How can choosing the correct pass in netball improve the effectiveness and accuracy of a game?

Introduction

Biomechanics is a sports science field that integrates the biological and mechanical principles of an activity for the purpose of improving human movement (Knudson, 2007). Understanding the biomechanical concepts of a skill is essential to improving the overall performance of that specific skill, this is done through modeling, stimulation and measurement (Topend Sports Network, 2013).

Passing a netball down a court using a variety of throws from one player to another appears to be a simple process that only requires speed, accuracy and distance. However, this ‘simple’ skill is very far from simple. The effectiveness and accuracy of passing in netball is essential for the success of the entire team. This blog examines the principles behind four of the fundamental passes in netball including the chest pass, the single arm shoulder pass, the double handed over head lob pass and the bounce pass. The purpose of this blog is to determine how understanding the biomechanical principles and skill progressions behind the different passes in netball can allow a player to improve their effectiveness and accuracy of passing within a game.

NETBALL PASSES: The biomechanical principles

Chest Pass

To execute a successful chest pass in netball, all of the joints in our kinetic chain extend simultaneously in a single movement (Blazevich, 2010).  There are two important benefits of this movement pattern. The first one is because the joints are acting simultaneously, the cumulative forces (or torques) generated about each joint result in a high overall force (Blazevich, 2010). The second important benefit is that simultaneous joint rotation often results in a straight-line movement at the end point of the chain (i.e. the hands), making the movement highly accurate (Blazevich, 2010). A chest past is generally used to cover small distances in a netball game. This is because the push-like pattern of the pass has a slow movement speed, therefore the speed of the pass movement is restricted by the shortening of our muscles (Blazevich, 2010), as seen in figure 1. However, if a step forward is taken when initiating the pass it will contribute to forward velocity and increase the momentum in the upper body and arms, meaning the ball will move at a higher force and more accurately, also shown in figure 1. This pass requires a two handed forward symmetrical execution to optimize accuracy and efficiency of the ball. Having two hands also means that the fingers can be spread apart around the ball, which helps in steering the direction of the chest pass (Russo & Izzo, 2011). For these reasons and contributing biomechanical factors, the chest pass is one of the most commonly used movements in a netball game, usually used to cover small and accurate distances as there is a relatively small force required for execution.

Figure 1: The push-like pattern of the chest pass, showing how the movement provides high levels of accuracy and efficiency (Image: Blazevich, 2010).

Single Arm Shoulder Pass

In netball, the shoulder pass is often a flat, hard pass covering large distances on the court. The shoulder pass is thrown using one hand (the hand behind the ball), however, it is controlled with two hands in the motion that brings the ball up to shoulder level. The key of this pass is to have it leave straight from your shoulder into the receiver’s hands. To perform this pass, the joints in the kinetic chain are required to extend sequentially one after the other, as shown in figure 2 and 3 (Blazevich, 2010). This is the differentiation from the chest pass, which requires a push like simultaneous movement. The shoulder pass requires momentum to be generated through the movement phases in order for it to be a successful and accurate pass. This pass beings with a ‘wind-up’ phase that entails the shoulder starting to extend, whilst the elbow gets drawn backwards while flexing. While this sequence is continuing, there is an increase in the extension velocity of the hand and fingers, resulting in a highball velocity. At the end of the sequence there is a flick movement of the wrist and fingers (seen in figure 3), which contributes to the speed at which the ball is released. While this sequence of movements is being performed, it is helping to generate momentum that is then transferred through the production of large muscle forces. Throwing a ball in this way results in what is called ‘angular momentum’.  A shoulder pass is usually used for covering distances during a netball game. This is because the throw-like movement pattern is efficient in gaining distance and as a result, uses tissues that have the fastest shortening speeds, the tendons (Blazevich, 2010). A tendon has high kinetic energy and stores elastic potential energy, thus when it is released it recoils very quickly at a high speed. Hence, why the shoulder pass (overarm throw) is used so often in a netball game to cover larger distances (Blazevich, 2010). This type of pass will have more power if a step forward is taken with the opposite foot to the hand holding the ball (International Netball, n.d.). The follow through from the whole arm down to the fingertips is a must to ensure a strong completed shoulder pass. However, as the distance the ball needs to be thrown increases, the accuracy of the throw decreases. Luckily this is not an issue for the single arm shoulder pass, as the end points of the kinetic chain (the hand and ball) follow a curved direction and the high speed and power generated through the ball still allow the pass to be very effective for a longer distances (Blazevich, 2010). Another way to improve the accuracy of this pass is to flatten the arc of the throw by rotating the hips (Hede, Russell & Weatherby, 2011).

Figure 2: The sequential pattern of the single arm shoulder pass (Image: Blazevich, 2010).

Figure 3: The movement phase begins with shoulder and hip rotation, elbow acceleration, wrist acceleration and finally finger and ball acceleration (Image: Blazevich, 2010).

Double-handed overhead ‘lob pass’

The double-handed overhead lob pass requires the back to be slightly arched, the arms to be lifted and extended and the elbows to be bent allowing the ball to be placed in the hands just behind the head, as shown in figure 4. This type of pass is not commonly used during a netball game. The ‘lob pass’ requires a significant amount of force to be applied to be able to offload the ball through the tension in the back and arms. The final movement phase of this pass concludes with a fast outward movement that comes from the thumbs and fingers to help propel the ball forward to the desired destination (Russo & Isso, 2011). When performing this skill, the force used to pass the ball will be more direct, greater and more accurate if the player takes a step forward as they release the ball (seen in figure 4). This is because having a wider stance increases the base of support and therefore, the stability of the player is also increased. Stepping forward while releasing the ball will also generate some forward velocity and an increased momentum in the upper body and the arms, hence the increase in force and accuracy. The end point of the kinetic chain for this pass would be the hand and the ball; this could potentially result in the ball following a slightly curved arc of motion. Although this pass still uses both hands and has the potential to generate a seemingly straight forward throw, there are more elements that can affect the overall performance of the pass, making it less accurate and effective than a chest pass (Blazevich, 2010). However, raising the arms for this throw will help to elevate the height of the pass and could be used as an advantage to clear the height or arms of an opponent. 

Figure 4: the extension of the arms above the head in preparation to release the ball for a lob pass (Image:  http://avcssbasketball.com/content/images/BasicPassing/overheadpassstick.jpg). 

Bounce Pass

A bounce pass is a low pass that is used over short distances, generally executed to feed into the shooting semi circles. This pass requires a low release, pushing the ball towards the receiver. The bounce pass entails the flexion and extension of the arms and elbows in order for it to be performed correctly. Newton’s Third Law of Motion states that “for every action there is an equal and opposite reaction” (Introduction to sports biomechanics, n.d.). This is put into practice in relation to the bounce pass. An action force is exerted onto the ball in a downward direction and whilst this is occurring the ball exerts a reaction force in an upright direction felt by a very slight increase in pressure on the fingers of the player, as shown in figure 5. A bounce pass means that the ball is travelling in a downward motion before making contact with the court. The court then exerts an upward reacting force back onto the ball causing it to bounce up and into the hands of the receiving player.

Figure 5: Newton's Third Law of Motion being executed through the biomechanical movments of the bounce pass (Image: https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhId3yix0fOHi7562tklLh64m-3ACX8HzaNrZ6vCxGzlFg6Q7LQIupvHu6nEO_EmNly3FWFWm9XcWc1Eo-YG8GmPbEKFtjoJYyDi1f9UCvsYStN9N8vp54F6-2UVj3ISSspd0CTyM3krpgJ/s1600/Bounce+Pass+vs+Chest+Pass.jpg).

The Answer

How can a netballer improve the effectiveness and accuracy of play through passing?”
To answer this question, it is important to understand the biomechanical principles and the movement phases behind the four different skilled passes that are used in netball. Before deciding on a type of pass to execute, the player will need to be aware of the desired outcomes from the pass and then select the best option. When deciding on a pass the player must take into consideration how far does the ball need to travel to the desired destination, where are the players in the team in relation to the players from the opposing team. The rules of the game will also need to considered, sometimes these can provide limitations for certain passes, such as the ball cannot be thrown longer than a third of the length of the netball court at one time (Steele, 1993). As you can see, there is a lot to consider when choosing what type of pass to perform during a netball game. If a player can understand the biomechanics of each type of pass they will be able to determine whether a chest pass, shoulder pass, two handed lob pass or a bounce pass is the best option for a particular play and to achieve effectiveness and accuracy of the ball.

This research has concluded that a chest pass is best used for accuracy and to produce power over shorter distances. This type of pass also reduces the risk of interception from the opposing team but will still satisfy the passing team to swiftly move the ball down the court towards the goal. A single arm shoulder pass is less accurate than the chest pass and has a higher chance of being intercepted. This pass is more effective when used to cover longer distances than the chest pass.  A double-handed overhead lob pass is usually used when the ball needs to be thrown with force and accuracy. This can be over shorter or longer distances and can be directed at a high height to try and clear opponents that may be in the path of the flight of the ball. A bounce pass, when used in correct circumstances, can make it a very efficient and accurate pass. They are used to maneuver the ball around defending players from the opposing team. Furthermore, all of these passes, in conjunction with stepping forward while executing the motion of the pass provides an increase in momentum and forward velocity. This is due to the greater power and forward movement of the body (Steele, 1993).
There are other biomechanical areas that this study has not delved into that could effect and determine the result of each of these passes. For example, the speed and angle at which a ball travels through the air may be influenced by the effect of gravity on the ball as it travels through distances and the rotation of the player’s hips will have an affect on the balls trajectory (Blazevich, 2010). These factors are evidence that further research into this area is needed in order to gain a greater understanding of these principles and how they can be integrated to netball.

How else can we use this information?When a thorough understanding of the biomechanical principles of the main passes used in netball is gained, it can help to improve the results in a game scenario. Having the knowledge of these principles will also help in understanding the biomechanics in other sports, where similar movements are produced. 

A chest past adopts a push like movement pattern that can also be applied to other sports that require a high degree of accuracy and force generation. This pattern is replicated in dart throwers, where the kinetic chain nature of the movement allows for the dart to be released with force over a relatively short distance. As the dart is released it usually continues along a straight line, with a high level of accuracy at the end point. A javelin throw has the same biomechanical principles applied to the movement as the single arm shoulder pass. The aim of the javelin throw, much like the shoulder pass, is to cover as much distance as possible. Throwing a javelin requires a large amount of force and power to be able to throw effectively and successfully. Most javelin throwers will also incorporate a forward movement in the run up phase and rotate their bodies while executing the throwing movement, this helps to gain further distance, very similar to the forward step before the shoulder pass. The biomechanics of the double-handed overhead lob pass can be applied to a soccer ball being thrown in from the sidelines during a soccer game. The player throwing the ball in must throw the ball over the heads of the opposition to land on the ground at the feet of one of their teammates. Accuracy, power and correct execution of the skill are all essential elements for maintaining possession within the game. The bounce pass in netball is also very similar to the bounce pass that is demonstrated in basketball. This type of pass can be used in both sports to effectively maneuver the ball at a lower ground level around an opposing player. This skill also requires a step forward to exert a force onto the ball so it will touch the ground and bounce back up into the hands of a teammate.

Netball is a very popular sport around the world and being able to understand the biomechanical concepts behind this sport allows the players and coaches to improve not only their skills but also their overall performance. This blog has only focused on the most common four passes used within a game, however, there are many other elements that could be improved by examining the biomechanical principles. For example, improving the accuracy and effectiveness of goal shooting, footwork and landings through the different areas of the court and dodging around players to receive/release passes. Researching the biomechanical principles for all of this information could lead to improvement in all performance areas of the game and result in very educated and understanding athletes.

References 

Blazevich, A. (2010). Sports biomechanics the basics: Optimising human performance (2^nd ed.). A&C Black Publishers.

Hede, C., Russell, K., & Weatherby, R. ( 2011). Applying biomechanics to sport (3^rd ed). New York: University of Oxford

International Netball. (n.d.). Shoulder Pass – Basic Passing. Retrieved from  http://www.internationalnetball.com/shoulder_pass.html

Introduction to sports biomechanics. (n.d.). Movement Patterns - The essence of sports biomechanics. Retrieved

from http://cw.routledge.com/textbooks/9780415339940/downloads/sample.pdf  

Knusdon, D. ( 2007). Fundamentals of biomechanics: Department of Kinesiology. California Springer Publishing, 1-334.

Newell, K. (1986). Constraints on the development of coordination, In M.G. Wade and H.T.A. Whiting (Eds.), Motor development in children: Aspects of coordination and control (pp.341-360). Dordrecht, Netherlands: Martinus Nijhoff.

Russo, L., & Izzo, R.E. (2011). Analysis of Biomechanical Structure and Passing Techniques in Basketball, Timisoara physical Education and Rehabilitation Journal, 3(6), 41-45.

Steele, J. (1993). Biomechanical factors affecting performance in netball. Department of Biomedical Science. 3-17

Topend Sports Network. (2014). Biomechanics and Physics of Sport. Retrieved from http://www.topendsports.com/biomechanics/