Efficacy in positions 1 and 2 in simple temporary numerical inequality at 15th Water polo World Championship

The aim of this study was twofold: to know if the left-handed players are more effective in the goal categories and getting positive actions, in 1 and 2 position, than the right-handed in the same position at numerical inequality. To ascertain if the shots in 1 and 2 position, are less effective than the rest of the positions in the goal categories. A nomothetic observational, multidimensional and punctual design was used. The sample was the 389 shots and the 182 positive actions of 24 games (12 male and 12 female) at 15th FINA World Championship held in Barcelona. To record the data was used an ad hoc instrument for observation through the Sport Code Version Pro V9. Descriptive and Chi-square test was applied to study the relationship between variables. Left-handed players are more effective than right-handed players are if they are related to the goal and positive action categories in position 1. Shots from position 1 are the second least effective while position 2 is the fifth most effective.


Introduction
Water polo first emerged in the United Kingdom at the end of the 19th century as an alternative to football during the summer months, and it was the first Olympic team sport. It is a complex team intermittent sport, comprising of high and low intensity efforts. As it is also a contact sport, complementarily to swimming, jumping in the vertical plane and receiving, passing and shooting the ball, water polo players must face their opponents through blocking, contacting and pushing (Smith, 1998;Van der Wende, 2005;Stevens et al., 2010).
The methods used to analyse technical and tactical actions in sports performance are notational analysis (Özkol, Turunç, & Dopsaj, 2013) or match analysis (Haydée, Ferragut, & Abraldes, 2016), where one or more experts quantify the previously selected indicators to define sports performance factors over a set time (Hughes & Bartlett, 2002).
For other side, scientific study of water polo is characterized by a great complexity of behaviours and actions that hinder their observation and analysis (Carling, Williams, & Reilly, 2005). It is for this reason that in order to facilitate it, it is divided into smaller units that maintain the structure and dynamics of the sport in order to analyse and transfer the results to the training and competition planning, called playing microsituations (Argudo, 2005). These units are not all the same; developed in different contexts called situational frameworks, which according to Argudo (2005) are defined as the set of motor behaviours present in the game dynamics in team sports, determined by the factors of symmetry, organization of the game systems and ball possession. It can be distinguished in the case of water polo: numerical equality, numerical inequality, transition and penalty.
The framework of numerical inequality in water polo is a playing micro-situation determined by the rules in which the number of players in either team is altered. Depending on the offence, a temporary duration, 20 seconds or recovery-loss of ball possession, or definitive without substitution, can be distinguished for the rest of the match. Likewise, for the first case, the number of players can be differentiated, single or double, specifying the ball possession or not (Argudo, 2005).
Specifically in this study, Simple Temporary Numerical Inequality (STNI) gained importance because of its relevance and impact on the final result, since it determines between 23% and 46% of the goals of a match and has a frequency of appearance of 4 to 12 times per match (Platanou, 2004;Takagi et al., 2005;García, Argudo, & Alonso, 2012. Therefore, it is essential in the field of sports performance to know and identify the motor actions that achieve the highest levels of effectiveness and justify their training in the scheduled sessions (Simoviae et al., 2012;Hassan, 2014). In short, its analysis will provide the necessary scientific knowledge that every sport needs to evolve and progress (Borrie, Jonsson, & Magnusson, 2002).
Another few examples of previous studies in this respect is Petrov (1986), who points out the principles on which the success of the attack in STNI is based and analyses the different variants that can be adopted by the teams in attack. Platanou (2004) investigates the shot effectiveness in this micro-situation and looks for differences between field positions and winning or losing teams. Similarly, Soares (2004) directs his study on efficacy in STNI and performs an analysis of 2001-2002 Portuguese Men's League, comparing it with studies of Argudo (2000). García, Argudo, & Alonso (2012), analysed the 96 matches played in the X Water Polo World Championships held in Barcelona and the 1230 microsituations in STNI were observed. This analysis revealed that the most used game systems were 4:2 (56.5%), followed by 4:2/3:3 (19.1%) and 3:3 systems (16.3%) discarding the (8%) of micro-situations that end without system, being penalized with the last regulatory modification approved by the FINA. In this sense, this type of micro-situation has a great relevance in the result of the encounter given its high occurrence frequency (12.81 micro-situations per match), great influence on the result (4.78 goals per match) and its high efficiency percentage (31.74% of the STNI finish in goal).
From the several abilities that influence water polo performance, shooting seems to be one of the most decisive technical skills (Smith, 1998;Van der Wende, 2005;McCluskey et al., 2010;Stevens et al., 2010). A shot in water polo is the action that allows a goal to be obtained, influencing the score during a match and contributing to its result (Platanou & Varamenti, 2011;Vila et al., 2011). A shot is typically executed under the influence of fatigue and defensive pressure from an opponent (Platanou, 2009). As a result, this technical gesture has been considered one of the primary indicators of performance in water polo (Smith, 1998;Takagi et al., 2005;Tucher et al., 2014).
Regarding shooting position, in STNI, most of shots are executed from positions near to the goal (>60%) (Lupo et al., 2011;Platanou, 2004). Additionally, in all situational frameworks, shots from the sides of the field are more common than those from situational central positions Lupo, Condello et al., 2012;Özkol et al., 2013). Likewise, Lupo et al. (2010) demonstrated that the championship level influences the shooting positions used by the players. Other works have also corroborated that winners have greater capacity to shot from close positions more often (García, Argudo, & Alonso, 2013;Lupo, Condello et al., 2012;Lupo et al., 2011).
Based on precedents, the objectives of this study were: (1) to know if the left-handed players are more effective in the goal categories and getting positive actions, in 1 and 2 position, than the right-handed in the same position at STNI; and (2) to ascertain if the shots in 1 and 2 position, are less effective than the rest of the positions in the goal categories.

Methods
The FINA and the 15 th Water Polo World Championship Organizing Committee approved the study in which efficacy shot indicators are compared in simple temporary numerical inequality between lefties and righties in position 1 and 2. To accomplish this objective a nomothetic, multidimensional and punctual design was used, with a nature of the frequency factor (Anguera, Blanco, Hernández, & Losada, 2011).

Match analysis
All shots, positive actions (exclusion, penalty, rebound and corner) and negative actions (turnover, out, post, save and block) in position 1 and 2, of the 24 selected matches at the 15 th Water Polo World Championship, were quantified and analysed. The 389 shots and the 182 positive actions were categorized (Table 1).
No informed consent was required from players because the Word Championship is a public event, which would cover the ethical aspect.

Procedure
The shots and positive actions analysed were recorded with a video camera (SONY, FDRAXP33B.CEN, JAPAN) that was placed on one side of midfield of the pool, at a height and distance greater than 10 m. Video broadcasts, available online from the Spanish Radio Television were also obtained. Both resources made it possible to combine horizontal plane images obtained with the video camera with those of the frontal plane provided by the television operator. In all of the playing actions examined, the shooter could be clearly seen.
To ensure the quality of the data, the reliability of the observational record, which is related to validity and accuracy, must be taken into account (Anguera et al., 2011). For content validity, a survey was used, using the authority criterion, where 12 coaches (6 from male teams and the same number from female teams)   answered some questions and thus corroborated the agreement on the variables and categories to be observed. These coaches had to be active, have more than 5 years of experience in the highest national and/ or international category, have the highest specific water polo qualification. The 12 coaches surveyed agreed on the variables and categories by more than 90%.
With regard to reliability, in this study, consensus agreement was first used, i.e. agreement was reached among observers prior to registration, which allowed discussion of which category or field format code each action was assigned to.
Inter-observer and intra-observer matching using the same variables, categories and code system was used to control data quality. The men's quarterfinal between Greece and Hungary was chosen for intra-observer matching. It was observed on three occasions, by a previously trained specialist, with an interval of seven days between each analysis. For inter-observer matching, the women's quarterfinal between Spain and the United States was chosen. This was observed by a previously trained expert with more than 10 years of experience as a coach and by the expert mentioned above. They both performed the test-retest on a computer at the same time, in the same room, each with a laptop and an isolated.
Cohen's Kappa test (1960) was used to establish the matches with IBM® SPSS® (version 21.0). The results of the inter-observer and intra-observer concordance calculation (Table 2) showed that the instrument was reliable, since the values obtained were greater than 0.80, and therefore the validity of the contents could be guaranteed.
Sport Code Version Pro V9 was used to analyse and keep all the information. Following the ad hoc instrument designed by Sabio, Guerra, Cabedo, Solà, & Argudo (2018), already reliable and validated, the shots of the 24 games were analysed (Figure 1).

Statistical analysis
The statistical analysis was obtained using the statistical program IBM® SPSS® Statistics version 21.0. Descriptive for all variables were obtained. Chi-square test was applied to study the relationship between variables.
Analyzing the shots from position 2, the majority of them were stopped or finished in goal 4.1% (right side). Adding the categories related to the goal (goals scored at the central, right or left part of the cage) it is observed that from this position it is achieved 7.2% compared to the total 19.3%. The negative actions were 8,7% and the positive ones were 10,5%. We also focus on the shots from position 1, which were the 13.4% in STNI. The majority were finished in goal 4.1% (left side). Adding the categories related to the goal (goals scored at the central, right or left part of the cage) it is observed that from this position it is achieved 7.1% compared to Table 2.

Results of the calculation of the inter-observer and intra-observer agreement.
Inter-observer Intra-observer   the total 13.4%. The negative actions were 4,3% and the positive ones were 9% (Table 3). Table 4 show the results from position 1. It is observed how the left-handed players performed more total shots compared to the right-handed players (31 vs. 21). Adding the categories related to the goal, the lefthanders got 30.8% and the right-handers 23.1%, in total 53,9%. When adding the categories related to positive actions (exclusion, penalty, rebound and corner), the left-handers got 42.3% while the right-handers 25%, in total 67,3%. Adding the categories that refer to negative actions (out, bar, save and block), the lefthanders added up to 17.2% and the right-handers 15.3%, in total 32,5%. It has to be noted that the 30% of the shots were goals scored on the left side and the 11,5% were saved.
In Table 5 can observe how from position 2 the righthanded players make more shots compared to lefthanded players (50 right-handers and 25 left-handers). Adding the categories related to the goal, the lefthanders got 10.7% and the right-handers 26.7%, in total 37,4%. Adding the categories related to positive actions, the left-handers got 16% while the right-handers 38.7%, in total 54,7%. When adding the categories that refer to negative actions, left-handers had 17.3% and right-handers 28%, in total 45,3%. It has to be noted that the 21,3% of the shots were goals scored on the right side and the 21,3% were saved.
To know the Specific Position (PE) and Player's Laterality (LJ) of the shots from position 1 and 2 that finish in goal in STNI, a Chi-square test was applied. This analysis showed a chi-square of 4.667 and a p = 0.031, that indicates there were differences between the variables, considering a p < .05 (Table 6).

Discussion
The position 1 and 2 are weak side without lefthanded players in these positions (García, 2009), which gives relevance to this study. Argudo, García, & Ruiz (2016) and  affirmed that the capacity to circulate the ball with long passes from one side of the field to the other, with receptions by hand, and to positions close to the goal are shot indicators to discriminate winner from losers and the efficiency of the shots.
The results obtained are close to Garcia's (2009), who shows a 12.2% from position 1 and 22.2% from position 2, while in this study are 13.4% in position 1 and 19.30% in position 2. However, García (2009) does not get any shot from position 3 and in this study; there is a 10.5% from the same position.
The results do not match with Argudo, Ruiz & Borges (2016) who found a direct and negative relationship between scoring efficacy (a 7,4% decrease) and increasing shooting distance, nevertheless it should be noted that the angle in position 1 is worst. Platanou (2004) obtains the 43.71% of shots from positions 1 and 5 and the 36.44% of shots from positions 2 and 4, while García (2009) in reverse, shows more shots from the lateral positions (2 and 4), the 44.8%, than from the wings (1 and 5), the 34%. In this study, also get more shots from the lateral positions, but the results are closer together, the 36.3% of the laterals   In position 1, the right-handers are more effective with respect to the categories related to the goal, the 51.6% for the lefties and the 57.1% for the right-hander, and in position 2 the same happened, the 32% for lefthanders versus the 40% for right-handers. It is worth mentioning that from position 1 there are more shots with left-handers than with right-handers, that shows that even though most players are right-handed, coaches have a tendency to select left-handers in position 1 in STNI, since up to the analysed have always been more shots in position 1 of right-handed than of left-handed.
In position 2, adding the positive actions by the different shots, the right-handers get better results against lefties, 58% versus 48% respectively. However, from position 1, left-handers get positive actions, with the 70.7% compared to the 61.9% of right-handers.
We must think about how the defenders use to act. The defence will generally make in a manner that promotes the shot of the player and/or the area, which they believe is weaker or less dangerous. That may explain it why the majority of shots in STNI are from position 2, since most of those shots were saved and that the right-handers are more effective than the lefthanders are, since the teams in inferiority will incite to shot to the righties from that position.
Analysing the positive and negative actions that are achieved by the weak side (1 and 2) and the strong side (4 and 5) is observed that the weak side gets 20 positive and 51 negative actions, and the strong side, 20 positive actions and 52 negatives. Therefore, the weak side gets the same positive and one less negative actions, but the differences are minimal. Considering separately the effectiveness in terms of the goal, positive and negative actions, the 46.8% ends in a goal, the 14.9% are positive actions and the 38.3% are negative actions.
The position that scores the most goals is position 5 and the categories «goals by the right and by the left» are the most frequent in STNI, the 22.6% on the right and, the 21.6% on the left. The STNI is the second phase of the game where more shots occur (33.3%) and it has a goal efficiency of 46.7%. It is the third most effective phase. In reference to the total of goals scored in STNI, it is where most of the goals happen, 182 goals (44.7%).
STNI is very important in the game (García, 2009). In his study got a 31.74%, while Soares (2004) registered a 29.4%. However, the results agree more with the influence of the STNI indicated by Platanou (2004), with the 40.2%, and with Canossa (2001), with the 46%.
The majority of goals in STNI are scored by the right (88, the 48% of the goals in STNI), followed by the goals that enter from the left (84, the 46.2% of the goals in STNI) and by last the central positions closest to the goalpost ones (10, the 5.5% of the goals in STNI). We agree with García (2009), who in his study states that most shots are made by the right, followed by those made to the left and finally the central ones, although with different values. Following Alcaraz et al. (2012) it could happen not only due to the laterality but also due to the anthropometrical characteristics and the previous study of the opponent.
In STNI is observed that the most effective shots according to the categories related to the goal are made from position PEP6, the goalpost position, with the 67%, followed by PEP1, which refers to position 1, with the 53.9%, and PEP5, position 5, with the 53.5%. The least effective position is PEP2, position 2, with the 37.3%.
It is worth mentioning that the rules at that time allowed, by getting an exclusion in the perimeter and pass it quickly to the centre forward to shot directly. That is why surely the percentage of goal efficiency is high, since they can shot hardly without opposition. In this same line, García (2009) points out that the most notable difference in the STNI between winning teams and losers is when it ends without a system, where the winning teams get the 66.1%.

Conclusions
The results of this study lead us to believe that in STNI the left-handed players are more effective if relate them to the goal categories and positive actions. However, in position 2, the right-handed players are more effective if only the categories related to the goal are taken into account in position 1 as in 2. The position 1 is the second least effective, but in the case of position 2, which achieves the 22.7% efficiency, is the fifth most effective position.
Future studies could separate women's and men's shots, taking into account García, Ruiz, Argudo, & Borges (2017) who found differences depending on distance and micro-situations variables. In addition, the effect of the regulatory changes proposed by FINA in 2019 can be analysed. Argudo, García, Borges, & Sillero (2020), comparing the 2003 Water polo World Championship with the one held in 2013 found differences in the STNI. Specifically, the frequency of shots decreased and more goals were scored at close range, from the side and with rebound.
It is necessary to emphasize and teach right-handed players the importance of technique and body position in the water. It is very important everywhere, but especially in 1 and 2 positions, since it is the weak side and it will be essential to play around. It will also be important for these players to perform many tasks that involve shooting and/or assisting attacking the opposite arm, as demonstrated, they receive many zonal defenses of different types. Provide it with enough technical resources to overcome the arm, either above, inside and outside to assist and to shot.