Introduction
Australian Rules Football (AFL) is an ever changing game with skill evolution and rapid rule changes to create a fast attractive sport. Fundamentals however still remain the essence of the sport. Kicking effectively and kicking long can still give a player an offensive or defensive advantage. Allowing for that player to score from longer distances and pass the ball to teammates further away. With this in mind how can a player increase their distance using biomechanics?
Upon developing this question two characteristics were considered. Firstly, How can any given player increase their kicking distance through altering technique? Secondly, Is accuracy a component of effectiveness?
In relation to accuracy, the concept is not determined through biomechanics like distance, accuracy in AFL can be determined by others (for instance a team-mate receiving the ball could have mistimed a run or an opponent could intercept the ball), and therefore accuracy in this case is not a component of effectiveness when kicking for distance.
To be effective in this principle of kicking long, we will determine the distance of kick and isolate the biomechanical components someone who kicks longer possess more so than others.
Upon developing this question two characteristics were considered. Firstly, How can any given player increase their kicking distance through altering technique? Secondly, Is accuracy a component of effectiveness?
In relation to accuracy, the concept is not determined through biomechanics like distance, accuracy in AFL can be determined by others (for instance a team-mate receiving the ball could have mistimed a run or an opponent could intercept the ball), and therefore accuracy in this case is not a component of effectiveness when kicking for distance.
To be effective in this principle of kicking long, we will determine the distance of kick and isolate the biomechanical components someone who kicks longer possess more so than others.
Within this blog these biomechanical principles will be explored:
- Linear momentum of subject
- Angular velocity of leg
- Foot speed
- Magnus Force
Professional footballers kicking technique
By using professional footballers’ techniques we can address specific criteria and assume that in order to maximize kicking distance we should vaguely mimic what professionals do. However it should be noted that not all professionals kick with an ‘optimal’ technique and therefore what feels comfortable is always encouraged.
Within this question it is assumed that: subjects have full range of motion, are physically strong and healthy, and are of no (or minimal) injury issues especially regarding the legs and have preferred kicking techniques established and practiced over many hours.
Kevin Ball, is an Australian sport scientist who has looked at kicking techniques before, his research into preferred and non-preferred kicking feet can be found here:
http://www.tandfonline.com/doi/abs/10.1080/02640414.2011.605163
Using Ball’s data, cumulated of seventeen professional footballers kicking actions over a forty-five pass or a ‘comfortable' distance, we are able to understand common angles of body position during contact. These numbers are a component of angular velocity and linear momentum as the leg transfers through the football and therefore at the point of contact the knee, thigh and hip angles produce a forty-five metre kick or thereabouts. The leg has a high range of motion and suggests that the pelvis, knee and shank of the leg are producing a bulk of the force during impact while allowing sufficient time from hand to foot to produce ‘ideal’ contact (Knudson, 2008, Blazevich, 2011, & Ball, 2011).
Within this question it is assumed that: subjects have full range of motion, are physically strong and healthy, and are of no (or minimal) injury issues especially regarding the legs and have preferred kicking techniques established and practiced over many hours.
Kevin Ball, is an Australian sport scientist who has looked at kicking techniques before, his research into preferred and non-preferred kicking feet can be found here:
http://www.tandfonline.com/doi/abs/10.1080/02640414.2011.605163
Using Ball’s data, cumulated of seventeen professional footballers kicking actions over a forty-five pass or a ‘comfortable' distance, we are able to understand common angles of body position during contact. These numbers are a component of angular velocity and linear momentum as the leg transfers through the football and therefore at the point of contact the knee, thigh and hip angles produce a forty-five metre kick or thereabouts. The leg has a high range of motion and suggests that the pelvis, knee and shank of the leg are producing a bulk of the force during impact while allowing sufficient time from hand to foot to produce ‘ideal’ contact (Knudson, 2008, Blazevich, 2011, & Ball, 2011).
Breakdown of Skill
The Approach - as the subject prepares to kick the football his torso is slightly forward. David Rath is a scientist hired by the Hawthorn Football Club in 2005, his role is to ‘perfect’ the kicking techniques of the Hawthorn players (Clark, 2012). Rath suggests that a sufficient approach displays forward momentum and includes vertical bounce that lengthens the backswing of the leg and provides bracing of the support leg (2000). This component is related to the Kinetic Chain, as the energy is transferred from trunk to pelvis, to upper leg then to lower leg, resulting in foot speed upon ball contact. But to take a step back, the approach component is the process of potential elastic energy allowing the leg to produce force from this point (Blazevich, 2010., Knudson, 2007).
Grip and Release - the hand dropping the football has shown to influence the performance. If a drop is off skew it can reduce distance and accuracy (Pavely et.al., 2010). During this stage Rath refers to this transition from hand to foot as the ‘guiding path’ noting balance is of key importance (2000). This component also requires Inertia of the football. Inertia is related to Newton’s First Law and allows the football to remain in its state upon release as gravity forces the ball to drop it will continue its constant angular velocity and motion remains relatively the same (Blazevich, 2010).
Foot Speed - It must be noted that this is not the speed of the feet during the approach or running but rather the speed at which that foot travels prior and during the kick. This component is again related to the Kinetic Chain, think of this process like a spring, whereby the spring is brought in, building energy and its release is the speed measured (Blazevich, 2010). Foot speed has an impact on the distance of the kick as Ball suggests a kick travelling 45 metres has a foot speed of around 19 metres per second (m*s-1). Does that speed improve for a longer distance? This will be discussed in more detail shortly. It must be noted that foot speed has the greatest effect/reaction on the football's direction. Rath’s image isolates some key points in the biomechanics of ‘releasing the spring’
Role of Supporting leg - allows for the body to brace and balance the momentum of the kicking leg. It also establishes the technical position of the hips allowing them to rotate coinciding with the upper kicking leg (Orchard et al., 1999). A strong supportive leg provides flexion and extension to assist the push through the football. The Diagram below illustrates the flexion and extension of the supporting leg as the momentum shifts due to ground reaction forces (Orchard et al., 1999).
Ball Contact - At this point there are little components to alter the outcome of the distance, trajectory or accuracy of a kick. Rather there are factors that affect impact. The ball drop and supporting leg provide the basis for the result of the kick. However if a subject was to kick a torpedo punt, where by the ball rotates around itself, as opposed to a common drop punt, ball rotates over itself, then contact can provide different results related to distance.
This product is known as the Magnus Effect, which affects a drop punt and creates a more ‘controlled’ kick. It does this by applying upward force as the object spins backwards with the air rotating over the ball (1veritasium, 2011). The drop punt is the most used kick in Australian Rules Football (Cameron & Adams, 2003) and is used to kick short and long distances, all subjects in the above photos are kicking drop punts. However the Magnus effect also impacts a torpedo punt, which spirals through the air rotating about its long axis, similar to that of an American football punt. A successfully punted American football is one that spirals effectively from left to right and it is essential that the ball be launched in a nose first orientation, thus causing minimal drag downward on the object (Hartschuh, 2002. & Brancazio, 1985). Therefore the Magnus effect of a torpedo punt has less drag through the air when compared to a drop punt. This occurs as the air transfers over the ball from left to right as opposed to under and over.
Follow Through - According to Rath a follow through should provide immediate feedback of a quality kicking technique. Noting the following three components will provide an appropriate follow through and prevent potential injury concerns:
- Balanced
- Transfer of weight through extension
- Toe is straight toward target
Compositions of the body that is most relevant to distance kicking.
Within the kicking action, certain areas provide feedback related to distance. None more so than foot speed. Studies looking at junior footballers (Baker & Ball, 1996), senior footballers using preferred and non-preferred kicking feet (Ball, 2011) and looking at distance kicking (Ball, 2008) suggest that foot speed has an impact on the distance of the kick. However this result is specific to Kicking transferred from hand to foot, such as American Football, Australian Rules football and Gaelic Football. Soccer players are more reliant on the point of contact and the transfer of velocity linked to the knee in order to provide more distance and not necessarily more speed (Dorge et al., 2002).
The graph below illustrates how relevant foot speed is to maximizing distance for Australian Rules Footballers, It is interesting to note that a Gridiron Ball travels a lot further with less speed in comparison to an Australian Rules Football. This could be due to a number of reasons including a one-step approach, lighter ball and spiral action, related to the Magnus Effect. Brancazio suggests that increased foot speed results in increased risk, suggesting that a more comfortable approach allows for more control during a punt (1985).
The graph below illustrates how relevant foot speed is to maximizing distance for Australian Rules Footballers, It is interesting to note that a Gridiron Ball travels a lot further with less speed in comparison to an Australian Rules Football. This could be due to a number of reasons including a one-step approach, lighter ball and spiral action, related to the Magnus Effect. Brancazio suggests that increased foot speed results in increased risk, suggesting that a more comfortable approach allows for more control during a punt (1985).
Ball also found that shank angle of subjects increased when they kicked longer distances. The average shank angle of those subjects kicking for distance was on average 97 degrees (2008), if we compare this to a ‘comfortable kick’ provided earlier of around 78 degrees which produced average distances of forty-five metres (2011). Therefore we begin to notice some differentiating variables.
Finally Ball found that a lengthy step during the approach also assisted maximizing distance. Subjects who kicked around 61 metres had a last step distance of 1.71 metres measured between the heel of the kicking foot and the toe of the supporting leg during impact. This ultimately allows the kicking leg to have a larger range of motion and allows for subjects to increase foot speed (2008). However it is noted that ‘overstepping’ or trying to lengthen the final step to much can affect the technique of the kick, therefore the main priority is to feel comfortable with your kick (Rath, 2000).
Finally Ball found that a lengthy step during the approach also assisted maximizing distance. Subjects who kicked around 61 metres had a last step distance of 1.71 metres measured between the heel of the kicking foot and the toe of the supporting leg during impact. This ultimately allows the kicking leg to have a larger range of motion and allows for subjects to increase foot speed (2008). However it is noted that ‘overstepping’ or trying to lengthen the final step to much can affect the technique of the kick, therefore the main priority is to feel comfortable with your kick (Rath, 2000).
Answer
To increase kicking distance in Australian Rules Football, it is recommended to improve foot speed and shank angle at ball contact during maximal effort. By increasing your final step during your approach allows your foot a higher range of motion prior to contact, which potentially improves foot speed. However remember not to ‘overstep’ which can severely affect technique. Along with these key points, as with any kick, maintain technique by having a strong and balanced support leg and a level approach. A follow through toward the target is detrimental to the skill, preventing injury and completing the skill with a transfer of weight through extension and propulsion.
The result? A kick with maximum distance. (BigPondAFL, 2012)
The result? A kick with maximum distance. (BigPondAFL, 2012)
How else can we use this information?
Like any sport, maximums are always desired achievements. It is imperative to remember that technique is fundamentally important to achieve longer distances. Injury can result from subjects applying too much ‘muscle’ without maintaining technique. This example on improving kicking distance has illustrated tweaking certain areas of a skill. For this to happen, a coach or educator should prescribe step by step differences over a period of time. Rath suggests correcting early mistakes immediately , stressing that no matter what your performing, if the product is failing due to a technical flaw, fix it (2008). In order to achieve maximums, high levels of flexibility and strength training are involved in conjunction with technical alteration. Change will never occur over night so like any skill, practice is the key.
References
Baker, J. and Ball, K. (1996). Biomechanical considerations of the drop punt. Technical report for the Australian Institute of Sport: AFLFootball Development Squad. Australian Institute of Sport, Canberra.
Ball, K. (2008): Biomechanical considerations of distance kicking in Australian Rules Football. Sports Biomechanics, 7 (1). P10-23.
Ball, K. (2011). Kinematic comparison of the preferred and non-preferred foot punt kick. Journal of Sport Science, 29 (14). p1545-1552.
BigPondAFL. (2012, August 2012). Tom Hawkins goal on the siren - AFL [Video file]. Retrieved from http://www.youtube.com/watch?v=2h9OVHIGNAE
Blazevich, A. (2010). Sports Biomechanics the Basics: Optimising Human Performance. London: A&C Black.
Brancazio, P. (1985). The Physics of Kicking a Football. The Physics Teacher, 23 (20). p403-407.
Cameron, M., Adams, R. (2003) Kicking Footedness and Movement Discrimination by Elite Australian Rules Footballers. Journal of Science and Medicine in Sport, 6 (3). p266-274.
Clark, J. (2012, September 21). Hawthorn’s secret weapon- a mad scientist in shorts-pushes the boundaries. Herald Sun. page unknown.
Dorge, H., Bull-Andersen, T., Sorensen, H. and Simonsen, E. (2002). Biomechanical differences in soccer kicking with the preferred and the non-preferred leg. Journal of Sports Sciences, 20. p293–299.
Knudson, D. (2007). Fundamentals of Biomechanics. USA. Springer.
Orchard, J., Walt, S., McIntosh, A., Garlick, D. (1999) Muscle Activity During the Drop Punt Kick. Journal of Sports Science, 17(10). P837-838.
Pavely, S., Adams, R., DiFrancescio, T., Larkham,S & Maher, C. (2010). Bilateral clearance punt kicking in rugby union: Effects of hand used for ball delivery. International Journal of Performance Analysis of Sport, 10: 187–196.
Rath, D. (2000, December). Biomechanics of kicking. Presentation. Australian Rules Coaching Course. Amsterdam, Netherlands.
Hartschuh, R. (2002). Physics of Punting a Football. Physics Department, The College of Wooster. Ohio, United States of America.
1veritasium. (2011, November 24). What is Magnus Force [Video file]. Retrieved from http://www.youtube.com/watch?v=23f1jvGUWJs
Ball, K. (2008): Biomechanical considerations of distance kicking in Australian Rules Football. Sports Biomechanics, 7 (1). P10-23.
Ball, K. (2011). Kinematic comparison of the preferred and non-preferred foot punt kick. Journal of Sport Science, 29 (14). p1545-1552.
BigPondAFL. (2012, August 2012). Tom Hawkins goal on the siren - AFL [Video file]. Retrieved from http://www.youtube.com/watch?v=2h9OVHIGNAE
Blazevich, A. (2010). Sports Biomechanics the Basics: Optimising Human Performance. London: A&C Black.
Brancazio, P. (1985). The Physics of Kicking a Football. The Physics Teacher, 23 (20). p403-407.
Cameron, M., Adams, R. (2003) Kicking Footedness and Movement Discrimination by Elite Australian Rules Footballers. Journal of Science and Medicine in Sport, 6 (3). p266-274.
Clark, J. (2012, September 21). Hawthorn’s secret weapon- a mad scientist in shorts-pushes the boundaries. Herald Sun. page unknown.
Dorge, H., Bull-Andersen, T., Sorensen, H. and Simonsen, E. (2002). Biomechanical differences in soccer kicking with the preferred and the non-preferred leg. Journal of Sports Sciences, 20. p293–299.
Knudson, D. (2007). Fundamentals of Biomechanics. USA. Springer.
Orchard, J., Walt, S., McIntosh, A., Garlick, D. (1999) Muscle Activity During the Drop Punt Kick. Journal of Sports Science, 17(10). P837-838.
Pavely, S., Adams, R., DiFrancescio, T., Larkham,S & Maher, C. (2010). Bilateral clearance punt kicking in rugby union: Effects of hand used for ball delivery. International Journal of Performance Analysis of Sport, 10: 187–196.
Rath, D. (2000, December). Biomechanics of kicking. Presentation. Australian Rules Coaching Course. Amsterdam, Netherlands.
Hartschuh, R. (2002). Physics of Punting a Football. Physics Department, The College of Wooster. Ohio, United States of America.
1veritasium. (2011, November 24). What is Magnus Force [Video file]. Retrieved from http://www.youtube.com/watch?v=23f1jvGUWJs