RESULTADOS DEL ESTUDIO DE CRITICIDAD

The different situations and contexts surrounding matches have been extensively analysed, in particular looking at the advantages of playing at a team’s “home ground” (Bradley, Lago-Peñas, et al., 2014; Jacklin, 2005;

Lago et al., 2010; Ballesteros et al., 2012; Peñas & Lago-Ballesteros, 2011; Pollard, 2008; Poulter, 2009; Redwood-Brown, Bussell, et al., 2012; Sánchez et al., 2009; Taylor et al., 2008). In addition to analysing the advantage of playing at home stadiums, research has also investigated the effect of playing against different standards of opposition and the effect of match result (winning, losing or drawing).

Out of all the contextual factors, match location has the largest influence on match outcome than any other contextual factors (Bradley, Lago-Peñas, et al., 2014; Jacklin, 2005; Lago et al., 2010; Pollard, 2008;

Pollard & Pollard, 2005). Home team advantage in sport has been evident since the early days of sport itself (Jacklin, 2005; Pollard, 2008; Pollard &

Pollard, 2005; Sánchez et al., 2009). However, recent research has shown that the advantage for the home team playing in their own stadium is diminishing and is less prevalent in modern sports compared to previous years (Jacklin, 2005; Pollard & Pollard, 2005; Sánchez et al., 2009). Back in the 1940’s, soccer teams were likely to win two home games for every one away game, by the 1970’s this had increased to approximately 2.5 homes games for one away game win, although by the early 2000’s this had reduced to being approximately 1.5 home wins for one away win (Jacklin, 2005). Interestingly, this is despite changes in the points system where teams are awarded three points for a win compared to two points for a win

pre-1981 (Jacklin, 2005). This decrease in home advantage is most prevalent in ice hockey, although has also been measured in American football, soccer, basketball and baseball (Pollard & Pollard, 2005). The causes for home advantage are less clear than the effects; nevertheless there have been some proposals as to the causes. Territoriality and familiarity have been proposed as major factors in home advantage due to the nature of humans protectionism and the feeling of the away team invading the home teams territory, as well as the feeling of comfort playing in familiar surroundings (Pollard, 2008; Pollard & Pollard, 2005). This is plausible as teams who transfer to play in a new stadium often see a reduction in home advantage (Pollard, 2002). Familiarity and territoriality may be further supported by the reduction observed in home advantage in recent years. Football clubs in England are seeing ever increasing numbers of non-native players performing (BBC, 2013), and as a result the feelings of protecting territory and familiarisation will be less prevalent in non-native players compared to native players (Pollard & Pollard, 2005). Other potential factors include the effects of the crowd, where home teams traditionally have greater support than the away teams, thus with the close proximity of the crowd at football grounds, the additional noise providing a sense of greater support for the home team (Pollard, 2008). In addition, the crowd noise has been shown to influence a further factor of referee bias, where referee decisions have been shown to favour the home team as a result of the increased crowd noise (Nevill, Balmer, & Williams, 2002; Unkelbach &

Memmert, 2010). The change in points system in English soccer is also an important factor, even though it is isolated to one example. It is possible that

the change in points system has increased the importance of winning matches for away teams rather than drawing or losing, purely down to the factor of the increased number of points for a win (Jacklin, 2005). Teams now need to draw three matches to gain the same number of points for a single win, thus increasing the incentive for teams to win matches instead of setting for a draw. It is unlikely to be a single factor that encourages home advantage but it more likely to be a combination of all of the factors above, as well as other potential factors, which cause home teams to win a greater number of matches (Pollard, 2008).

The effects of match location has been more widely reported for technical performance variables compared to physical performance, although the total distance covered by away teams is approximately 260 metres less than the home team (Lago et al., 2010). Nevertheless, as the majority of this deficit for away teams is observed at low intensities, and as the high-intensity running distance strongly influences match result in football, the differences in total distance covered between home and away teams is unlikely to impact match result (Bangsbo et al., 2006; Bradley, Carling, et al., 2013; Lago et al., 2010; Mohr et al., 2003). In contrast, home teams have consistently been measured to perform better technical performances than away teams, including performing fewer fouls, losing possession fewer times, and receiving fewer cards (yellow and red), whilst also performing more passes, successful passes, crosses, possession regains as well as key variables such as the number of shots, shots on target and goals (Peñas & Lago-Ballesteros, 2011; Poulter, 2009).

Match status (winning, drawing or losing) and opposition standard has less of an effect on match parameters compared to match location although still had a minor effect on technical performance (Bradley, Lago-Peñas, et al., 2014; Lago et al., 2010). Matches played against strong opposition (typically those that finish in the top places in their respective league) result in the weaker team traditionally having fewer ball possession, fewer shots, passes, final third entries and goals scored compared to matches played against middle and low placed teams in the league (Peñas & Lago-Ballesteros, 2011; Redwood-Brown, Bussell, et al., 2012; Taylor et al., 2008).

When teams are losing, they cover greater distances at high-intensities compared to teams who are winning, this is in addition to differences in technical factors where losing teams perform more shots, although there is no difference in the accuracy of these shots (Lago et al., 2010; Lago-Peñas

& Dellal, 2010; Taylor et al., 2008), it is unclear for the reasoning behind these changes although it is possible that losing teams perform more high-intensity actions and take more shots in order to equalise and therefore avoid defeat (Lago, 2009). Although there is clear evidence of match context affecting both technical and physical performance, some match contexts are easier to account for than others. For example, match location is fairly simple to monitor and take into account compared to evolving match score or final result that are simple to measure but more random to control. Despite the ease of measuring some contextual factors, research generally negates factoring these within the methodological process. It is possible that research groups fail to account for these factors, as they do not see the need to include them in the analysis or fail to refer to the impact or effects they may

have on the results identified. Alternatively, researchers may not feel the need, have the time or the abilities to carry out resampling procedures in order to mitigate or reduce potential interpretation errors when analysing data with varying samples for contextual factors. The reasons behind research not accounting for these factors is unclear, nevertheless given the results highlighting the impact of contextual factors it should become an essential element of all research articles. This could be as simple as research recording the different sample sizes for contextual factors, or a resampling process which takes contextual factors into account and minimises data interpretation errors.