was used to compute tactical and time-motion variables. Also, technical analysis was comprised using video footage. Results: Results showed similar tactical, physical and technical performances between the Lines and Dashed conditions. In contrast, the Lines condition showed small higher effects than Corners scenario in the time spent synchronized in longitudinal and lateral displacements, game pace, total distance covered, distance covered while jogging, number successful dribbles and shots on target. The Lines scenario has also revealed a lower effective playing space, distance covered at walking and running and a lower number of passes (small effects) compared to Corners. Conclusions: These results highlight that these changes in informational perception constraints modify players movement behavior. Accordingly, pitches with more visible boundaries were likely to decrease team dispersion, which may optimize team synchrony and technical performances, while decreasing the distance covered at higher speeds. Coaches may use this information to modify the types of pitch external boundaries markings, exposing the players to different environmental information.

PurposeThe aim of this study was to describe the physical demands during U18 elite basketball games according to the game quarter and to identify a smaller subset of variables and threshold scores that distinguish players' physical performance in each quarter.MethodsData was collected from ninety-four players who participated in the study (age: 17.4 ± 0.74 years; height: 199.0 ± 0.1 cm; body mass: 87.1 ± 13.1 kg) competing in the Euroleague Basketball Next Generation Tournament. Players' movements during the games were measured using a portable local positioning system (LPS) (WIMU PRO®, Realtrack Systems SL, Almería, Spain) and included relative distance (total distance / playing duration), relative distance in established speed zones, high-intensity running (18.1-24.0 km·h-1) and sprinting (> 24.1 km·h-1). player load, peak speed (km·h-1) and peak acceleration (m·s-2) number of total accelerations and total decelerations, high intensity accelerations (> 2 m·s-2) and decelerations (< -2 m·s-2).ResultsThere was an overall decrease in distance covered, player load, number of high intensity accelerations and decelerations between the first and last quarter of the games in all playing positions. A classification tree analysis showed that the first quarter had much influence of distance covered (above 69.0 meters), distance covered 2 m·s-2), whereas the fourth quarter performance had much influence of distance covered (below 69.0) and distance covered 12.1-18.0 km·h-1.ConclusionsA significant reduction in physical demands occurs during basketball, especially between first and last quarter for players in all playing positions during basketball games of under 18 elite players.

Purpose: To describe and identify individual trends and changes in training load, neuromuscular readiness, and perceptual fatigue measures in 2 youth elite long jumpers, finalists at the European Athletics U18 (Under 18) Championships (athlete A, female, age 16.5 y, long-jump record 6.25 m; athlete B, male, age 16.0 y, long-jump record 7.28 m). Methods: Data were collected from both training sessions and athletics competitions during a 16-week period, divided into a preparation (weeks 1–8) and a competitive phase (weeks 9–16). Training load was computed through training diaries (training time, sprint, jumping, and weights volume). The countermovement jump and the 10-to-5 repeated-jump test were executed on a weekly basis to assess neuromuscular readiness, and perceptual fatigue measures were collected through a wellness questionnaire. Statistical analysis was conducted using a magnitude-based decisions approach. Results: The results highlighted a decrease in training load during the competitive period with moderate to large differences for training time, sprint, and jump volume. Moreover, data showed an upward trend and very likely higher scores in vertical-jump performance across the competitive phase together with a very likely lower perceptual fatigue. Conclusions: This scenario seemed to be favorable to achieve competition performance very close to the personal record during the competitive season. This study provided an example of application of a comprehensive monitoring system with young athletes involved in track-and-field jumping events.

The aims of this study were (a) to compare players' physical demands between different playing positions in elite U18 basketball games and (b) to identify different clusters of performance. Data were collected from 94 male subjects (age: 17.4 ± 0.7 years), competing in a Euroleague Basketball Tournament. Guards covered a greater relative distance than centres and forwards (small to moderate effect). Forwards and guards had more peak accelerations, high accelerations and high decelerations than centres (moderate to large effects). A cluster analysis allowed to classify all cases into three different groups (Lower, Medium and Higher activity demands), containing 37.4%, 52.8% and 9.8% of the cases, respectively. The high accelerations, high decelerations, peak accelerations and total distance covered were the variables that most contributed to classify the players into the new groups. The percentage of cases distributed in the clusters according to playing position, game type (worst vs worst, mixed opposition, best vs best) and team were different. Centres have lower physical demands specially related with the number of accelerations and decelerations at high intensity and the peak acceleration when compared with guards. Each team has a different activity profile, that does not seem to influence the tournament outcome.

Optimizing basketball performance during the stages of long-term athlete development require to identify the trainability and variation of specific technical skills, when adjusting for anthropometric changes. The aim of this study was to describe differences in height, body mass, arm span, and technical-related fitness (movement, dribbling, shooting) along the long-term development of 7–17 years Lithuanian basketball players. This cross-sectional analysis involved a total of 1051 basketball players from the Sabonis Basketball Center in Lithuania. Testing sessions were performed during 1 day of the competition period in an indoor court. The participants performed technical-related fitness tests to assess dribbling (control dribble, 20 m dribble, two balls of 20 m dribble, Illinois agility dribble), shooting (30 free-throw shoots, 1 min shooting, modified medium and long-range shots, close range shots) and defensive movements. The dribbling skills had substantial improvements (7 to 8-years-old: 20 m sprint with dribbling, effect size = 1.86; control dribble effect size = 2.18; 9 to 10-year-old: 20 m sprint with dribbling, effect size = 1.85; Illinois agility test with dribbling effect size = 1.82). Changes in defensive movement occurred mostly at the 14–15-age period. The best periods to develop dribbling and shooting skills were between 7–10 and 12–13 years, whereas defensive movements can be trained in later adolescent years. Current results and consequent normative profiles, presented as percentile tables, allow to accurately follow the players’ development. Keywords: basketball, technical testing, fitness testing, long-term development, physical profile.

The study was aimed to explore distinct players' groups according to their anthropometric and individual features, and to identify the key performance indicators that discriminate player groups. Match statistics, anthropometric and personal features of 1188 male players competing during 2015-2017 main draw Grand Slam singles events were collected. Height, weight, experience, handedness and backhand style were used to automatically classify players into different clusters through unsupervised learning model. Afterwards, 29 match variables were analysed through MANOVA and discriminant analysis in order to evaluate the different match performance among player groups and to identify the key performance indicators that best differentiate player clusters in each Grand Slam. The analysis revealed the existence of four clusters, they were classified as Big-sized Right Two-handed Players (

OBJECTIVES: The XXI Century Academy was a 6- year state-initiated intervention program that served as an alternative to basketball clubs for players in the u-14 and u-18 age groups in Spain, under guidelines established by the Spanish Basketball Federation. It was an important and unique project on talent development in basketball. To the best of the authors' knowledge, no evidence has been reported on long-term athlete development programs in basketball worldwide. The main aim of this report is to describe the design and evaluation methods used for the XXI Century Academy as a long-term intervention program in the elite Spanish Basketball Academy, aiming to prepare basketball players to compete at the elite level. METHODS: The monitoring time lasted from 1996 to 2001. A total of 55 players were assigned to the intervention groups based on age, position, maturation level, and country of origin. During this process, participants competed in up to two categories in addition to playing competitive official matches worldwide in international tournaments in their categories and with the national team in the European and World Championships (u-14 - u-18). Participants included 1 NBA player, 3 national A Team players, 10 ACB (First Spanish League) players, 5 LEB (second League) players and 39 LEB-2 EBA (third League) players. Assessments took place in a High-Performance Sports Center (CPT FADURA-GETXO- Basque Government, Getxo, Vizcaya, Spain) and consisted of health questionnaires, anthropometric measures, blood parameters, maturation level, birth age, fitness tests, training volume and intensity, physical activity, technical and tactical training, dietary intake, supplementation and injuries. Each player was assessed 4 times per year (September, December, April, June) for 4 years (16 data points). RESULTS: This is a purely methodological paper describing the design and evaluation methods used in the XXI Century Project, which will be used as a basis for future reporting of results. Therefore, the results of the project will be reported in subsequent publications. CONCLUSION: The viability of the Century XXI Project protocols has been described. This national project of training in basketball closely replicates the physical and technical match-play conditions for professionals and may constitute a useful training tool.

This study analysed the game-scoring coordination in men’s Spanish Handball League when controlling for quality of opposition, game location, game period and their potential interactive effects. Th...

The aim of the current study was (i) to identify how important was a good season start in relation to elite handball teams’ performance, and (ii) to examine if this impact was related to the clubs’ financial budget. The match performances and annual budgets of all teams were collected from the Spanish Professional Handball League during ten seasons. The dependent variable was the difference between the ranking of each team in accordance to the annual budget and the ranking of each team at the end of the season. A k-means cluster analysis classified the clubs according to their budget as High Range Budget Clubs (HRBC), Upper-Mid Range Budget Clubs (UMRBC), Lower-Mid Range Budget Clubs (LMRBC) and Low Range Budget Clubs (LRBC). Data were examined through linear regression models. Overall, the results suggested that the better the team performance at the beginning of the season, the better the ranking at the end of the season. Each position in the ranking above expected in accordance to the budget of the teams in Rounds 3, 4 or 5 improved by 0.47, 0.50 or 0.49, respectively, in the ranking at the end of the season (p

Optimizing collective behaviour helps to increase performance in mutual tasks. In team sports settings, the small-sided games (SSG) have been used as key context tools to stress out the players' awareness about their in-game required behaviours. Research has mostly described these behaviours when confronting teams have the same number of players, disregarding the frequent situations of low and high inequality. This study compared the players' positioning dynamics when manipulating the number of opponents and teammates during professional and amateur football SSG. The participants played 4v3, 4v5 and 4v7 games, where one team was confronted with low-superiority, low- and high-inferiority situations, and their opponents with low-, medium- and high-cooperation situations. Positional data were used to calculate effective playing space and distances from each player to team centroid, opponent team centroid and nearest opponent. Outcomes suggested that increasing the number of opponents in professional teams resulted in moderate/large decrease in approximate entropy (ApEn) values to both distance to team and opponent team centroid (i.e., the variables present higher regularity/predictability pattern). In low-cooperation game scenarios, the ApEn in amateurs' tactical variables presented a moderate/large increase. The professional teams presented an increase in the distance to nearest opponent with the increase of the cooperation level. Increasing the number of opponents was effective to overemphasise the need to use local information in the positioning decision-making process from professionals. Conversely, amateur still rely on external informational feedback. Increasing the cooperation promoted more regularity in spatial organisation in amateurs and emphasise their players' local perceptions.

Collective behavior is a hallmark of every living system and utilizing methods from statistical physics (such as correlation functions) could aid in our understanding of their underlying rules. We analyzed five football (soccer) matches as this game provides a unique but yet mostly unexplored example to study a system of collective cooperation and competition. The aim of our study was to analyze the collective motion patterns exhibited by football players to unfold the underlying coordination among them in order to understand collective strategies associated with team performance. By analyzing pairwise relationships among all the players using spatio-temporal correlation functions we reveal that there exist identifiable collective dynamics that characterize winning and losing teams. Using our metric we find clear and robust differences between the players, indicating a difference in their behavior and their interactions. And this enables us to assign a unique behavioral pattern - a ‘fingerprint’ - for each individual and for each team. Furthermore, we reveal there exists a relationship between the market value of the players and the metrics introduced here, suggesting that these metrics could potentially serve as valuable performance indicators in the future, with applications ranging from talent identification to player scouting. In a broader context team sports could open up new directions for quantitative analyses of human collective behavior.

Summary Aim The aim of this study was to compare the effects of a 4-week combined sloped training program with a standard flat training program performed by basketball players. Methods A total of 31 male elite youth basketball players were randomly allocated into an experimental (SLOPE, n = 15, age 13.4 ± 0.4 y, height 168.8 ± 14.2 cm, weight 52.6 ± 12.7 kg) and control training group (FLAT, n = 16, age 12.9 ± 0.3 y, height 169.5 ± 9.3 cm, weight 56.2 ± 11.3 kg). A pre- to post-test design was used to explore the effects in performance variables. Results The comparison between groups showed moderate higher values in FLAT training group for standing height jump (differences in groups means: % [90% confidence intervals], −10.2% [−14.9% to −5.3%]) and reaction time (5.8% [1.3% to 10.5%]). On the other hand, SLOPE training promoted a small improve in anaerobic-alactic power (W/kg) (3.4% [−1.2% to 8.1%]). The FLAT group presented small improvements in peak power (W), (−9.2% [−15.0% to −3.0%]) and moderate in relative peak power (W/kg) (−9.8% [−15.3% to −4.0%]). Power results suggested a more efficient movement pattern, probably due to a better propulsive phase supported by an improved ability to produce equivalent levels of force in a shorter period of time. Despite the identified benefits of combined uphill/downhill/flat training method, results suggest that young non-familiarize players need a progressive reduction of training load to optimize performance. These results represent important evidence into the planning guidelines of strength and conditioning coaches to support daily planning by choosing the most appropriate tasks to enhance players’ performance.

Literature is scarce on how players with poorly and well developed physical qualities respond to different combinations of strength-power training during in-season. The aim of this study was to investigate the effects of (i) compound training performed by stronger athletes at different days and (ii) complex training performed by weaker athletes within the same training session. Twenty male handball players were classified as strong or weak according to countermovement jump performance and assigned to a 12-week training programme. Linear sprint, changes of direction, repeated sprint ability and vertical jump capacity were used to assess physical profiles. Compound training performed by stronger players resulted in unclear effects on vertical jump, 20-m and repeated sprint. Likely improvements were found in 10-m sprint (-11.3%; 11.9%). Weaker players who performed complex training presented likely and very likely improvements on vertical jump (13.7%; 5.4%), sprint (10 m, -10.7%; 10.3%; 20 m, -6.0%; 3.4%) and repeated sprint (-4.1%; 3.7%) with moderate to large effect size. The results show that complex and compound strategies are useful in improving the physical profiles of weaker players and maintaining stronger players' capacities during in-season, respectively. Players involved in the same competitive context, even from the same team, may require different strength training strategies. info:eu-repo/semantics/publishedVersion

The use of unstable surfaces during resistance training has demonstrated a maintenance or reduction on force production. However, the use of unstable surface on force variability has not been assessed using non-linear methods that may be better suited to detect changes in movement variability throughout a given movement. Consequently, this study compared the use of stable vs unstable surfaces on force variability during bilateral squats performed with an inertial flywheel device (Eccoteck, Byomedic System SCP, Spain). Twenty healthy men (mean ± SD: age 22.9 ± 2.9 years, height 1.81 ± 0.7 m, body mass 76.4 ± 7.6 kg and 1RM back squat 110.9 ± 19.7 kg) with a minimum of four years in resistance training performed six sets of six repetitions of squats at maximal concentric effort with one minute rest between sets. Force output on the vertical axes was measured using a strain gauge and the results were processed using nonlinear sample entropy (SampEn). Results showed no differences for any of the dependent variables between stable and unstable conditions. SampEn showed no differences between conditions (chi-squared = 0.048 P = 0.827), while Forcemean and SampEn presented a small correlation (r = 0.184; p < 0.01). No changes in entropy were found over the course of the series. Together, these results suggest that the structure of force variability between stable and unstable surfaces are similar. This lack of difference between surfaces may be due to postural and anticipatory adjustments. Consequently, by introducing unstable surfaces to the flywheel bilateral squat exercise, practitioners may not observe changes in Forcemean and force variability when compared to stable surface training suggesting that increased training volumes or intensity may be required during unstable environments to cause a desired training stimulus.

Ecological psychology suggests performer-environment relationship is the appropriate scale for examining the relationship between perception, action and cognition. Developing performance requires variation in practice in order to design the attractor-fluctuation landscape. The present study aimed to identify the effects of varying levels of familiarity and sensorimotor stimuli within the environment in runners' speed and heart rate (HR) regularity degree, and short-term memory Twelve amateur runners accomplished three 45-min running trials in their usual route, in an unusual route, and an athletics 400-m track, wearing a GPS and an HR monitor. Sample entropy (SampEn) and complexity index (CI), over speed and HR, were calculated. Pre and post-trial, participants performed the Backward Digit Span task for cognitive assessment. Higher entropies were found for the 400-m track, compared to the usual and unusual routes. Usual routes increased speed SampEn (63% of chances), but decreased HR CI when compared to unusual routes (60% of chances). Runners showed higher overall short-term memory performance after unusual routes, when compared to usual routes (85% of chances), indicating positive relation to attentional control. The contexts of practice may contribute to change predictability from single to multiple timescales. Thus, by considering that time structuring issues can help diagnosing habituation of training routes, this study brings novel information to the long-term process of training. The authors thank the support of the North Portugal Regional Operational Programme (NORTE 2020), under the PORTUGAL 2020 Partnership Agreement, and the European Regional Development Fund, (ERDF) under Grant Project NanoSTIMA: Macro-to-Nano Human Sensing: Toward Integrated Multimodal Health Monitoring and Analytics/NORTE-01-0145-FEDER-000016.

The aim of this study was to identify the relationships between the variation of match variables and teams’ match performance. Data from all 768 matches played at the group stage of the UEFA Champions League from season 2009/1010 to 2016/2017 were analysed. The non-clinical magnitude-based inferences were used to identify the differences of technical variation between the teams. Autocorrelation function, correlation analysis and generalised linear model were used to examine the relationships between the variation of match variables and teams’ match performance. Results showed that the qualified teams demonstrated a more stable match performance on the variables related to goal scoring, attacking and passing, while the non-qualified teams displayed a more stable match performance on the variables related to defending. The coefficients of variation (CV) of all the variables related to goal scoring and the variables related to attacking and passing showed negative relationships with the teams’ match performance, while the CVs of the variables related to defending showed positive relationships with the teams’ match performance. Findings of this study can provide useful information about the fluctuation of match variables, contributing to the development of specific training interventions to enhance teams’ performance in key indicators.

If done properly, physical exercise can help maintain fitness and health. The benefits of physical exercise could be increased with real time monitoring by measuring physical exercise intensity, which refers to how hard it is for a person to perform a specific task. This parameter can be estimated using various sensors, including contactless technology. Physical exercise intensity is usually synchronous to heart rate; therefore, if we measure heart rate, we can define a particular level of physical exercise. In this paper, we proposed a Convolutional Neural Network (CNN) to classify physical exercise intensity based on the analysis of facial images extracted from a video collected during sub-maximal exercises in a stationary bicycle, according to standard protocol. The time slots of the video used to extract the frames were determined by heart rate. We tested different CNN models using as input parameters the individual color components and grayscale images. The experiments were carried out separately with various numbers of classes. The ground truth level for each class was defined by the heart rate. The dataset was prepared to classify the physical exercise intensity into two, three, and four classes. For each color model a CNN was trained and tested. The model performance was presented using confusion matrix as metrics for each case. The most significant color channel in terms of accuracy was Green. The average model accuracy was 100%, 99% and 96%, for two, three and four classes classification, respectively.

In soccer, understanding of collective tactical behaviour has become an integral part in sports analysis at elite levels. Evolution of technology allows collection of in-creasingly larger and more specific data sets related to sport activities in cost-effective and accessible manner. All this information is minutely scrutinized by thousands of analysts around the globe in search of an-swers that can in the long term help increase the performance of indi-viduals or teams in their respective competitions. As the volume of data increases in size, so does the complexity of the problem and the need for suitable tools that leverage the cognitive load involved in the inves-tigation. It is proven that visualization and computer-vision techniques, correctly applied to the context of a problem, help data analysts focus on the relevant information at each stage of the process, and generally lead to a better understanding of the facts that lie behind the data. In the current study, we presented a software prototype capable of assisting researchers and performance analysts in their duty of studying group collective behavior in soccer games and trainings. We used geospatial data acquired from a professional match to demonstrate its capabilities in two different case studies. Furthermore, we successfully proved the efficiency of the different visualization techniques implemented in the prototype and demonstrated how visual analysis can effectively improve some of the basic tasks employed by sports experts on their daily work, complementing more traditional approaches.

Many cloud vision APIs are available on the internet to recognize emotion from facial images and video analysis. The capacity to recognize emotions under various poses is a fundamental requirement in the area of emotion recognition. In this paper, the performance of two famous emotion recognition APIs is evaluated under the facial images of various poses. The experiments were done with the public dataset containing 980 images of each type of five poses [full-left, half-left, straight, half-right, and full-right] with the seven emotions (Anger, Afraid, Disgust, Happiness, Neutral, Sadness, Surprise). It has been discovered that overall recognition accuracy is best in Microsoft Azure for straight images, whereas the face detection capability is better in Google. The Microsoft did not detect almost any of the images with full left and full right profile, but Google detected almost all of them. The Microsoft API presents an average true positive value up to 60%, whereas Google presents the maximum true positive value 45.25%.

The present study aims to identify the accuracy of the NBN23&reg, system, an indoor tracking system based on radio-frequency and standard Bluetooth Low Energy channels. Twelve capture tags were attached to a custom cart with fixed distances of 0.5, 1.0, 1.5, and 1.8 m. The cart was pushed along a predetermined course following the lines of a standard dimensions Basketball court. The course was performed at low speed (&lt, 10.0 km/h), medium speed (&gt, 10.0 km/h and &lt, 20.0 km/h) and high speed (&gt, 20.0 km/h). Root mean square error (RMSE) and percentage of variance accounted for (%VAF) were used as accuracy measures. The obtained data showed acceptable accuracy results for both RMSE and %VAF, despite the expected degree of error in position measurement at higher speeds. The RMSE for all the distances and velocities presented an average absolute error of 0.30 &plusmn, 0.13 cm with 90.61 &plusmn, 8.34 of %VAF, in line with most available systems, and considered acceptable for indoor sports. The processing of data with filter correction seemed to reduce the noise and promote a lower relative error, increasing the %VAF for each measured distance. Research using positional-derived variables in Basketball is still very scarce, thus, this independent test of the NBN23&reg, tracking system provides accuracy details and opens up opportunities to develop new performance indicators that help to optimize training adaptations and performance.

Facial expressions are a spontaneous way of perceiving emotions, which can provide information related to the cognitive state of a person. Facial expression recognition of the elderly is an important aid to better care them, according to their state of mind, although it can be a difficult task because their expressions might not be as easily perceived as those from younger persons. We proposed a model to classify the facial expressions of the elderly, presenting the differences between facial expression recognition in the elder and in other age group, as well as methods to surpass these difficulties. Viola Jones with Haar Features was used to extract the faces and Gabor Filter to extract the facial characteristics. These characteristics are classified using a Multiclass Support Vector Machine. We got an accuracy of 90.32%, 84.61%and 66.6%, when detecting the neutral state, happiness and sadness respectively in the elderly. In the other age group, we got an accuracy of 95.24%, 88.57%, and 80%, while detecting the neutral, happiness, and sadness states and concluded that aging influences negatively the facial expressions recognition tasks.

The study aimed to compare footballers' performances when playing with teammates and opponents from the same age group with performances when playing with teammates and opponents of different age groups. Three football matches were played: i) under-15 (U15) players played with each other; ii) under-17 (U17) players played with each other; and iii) players under the age of 15 and 17 played with each other in two equivalent mixed age teams. The players' physical performance was measured using the distances covered at different speed categories and tactical behaviour was assessed using several positioning-derived variables. The results showed that, when playing in the mixed age condition, the U15 players increased the distance covered in sprinting intensity (18.1%; +/- 21.1%) and the U17 players increased the distance covered in jogging zones (6.8%; +/- 6.5%). The intra-team movement synchronization in longitudinal and lateral displacements was higher when U15 players confronted peers of the same age, in the first half (-13.4%; +/- 2.0%, -20.3%; +/- 5.7% respectively), and when U17 players confronting the mixed group, in both halves (-16.9%; +/- 2.5%, 9.8%; +/- 4.0% and 7.9%; +/- 5.7%, 10.6% +/- 4.4%, respectively). The differences between age groups and the mixed condition may be connected with the level of players' tactical expertise and adaptive positioning according to the dynamic environmental information. In general, these results suggest that mixing the age groups may be useful to promote a wider range of training session stimuli in these young football players.

Facial expression analysis has a wide area of applications including health, psychology, sports etc. In this study, we explored different methods of automatic classification of exercise intensities using facial image processing of a subject performing exercise on a cycloergometer during an incremental standardized protocol. The method can be implemented in real time using facial video analysis. The experiments were done with images extracted from a 12 min HD video collected in laboratorial normalized settings (TechSport from the University of Tras-os-Montes e Alto Douro) with a static camera (90° angle with face and camera). The time slot for video to extract images for a particular class of exercise intensity is correspondence to the incremental heart rate. The facial expression recognition has been performed mainly in two steps: facial landmark detection and classification using the facial landmarks. Luxand application was used to detect 70 landmarks were detect using the adaptation of code available in Luxand application and we applied machine learning classification algorithms including discriminant analysis, KNN and SVM to classify the exercise intensities from the facial images. KNN algorithms presents up to 100% accuracy in classification into 2 and 3 classes. The distances between a lowermost landmark of the faces, which is indicated in landmark number 11 in the Luxand application, and the 26 landmarks around mouth were calculated and considered as features vector to train and test the classifier. Separate experiments were done for classification into two, three, and four classes and the accuracy of each algorithm was analyzed. From the overall results, classification into two and three classes was easy and resulted in very good classification performance whereas the classification with four classes had poor classification performance in each algorithm. Preliminary results suggest that distinguishing more levels of exertion, might require additional feature variables.

This study identified temporal effects (immediate, short-term, and medium-term effect) of team timeouts on elite handball scoring performance in reference to several situational variables that may influence performance: match status, game location, quality of the opposition, game period, and game type. The sample consisted of 646 team timeouts from 142 close games (score differences less than or equal to five goals) of the 2011/2012 men’s Spanish Professional Handball League (ASOBAL League). For each team timeout, the goals scored and conceded within the previous and post timeout 1st, 3rd and 5th ball possessions were recorded for the teams that called a timeout and for their opponents. Multiple linear regression models were used for analysis. The results showed positive effects on goals scored for the teams that called a timeout, with increases of 0.59, 1.40 and 1.85 goals for the periods within the previous and post team timeout 1st, 3rd and 5th ball possessions. Conversely, significant negative effects on goals scored were found for the opposing teams, with decreases of 0.59, 1.43 and 2.04 goals for the same periods, respectively. Unexpectedly, the influence of situational variables on scoring performance of the teams was only registered for certain game periods. These findings could be useful for a better team timeout management during games and competitions.

The aims of this study were to compare the training load intended by a coach with the training load perceived by the players, over a 45-week professional futsal team season and to compare the variation of session rating of perceived exertion (sRPE) across different periods of the season. Eighteen Brazilian professional futsal players participated in the study. The players' rating of perceived exertion (RPE) and coach's rating of intended exertion (RIE) were collected daily throughout the study. To compare the sRPE variation, the season was divided into 4 periods as follows: preseason (PRE-SEASON), first competitive period (COMP1), intercompetition period (INTER-COMP), and second competitive period (COMP2). Based on the cluster analyses, the training sessions were classified into 3 different intensity zones (low, moderate, and high). In all the season periods and intensity zones, the players' RPEs were lower than the coach's RIE. In the low-intensity zone, the INTER-COMP demonstrated higher sRPE values than did the other periods. In the moderate-intensity zones, the INTER-COMP and COMP2 were similar. Finally, for the high-zone intensity, the PRE-SEASON demonstrated higher values than did the other periods. We concluded that the coach overestimated the training load reported by the players in almost all intensity training zones and season periods. The RPE scale does not seem to be a suitable tool when used by the coach for intended training load. Therefore, technical staff should constantly review the training goals in each season period through daily training load control, always taking into consideration the possibilities and limitations of the RPE method.

This study aimed to compare the differences in game-to-game variability of technical and physical parameters of basketball players, according to game location and game outcome. Game data (n=712) were collated from the official box-score and player-tracking of the 2013-14 NBA regular season. The players were separated according to their court specific position. A two-step cluster analysis was performed to group players according to time played into 3 groups: short, medium, and long-time played. The coefficient of variation (CV) was calculated from game-to-game parameters. The results showed that short-time players demonstrated great CV for technical and physical statistics, long-time players displayed larger CV in losing and away games, technical indicators such free-throws revealed substantial variability in losing games and guards and centers presented high CV for some performance statistics. CV values were inversely proportional to time played, probably because playing less time decreases the probabilit...