EQOL Journal (2017) 9(2): 5-11

ORIGINAL ARTICLE

Factors Associated with Shooting Efficacy in Elite Competition Water Polo

Francisco Manuel Argudo Iturriaga1• Pablo José Borges Hernández1 • Encarnación Ruiz Lara2

© The Author(s) 2017. This article is published with open access.

Abstract

The main aim of the study was to analyze the relationship between scoring and missing a goal in water polo and other associated factors such as the game micro situation, throw distance and throw angle. The investigation followed an observational design methodology. The sample was composed of 7,215 shots. It was analyzed using the Pearson chi- squared test and with multiple binary logistic regression. The goal success rate of penalty shots was greater in both male and female categories than for non-penalty shots (p < .001). A model was identified in woman's water polo that was able to predict 63% of the goals, in which the highest possibility of goal success was observed for shots taken during 'man-up' situations, i.e. a numerical advantage (OR = 2.65) and transitions (OR = 2.04), whereas the least possibility of goal success applied to shots affected from more than 5 meters (OR =

.57). The model applied to male water polo was able to predict 65% of the goals, the highest possibility of scoring a goal corresponded to shots taken during inequality situations (OR = 2.59), then transitions (OR = 2) and those from a central area in front of the goal (OR = 1.33); as in the case of women, the least possibility of goal success was also observed for shots taken from over 5 meters away (OR = .37).

mquico.argudo@uam.es

1Autonomous University of Madrid, Faculty of Teacher Training and Education, Madrid, Spain

2Universidad Católica San Antonio Murcia, Faculty of Sport, Murcia, Spain

Keywords tactical analysis shot match analysis

gameplay

Introduction

Traditionally, water polo studies have concentrated on evaluating possible factors related to the sporting performance and anthropometric characteristics of the players (D'Auria & Gabbett, 2008; Ferragut et al., 2011a; Ferragut et al., 2011b; Kavouras et al., 2006; Steel, Adams, & Canning, 2007; Tsekouras et al., 2005; Vila, Ferragut, Abraldes, Rodríguez, & Argudo, 2010). However, recently authors have demonstrated a greater interest in analyzing the game action involved in water polo.

Studies which follow this line of investigation analyze the match (Canossa, Garganta, Argudo, & Fernandes, 2009; Platanou & Geladas, 2006), technical actions (Alcaraz et al., 2011; Vila, Abraldes, Alcaraz, Rodríguez, & Ferragut, 2011), specific playing positions (Argudo, Gabaldón, & García, 2006; Lozovina, Pavicic, & Lozovina, 2007; Lupo et al., 2012) and various situational circumstances (Argudo, García, Alonso, & Ruiz, 2007a; Argudo, García, Alonso, & Ruiz, 2007b; Smith, 2004).

Analysis of team-play actions is a very complex task due to the simultaneous interaction of multiple factors. To facilitate analysis, it is therefore convenient to divide the game action into smaller units, giving rise to the concept of situational set- ups, understood to be the group of driving actions predetermined by symmetry factors, organization

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EQOL Journal (2017) 9(2): 5-11

of tactical systems of play and ball possession (Argudo, 2000). Four situational set-ups have been defined for the specific case of water polo: numeric equality, transition, inequality and penalty (Argudo, 2000). Numeric equality in water polo comprises the organization and structure of the tactical system of play, with or without possession, until the loss or recovery of ball possession and is characterized by the presence of all players, permitted under the rules, on both teams, i.e. six field players and a goalkeeper per team. The transition starts when possession of the ball is lost or gained and lasts until the tactical system of play is organized and structured, with or without possession, in the opposite goal area. There are two forms of action within this situational set-up: offensive transition and defensive transition. Inequality situations are characterized by a change in the number of players on either of the teams, whether due to a foul or because of recovery-loss of ball possession. Penalties are determined by the rules, being characterized by the single action of one player on the team awarded the penalty against the other team's goalkeeper (Argudo, 2000).

Due to the particular characteristics of each situational set-up, various authors have reported significant differences in the effects of efficacy coefficients corresponding to each game micro situation on the win/loss outcome of both male and female water polo matches (Argudo, 2000; Argudo et al., 2007a; Argudo et al., 2007b; Argudo, 2009a; Argudo, 2009b; Enomoto, 2004; Lloret, 1994; Sarmento & Magalhaes, 1991).

And so the present study was conducted with the aim of achieving three objectives: (1) to demonstrate the singularity of penalty shots in comparison with all other throw, from the perspective of shooting efficacy; (2) to analyze the association between the goal/miss variable and other possible determinants: game micro situation, throw distance and throw angle; and (3) to confirm that the variables are capable of predicting the throw efficacy variable, estimating their combined forecasting capacity. All of these factors were investigated in the context of high competition water polo, in both male and female categories.

Method

The study analyzed all of the shots affected during European and World Water Polo Championship. The organizing committees of both competitions granted

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the relevant permissions required for the study. Furthermore, due to the nature of the study, filming in the context of a public competition meant that the approval of an ethics committee was not required. To perform the study, and to test the proposed hypotheses, two techniques were employed; the matches were filmed and they were observed directly. The sample included a total of 7,215 shots, of which 3,371 were executed in the women's category (1,080 in the European Championship and 2,291 in the World Championship) and 3,844 in the men's category (1,412 and 2,423 shots in the European and World Championships, respectively).

The study followed an observational design with aims that are descriptive in nature and of predictive inference. The investigation involved the analysis of 160 matches, 68 of which were in the women's category (20 and 48 games in the European and World Championships, respectively) and 92 in the men's category (44 and 48 matches in the European and World Championships, respectively). In all matches, every single shot was filmed. A digital video camera (JVC, GZ-MG50E, JAPAN) was used to film the shots, located in an elevated position above the center and in line with the midpoint of the pool (Figure 1). Afterwards, different monitors with no vested interest in the investigation, previously trained in observational categorization, analyzed all of the shots with the aid of Polo Análisis Directo v1.0 software (Argudo, Alonso, & Fuentes, 2005). The reliability between the observers was verified using the kappa correlation coefficient, ensuring that in all cases the coefficients were greater than .85.

The present investigation analyzed five variables. Following the order in which they are referenced, the first four are considered to be independent or predictors and the fifth is considered dependent or criterion. (1) Type of shot, divided into two categories: penalty and open play. (2) Throw action or the micro situation of play when the throw is taken, divided into three categories: (a) numerical equality between the two teams; transition from one goal area to the other which produces a temporary man up situation or a inequality situation between the two teams due to the temporary exclusion (20") of a player. (3) Shooting corridor or angle with respect to the center of the goal area being attacked formed by two categories: shot taken from the central corridor or from either of the lateral corridors (Figure 1). (4) Throw distance, with three categories established, measured from the goal-line being attacked: in 2 meters, those between 2 and 5 meters, and those of

EQOL Journal (2017) 9(2): 5-11

more than 5 meters (Figure 1). (5) Throw efficacy, composed of two categories: goal or not goal.

0-2

2-5

> 5

½

½

> 5

5-2

2-0

 

 

 

Lateral

corridor

 

 

 

 

 

 

Central

corridor

 

 

 

 

 

 

Lateral

corridor

 

 

 

0-2

2-5

> 5

½

½

> 5

5-2

2-0

Video camera

Figure 1. Video camera position and court division. Central (within the trajectories of the posts of goals) and lateral

(externally to the trajectories of the posts of goals) zones, in relation to the 0-2, 2-5,

Results

The results demonstrated that the rate of goal success for penalty shots was statistically greater than that of shots taken in open play, in both female (goal =

73.7%, miss = 26.3%) and male categories (goal = 76.5%, miss = 23.5%). Or presented differently, the miss % of shots taken in open play was statistically greater than the miss % for penalty shots, for both women (goal = 32.3%, miss = 67.7%) and men (goal = 31.3%, miss = 68.7%). See Table 1.

Table 1. Chi-squared test. Association between the type of shot (penalty vs. open play) and shooting efficacy

 

 

 

Efficacy %(Z)

 

 

 

 

 

 

 

 

 

χ2

 

 

 

Category

Shot type

n

Goal

Miss

df

p

φ

Women

Penalty

133

73.7(9.9)

26.3(-9.9)

97.3

1

< .001

.17

Open play

3,238

32.3(-9.9)

67.7(9.9)

 

 

 

 

 

Men

Penalty

153

76.5(11.6)

23.5(-11.6)

135.4

1

< .001

.19

Open play

3,691

31.3(-11.6)

68.7(11.6)

 

 

 

 

 

Legend: % = percentage of shots; Z = corrected standardized residuals; χ2 = value of chi-squared test; df = degrees of freedom; p = probability of statistical significance; φ = phy coefficient. In bold: statistically significant standardized residuals.

In women's water polo, an association between the throw efficacy variable and the game micro situation variables (χ2 = 186.3, df = 2, p < .001; C = .23) and distance (χ2 = 120.5, df = 2, p < .001; C = .19) was observed. Conversely, the shooting efficacy variable

was shown to be independent of the shooting corridor or angle variable (χ2 = 1.0, df = 1, p = .30). In men's water polo, shooting efficacy showed an association with all the other variables studied; namely, from greatest to least frequency: game micro situation (χ2

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EQOL Journal (2017) 9(2): 5-11

=224.3, df = 2, p < .001; C = .24), distance (χ2 = 181, df = 2, p < .001; C = .21) and shooting corridor or

angle (χ2 = 8.6, df = 1, p = .003; C = .05). See Table 2.

Table 2. Chi-squared test. Association between the different shot variables and shooting efficacy (goal vs. miss).

 

 

 

 

Efficacy %(Z)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Category

Variables

Shot type

n

Goal

Miss

χ2

df

p

φ

 

 

 

 

 

 

 

 

 

 

 

 

Equality

 

22.8(-13.5)

77.2(13.5)

 

 

 

 

 

Game

Transition

496

41.7(4.9)

58.3(-4.9)

186.3

2

<.001

.24

 

microsituation

 

 

 

 

 

 

 

 

 

 

 

Inequality

873

47.3(11.1)

52.7(-11.1)

 

 

 

 

 

 

< 2 m

62

40.3(1.4)

59.7(-1.4)

 

 

 

 

Women

 

 

 

 

 

 

 

 

 

 

Distance

2 - 5 m

1,439

42.1(10.6)

57.9(-10.6)

120.5

2

<.001

.19

 

 

> 5 m

1,737

23.9(-11)

76.1(11)

 

 

 

 

 

Corridor

Laterals

951

31.8(-1)

68.2(1)

 

 

 

 

 

 

 

 

 

1.0

1

.30

 

(throw angle)

 

 

 

 

 

Central

2,287

33.6(1)

66.4(1)

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

 

Equality

2,021

21(-14.8)

79(14.8)

 

 

 

 

 

Game

Transition

607

40.2(5.2)

63(-5.2)

224.3

2

<.001

.24

 

microsituation

 

 

 

 

 

 

 

 

 

 

 

Inequality

1,063

45.7(12)

54.3(-12)

 

 

 

 

 

 

< 2 m

76

48.7(3.3)

51.3(-3.3)

 

 

 

 

Men

 

 

 

 

 

 

 

 

 

 

Distance

2 - 5 m

1,512

42.8(12.6)

57.2(-12.6)

181

2

<.001

.22

 

 

> 5 m

2,103

22.4(-13.4)

77.6(13.4)

 

 

 

 

 

Corridor

Laterals

2,647

29.9(-2.9)

70.1(2.9)

 

 

 

 

 

 

 

 

 

8.6

1

.003

.05

 

(throw angle)

 

 

 

 

 

Central

1,044

34.9(2.9)

65.1(-2.9)

 

 

 

 

 

 

 

 

 

 

Legend: % = percentage of shots; Z = corrected standardized residuals; χ2 = value of chi-squared test; df = degrees of

freedom; p = probability of statistical significance; φ = phy coefficient. In bold: statistically significant standardized residuals.

For women's water polo, a model was identified with the ability to predict 63% of the goals and 62% of the misses. It was observed that there was a greater probability of scoring a goal from shots taken during inequality situations (OR = 2.65, CI = 2.22 - 3.16, p

<.001) and for shots taken during transitions (OR = 2.04, CI = 1.64 - 2.53, p < .001) with respect to shots

affected in moments of numerical equality. It was also found that shots taken from a distance of more than 5 meters had less probability of resulting in a goal compared to those taken from 2 meters (OR = 0.57, CI = 0.20 - 0.53, p = .043). A model was attained for men's water polo with the ability to predict up to 65% of the goals and 62% of the misses. Compared to

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EQOL Journal (2017) 9(2): 5-11

shots taken during numerical equality, a greater probability of scoring was observed for shots affected during inequality situations (OR = 2.59, CI = 2.18 - 3.07, p < .001) or transitions (OR = 2.00, CI = 1.63 - 2.45, p < .001); shots executed from the central corridor had a greater probability of success with

respect to those taken from the lateral corridors (OR

=1.33, CI = 1.14 - 1.56, p < .001). However, taking shots from 2 meters in distance as the reference, shooting from more than 5 meters away had less probability of resulting in a goal (OR = 0.37, CI = 0.23 - 0.60, p < .001). See Table 3.

Table 3. Multiple binary logistic regression model. Possibility that a shot results in a goal

Category

Variables

OR

CI (95%)

p

 

Game microsituation

 

 

 

 

Equality

1

reference

 

Transition

2.04

1.64 - 2.53

< .001

Women

Inequality

2.65

2.22 - 3.16

< .001

Distance

 

 

 

 

 

 

 

 

< 2 m

1

reference

 

2 - 5 m

1.07

0.63 - 1.83

.77

 

> 5 m

0.57

0.20 - 0.53

.043

 

 

 

 

 

 

Game microsituation

 

 

 

 

Equality

1

reference

 

Transition

2.00

1.63 - 2.45

< .001

 

Inequality

2.59

2.18 - 3.07

< .001

 

Distance

 

 

 

Men

< 2 m

1

reference

 

2 - 5 m

0.72

0.45 - 1.16

.17

 

> 5 m

0.37

0.23 - 0.60

< .001

 

Corridor (shooting angle)

 

 

 

 

Laterals

1

reference

 

Central

1.33

1.14 - 1.56

< .001

Legend: OR = odds ratio; CI (95%) = 95% confidence interval; p = probability of statistical significance. In bold: odds ratio and 95% confidence intervals, statistically significant.

Discussion

In the quantitative tactical evaluation of shots affected during the European and World Water Polo Championship, which considered the throw distance, situational set-up and throw angle, it was observed that in both male and female high competition approximately 75% of penalty shots resulted in a goal, whereas the goal success rate for all other shots was approx. 31%. Specifically, in the men's category the shooting efficacy of penalty shots (76.5%) was slightly higher than in the women's category (73.7%). These findings are similar to those of Escalante et al. (2012), who presented results of 68.9% and 71.6% for male and female categories, respectively, for penalty shots taken during the 2008 Olympic Games held in Beijing.

Regarding the analysis of the goal/miss variable with respect to other possible determinants in women's water polo, the differences observed in throw efficacy percentages based on the game micro situation have been reported by authors such as Lupo et al. (2011), who found greater rates of shot success in transition and inequality micro situations between winning and losing teams. Moreover, Escalante et al. (2012) reported throw efficacy values that were greatest during inequality situations for both winning and losing teams throughout the various phases of the European and World Championships. In male water polo, throw efficacy was also observed to be highest during inequality situations, results that are in agreement with those already presented by other authors investigating elite competitors (Lupo, Tessitore, Monganti, & Capranica, 2010).

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EQOL Journal (2017) 9(2): 5-11

With regard to the relation between throw distance and efficacy, we observed for the female category that the distance which produced the highest goal success rate was for shots taken between 2 and 5 meters away, while in the male category shots affected from 2 meters proved to have the greatest success rate. The literature available that analyses the throw efficacy with respect to shooting distance reveals a greater percentage of success in shots affected from within the 5-meter area (Alcaraz et al., 2012; Lupo et al., 2011), however the authors do not specify the exact distance.

Finally, although shots taken from the central area had a slightly higher goal success rate than those from the lateral corridors, a significant correlation between the throw angle and throw efficacy was not observed in women's water polo.

However, in men's water polo a significant correlation between the two variables was observed, with shots from a central area (forward angle) found to be the most effective. Overall, the variables analyzed above present a prediction for a slightly higher throw efficacy in men's water polo (65%) than in women's (63%). This is due to the fact that shots taken from the central corridor increased the goal success rate in the male category whereas in the female category this variable (throw angle) did not influence whether a shot resulted in a goal or a miss. Hence further research should include the specific shooting categories which greatly contribute to the efficiency and performance such as shots after foul in counter attack and without or after balking.

The differences observed between male and female water polo with regard to the throw distance and angle, and their influence on throw efficacy, can be attributed to the technical-tactical differences between the categories as well as the ability of the goalkeepers. Therefore, future studies could include an evaluation of these variables with the aim of yielding greater technical-tactical specifications.

If extrapolating the results to training situations, for both men's and women's water polo, it is important to follow two main guiding principles: persist with the variables which have the greater probability of resulting in a goal and develop those in which shooting efficacy is more complicated. In the first case, from an attacking point of view, training should concentrate on precision work for shots taken from less than 5 meters away in both inequality and transitional game micro situations. With regard to penalty micro situations, training should place an emphasis on the accuracy of shots, as has been

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demonstrated in earlier studies, because penalties comprise a key indicator in deciding the outcome of matches (Argudo, 2009a; Argudo, Ruiz, & Abraldes, 2010).

And from a defensive perspective, training in shot blocking takes on special importance. Especially since the rule change which determined that, whenever the ball leaves the limits of play because a defending player blocked a shot, the defending team recovers ball possession. For the second case, and with the purpose of increasing throw efficacy in those game micro situations in which scoring a goal is more difficult, training should concentrate on shots taken in micro situations of numerical equality, at a distance of more than 5 meters and from lateral positions.

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