Saturday, February 27, 2016

Analysis of Penalty Kick in Rugby


 -Biomechanical 



Biomechanical analysis of the Penalty kick in Rugby Preparatory phase/wind-up "During a rugby union game, place kicking for maximal resultant ball velocity is often desirable. Similar to soccer instep kicks, place kicks in rugby involve a series of motions that include an initial address to the ball, planting of the support leg beside the ball, and striking of the ball with the instep of the kicking foot"
(Barfield et. al., 2002; Isokawa and Lees, 1988) While the basic pattern of a place kick is similar to the instep soccer kick, the differences of the ball shape, tee support, and release angles make the rugby place kicking technique unique. Three components of qualitative analysis: Dan and Caoimhin are left footed kickers, so note that they approach the ball at an angle from the right.
The reason for this angled approach is to open up the hips allowing for increased hyper-extension creating a larger back swing and as well an increased abduction of the legs. 


Notice that Carter is closer to ground = lower center of gravity which aids dynamic balance and control for a more accurate penalty kick After analysing Carter’s kick we can see that he takes a few steps back and another few to his right to give him a good angle to approach the kick.
By taking fewer steps also reduces the possibility of not being in exactly the right position to take the kick. 2) Wind-up/backswing During the back swing phase, flexion at the hip and knee are the most important contributors while the linear velocities of the pelvis and pelvis rotation cause a negative contribution to the total speed. For this study, a clear picture of the kinematic chain of the rugby kick can be represented by following steps. In the final step, the kicking leg generates back swing: the farther back the leg is, the more force and leg speed can be potentially generated; then, the thigh moves forward followed by the passive movement of the shank through the knee; finally, the shank extends to yield the maximum speed right as the instep contacts the ball while the thigh decelerates. As the major contributor to knee extension, the quadriceps would generate high intensity forces. Therefore, from a biomechanical point of view, the strength training for knee muscle groups may be of particular importance for rugby players, not only for performance enhancement, but also for injury prevention during kicking. 2) Wind-up/Force producing 

movements Dan plants his right foot just adjacent to the ball. If he placed this standing leg behind the ball it would force his kicking foot further under the ball forcing the ball higher in to the air but getting less distance. Alternatively if he overran the ball, placing his support leg past the ball he would not be able to swing his leg through and get under the ball sufficiently to get the distance required. His hips, leg and foot kick through the ball in sequence. His hips rotate through toward the target first and his knee is left bent behind. 

The knee then straightens out and brings the foot through the ball toward the target. He keeps his head down over the ball as he kicks. Keeping your head down looking at the ball ensures that you are balanced for the kick and that you strike the ball cleanly. 3) Follow through In this picture you can see that Carter rolls over his support ankle during the follow through. This happens because of his angle of approach toward the ball, allows him to get a bigger swing at the ball. Although this looks dangerous, the roll is forced by his follow through when most of his weight has been lifted from the support leg. You will see that some kickers look like their support leg is lifting into the air, rather than rolling, with the force of the follow through. Biomechanical studies regarding rugby union place-kicking techniques are very limited. A two-dimensional analysis by Aitcheson and Lees (1983) found that 'two-stage acceleration' of the lower leg is yielded. The first stage is due to the lower leg falling against gravity and the second stage is due to the interaction between the upper and lower leg segments. Bezodis et. al., (2007) investigated non-kicking-side arm motion during rugby place kicking. They found that the longitudinal angular momentum of the non-kicking-side arm can increase accuracy in maximum distance kicking. By: Eoin McArdle (C)
Marie Daly (VC)
Orla Donaldson
Ryan Lynch About the Penalty Kick Definition of Biomechanics “Biomechanics is the science associated with internal forces, mainly the muscle contractions, and also the external forces which act upon the body and the subsequent effects produced by these forces”.
Hall (1991) When is it rewarded? Closed skill Position of Standing leg is different

Head position is similar Caoimhin = 70 degrees Dan Carter = 45 degrees This phase is referred to as the wind up or back swing. This is the phase where the force producing movements occur in order to generate as much force and accuracy before the body comes into contact with the ball.

In this kicking action below, although the whole body is involved, the majority of power and strength is generated from the left leg as this is Dan Carter’s preferred foot. Due to speed and power generated during the kicking movement of the elite performer the follow through came natural and he was able to control his movements to stop.
In comparison Caoimhin did follow through, however he did not display control or balance, illustrating poor technique which could result in a missed penalty shot. How to Improve Performance Rugby is a sport which involves strength and effective training and drills Strengthening muscles in the lower body and core muscles Effective training and drills - start from close in to goals and as you get more confident and perfect your technique then move further away from goals Skill and tactics are more important than sheer size and strength Main Techniques to remember Place non-kicking foot beside the ball Keeping your head down Transferring your weight; through your hips through the ball Use your hands/arms to aid balance Less steps in the preparatory phase will minimise chance of error Hip, quadriceps and hamstring flexibility are important in gaining maximum velocity In summary, from a kinematic point of view, the velocity of the kicking foot is not only dependent upon the most distal segments, but also on other proximal segments. It has been generally recognised that place ball kicking is a combination of segmental and joint rotations in multiple planes following a proximal to distal sequence to achieve maximal foot velocity, which results in maximal ball release speed

No comments:

Post a Comment