Shots for Goal

Katrina van der Wende and Justin Keogh; Auckland University of Technology, New Zealand

Untitled Document

Summary

The overhead shot is the most commonly used and coached shot in water polo. However a number of alternative shots such as the back and push shot have been developed for differing situations.
The overhead shot can achieve high end point velocity through the use of the kinetic link principle. The accuracy of this shot can be increased by moving the trunk forward, resulting in a flattening of the path of the ball.
The back shot is a useful shot for the element of surprise. Although this shot also utilises the kinetic link principle the segments involved are not capable of producing as high forces as in the overhead shot. Accuracy is decreased due to obstruction of vision and the curvilinear path of the hand.
The push shot is accurate at close range. Due to the use of the simultaneous (push) movement pattern the velocity of this shot is decreased in comparison to the overhead and back shot. However accuracy is increased due to the linear path of the hand at release.
Video footage will be included to assist in demonstrating the main coaching points of the three shots. Recommendations for what situations during a game these shots have the best potential to score will also be discussed.

Introduction

The shot for goal is one of the most important skills in water polo. This is traditionally performed using an overhead motion and is referred to as the overhead shot. While a shot can be taken from various positions in the pool, the defenders and goal-keeper are continually moving into a position to block the shot. Thus, a number of alternative shots have been developed in the hope that they may be more suitable than the overhead shot in some situations. Examples of these alternative shots include the back shot and the push shot. Following game analysis of the scoring shots from three male and three female junior international level water polo matches it was identified that 81% of the shots came from the overhead technique (van der Wende, unpublished observations) compared with 5% and 7% from the back shot and push shot, respectively in the six junior international matches observed (van der Wende, unpublished observations).

This article will focus on describing some of the key coaching points for these alternative shots and discuss how they differ to that of the overhead shot in terms of the speed generated and the accuracy obtained. Video footage will be included to assist in demonstrating the kinesiology and main coaching points of the three shots. A recommendation for what situations during a game these shots have the best potential to score will also be given.

Overhead shot

The overhead shot is the most commonly used and researched shot in water polo and has also been detailed in “The Shot: Described” on this website. A description is also included here for comparison with the other shots tested. It provides the greatest ball velocity, up to 20 m.s-1 in elite male players (Davis & Blanksby, 1977; Elliott & Armour, 1988; Feltner & Taylor, 1997; Whiting, Puffer, Finerman, Gregor, & Maletis, 1984) and has been reported to have an accuracy of 67.3% (Clarys & Lewillie, 1970). Unfortunately, the methods used to determine shooting accuracy and the standard of players used by Clarys and Lewille (1970) was not described.

Key Coaching Points

The ball is positioned behind the player who is looking at the goal from a side on position. This enables the player to initiate the shot from the hips.
The legs should begin to move upward by hip and knee flexion and the trunk becomes more horizontal at the height of the water’s surface to prepare for the upward egg-beater boost. Simultaneously, the player picks up the ball by pressing down into the water or by lifting from underneath.
As the upper body rises out of the water, the throwing arm is pulled behind the body (backswing).
At the top of the back swing, the hips and then the upper body (trunk) should start to rotate forwards.
The hand has rotated, so during the forward swing the hand is behind the ball.
Halfway through the forward swing the hips have completed their rotation, the trunk is rapidly rotating forward and the arm should be externally rotated (somewhat lagging in preparation for the whip forward at release).
The upper body and trunk moves forward to contribute additional velocity to the throw.
Approaching ball release, the elbow extends rapidly and the wrist and fingers flex at release.
During the follow through the arm continues along the path of travel as it decelerates, which is necessary to minimise the mechanical stress to the elbow extensors and the external rotators of the shoulder (rotator cuff).

The three videos below show different angles of the overhead shot.

To download or play this video, click one of the following buttons:

Movies 1, 2, and 3

Side view: showing the "lagging" externally rotated arm during forward
swing and trunk flexion at release.

Front/Back Views: showing the large elbow angle during the forward swing and lateral flexion of the trunk at release.

Back shot

The back shot when performed effectively may be a useful offensive weapon with a large element of surprise. However this method of shot has not been widely studied. Therefore the optimal technique for maximising accuracy and/or velocity is relatively unknown. This type of shot has been reported to have an accuracy of 27.3% (Clarys & Lewillie, 1970).

Key Coaching Points

The player starts with their back to the goal, with the ball positioned in front of the body.
The ball is picked up by either pushing the ball down or picking up the ball from underneath.
As the ball is lifted from the water, an egg beater boost is executed.
The ball is lifted sideways as the arm abducts with a bent elbow to reduce the moment of inertia around the shoulder and trunk.
The player then begins rotating towards the goal with the forearm lagging and the elbow flexed.
As the arm reaches a fully abducted position and the body is slightly rotated allowing the player to see the goal, the elbow extends and the wrist and fingers flex as the ball is released, at which point the player is at maximum boost height.
The follow through allows the arm to continue along its path to an extended position and the player continues to rotate.

The three videos below show different angles of the back shot.

To download or play this video, click one of the following buttons:

Movies 4, 5and 6

Side view: showing the height out the water and speed of spin round.

Front/Back Views: showing the elbow extension at release.

Push shot

When executed at high speeds the push shot has been shown to have an accuracy of 50% (Clarys & Lewillie, 1970). However little information is available on the optimal kinesiology for maximising the velocity and accuracy of the push shot.

Key Coaching Points

In a front crawl position the player swims at full speed towards the goal dribbling the ball.
The ball is then pushed under the water and rotated so as to pick the ball up.
The player then pulls the ball towards their body making sure that the shoulder, elbow and ball are all above the water. The backswing terminates with the ball just in front of the shoulders and the elbow behind the ball.
As the other arm pulls back in a freestyle stroke the ball is pushed forward with some contribution from a breaststroke whip kick with the legs.
The elbow then extends rapidly with some shoulder and hip rotation.
The follow through carries the arm across the front of the body with some further rotating of the body also occurring.

The three videos below show different angles of the push shot.

To download or play this video, click one of the following buttons:

Movies 7, 8, and 9

Side view: showing the height out the water and speed of spin round.

Front/Back Views: showing the elbow extension at release.

Throw velocity

The velocity obtained for the overhead, back and push shots from a junior national level girl’s team (16.9 ± 0.5 years, N=14) are shown in Table 1. The New Zealand School girl’s national team was measured prior to a Trans-Tasman tri-series.

Table 1: Mean, standard deviation and range of the over head, back and push shot velocities from a national level junior girl’s team.

	Mean ± SD	Range
Overhead shot (m/s)	14.8 ± 1.2	11.9 - 15.8
Back shot (m/s)	11.4 ± 1.4	8.1 - 13.5
Push shot (m/s)	8.9 ± 1.2	6.9 - 10.9

The over head shot in water polo utilizes the overhead throw pattern whereby the ball that was initially positioned behind the body, is moved up and over the head with the ball being released in front of the body. The goal of this overhead throw pattern is to achieve high end-point velocity by using the kinetic link principle, which has also been detailed in “The Shot: Described” on this website.

The kinetic link principle is a biomechanical principle that is used to maximize velocity in throwing-type motions (Kreighbaum & Barthels, 1996). It is a sequential movement pattern that is initiated with contraction of muscles that act to accelerate the more massive proximal segments (e.g. the hips). The torques produced around the hip result in acceleration of the hip segment. Although the next segment in the chain (i.e. the trunk) initially lags behind the hips the momentum generated by the movement of the hips also tends to accelerate the trunk. The sequence of ‘whipping’ actions continues throughout the upper extremities, finishing with the ball being released from the finger tips. The lagging of the proximal segments results in a rapid stretch of the muscles, allowing utilization of the stretch-shorten cycle. Thus, the kinetic link principle takes advantage of both active and passive neuromuscular forces (Kreighbaum & Barthels, 1996). Therefore, the greater the number of segments used in a sequential pattern (assuming their activations are timed correctly), the greater the velocity of the ball at release.

The back shot also utilizes the kinetic link principle. However the back shot has fewer segments that contribute to the movement than that of the overhead shot. The segments involved in the back shot also are not as capable of producing large torques as those of the overhead shot. Therefore, the finding that the mean velocity of the back shot was only 77% of overhead shot appears reasonable.

In contrast to the overhead and back shot, the push shot utilizes a simultaneous (push) movement pattern where the ball is pushed forward in one movement with all of the segments positioned behind the ball (Kreighbaum & Barthels, 1996). This pattern does not allow as much velocity as that of the sequential pattern used in the overhead or back shot, as there are fewer segments involved and therefore less summation of forces through the number of segments used. The velocity of the push shot was the lowest of the three shots analyzed (60% of the overhead shot).

Throw accuracy

According to Newton’s laws of motion, the acceleration of an object occurs in the direction of the applied force. As a result, the more linear the movement of the ball during the forward swing, the greater the chance the ball will go in the intended direction.

During the overhead shot, the hand has somewhat of a curvilinear path. This may decrease the accuracy potential of this shot as there is a shorter section to release the object in line with the intended direction of travel (see Figure 1). Therefore to achieve both high velocity and accuracy the trunk is moved forward during the forward swing, this allows the arc of ball motion in the forward swing to be flattened.

Figure 1: Over head shot path of hand and optimal release point

The back shot is a rotational movement where the ball follows a curvilinear path; this leads to a short section in which the object can be released in line with the optimal direction of travel to score a goal (see Figure 2). In combination with the obstruction of vision the players experience with this type of shot, the accuracy of this shot would be expected to be less than the overhead and push shots. This is supported by the results of Clarys and Lewillie (1970).

Figure 2: Back shot path of hand and optimal release point

The push shot is a linear movement which allows the performer a longer time to align and project the ball in the direction of intended travel (see Figure 3). Thus, it would be expected that the push shot would have the greatest potential for accuracy of the three shots analyzed. Although Clarys and Lewillie (1970) found greater accuracy in the overhead than push shot, the lack of description of these tasks makes it difficult to determine the reason for such a result. This surprising result may be due to the size of the target, the distance the shots were taken from goal, level of players used and/or the players’ familiarity with the push shot.

Figure 3: Push shot path of hand and optimal release point

Conclusion

The overhead shot is the most commonly used shot in water polo as it produces a high velocity that generally results in scoring. To perform this type of shot well the kinetic link principle should be used which requires using the whole body to produce a ‘whip like’ movement to produce high endpoint velocity. However the overhead shot requires a lot of strength through the internal and external shoulder rotators as the shoulder structure is put under a lot of stress during the movement. The overhead shot is a versatile shot and can therefore be used in a variety of settings such as long distance from goal, with or without the presence of defenders and a goal keeper.

The back shot may be a useful surprise shot even though it is difficult to perform well. As the velocity that you can obtain is less than that of the overhead throw, in most situations you should only use the back shot from relatively close range, such as within the 4-m area. To perform this shot well a high egg beater boost is needed combined with a fast spin at maximum height to achieve maximal velocity of the ball and therefore further enhance the surprise of the shot.

The push shot is a useful shot when a player is driving towards goal, especially in a run-away situation where you are closer to the goal than the nearest defender. The shot is very accurate if used close to goal but requires good strength of the elbow extensors for the push motion and a fast swim speed. However, if the push shot is taken too far from goal, the lack of velocity of this shot will make it relatively easy for the goal keeper to block it. Therefore the push shot should only be attempted within the 2–m area (dependent on the player’s strength).

Players should be proficient in all of these shots so as when the situation arises to use any of the shots during a game they can be performed optimally with maximum velocity and accuracy. Therefore during practice coaches should include each of the three throws in reasonable proportions to ensure players improve the performance of these shots.

Acknowledgements

Thanks go to:

- Steve Knights (New Zealand School girls coach) and Jessica Milich (New Zealand School girls assistant coach) for their assistance and time.

- 2004 NZ School girls team for their time and effort.

References

Clarys, J. P., & Lewillie, L. (1970). The description of wrist and shoulder motion of different waterpolo shots using a simple light trace technique. In L. Lewillie & J. P. Clarys (Eds.), Biomechanics in swimming (pp. 249-256). Belgium: Universite Libre De Bruxelles.
Ball, K. (2004). The Shot described. Retrieved 28th May 2004, from www.coachesinfo.com
Davis, T., & Blanksby, B. A. (1977). Cinematographic analysis of the overhand water polo throw. Journal of sports medicine and physical fitness, 17(1), 5-16.
Elliott, B. C., & Armour, J. (1988). The penalty throw in water polo: a cinematographic analysis. Journal of sports sciences, 6(2), 103-114.
Feltner, M. E., & Taylor, G. (1997). Three-dimensional kinetics of the shoulder, elbow, and wrist during a penalty throw in water polo. Journal of applied biomechanics, 13(3), 347-372.
Kreighbaum, E., & Barthels, K. M. (1996). Biomechanics: A qualitative approach for studying human movement (4th ed.). USA: Allyn & Bacon.
Whiting, W. C., Puffer, J. C., Finerman, G. A., Gregor, R. J., & Maletis, G. B. (1984). Three-dimensional cinematographic analysis of water polo throwing in elite performers. American journal of sports medicine, 13(2), 95-98.

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