Goals scored and received in 5vs4 GK game strategy are constrained by critical moment and situational variables in elite futsal

The aim of this study was to identify the importance and meaning of goals using the goalkeeper as an outfield player in elite futsal according to critical and situational variables. The sample consisted of 11,446 actions corresponding to 1,325 matches from the 1^st division Spanish Futsal League during the seasons from 2010 to 2015. Multinomial logistic regression and classification tree multivariate models were used to identify the best predictor variables related to the likelihood of scoring goals, receiving goals, or no goals. Results from Multinomial logistic regression emphasised goals scored in balanced matches and playing with the goalkeeper as an outfield player before the last eight minutes. When the teams were drawing or losing, finished with goals received or without goals. The classification tree results identified a greater likelihood of scoring goals when the teams were winning, in balanced matches, and within the last eight minutes. Conversely, a greater likelihood of suffering goals was observed using the goalkeeper as an outfield player when the teams were losing, in unbalanced matches and in the last eight minutes. The identified trends will allow futsal coaches to recognise the most suitable situations for achieving efficacy when using the goalkeeper as an outfield player strategy.

Adductor squeeze test and groin injuries in elite football players: A prospective study

OBJECTIVE

To examining the relationship between hip adductor strength and groin injury incidence during the competitive season of professional football teams.

DESIGN

Prospective Cohort study.

SETTING

Controlled laboratory environment.

PARTICIPANTS

Seventy-one players volunteered to participate.

MAIN OUTCOME MEASURES

In the pre-season, maximal hip adductor strength was measured by means of the isometric adductor squeeze test. Hip adductor strength, normalized by body mass, was compared between players who suffered a groin injury (n = 18) vs uninjured players (n = 53). Risk ratios (RR) were used to evaluate the likelihood of players to suffer this type of injury.

RESULTS

Most of the reported groin injuries occurred during competitive matches (5.5 per 1000 match hours). Maximal isometric hip adductor strength was lower in the groin-injured group compared with their uninjured counterparts (429.8 ± 100 vs 564 ± 58.7 N, d = -1.58 and 5.40 ± 1.27 vs 7.71 ± 0.89 N/kg, d = -1.88, respectively). Results revealed that values of maximal isometric adductor strength lower than 465.33 N increased the probability to suffer a groin injury by 72%. Furthermore, values of force relative to body mass lower than 6.971 N/kg increased the probability to suffer a groin injury by 83%.

CONCLUSION

The assessment of Hip adductor strength, in addition to other measurements, might help practitioners to determine the probability of suffering an overuse groin injuries in elite football players.

Adaptive behaviours of attacking futsal teams to opposition defensive formations

This study evaluated tendencies towards flexibility/stability of coordinated behaviours in international futsal teams, considered as complex collective systems, according to changes in opposition defensive formations. Six games of two international futsal teams (Spain and Portugal) were selected for Social Network Analysis to capture the coordination tendencies that emerge in the tactical behaviours of players when performing against different defensive formations. Ball trajectories in each offensive pattern of play were notated in an adjacency matrix where each entry accounted for the linkages between 12 spatial field areas. Each offensive play was coded according to the defensive formation of an opposing team (i.e. conservative or risky formation). Results revealed similar network properties between teams when competing against more risky defensive formations, while notable differences were observed against conservative defences. Effect of defensive formation of opponents on macro network properties was observed in both the Portuguese and Spanish teams. At a meso-level, only the Spanish national team exhibited notable changes, suggesting a greater level of adaptability to unfolding performance events. The observed flexibility in tactical behaviours of the Spanish team appeared to express their greater expertise levels.

Interpersonal coordination and ball dynamics in futsal (indoor football)

Here, we report an investigation of the patterned movement behavior of players for a specific sub-phase of the game of futsal, namely when the goalkeeper for the attacking team is substituted with an extra outfield player. The movement trajectories of the ball and players were recorded in both lateral and longitudinal directions and investigated using relative phase analysis. Some differences in phase relations between different playing dyads were noted, indicating specificity of phase attractions, or otherwise, for certain players. In general terms, the defenders demonstrated strong in-phase attractions with the ball and with each other, whereas weaker phase attractions, indicated by increased relative phase variability, were observed for the attackers and ball, as well as between attackers themselves. These results demonstrate different coordination dynamics for the defending and attacking dyads, from which we interpret evidence for different playing sub-systems consistent with different team objectives linked together in an overarching game structure. In keeping with dynamical systems theory for complex systems, we view this sub-phase of futsal as being characterized by coordinated behavior patterns that emerge as a result of self-organizing processes. These dynamic patterns are generated within functional constraints, with players and teams exerting mutual influence on each other.

Tactical skills are not verbal skills: a comment on Kannekens and colleagues

In 2009, Kannekens and colleagues evaluated the development of tactical skills of elite youth football players using a method based on verbal reports. Results showed no improvements in players' tactical skills over the years of their longitudinal study. These results are based on an erroneous assumption that tactical skills and verbalizations about tactical skills are equivalent. This note comprises an explanation of why verbal reports are not a valid measure of tactical skills.