Notational Analysis - D1

D1 – Notational Analysis

Performing a notational analysis allowed me to identify strengths and areas for improvement for the athlete. These components can have both positive and negative effects on performance.

For example, Passing was a component of performance at which I looked at whilst performing a notational analysis as I felt this was a vital component to netball. As the players are unable to move with the ball, passing is the main mechanism to move the ball around the court in order to create shooting opportunities. Across 2 games, my athlete had an average pass completion 92%. This indicates that it was a component of the athlete’s performance which was already very strong and needed to be maintained in order to perform well and succeed in sport.

A high pass completion rate means that the athlete and their team is able to retain possession of the ball and in effect are able to produce more attacking opportunities. This also has an effect on the opposition as if they do not have possession of the ball it reduces the chances in which the opposition are able to score points. Passes which are not completed may usually result in the opposition obtaining possession and being able to score. If the athlete and their team is able to retain passion by completing passes they increase their chances of being successful on competition as they are likely to score more points than their opponents. “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”- Threadgold, A (2015). This statement suggests that when we understand the principles of passing and if we make passes successful it means that results in competition can be improved, therefore influencing how successful the athlete can be.

“Passing is fundamental to netball: The core fundamental skill of a chosen sport must be practiced constantly. In road racing (cycling) it is spinning the pedals and in netball it is passing” is a statement made by ILoveNetball, Australia which supports my statements on the importance of passing in order to be successful in netball. Therefore, the athlete needs to maintain the high pass completion percentage in order to be successful in netball.

A second component of netball which is almost as important, is catching. Passes cannot be considered complete if they are not caught by the receiving player. The athlete had an average catch percentage of 87% over the time I spent analysing her. Although it was not as high as the pass completion, it was still high enough to be considered a strength.  Online Coaching Manual, Net Set Go, suggest that “Catching is one of the most important skills in netball, you need to get the technique correct and then have lots of practise."- Net Set Go (2013). This evidence says that catching is fundamental to the success of a netball player. Catching the ball, in a similar way to passing, means that the athlete and their team are able to retain possession of the ball for longer periods of time which reduces how often the opposition are able to create shooting and scoring opportunities. As a result, it increases how prosperous the athlete is able to be within their sport as they increase the likelihood of winning competitions.

As my athlete plays as a Goal Shooter (GS), I chose to look at shooting as a component of her performance. My reasoning for this was that shooting and scoring is the main responsibility of the GS in a netball team as they are one of only two players who are allowed in the scoring zone.

The athlete had a very high successful shooting percentage, 81%, across a number of performances. To me, this suggests that her shooting is very strong and successful, but she would gave to maintain this to ensure it does not drop any lower as this could be detrimental to performance. If her shooting percentage was to drop any lower, it would decrease her chances of being successful in competition. This is because, if the opponents shooting percentage excels my athlete, it is likely that the opposition are going to be able to score my points, resulting in a loss for their team. "In Netball, shooting is arguably the most important aspect of the game. Without it, all netball games would end as 0-0 ties, so let’s agree that it is, to some degree, essential to the functioning of the sport" - Netball Fun (2016). Therefore, it is important for the athlete to have a high successful shooting percentage in order to be successful in competition. More importantly, they need to have a higher successful shooting percentage than their opponent in order to increase their chances of winning each game.

Finally, I looked at rebounding as a component of netball. Rebounding usually occurs after a shot has been unsuccessful and the ball comes back into play. Both the offensive and defensive team attempt to try and rebound the ball. For a GS, it’s important to make offensive rebounds as it prevents the opposition from gaining possession of the ball. If they miss a shot, rebounding the ball will give the shooters a second chance to try and score. This increases the chances of the player scoring more points and therefore winning the game. Preventing the opposition from gaining possession reduces the opponent’s chances of being able to form attacking opportunities.

Coaching Manual, Sport Plan, also suggest that rebounding is an important component for netball which can be either detrimental or enhancing toward to athlete’s performance. “how they react to a rebounded shot might mean the difference between scoring or conceding a goal" - SportPlan (2016).

My athlete had a very low rebound rate, only 29% on average. Therefore, the athlete needs to improve this component of their performance in order to increase their chances of being successful. If this rebound rate remains low, it means that the athlete and their team are at risk of conceding additional points and then each game becomes more difficult to win. 

Numerical Model - Methodology

Numerical Model – Methodology

In order to carry out my Numerical Analysis, I had to use 2D Video Analysis in order to assess the angles and distances which were relevant to my athlete’s skill, in this case, a netball shot. The main software I used in order to carry out this analysis was Kinovea which allows me to measure angles and distances of joints, release heights and the athlete’s height. However, to be able to use Kinovea in this way, a number of steps must be taken first in order to correctly prepare the video footage for importing into the software to be analysed. Other precautions must be taken to prevent errors which could affect the reliability of my data analysis.

The stages of 2D Video Analysis can be displayed in the following flow chart:

Once the video has been imported into Kinovea, I merged the scale video and the ‘skill’ video on top of one another so that I could create a 1m scale in Kinovea. This allows me to create lines and angles on the video and the programme will provide me with a ‘real life’ measurement.

It’s also important that the video recording takes place in front of a plain background with no additional lighting. This is so that the anatomical markers are clearly visible once the video has been imported into Kinovea. This makes measuring joint angles and body distances much clearer and prevents the occurrence of errors.

Scaling is an important step when performing 2D Video Analysis as it prevents perspective and parallax errors occurring which could hinder the reliability of my results. Without scaling, displacements would be measured in ‘pixels’ by the programme and not measured in M and Cm which we require. This also makes the comparison of subjects much easier if they are measured by the same unit.

Once the scale has been set, it’s important not to move the frame of capture away from this point as we risk perspective error. Perspective error results in subjects appearing larger or smaller than they actually are. Using a scaling factor means that we can obtain realistic measurements (i.e 1.2m) rather than the 2-3 cm that it may appear as on the screen. If we move the frame of capture away from the location in which the scale was created, when the video is imported into Kinovea the 1m scale will not actually be 1m in ‘real life’. As a result, our analysis cannot be considered valid or reliable and its makes the feedback we can provide in-effective.

Technical Model

Technical Model (P3)

A Technical Model uses qualitative information to analyse and compare performance to the ‘ideal’ model in order to produce strengths and areas for improvement for the athlete. This model can be used to identify differences between how we believe the skill should be performed in order to achieve maximum proficiency and how the athlete is actually performing the skill. Technical analysis is more descriptive than the other methods and looks at ‘form’ and technique, rather than speed, angles or distances. This method is described as ‘subjective’ as it is based on opinion and there is no statistical data to support this.

Balance

The term ‘balance’ is defined as “an even distribution of weight enabling someone or something to remain upright and steady”. Balance is key in a wide variety of sports, if not all of them, but in this instance balance can be applied to the netball shot in order to make the skill effective.

If the athlete is unbalanced when taking a netball shot, it can cause them to stumble or fall away from the line they are attempting to shoot, causing the shot to loose accuracy. For this reason, balance is important factor to the shot to ensure that the ball follows its intended path into the net.

In this frame, we can observe that the athlete appears to be well balanced. Her body is upright and the extremities and limbs are distributed evenly which means that her weight is dispersed in a way which created an equilibrium, therefore balancing the athlete. Balanced is achieved by keeping the centre of mass, or gravity, low. The athlete achieved this by bending her knees and resultantly her centre of gravity is lowered. By keeping her spine perpendicular to the ground, it means that the centre of mass remains in a position in line with the centre of the body, therefore maintaining balance.

This still image show Helen Housby, England and Manchester GA, taking similar shot to the one in which I had analysed my own athlete. From this, I can gather that my athlete maintains a similar body position to the elite model whilst shooting in order to maintain balance. Housby maintains a similar body and spine shape to my athlete which allows her centre of mass to be in a position which assists with the maintenance of balance whilst shooting.

Grip

It’s important for the athlete to maintain a strong, firm, hold on the ball when shooting. In other words, a good grip will mean that the athlete will not be at risk of dropping the ball or shooting the ball in a way which is unsuccessful. The advised way to grip the ball when shooting is to hold underneath the ball with one hand, whilst the other hand supports the ball to prevent it from falling from the shooting hand.

Supporting evidence from TeachPE.com states that: “Ball held by dominant hand and high above the head. Fingers point back and are slightly open, ball sits in your hand” and that “second hand is placed at the side of the ball to steady its position” - TeachPE (2016). I can use this model in order to compare to and analyse my athlete’s technique when shooting in order to produce information on her strengths and areas for improvement.

During the preparation stage of my athletes shot, they appear to be holding the ball with their fingertips on either side of the ball, in contrast to the suggested technique. This means that the athlete is at risk of the ball tipping or falling in a way which means the shot will not travel along its intended path, into the net. She is at risk of dropping or ‘spilling’ the ball by gripping it in this way and that may result in the opponents obtaining possession and being able to start their own attack. So, this is an area of the athlete’s technique in which they could look to adjust and improve.

Stance

The description of the ideal netball shot from TeachPE.com suggests that stance is an important part of the shot being taken correctly. They say that “Feet should be in a comfortable forward facing position, not too far apart” and that “a balanced position, with equal weight on both feet and hips facing the front” should be taken TeachPe.com(2016). This stance links back to my earlier points which addressed the athletes balance when taking a shot. A perfect stance will mean that the athlete will remain balanced whilst taking the shot which increases the chances of the shot being successful.

 

This frame shows the stance of my athlete whilst they are preparing to take the shot. The feet appear to be an ideal distance a part which provides stability and balance, therefore this makes this part of the stance an area of strength for the athlete. However, the athlete’s heels are slightly raised off of the floor which suggests that she is baring most of her weight through the balls of her feet and her toes. In effect, it means that the athlete is leaning slightly forward during the shot which means that she is at risk of becoming off balance and toppling or falling whilst taking the shot and therefore reducing the chance of the shot being successful.

Body Position

The positioning of the athletes body is very important to the skill itself as it will determine where the ball takes flight and where the ball finishes. If the athlete positioned in a way which doesn’t line up with the net, it may result in the ball taking flight to a tangent away from its intended target, which in effect reduces the level of performance in which the athlete is able to achieve. So, for the shot to be successful the athlete’s body needs to be positioned directly facing the net with the shoulders, hips and feet all running parallel to one another. Any rotation at the hips could mean that the shot will not be executed in a straight line which reduces the chances of the shot being successful.

“Stand with your feet shoulder width apart and keep your body straight.” BBC Sport (2005) this is the recommendation of BBC Sport when it comes to the technique and body position of an athlete when shooting. This statement supports my point about how the athlete should be positioned when shooting in netball. As a result, I can compare these points to the actual technique of my athlete.

 

As the frame shows, my athlete has positioned her body in a way which is aligned and facing toward the netball post. Although her knees are bent as she is in the preparation stage of the shot, her shoulders and hips and feet all align to allow the body to be directly upright in order to take the shot. The correct technique being performed in this way means that the chances of the shot being successful are increased. 

Numerical Model

Numerical Model

The Netball Shot

The Numerical Model is a form of Quantitative Analysis in which we can use to analyse technique and sports performance. Analysing the biomechanics of a technique in this way means that we can advise the athlete to make small changes to their form in order to improve performance and maximise efficiency. 

Using analytic software allows us to record a technique and by using a scaling factor we can obtain information such as distances and angles of the technique. This data can then be used to edit and improve the overall performance. 

 I chose to analyse, Angle of Elbow, Angle of Release and Height of Release for the netball shot in which my athlete was performing. 

 I used video analysis software, Kinovea in order to analyse my athlete performing a netball shot. in the above frame we can see the height of the athlete (1.71m) and the angle of the elbow as she is set to take a shot (103 Degrees). 

As the athlete sets to take the shot, the angle at the elbow slightly opens up to 113 Degrees showing that she doesn't maintain her original body position once she bends her knees in order to take the shot. Steele (1993) suggests that the ball should be release from directly above the head in order to perform a successful shot when shooting from close to the basket. The angle of 113 degrees means that the ball is positioned directly above the head of the shooter, on this basis it would be fair to suggest the this stage of the shot is currently being performed correctly. 

In the next frame, when the ball is being released, we can see that the angle of release is 133 degrees during this shot. From this frame we can look at the projectile motion of the ball, projectile motion is the motion of an object (Blazevich, 2010), in this case it is the ball. Steele (1993) implies that the average entry angle for a ball successfully going through a ring is 43 degrees and that when a shooter is close to the goal the projectile motion is 90 degrees vertical and 0 degrees horizontal. On this basis we can see that the athlete needs to edit the angle of release to a smaller angle in order to increase her successful shooting ratio. When the ball enters the ring at an angle of 90 degrees it has a much greater opening for entry compared to entering the ring at an angle of 30 degrees. Hay (1993) suggests that an angle of entry of 90 degrees provides a margin for error of +-10.5 yet when the angle of entry is 32 degrees there is a 0.0 margin for error. 

From this final frame i am able to analyse the height of release for this particular netball shot. from the video analysis i can see that the shot is released from 2.02m away from the ground. Hay (1993( published a statement that jump shots can be released from heights as low as 2.5m and set shots even lower. Although this particular height of release is slightly below the recommended value it is very difficult for the athlete to control. In the frame we can see that the knees and elbow are fully extended and the athlete may struggle to be able to release the ball any higher as in the first frame we see that she is only 1.71m in height."Release height can be influenced and improved by extension at the knees and at the elbow of the shooting arm" -  (Steele, 1993).  This evidence from Biomechnical Factors affecting Performance in Netball reinforces my point about the athlete being able to release the ball at a point any higher than is illustrated in the above frame as she has already fully extended the knees and legs. As a result, it would be difficult to suggest any coaching points in order to improve this section of the shooting sequence. 

References

  Blazevich, A. (2010). Sports biomechanics the basics: Optimising human performance. Bloomsbury: Black Publishing. 

Steele, J. ( 1993). Biomechanical factors affecting performance in netball. Department of Biomedical Science. 3, 1-18.

Hay, J (1993). The Biomechanics of Sports Techniques. USA: Prentice-Hall. 225-250.