Web-based training improves on-ﬁeld offside decision-making performance Koen Put a , Johan Wagemans b , Arne Jaspers a , Werner F. Helsen a, * a Department of Kinesiology, Movement Control and Neuroplasticity Research Group, University of Leuven (KU Leuven), Tervuursevest 101, Bus 1501, B-3001 Leuven, Belgium b Laboratory of Experimental Psychology, University of Leuven (KU Leuven), Tiensestraat 102, Bus 3711, B-3000 Leuven, Belgium article info Article history: Received 28 October 2012 Received in revised form 8 March 2013 Accepted 8 March 2013 Available online 21 March 2013 Keywords: Transfer On-ﬁeld performance Web-based training program Flash-lag effect abstract Objective: The present study examined to what extent off-ﬁeld offside decision-making training transfers to real-life offside situations. Design/methods: Eighteen Belgian assistant referees were included in the experiment. Ten assistant referees (i.e., training group) were exposed to a pre- and posttest and, in between, four off-ﬁeld offside training sessions via a web-based training protocol. The remaining eight assistant referees participated in the control group and only completed the pre- and posttest. During both test sessions, which were conducted separately for each group, both an on- and off-ﬁeld offside decision-making test was completed. Results: First, an increase in response accuracy and a decrease in ﬂag errors were observed for the training group from pre- to posttest in both the on- and off-ﬁeld offside test. Second, only the training group improved in the recall and recognition accuracy of the position of the receiving attacker at the moment of the pass. Conclusions: This study demonstrates that perceptual-cognitive skill training results in a positive and direct transfer to on-ﬁeld offside decisions. Therefore, the structure and the content of the current training intervention mimics the perceptual difﬁculties of real-match situations and can help the as- sistant referees to mediate and enhance their offside decision-making skills, both on- and off-ﬁeld. Ó 2013 Elsevier Ltd. All rights reserved. Although the offside law in association football (also known as soccer in North-America) is very precisely deﬁned, it remains obvious that assessing offside situations under time-constrained circum- stances is a very demanding and complex task, even for well-trained international assistant referees (i.e., Catteeuw, Gilis, Garçia-Aranda, et al., 2010). Law 11 (FIFA, 2012) states that “A player is in an offside position if he is nearer to his opponents’ goal line than both the ball and the second-last opponent”. The assistant referee has to assess the exact position of the receiving attacker relative to the second-last defender at the exact moment the ball is played. In the literature, two well-known hypotheses have been intro- duced to explain incorrect offside decision making. Oudejans et al. (2000, 2005) suggested the ‘optical error hypothesis’ to clarify incorrect offside judgments. First, these authors differentiated be- tween two types of errors: a ﬂag error occurs when an assistant referee indicates offside, or raises his ﬂag, while the attacker was in an onside position. The opposite (i.e., non-ﬂag error) takes place when an assistant referee indicates onside, or does not raise his ﬂag, while the attacker is in an offside position. Second, they pointed out that the position of the assistant referee in relation to the second-last defender has a detrimental impact on the accuracy of their decisions. Therefore, both types of errors (i.e., ﬂag error and non-ﬂag error) seemed to depend on an inappropriate position of the assistant referee (i.e., leading or trailing the offside line) and the corre- sponding incorrect viewing angle. When the assistant referee is leading the offside line, more ﬂag errors will be made when the attacker is on the opposite side of the second-last defender and more non-ﬂag errors when the attacker is on the near side. On the other hand, when the assistant referee is trailing the offside line, more non-ﬂag errors are expected when the attacker is on the opposite side of the second-last defender and more ﬂag errors will be found when the attacker in on the near side. Mallo, Frutos, Juarez, and Navarro (2012), however, recently demonstrated that the distance of the assistant referee to the offside line did not have an impact on the quality of the offside decision. The viewing angle did not seem to affect correct offside decision making, as they did not report differ- ences between correct (29  ) and incorrect (25  ) decisions. The second hypothesis and a major contributor to errors in judging offside situations, refers to the ‘ﬂash-lag effect’. This is a * Corresponding author. Tel.: þ32 16 32 90 68; fax: þ32 16 32 91 97. E-mail addresses: Koen.Put@faber.kuleuven.be (K. Put), Johan.Wagemans@ psy.kuleuven.be (J. Wagemans), Arne.Jaspers@student.kuleuven.be (A. Jaspers), Werner.Helsen@faber.kuleuven.be (W.F. Helsen). Contents lists available at SciVerse ScienceDirect Psychology of Sport and Exercise journal homepage: www.elsevier.com/locate/psychsport 1469-0292/$ e see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.psychsport.2013.03.005 Psychology of Sport and Exercise 14 (2013) 577e585