How can a goal shooter improve their shooting accuracy through biomechanical principles?

Biomechanical principles of the netball shot are the basis of this blog and how they can help improve a player’s accuracy and technique. This being important to understand as stated by Steele (1993, p.3) ‘ shooters shoot goals and goals win games’ so by applying the skill cues and biomechanics to drills and games, individuals can become more effective and accurate at performing the netball goal shot or teaching it.

Biomechanics is the study of all living organisms and factors that act on these bodies. It looks at both the internal and external factors that can act upon the body and by understanding these concepts it become clear how the body parts all work together and create different types of motion. The study of biomechanics also allows for the correction of technical error, a decrease in injuries and a better understanding of equipment, knowing all of this can allow a person the best chance at being the best they can be at movement pattern and execution (Wilson, Hodgson & McNaughton,2011, p.278)

In the netball shot there are 3 phases of movement. The preparation phase, the release phase and follow through, all of these phases have certain skill cues and biomechanical principles that relate to them and need to be understood and carried out in order to be the best player possible.

What in the preparation phase can help accuracy of shooters?

The preparation phase is the most important phase as more than half the time in possession of the ball is taken in becoming balanced and concentrating before then performing the action of a netball shot.

Balance and Stability

Center of gravity  - (Hede, Russell & Weatherby, 2011, p.80). 

Balance and stability is the major factor of this stage and will increase accuracy amongst players and improve technique. Balance is all about having the centre of gravity over the base support of an individual to ensure the best stability. The centre of gravity as Blazevich (2010) states is ‘the point around which all the particles of the body are evenly distributed and therefore the point at which we could place a single weight’, which can be hard to identify during sport.

As a netball goalie having your legs shoulder width apart allows for optimum support as this creates a very wide and sturdy base support in which the centre of gravity will be located over, creating increased stability. Along with maintaining minimal trunk and head movement throughout the shooting action, there will be a very solid structure and this will mean the execution of the shot will be as accurate as possible (Steele, 1993, p.14).

Landing

The landing of a shooter after receiving the ball is also another significant movement in the preparation phase. Landing with an upright trunk and flexed knees enhances the stability by ensuring the centre of gravity remains within the limits of the player’s base of support (Steele & Milburn, 1987, p.25). The landing process will also be the beginning of the summation of forces and kinetic chain as Newton’s 3^rd law of motion comes into play.

The 3^rd law states that ‘for every action, there is an equal or opposite reaction’. This reaction of force always happens in pairs, but that’s not to say that the force exerted on each body is the same (Hede, Russell & Weatherby, 2011, p.77).  A vertical downward force is applied when a player is landing and the foot contacts the ground, the ground then exerts the equal and opposite reaction force and in doing so it means the foot doesn’t sink into the ground but the force penetrates back up through the players legs and begins the summation of forces (Wilson, Hodgson & McNaughton, 2011, p. 45).

Release phase and its impact:

The next phase in the netball shooting action is the release phase and it has many biomechanical principles that occur and therefore many aspects that can be improved to make the best shooters possible out of players.

Force

Force is a big aspect as it sets up and determines if the netball will make the distance of the shot and is defined as anything that causes or has the potential to cause the movement, diversion or slowing of the object on which it acts. In simple terms, a force can be a push, a pull, a blow, a collision, gravity or friction (Hede, Russell & Weatherby, 2011, p.85). It can also be internal such as from the muscles and bones or external such as from gravity and air resistance, but all force has 4 common properties.

The 4 common properties are: (Hede, Russell & Weatherby, 2011, p.85).

• Magnitude (the amount of force, or how much is applied)
• Direction (the angle at which the force is applied)
• A point of application (the specific point at which the force is applied)
• A line of action (represented by a straight line through the point of application in the direction that the force is acting)

Summation of forces

In terms of the netball shot force is described as a push-like movement pattern though as all the joints are extended simultaneously in an open kinetic chain in a single fluid like movement. The force in netball penetrates up through the legs, trunk, shoulders, hand and wrist to produce the kinetic energy needed; this is known as the summation of forces. This allows for the highest accuracy and highest levels of force production to be achieved (Blazevich, 2010, p.197).

This movement relates to Newtons 2^nd law of motion; the law of mass, force and acceleration, which is when ‘the acceleration of an object is directly proportional to the net force acting on it and is inversely proportional to the mass of the object’ (Blazevich, 2010, p. 45). Newton’s second law would say that the greater the mass of a netball, the more force that must act upon it. The force that must be applied to the netball when shooting for a goal is dependent on the distance in which the ball must travel. More force will move the ball further and the force is generated by the flexion and extension of the knees and elbows and in the kinetic chain. The push-like movement will determine the direction of the force applied to the netball, depending on where the player is shooting from to whether they need more vertical or horizontal force (Blazevich, 2010, p.197).

The Magnus Effect and Backspin

Magnus Effect and backspin

The Magnus effect occurs when a spinning object is moving through air or water and can affect the projectile motion. According to the Magnus effect, if you put spin on the ball, where the top of the ball spins over the bottom of the ball, the air on top would slow down and the air underneath would move relatively quicker (Blazevich, 2012). In a netball shot though a player wants to apply backspin and have the opposite occur, which happens by the flick of the wrist and fingers. The amount of spin applied should be between 1 to 1.5 revolutions from the point of release to the entry through the goal ring. In a study done by Elliott and Smith (1983), it was found that backspin improved accuracy of the shot as it maintained the flight direction of the ball better; it also reduced the velocity (speed) of the ball, but gave it a better chance of going through the net rather than bouncing off the rim (steele,1993, p.15). Wrist flexibility can be modified through training exercises to make this process easier and more subconscious.

Distance from post

The distance a player shoots from the post is a big influencing factor which can have a major effect on the other mechanics of the netball shot. Each player has their own individual preference about where they like to shoot from in the goal ring, but the optimal distance to shoot stated by Elliot and Smith (1983, p. 180) is between 3  to 5 ft. (0.9m to 1.5m) away from the post. Reasons behind why players might shoot from outside this distance is because of the defensive pressure. They may need to step backwards to have more space to perform the shot or don’t have any other options of passing so need to attempt at scoring.

When shooting from a further distance though the mechanics of their shot will need to be altered as well. For example if shooting from 3-5 metres away from the goal post:

• More force will need to be applied on the object (netball) (magnitude increases)
•  The angle of release will need to be increased, therefore the height of the projectile will also be increased (direction and point of application changes)
• Deeper flexion of knees and elbows will need to occur in order to produce a greater force
•  More time for external factors to act upon and influence flight of the netball

 All of these factors will influence the accuracy of the shot and will potentially decrease how successful a player is, but if a player can master shooting from various distances from the goal post then it will make them a more versatile player and allow them to have a greater impact on the game as the defender won’t have as much of an impact

Follow through phase and its important factors:

These factors are what is happening last in the netball shooting action and therefore is the last opportunity to increase a player’s accuracy and have all aspects working together to perform the best shot possible.

Projectile motion

The ball release is a very important aspect of the netball shot and needs to be addressed with great care and knowledge. The netball needs to be released at the highest point when the whole body is extended and also at the optimal angle which Steele (1993, p. 15) states is 60˚ to allow for the flight path to be accurate and successful. Once the ball is released it is known as the projectile and all of this affects the projectile motion (Blazevich, 2010, p.25). The projectile follows a predetermined parabolic path affected only by gravity and air resistance and this is why the lead up elements of the netball shot are vitally important and need to be executed to the highest degree for success (Wilson, Hodgson, McNaughton, 2011, p. 282).  

Impulse and momentum:

When a netball shooter finishes their shot, they usually finish up on their toes, which then leads into the movement to get a rebound if needed. There are propulsive impulses that help in order to move from being stationary to being on their toes accelerating towards the goal ring in order to get rebounds. Propulsion is the force that drives an object forward and results when pushing against a solid object in this case the ground, which then ties back in with newton’s 3^rd law.

Movement phases:

Sequence of shooting and relevant skill cues:

Preparation Phase

•   Land with two feet
•    Body facing the ring square on
•    Balanced position with legs shoulder width apart and looking at the centre of the ring

Release Phase

•  Slightly bend knees and elbows (flexion)
•   Push up (extension) of knees and elbows
•   flick of wrist on release

Follow through

• Release the ball at the highest point.
• Get ready for rebound by following ball to ring with arms up and bouncing on toes

How else we can use this information:

So as this blog shows there are many factors to consider when performing a netball shot in the limited time of 3 seconds and so in order to be as successful and accurate as possible, all these biomechanical principles need to be taken into account, learnt and practiced.

These aspects identified throughout the netball shot can also be transferred to other ball sports that have similar actions such as basketball, but most importantly all sports have biomechanical principles to identify and analyse it’s just about recognising them.

Through a biomechanical analysis, any skill of any sport/game can be examined and interpreted through scientific principles to get the best outcome and movement patterns. The information gathered through this analysis can provide coaches, teachers and players the necessary background information to teach the basics to junior players and then advance and refine the techniques of experienced players. This will allow players to achieve optimal results, while also reducing the potential for injuries (Steele, 1993, p. 17). Some aspects of technique can vary due to individual preference, but the majority of biomechanical principles are unchangeable and therefore vitally important to comprehend in order to become better as a coach, teacher or player. 

Here is a video that explains the netball shot and shows the technique https://www.youtube.com/watch?v=N20vo_pXNnU

References:

Blazevich, A. J. (2010). Sports Biomechanics: The basics optimising human performance (2nd ed.). London A&C Black.

Elliott, B. and Smith, J. (1983). The relationship of selected biomechanics and anthropometric measures to accuracy in netball shooting. Journal of Human Movement Studies, 9, 171-187.

Hede, C., Russell, K., & Weatherby, R. (2011). Chapter 3: Applying Biomechanics to Sport, In PE: Senior Physical Education for Queensland (pp. 72-119). Melbourne, Victoria: Oxford University Press.

Steele, J (1993). Biomechanical factors affecting performance in netball. National Sports Research Centre, Australian Sports Commission, Belconnen, A.C.T.

Steele, J.R., & Milburn, P.D.( 1987). A kinematic analysis of netball landing techniques. Australian Journal of Science and Medicine in Sport, 19(2): 23-27.

Wilson, A., Hodgson, C., & McNaughton, N. (2011). Physical Education: SACE workbook (2nd ed.): Adelaide Tuition Centre.