Biomechanics

Notational analysis

I have chosen to focus my notational analysis on two games of Rugby 10s, on separate occasions. I analysed the performance of the scrum half and focused on three key components of their game, including breaking of laws, tackles, and passing.

Game 1:

Breaking of laws		Tackles		Passing
For	Against	Successful	Unsuccessful	Successful	Unsuccessful
2	1	5	2	9	1
66%	33%	71%	28%	90%	10%

Game 2:

Breaking of laws		Tackles		Passing
For	Against	Successful	Unsuccessful	Successful	Unsuccessful
0	1	4	0	13	1
0	100%	100%	0	92%	7%

 

This collection of data is quite similar for both matches, which is evident by the score line as they were both close wins. In the first game the player won two penalties and lost one, this means that they had a good understanding of the rules to be able to win them for their team. In comparison to the second game the player had a penalty awarded against them and didn’t win any, signifying that poor discipline occurred. During the Scotland vs Ireland game in the six nations match statistics show that players tend to give away no, or one penalty in a full 80-minute game, as the player I am analysing gave away a penalty in each 20 minute game, this is an aspect to develop as giving away penalties, allows the opposition to gain possession and gives them an opportunity to gain points. Another reason this is an area to develop is that this statistic is quite high and in rugby a player should aim to give away as little penalties as possible. This is backed up by iSports report on Rugby Penalties explained by the statement “It’s important to know which actions will result in penalties – mostly so they can be avoided as much as possible”. By reducing the number of penalties the player gives away within a game it allows their team more time with the ball and will be defending less, allowing them to have more opportunities to score. At a higher level a team would also take advantage of penalties and take it as a chance to penalty kick and gain three points, in some games, these penalty kicks can make the difference in the game outcome, so giving the opposition less chances to get points would benefit the team. Scotland’s win against Ireland in the 2017 six nations was won on penalty kicking success and is evident in their match report: “They found a way to win the game with two penalties during the final ten minutes”.

Tackles are important in rugby to prevent the attacking team from moving forwards and to allow the opportunity for the defence to turn the ball over. The tackle success rate was high for both occasions, but the success rate in the second game was better as 100% of tackles were made, compared to 71% in the first game. This means that no tackles were missed and that the player’s cover in defence was good and upfront tackles were made successfully. This is an area of strength for the player as during the six nations, Danny Care, who also plays scrum half has the tackling success rate of 83.3%, therefore having success rates of 71% and 100% are very good for a player not at elite level. Tackling is an important factor of rugby and stated by Gavin Hickie, 2013,“There is no doubt whatsoever that a big tackle can turn a game as much as a try. A well-timed big impact tackle can lift your whole team and shift the momentum of the game.” There is room for the analysed individual to improve as during the first game they made 9 successful tackles out of 11, and the two missed tackles could have created an opportunity for the opposition to score. If the player was able to make more successful tackles in the game it would prevent the opposition from making ground towards the try line and force them to make errors in the contact.

The final analysis was the player’s strongest area, their passing. In the first game 90% of the passes were successful, with only one not going to hand, and in the second game, 92% were successful, with again 1 not going to hand. In rugby, it is known that passing is an important skill for all positions to perform and is indicated in the report on passing that the ability of performing the skill often affects the outcome of the game. The report by Andy Howell, 2015, shows that passing success rate is influential on a team’s performance during the 2015 World Cup. New Zealand, the winners of the world cup, had 5 seconds between each pass, this means that a higher the number of passes were completed by a top team of the tournament. Therefore, indicating that if the player increases her passing success rate then her team has more opportunity to win games and progress.

Biomechanics resubmission

D1- Notational analysis

Conducting notational analysis on two games of rugby 10s is significant in identifying the strengths and weakness of an athlete and their team and highlights the effects of the skill on the overall performance. One of the components of the game that I analysed was penalties given or awarded, I chose this part of the game as turnover ball can create opportunities for a team to score tries or kick for points. During the first game the player won two penalties for their team and conceded one, this meant that they had a good understanding of the rules to be able to win them for their team. During the game for the athlete it would have allowed them to maintain a positive mindset as winning back penalties would increase the overall team morale and motivation levels. For the opposition, it would have been demotivating for them to have the ball turned over as a result of them breaking the laws of the game and having that area exploited by the athlete. Physically having a penalty awarded against them would have a negative effect on the opposition, as they would have to work hard to get onside so that the penalty is not moved down the pitch for players being offside.

However, during the second game the player had a penalty awarded against them and didn’t win any, signifying that poor discipline occurred, and that they were unable to win any penalties themselves. This could have been influenced by the team and players that the athlete was facing, because if they are a well drilled team they are unlikely to give penalties away. If the player conceded an unnecessary penalty than it would disrupt their game performance as they are likely to lose focus during the game as it could have been avoidable so will disrupt their concentration. The lost penalty could lead to tension within the team as they could be frustrated at the player, therefore may not trust them during the game to take an offload etc. When a penalty is given to the opposite team it will increase their motivation as it allows them to have more time with the ball and create a try scoring opportunity, they will also notice the athlete’s team drop their heads which will give them a positive mindset.

During the Clermont Auvergne vs Saracens during the European Rugby Champions Cup in 2017 the statistics show that neither scrum half conceded a penalty during the game and that only half the players conceded at least one penalty in a full 80 minutes game. As the player I am analysing gave away a penalty in each 20-minute game, this is another reason why it is an area for the athlete to develop, as it allows the opposition to gain possession and gives them an opportunity to gain points.

The second component of the game that I performed notational analysis on was tackling, this is an important element of the game as it is the only way to effectively bring down defenders and prevent them from breaking the line and gaining space. Within the first game the player had a good tackling success rate at 71%, this would help her during a game, because if she missed few tackles than she would be pleased with her performance and be able to maintain a positive mindset during the game, therefore would have a strong tactical ability. When she did miss some tackles, (2 out of 7) it could have had a drop in her performance as she would be disappointed with herself and may have lost motivation. Her success rate in tackling would have had a positive effect on her team physically and mentally. As she didn’t miss many tackles it would have meant her team didn’t have to do as much work on the pitch, so would have had enough energy to do what is required at their position. However, they would have had to make cover tackles when the athlete did miss her tackles, otherwise the opposition could have scored. When team players had to cover for the missed tackles they may have been frustrated that they had to work to cover up someone else’s mistakes, which could have decreased team cohesion. For the opposition, the success rate of the athlete’s tackles meant that it was hard for them to break the line as she made minimal mistakes, however when tackles were missed it allowed them to get an opportunity to score from a line break.

In the second game the athlete’s tackling rate was better as she didn’t miss any tackles and made four, making her tackling percentage rate 100%. Having a high success rate in the game would have enabled the athlete to maintain a good mindset as she would have been confident in her ability to make tackles on the opposition, even the bigger players. Her teammates would have trusted her more during this game if they noticed that she didn’t miss a tackle and would have backed her in 1v1 situations. Physically her team would have benefitted, because they would have not had to cover for any missed tackles or have to work harder than required because the tackle would have been made at the first opportunity. Mentally a big hit can have a positive effect on the team’s morale as it keeps them aroused for the game, as stated by Gavin Hickie, 2013,“There is no doubt whatsoever that a big tackle can turn a game as much as a try. A well-timed big impact tackle can lift your whole team and shift the momentum of the game.” The opposition would have found it harder to break through the defensive line if the athlete had a 100% tackling rate, because they would have to work to make breaks on the outside rather than through the middle of the pitch if the team was strong in defence. Physically it would have been hard for the opposition as they would have had to take the contact more rather have time running with the ball so would have felt more fatigued and disheartened.

In the Aviva Premiership final, scrum half Dan Robson for Wasps also had a 100% success rate, but the scrum half for Exeter Chiefs, Townsend only had a success rate of 40%. This shows that for her position the player’s cover in defence was good and upfront tackles were made successfully and it is an area of strength in comparison to elite athletes at the top of the Premiership.

The final component that I analysed was passing, this is an important element of the game as it is the easiest way to get the ball into space and to exploit the opposition to allow try scoring opportunities to be used. New Zealand who are rankest as the current best team in the world highlight this, as during the 2015 World cup they completed the most passing out of all the other teams and performed passes with the least time between them at an average of 6 seconds, this is suggested by Andy Howell, 2015.

In the first game the success rate of the passes was 90%, this was similar to the second game at 92%, with only one pass not going to hand in each of the games. For a player to have a high success rate with their passing during their game they will maintain a good performance, because it means they would have not made as many mistakes. Mentally they would remain focused as with good passes they would have confidence in their handling abilities and their head wouldn’t drop and have negative thoughts. Tactically if her passes were successful it would allow her to exploit any opportunities to score and use the space effectively by moving the ball. The team would benefit from the athlete’s high passing success rate because it would mean they trust the player to perform long passes and get teammates into space, therefore they would stand further away from the athlete to receive the ball, which would move the defenders and create space on the pitch for other players. For the opposition if the athlete has a high success rate of passing it would be difficult to defend against as they would have to work harder to track down the ball and close down the space quickly without feeling fatigued.

Having a success rate of 90% and 92% over two games makes passing a strength of the player, as Ruck.com state that “A passing completion rate of 80% or more is generally considered a good statistic for any elite player”.

Numerical analysis

Athlete's angular displacement-

First angle= 57 degrees

Angle at contact=142 degrees

=85 degrees                       = 1.48353 radians

Athlete's angular velocity of ankle/toe-

=85/0.07 seconds

=1,214.28571 degrees/second                                   = 21.19 radians/second

Athlete's ball velocity

0.58/0.03= 19.3m/s

Elite model's angular displacement

First angle= 85

Angle at contact= 142

Angular displacement=57                             = 0.994838 radians

Elite model's angular velocity of knee/toe

=57/0.055

=1036.36 degrees/second                           =18.09 radian/second

Elite model's ball velocity

=0.7/0.03

=23.3m/s

Angular displacement is the angle through which an object moves on a circular path, in this instance it is the difference between the starting angle when the kicker draws back their leg at the knee, and the angle when the foot contacts the ball. Within a place kick the larger the angular displacement generally creates more power, as more force can be built up before making contact on the ball. As shown in the graph above, the athlete achieved a greater angular displacement then the elite athlete, with a difference of 0.489 radians, or 28 degrees. This makes the angular displacement of the athlete a strength within place kicking, as it is at a similar level to an international player. The impact of angular displacement is that it can increase the distance reached in a kick, increasing success rate, and means that the team could be awarded the points if the kick outcome is successful.

The angular velocity is also a strength of the fist athlete as it is bigger than the elite athlete. Angular velocity is the rate of change of angular position of a rotating body. It means that the faster the rate of change, the faster the leg moves from one angle to another. The individual’s angular velocity of the knee joint was 21.19 radians/second, whereas the elite athlete moved at 18.09 radians/second. Angular velocity could influence the success of the kick and as stated by Kellis et al “Powerful kicks are achieved through a high foot velocity”. Angular velocity can impact the game as with a better angular velocity the kick will be more powerful and direct, resulting in more positive outcomes.

Ball velocity is the time taken for the ball to move from one point to another. In the place kick, the elite athlete achieved a better ball velocity then the athlete showing that the ball had more power for its flight. This could be impacted by various factors, other than angular displacement and angular velocity, which could be why the individual did not reach a similar velocity result. The athlete’s ball velocity in the kick was 19.3m/s, whereas the elite athletes was 23.3m/s. This result is significant to analysing the kick as there was a 4m/s difference, which means that Emily Scarratt’s kick had more power. This could be influenced by the athlete themselves, as muscular strength and location of ball contact are all decided by the kicker themselves. Whereas there are also factors to consider such as wind direction that could change the ball velocity. Having a larger ball velocity means that when taking place kicks for penalties and conversions, the player can reach a further distance and the ball won’t be affected by wind as much, meaning that their success rate will increase and their team can get the points, which may be the deciding factor on the outcome of the game.

Technical analysis

Planting of standing foot

The planting of the standing foot is important when taking a kick as it influences the contact made on the ball. The location of the planting foot could be the deciding factor on a successful kick, if the foot is too close to the ball then it can make the player unbalanced as they would have a narrow base. Whereas if the foot is further away from the ball then the kicker would not make good contact and should stretch to reach the ball, meaning that they cannot put their weight through the kick. The ‘Place kicking in rugby’ report suggest that the non-kicking foot should be roughly one foot from the ball, and the toes should be pointed towards the post. Scotland’s and Harlequins fullback Ruaridh Jackson states that “Your planting foot should just lift off the floor easily and you should be able to move forward right away. If you come in too hard and plant your foot, you’ll get stuck on the ball and that’s when you lose power and accuracy”. The player above has her foot a good distance away from the ball, although better contact would be made if it was a little closer, as that would be were her feet would naturally meet. In comparison to the image of the elite model, Emily Scarratt, the individual’s foot placement id further back from the ball and it is also bearing a lot of the weight, as with the elite kicker her weight has not been put through the foot and it is not flat on the ground. In the image of Emily Scarratt her planting foot carries the weight on the outside of it, this allows her to get a larger swing on her kicking leg and get around the ball. To improve the planting of the standing foot, the athlete on the left should aim to move the foot a few centimetres closer to the ball, but remain the same width away.

Contact with the ball

Making solid contact with the ball has a significant impact on the outcome of the kick, as it generates the power of the kick. It is recommended by BBC sport that the contact is made around a third of the way up on the ball. In the image of the player kicking, her foot is shown to be near the bottom of the ball at an appropriate position. Another strength of the ball contact is that her foot is kept hard when it hits the ball, this makes the impact stronger increasing the power behind the kick. If her foot wasn’t tensed, then the contact would be weak and the ball wouldn’t go far. She also kicks the ball using the instep of her foot, this is a wider and flatter area meaning that it allows room for minimal errors to be made, so that they don’t impact the outcome of the kick too much. Kellis et al states that “The offset distance between the impact point and the center of the ball seems to play an important role for path and direction of the ball after impact. An increase in the offset distance decreases ball speed but it increases ball spin”. The image of the elite performer clearly shows that she is using the inside of her foot to make contact with the ball and does so quite close to the bottom. For the athlete on the left to improve her kick she should aim to turn her foot even more to open up the side of her foot to have a better strike on the ball.

Follow through

To perform most skills in sports a follow though provides more accuracy and helps to ensure that the power behind the kick goes through the ball and in a forwards direction. The individual above has maintained a good follow through as her kicking leg has gone through the ball in the direction she is aiming, meaning that the kick will be executed accurately and she will keep her balance. It is known that follow through is needed in a place kick, as supported by Peter Dawson, 2007 as he implies that the follow through is the most important element in a place kick. In comparison to the photo of Emily Scarratt the performer on the left has a very rigid follow through, rather than looking relaxed and natural, this could mean that the she could have been stiff when kicking , reducing the power and distance behind the kick.  The elite performer has allowed he head to come up during the follow through unlike the athlete on the left, this could be because the elite model is focusing on a specific point on the ball throughout the performance of the skill. If the other athlete were to do this than it would allow them to be consistent with where they strike the ball and make them more psychologically focused.

The approach

The approach to the ball is important to consider when kicking as it is the first forward direction to the ball, therefore generates power and momentum. Within the approach to the ball there are factors to consider, such as angle, speed, foot placement, and stride length. For a place kicker these elements of the game differ to suit their style, therefore can only be analysed to a certain extent. Comparing it to the kicker Dan Carter, it is implied that right kickers have to approach the ball from the left, “The reason for this angled approach is to open up the hips and allow the hips and then the legs to swing through a larger arc and therefore create more power for the kick”-  Dudley Tabakin . (2009). Emily Scarratt is also right footed, therefore approaches the ball from the same side to the athlete above, and they both have a similar approach to the ball. Both athletes take three steps towards the ball, starting with their left so that they finish with their strongest leg kicking the ball. Having less steps means that it reduces the possibility of not being in the right position to take a kick so is an aspect of strength for both during their approach to the ball. During Scarratt’s first step she raises her left knee to exaggerate the start of the movement with what is known as a power step. This is part of her routine and allows her to get the initial momentum of the kick. Emily Scarratt has a lower body position in approach and is closer to the ground meaning that her centre of gravity which aids dynamic balance and control to ensure accuracy. This is an area for the other athlete to improve and add to their kick. Both the individual and the elite model have kept their head down during the approach to the ball which ensures that they have balance and strike the ball cleanly, focusing on the ball during the approach also prevents any possible distractions from interfering with the kick.

Methodology

To conduct the methodology within this investigation we used various ways for each type of analysis:

·         Notational analysis- To collect the notational analysis we videoed two different games on different occasions of the same individual. This meant that our control variable was the selected player, and the team that she was playing changed. To then record each of the chosen components to analyse we watched back the videos and took a tally of when the skill was performed both successfully and unsuccessfully.

·         Numerical and technical analysis- For this analysis we videoed the same individual performing a skill that would be used within their sport, therefore we chose place kicking. The player had joint markers placed on one side of body at the joints that would be used to calculate the three numerical components, these were shoulder, hip, knee, ankle and toe. The camera positioning had an important part as we had to choose an area with a limited background, so that there were reduced interference when looking to analyse the video and had to ensure that the whole movement was in the camera’s plane of view. We also used a tripod to position the camera to the right height required for the movement and to keep the videoing stable. To reduce a scaling error from occurring it is important to use a scaling object, for us this meant using a 1 metre ruler in the field of view and plane of interest of the camera. This scaling method means that by understanding what would scale as 1m on the video, we could calculate the length of measurements when the player kicked the ball. To reduce perspective errors the camera positioning should aim to maximise the camera subject distance whilst maximising the size of the subject within the field of view. To reduce parallax errors we had to determine the plane of movement before placing the camera and ensured that the kicker moved in this plane of motion.

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