title: Informational constraints on interceptive actions of elite football goalkeepers in 1v1 dyads during competitive performance.
abstract: The aim of this study was to examine whether perceptual variables can provide informational constraints for the goalkeepers to intercept the ball successfully in 1v1 dyads. Video images of 42 actions (1v1 in direct shots) were selected randomly from different matches and divided into conceded goals (n = 20) and saved actions (n = 22) to investigate interceptive actions of 20 goalkeepers in the English Premier League in season 2013-2014. Time to Contact (TTC) of the closing distance gap between shooter and goalkeeper was obtained by digitising actions in the 18-yard penalty box. Statistical analyses revealed that, in sequences of play resulting in an intercepted shot at goal, goalkeepers closed down outfield players in the X axis, whereas when a goal was conceded, there was a significantly delayed movement by goalkeepers toward the shooters in this plane. The results of canonical correlations showed that a decreasing distance between a shooter and goalkeeper, and accompanied reduction in relative interpersonal velocity followed a temporal pattern. Findings of this study showed how perception of key informational constraints on dyadic system relations, such as TTC, interpersonal distance and relative velocity, constrain elite goalkeepers' interceptive actions, playing an important role in successful performance.
authors.affiliation: a Academy of Sport and Physical Activity, Faculty of Health and Wellbeing , Sheffield Hallam University , Sheffield , UK.
authors.forename: Mohsen
authors.initials: M
authors.lastname: Shafizadeh
authors.affiliation: b Centre for Sports Engineering Research , Sheffield Hallam University , Sheffield , UK.
authors.forename: Keith
authors.initials: K
authors.lastname: Davids
authors.affiliation: c School of Education and Communication, Department of Science and Sport , University of the Algarve , Algarve , Portugal.
authors.forename: Vanda
authors.initials: V
authors.lastname: Correia
authors.affiliation: b Centre for Sports Engineering Research , Sheffield Hallam University , Sheffield , UK.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Wheat
authors.affiliation: b Centre for Sports Engineering Research , Sheffield Hallam University , Sheffield , UK.|d Faculty of Sport Science and Coaching , Sultan Idris Education University , Tanjung Malim , Malaysia.
authors.forename: Hazuan
authors.initials: H
authors.lastname: Hizan
mesh_terms: D054874:Athletic Performance / Q000502:physiology*; D003163:Competitive Behavior / Q000502:physiology*; D003430:Cross-Sectional Studies; D006801:Humans; D011930:Reaction Time; D012916:Soccer / Q000502:physiology*; D013028:Space Perception / Q000502:physiology*; D013998:Time Perception / Q000502:physiology*
keywords: Ecological dynamics; association football; dyadic systems; elite goalkeepers; informational constraints; time to contact