Coaching Practice for an Explanation of Javelin Throw Movements - Literature review Example

Coaching practice Name Institution Date Introduction Like any other throwing activity of the body, the javelin is a dynamic activity that makes use of the full body. It requires the involvement of all major muscles. Specifically, its main stay of power and exertion is in the shoulder and arm muscles. However, it also requires a balanced involvement of the abdominals, the hips and the lower limbs. There has been literature and coaching practice indicating that javelin is more than just a ‘throw’. As such, whereas throws will only incorporate a predominantly activity of the arm, a javelin throw is a dynamic movement that is over arm with a whip-and-flail whole body technique (Rogers 2000). It is vital that a coach has an in-depth understanding of the principles and processes that underlie such combinations of movement. This paper is an explanation of javelin throw movements from the point of view of coaching science and practice using a right-hand throw. It will expound on the movement processes, muscle involved as well as key performance indicators. It will also evaluate a video of a javelin throw and use the indicators to point out the strengths and errors to which it will suggest possible workable interventions. Movement sequence and muscles The javelin throw is best done at the optimum moment. As a coach, the emphasis is made on the training the athlete for the technique of this release. This training is entrenched in ensuring that the performer understands and applies the relationship between the body and the javelin at the optimum release. This is in addition to the role of speed in approach and power in release. With reference to optimization, it is vital that all variables pertinent to a successful motion be either maximized or minimized. This variation of the interplay is tuned or balanced to a set of equation constraints relative to kinematic factors (Hughes & Franks 2004). The kinematic factors reveal a sequence of several phases: approach, transition, block and release and a follow through. Given the complexity of a javelin throw and its aerodynamic differences with other throws it is quite a task to differentiate these stages. Davids (2006) points out that the performance analysis of movements of such a complexity can only be predicted if explored over selected portions of the activity and not using isolated aspects. In the approach section, the performer prepares the throw with a run-up. This begins with a start and carry section where the javelin is a carried in the throwing arm in a relaxed muscle tone. At the start and carry, the athletes stands with the throwing foot forward, carries the javelin above the shoulders or the head with the carryng shoulder pointing forward. The grip entails having the palm facing up providing a place for the javelin to sit on (Ahalāvata 2009). As such, the javelin is in the direction of the throw. The approach is a run up in which the performer builds body velocity whose energy is transferred to the throw. The approach section has been indicated as a major difference affecting the quality and distance of throws amongt elites. This run up should be present gradual acceleration so that the athlete builds to the maximum controllable speed at the optimum in transition and release (Rogers 2000). The run is on the balls of the feet and high hips, preparing the body hip flexion at transition and release.. At this point, the javelin carry is level or tip down to enable in alignment at withdrawal and enhanced eye-hand coordination. The withdrawal cum transition phase prepares the javelin for the flail-and-whip-action. It also prepares the trunk and lower body for a fast and powerful block and release. For the withdrawal, the shoulders turn and the carrying arm is laid back so that it is above the shoulder plane with an extrernal rotation. This sets up a pre-torque position in which the javelin is aligned to the chin, and in tandem with the direction of the shoulders. It is balanced on the counter side by a swing of the opposite hand across the chest. The legs and hips are very important in this section. The left leg pulling pushes the trunk and hip forward to facilitate a shoulder turn. As Rogers (2000) indicates, the amount of foot placement and hip rotation is the basic influence in the extent of shoulder turn. Balance of movement and timeliness is required. Otherwise, one suffers decelleration especially with an additional turning of the his, sidewards. Fundamentally, this phase aims at placing the right foot to the front of the athlete’s centre of gravity to give the decribed lean back, 115o to the horizontal direction (Ahalāvata 2009). There is a push-pull impulse of the left leg which ends a the touch-down of the right one. at this, the left is air-borne. In this impulse, the right is advanced. As this happens, the left is also advanced in order to set for right foot landing at the end of this cross over phase. The block and release phase is the delivery stage and is an explosive phase. The amount of power at this phase is subject to the success of executing the preceeding phases. The delivery is done ‘from the ground up’ (Robinson 2010) indicating a right hip rotation and a finish with rotation to the throw direction. At the block, trunk and hips are pushed forward relative to a straight left leg. At the landing of the right foot, in the transition phase there is left-leg block and right-leg drive. These two cause a rapid acceleration of the hip and stretches the trunk. In order to stabilize the rotation, the left arm extends to the throwing direction as is the left shoulder, and is then rapidly lowered. This has an opening effect on the torso and chest causing a reflex trunk contraction to effect the flail-like action of the throw. The release angle considers aerodynamic lift and drag influence on the distance. Robinson (2010) argues that the trajectory of the javeline’s projectile is dependent on projection speed, projection height, and projection angle. The follow through completes the throw. The left foot is grounded firmly waiting on the right to land from flight and stop the athelete. One should be keen on the distance into the scratch line. This is dependent on the horizontal momentum created. In training, the coach may adjust the checkmark to ehance optimum runway distance. In this throw, the most important joints include the wrist, elbow, and shoulder of the arm involved, hips and the trunk. The elbow joint does not have much change exept in the release when there is extension. In the shoulder joint, there are external rotations. At the release point, there is a rapid internal rotation that happens in tandem with an abduction in order to maintain balance (MacGinnis 2005). This internal rotation is also characterised by an extension at the joint as the arm deliver and into the follow-through. Active involvement of the trunk begins at the transition with a slight right-rotation. This is a followed by interchanges between left and right with increasises in rapidity heightening at the release. The follow-through is effected by a reflexion as the upper body leans to the front. Similar interchanges characterize the hip right-left rotations and movements for both the right and the left hip. Hip rotation has a central role in this movement. It shifts the torsal in the throwing direction, influences the sequential acceleration and stretches abdominal and chest muscles which pull the shoulders for sling-shot action (Burkett & Carr, 2010). This sequence allows a flow from the lower body, into the hips, the trunk, throwing shoulder, elbow and finally into the wrist for a high end-velocity and power at release (Brown 2001). In the coaching of the throwing, there are key performance indicators. They should be made aligned to the coaches’ and athletes’ understanding of the neoromuscular and biomechanical considerations given the speed-power and complex technicality of the throw. A fundamental principal of training is specificity. The indicatiors of focus include the approach, rhythm of the feet movement, the backward lean at transition, wide throwing stance, and weight shift as effected by hip and chest rotation. These present an array of movements effecting the rate of force development and represent what happens at the phases aforementioned. Overall, the importance of power-inherent speed and angle of release cannot be over emphasized (O'Donoghue 2010). Therefore, in each of the phases, the overall intention is to train precision in muscle movement and production of the greatest power amount in the shortest time possible. Literature suggest that the most efficient way of doing this is by developing the stretch reflex and stretch-shortening cycle (Rogers 2000). However, the muscles should be strong enough in order to generate the required power in this cycle. Weight training is therefore a necessity. The practical in the video shows some strengths and weaknesses of the performance. Firstly, the performer has a commendable approach. His start and carry are initiated by a move of the right leg, from which he runs on the balls of the feet making a gradual acceleration towards the release. The withdrawal and transition is done by him rotating the right shoulder externally. There is apparent hip rotation. However, he drops the throwing arm too deep in the cross step causing an excessive increase of the angle of attack. This is also caused by the bending of the plant leg in the throw which shifts the performer’s centre of gravity. This has an counter influence on the trajectory and the velocity. The trajectory touches down faster. The correction for this is ensuring that the hips are relatively high and solid so that there is no bending and the throwing hand can travel upwards in the direction of the trajectory (Rogers 2000). For intervention, it is vital to train the performer on how to appreciate cross-step mechanics in which one delays the torsal in order to maintain the centre of gravity can remain under, and infront. Correct feet movent and hip alighnment are key factors to be addressed. The angle of the body to the groung at transition and release directly affects the angle of release. They have an influence on the height of projection, the angle and speed (Robinson 2010). Th performer also shows no follow-through and shows a troubled landing of the right foot the throw. There is a relatively incomplete flexion of the trunk. As such, the weight in the plant left leg is incapacitating to halt the thrower. The thrower therefore struggles to keep balance on the scratch line. In essence, delivery is a reaction to the sudden stop of energy flow in the body. The follow through should also be a sequence of the same process. As the right knee drops, the left should be flipped over with a outward turn of the right heel as the foot rolls over the toes. This represents a sequence of body segment movement, followed by a stabilization. When the lacks, the performer ‘pulls’ the trajectory down and predisposes himself to injuries. This may be as a result of neuromuscular lack of coordination or flexibilty, especially of the trunk. Such lack of coordination has been faulted for causing changes in aerodynamic characterstics as demonstrated in previous sections. This can be corrected by the use of simulation exercises which will imitate the phases of the throw (Silvester 2003). The performer also requires weight training to enhance muscle power and balance. According to Robinson (2010), javelin throwing is founded on the power and strength development. The weight training should be general as well as specific. However, the gains of the weight training should be applied to the biomechanics of the javelin throw. Conclusion In conclusion, the paper has attempted to explore skills and techniques of javelin throwing. This is a speed-power and highly technical skill that can be explained in several sequential activities: approach, transition, block and release and a follow through. It is a whole body dynamic skill involving major joints such as the wrist, elbow and shoulder of the throwing arm, the lower body, trunk and hips. It also has a main stay on the trunk and the chest. The related muscles moving the joints are also highly involved. The paper has also identified key performance indicators for coaches. In focusing on them, is important to make consideration of the principles of training, neuromuscular and biomechanical coordination. References Ahalāvata, R. 2009. Skills & rules, athletics. New Delhi: Khel Sahitya Kendra. Brown, S. 2001. Introduction to exercise science. Philadelphia: Lippincott Williams & Wilkins. Burkett, B., & Carr, G. 2010. Sport mechanics for coaches. Champaign: Human kinetics . Davids, K. 2006. Movement system and variability. Champaign: Human Kinetics . Hughes, M., & Franks, I. 2004. Notational analysis of sport: Systems for better coaching and performance in sport. London : Routledge. MacGinnis, P. 2005. Biomechanics of sport and exercise (2nd Ed). Champaign: Human Kinetics . O'Donoghue, P. 2010. Research Methods for Sports Performance Analysis . Oxon: Routledge. Robinson, P. 2010. Foundations of Sports Coaching . Oxon: Routledge . Rogers, J. 2000. USA Track & Field coaching manual. Champaign , Human kinetics . Silvester, L. 2003. Complete book of throws. Champaign: Human Kinetics . Read More