Lorena Torres-Ronda

Effects of emphasising opposition and cooperation on collective movement behaviour during football small-sided games

ABSTRACT 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.

Relationships Between Internal and External Training Load in Team Sport Athletes: Evidence for an Individualised Approach

PURPOSE The aim of this study was to quantify and predict relationships between rating of perceived exertion (RPE) and GPS training-load (TL) variables in professional Australian football (AF) players using group and individualized modeling approaches. METHODS TL data (GPS and RPE) for 41 professional AF players were obtained over a period of 27 wk. A total of 2711 training observations were analyzed with a total of 66 ± 13 sessions/player (range 39-89). Separate generalized estimating equations (GEEs) and artificial-neural-network analyses (ANNs) were conducted to determine the ability to predict RPE from TL variables (ie, session distance, high-speed running [HSR], HSR %, m/min) on a group and individual basis. RESULTS Prediction error for the individualized ANN (root-mean-square error [RMSE] 1.24 ± 0.41) was lower than the group ANN (RMSE 1.42 ± 0.44), individualized GEE (RMSE 1.58 ± 0.41), and group GEE (RMSE 1.85 ± 0.49). Both the GEE and ANN models determined session distance as the most important predictor of RPE. Furthermore, importance plots generated from the ANN revealed session distance as most predictive of RPE in 36 of the 41 players, whereas HSR was predictive of RPE in just 3 players and m/min was predictive of RPE in just 2 players. CONCLUSIONS This study demonstrates that machine learning approaches may outperform more traditional methodologies with respect to predicting athlete responses to TL. These approaches enable further individualization of load monitoring, leading to more accurate training prescription and evaluation.

Using testosterone and cortisol as biomarker for training individualization in elite basketball: a 4-year follow-up study.

Abstract Schelling, X, Calleja-González, J, Torres-Ronda, L, and Terrados, N. Using testosterone and cortisol as biomarker for training individualization in elite basketball. A 4-year follow-up study. J Strength Cond Res 29(2): 368–378, 2015—The purpose of this study was to determine the responses of testosterone and cortisol, with special reference to playing positions, playing time (PT), and phase of the season. We performed a follow-up study during 4 consecutive seasons to investigate the effects of PT, positional role, and phase of the season on anabolic-catabolic biomarkers (plasma total testosterone -TT- and cortisol -C-) on 20 professional male basketball players (27.0 ± 4.2 years; 24.4 ± 1.2 kg·m−2). First blood samples were collected right after the off-season period and considered as baseline. Samples were taken periodically every 4–6 weeks, always after a 24- to 36-hour break after the last game played. Statistical procedures were nonparametric mainly. Hormonal status was playing position-dependent, power forward (PF) showed the lowest TT values (median ± interquartile range [IQR]; PF: 18.1 ± 4.9; nmol·L−1), and small forwards showed the highest ones of cortisol (0.55 ± 0.118 &mgr;mol·L−1). Players who played between 13 and 25 minutes per game showed the highest values of TT (22.8 ± 6.9 nmol·L−1) and TT/C (47.1 ± 21.2). March and April showed the most catabolic or stressed hormonal state (low TT/C values and high ones of cortisol) and that is necessary to take into account according to PT (>25-minute per game) and specific playing position. Monitoring plasma TT and cortisol is recommended to prevent excessive stress caused by professional basketball season requirements.

Heart Rate, Time-Motion, and Body Impacts When Changing the Number of Teammates and Opponents in Soccer Small-Sided Games.

Abstract Torres-Ronda, L, Gonçalves, B, Marcelino, R, Torrents, C, Vicente, E, and Sampaio, J. Heart rate, time-motion, and body impacts when changing the number of teammates and opponents in soccer small-sided games. J Strength Cond Res 29(10): 2723–2730, 2015—The purpose of this study was to determine the internal (heart rate) and external load (body load, distance covered, and exertion index) during different types of unbalanced soccer small-sided games (SSGs) in professional (PRO) and amateur (AMA) players. In 2 separated sessions (PRO and AMA), participants played 3 SSG formats (4vs3, 4vs5, and 4v7). Data were analyzed from the fixed teams perspective (4vsX) according to the number of opponents (3, 5 and 7) and from the variable team (3 + Xvs4) according to the teammates (without teammates, 2 and 4 teammates). The time-motion and body impact data were collected using a nondifferential global positioning system with integrated heart rate measurement. Differences in internal and external workload between the game formats were compared using Cohens d unb effect sizes with 95% confidence intervals. Results reveal that the higher the number of players involved in the task, the lower the internal and external workload. The analysis also showed different teammates and opposition-related trends that need to be considered when planning and monitoring training performance. Playing in low-inferiority (4vs3 and 4vs5) had higher physiologic impact to players than the other higher unbalanced situations. This evidence was similar to both PRO and AMA players; however, the PRO presented higher physical and lower physiological responses across games. Our results suggest that coaches should consider the usage of unbalanced SSG formats to simultaneously facilitate the emergence of defensive and offensive proficient scenarios also representing opportunities to increase the practice workload.

Emergence of exploratory, technical and tactical behavior in small-sided soccer games when manipulating the number of teammates and opponents

The effects that different constraints have on the exploratory behavior, measured by the variety and quantity of different responses within a game situation, is of the utmost importance for successful performance in team sports. The aim of this study was to determine how the number of teammates and opponents affects the exploratory behavior of both professional and amateur players in small-sided soccer games. Twenty-two professional (age 25.6 ± 4.9 years) and 22 amateur (age 23.1 ± 0.7 years) male soccer players played three small-sided game formats (4 vs. 3, 4 vs. 5, and 4 vs. 7). These trials were video-recorded and a systematic observation instrument was used to notate the actions, which were subsequently analyzed by means of a principal component analysis and the dynamic overlap order parameter (measure to identify the rate and breadth of exploratory behavior on different time scales). Results revealed that a higher the number of opponents required for more frequent ball controls. Moreover, with a higher number of teammates, there were more defensive actions focused on protecting the goal, with more players balancing. In relation to attack, an increase in the number of opponents produced a decrease in passing, driving and controlling actions, while an increase in the number of teammates led to more time being spent in attacking situations. A numerical advantage led to less exploratory behavior, an effect that was especially clear when playing within a team of seven players against four opponents. All teams showed strong effects of the number of teammates on the exploratory behavior when comparing 5 vs 7 or 3 vs 7 teammates. These results seem to be independent of the players’ level.

Game-to-game variability of technical and physical performance in NBA players

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 probability of maintaining stable performance across games. Long-time players displayed larger CV in away and losing games, possibly due the constraints imposed by opponent teams. Free-throws seems to be the variables that best discriminate between winning and losing teams. Forward players are a very homogeneous group and mainly composed by all-round players with multiple roles.

Match activity demands of elite Spanish female basketball players by playing position

The primary aim of this study was to identify the effects of playing position on match activities of female basketball players. A secondary aim was to compare these match activities between quarters of play. Forty-two elite females players (25.9±4.3y, 183.4±9.0 cm) were studied during competitive matches. The frequency, duration and percentage of live time (%LT) were calculated. Differences between playing positions (PG, SG, SF, PF and C) and quarters were analyzed using repeated measures ANOVA. Results showed significantly more movements in PG than other positions (25.6±2.8 per min vs. 21.2±2.2 to 23.6±2.6 per min, P = 0.022), and more sprints in PG than PF and C (0.4±0.2 per min vs. 0.1±0.1 and 0.1±0.1, respectively for PG, PF and C, P = 0.040). Furthermore, PF and C performed more jumps and static exertion than other positions (jump frequencies and %LT static exertion of 1.2±0.2 per min and 4.8±2.1% for PF, 1.5±0.3 per min and 7.1±2.2% for C vs. 0.7±0.3 to 1.0±0.2 per min and 1.7±0.6 to 3.4±1.2 % in other positions, P = 0.002 to 0.028). A decrease in %LT for high-intensity movements was observed in the 4th compared to 1st and 3rd quarters (P = 0.048). These results highlight that physical conditioning by playing position might be worth considering by coaches, although longitudinal training studies are necessary to confirm this observation.

Dynamics of tactical behaviour in association football when manipulating players' space of interaction

The analysis of positional data in association football allows the spatial distribution of players during matches to be described in order to improve the understanding of tactical-related constraints on the behavioural dynamics of players. The aim of this study was to identify how players’ spatial restrictions affected the exploratory tactical behaviour and constrained the perceptual-motor workspace of players in possession of the ball, as well as inter-player passing interactions. Nineteen professional outfield male players were divided into two teams of 10 and 9 players, respectively. The game was played under three spatial constraints: a) players were not allowed to move out of their allocated zones, except for the player in possession of the ball; b) players were allowed to move to an adjacent zone, and; c) non-specific spatial constraints. Positional data was captured using a 5 Hz interpolated GPS tracking system and used to define the configuration states of players for each second in time. The configuration state comprised 37 categories derived from tactical actions, distance from the nearest opponent, distance from the target and movement speed. Notational analysis of players in possession of the ball allowed the mean time of ball possession and the probabilities of passing the ball between players to be calculated. The results revealed that the players’ long-term exploratory behaviour decreased and their short-term exploration increased when restricting their space of interaction. Relaxing players’ positional constraints seemed to increase the speed of ball flow dynamics. Allowing players to move to an adjacent sub-area increased the probabilities of interaction with the full-back during play build-up. The instability of the coordinative state defined by being free from opponents when players had the ball possession was an invariant feature under all three task constraints. By allowing players to move to adjacent sub-areas, the coordinative state became highly unstable when the distance from the target decreased. Ball location relative to the scoring zone and interpersonal distance constitute key environmental information that constrains the players’ coordinative behaviour. Based on our results, dynamic overlap is presented as a good option to capture tactical performance. Moreover, the selected collective (i.e. relational) variables would allow coaches to identify the effects of training drills on teams and players’ behaviour. More research is needed considering these type variables to understand how the manipulation of constraints induce a more stable or flexible dynamical structure of tactical behaviour.

Development of physical and skill training drill prescription systems for elite Australian Rules football

ABSTRACT Objectives: To develop three different training drill classification systems for Australian Rules football using physical and skill-related data. Methods: Forty professional Australian footballers wore 10 Hz Global Positioning System units for six matches and 17 training sessions including 35 drills. High intensity running per minute, metres per minute and high-intensity running as a percentage of total distance were obtained to represent each drills physical requirements. Velocity at kick (moving or stationary), time in possession (greater or less than 2 s) and the presence of pressure were coded for each kick to represent the constraints associated with each drill. Results: For the first system, two k-means clustering algorithms were run on physical and skill data separately to identify similarities between drills. For the second system, z-scores were calculated for each physical and skill characteristic to allow direct comparison of each drill with match conditions. For the third system, a “Specificity Index” was calculated using the absolute average of pooled z-scores for physical and skilled characteristics. Conclusions: The three systems developed in this study can be used to aid training prescription in elite Australian Rules football.

An Integrative Approach to Strength and Neuromuscular Power Training for Basketball

ABSTRACT BASKETBALL PLAYERS ACHIEVE EXCELLENCE BY FITNESS LEVELS, SPORT-SPECIFIC SKILLS, AND DECISION MAKING. IN THIS ARTICLE, THE AUTHORS PRESENT A STRENGTH AND NEUROMUSCULAR POWER TRAINING METHODOLOGY, WHICH INTEGRATES THE LATEST SCIENTIFIC KNOWLEDGE ON STRENGTH TRAINING, SUGGESTS A PRACTICAL, INTEGRATIVE, SPECIFICITY-BASED METHODOLOGY COVERING PLAYER DEVELOPMENT FROM THE WEIGHT ROOM TO THE COURT, AND INVOLVES ALL THE STAFF MEMBERS AROUND THE BASKETBALL PLAYER TO OPTIMIZE HIS/HER PREPARATION.