Observation and research is imperative to coaches to be able to provide the learner with detailed responses about their performance (Hay, 1994). Javelin throwing has shown little change in approach throughout the years and elite performers almost show equivalent techniques. Some sportsmen differ using their techniques by rotating the javelin arm forward, down and then prolong it again prior to tossing. The most frequent strategy of javelin keeps the javelin firm without any action then extends it back before forward action (Carr, 1999). Regarding to Rogers (2000) the javelin is split into a four period pattern. These stages are; approach, transition, stop and release and follow through.
The strategy is the run-up period prior to withdrawal of the javelin. The run-up develops velocity which energy created is transferred to the put. The momentum gathered from the run-up offers 30-40% distance from a javelin that is thrown from a standing position (Rogers, 2000). Runners would prefer to use 12-15 step run up but some find using 8-10 steps comfortable. During the approach there should be a steady acceleration eventually achieving a maximal, but controllable velocity that may be preserved through the transition and release phase. The sportsman should be calm during the run especially in the upper body and shoulders, maintaining a good pose. The javelin should be carried at the right viewpoint with the make with the javelin kept level and stable whilst in the run-up (Rogers, 2000).
The transition period is employed to withdraw the javelin in preparation for the explosive movement of the release of the javelin. The withdrawal is made with a five-step design (for right handed thrower this will go left, right, still left, right, remaining). The withdrawal starts when the still left ft. lands (after 12-15 step run-up). As the left feet lands shoulders turn 90 degrees to the right and the throwing is extended back with the palm facing upwards, so the arm is level or above the plane of the shoulders. The arm is slightly external rotated at the make joint to ensure the palm is facing upwards. The tip of the javelin should be aligned at the level of the chin with make kept level. During this phase the feet and hips are active. The turning of the make control buttons hip rotation and ft placement and making of the hips and foot cause deceleration (Rogers, 2000).
Figure 1. The transition between methodology and withdrawal phase with emphasis on the disadvantage of the javelin.
The final level of the transition is the main to get energy into the release of the javelin, the impulse step. The impulse stride drives the hips and trunk forwards. The trunk is kept upright to maintain forwards speed. The proper calf is swung infront forwards with knee flexed and bottom resulted in. The left ft. then lands forwards as the right contacts the bottom (Rogers, 2000).
Figure 2. Last Level of the transition stage the impulse stride. Emphasis on the high leg drive of the right knee.
The block and release stage is an explosive continuation from the preceding stage. During this stage the hips and trunk are thrust forward against a direct, left lower leg. The hips turn with them finishing facing the direction of the put. As the remaining knee is planted in a blocked action the right leg drive causes acceleration of the right hip, stretches the trunk. The throwing arm and everything the lower leg action is stored calm and trailing. Each one of these actions cause a stretch of the upper body and trunk muscles producing a flail like action of the throwing arm (Rogers, 2000).
Figure 3. The release phase showing the entire extension of the kept leg and the right knee driving a vehicle through the stop.
During the follow-through the athlete must think of generating through the block. This forces your body high and onto the left feet after release. Another step should check the forwards momentum to prevent exceeding the foul series (Rogers, 2000).
Analysis of Performance
Using the four stage routine devised by Rogers (2000) an research of any javelin performer comprising of their talents and weaknesses and contrasting these to a good model of practice.
Strengths of the athlete shown come in the methodology phase of the javelin chuck. The athlete runs on the 10-15 step run-up with a continuous acceleration which is managed by the athlete. A controllable speed enables the athlete to get momentum entering the transition and release phase where the more explosive motions take place. During the approach stage the athlete also shows a good pose with shoulders and chest muscles comfortable and javelin retained steady (Rogers, 2000).
During the transition phase of the put the athlete has good pose and the footwork is exemplary. The sportsman continues the hips high and upper body upright whilst doing the cross-over steps. During the cross-over steps the javelin is stable and is partially extended. The footwork of the athlete is right and goes on the progressive acceleration gained through the approach run.
Prioritising the weaknesses of the sportsman are essential therefore the accurate practice drills can be selected and eventually an improvement in strategy and performance. Both weaknesses concern the arm positioning and the impulse stride. The runners arm drops below the airplane of the shoulders. This effects the whip-and flail release as the upper body and torso are not kept wide open (Rogers, 2000; Paish, 2009). During the release phase the block of the remaining side causes a prestretch of the upper body and trunk producing a the flail-like action. This cannot take place if the arm drops below the airplane of the shoulder blades. The dropping of the arm below the plane of the shoulder blades also offers biomechanical impacts. The dropping of the arm causes the tip of the javelin to point up-wards, causing an over rotation of the javelin.
Fig. 4 this image obviously implies the drop of the make beyond the airplane of the make. The image plainly shows the impact it has on the hips, leading to them to sink and the details of the javelin, which should be kept steady.
The second weakness through the transition phase is the lack of an impulse stride. The impulse energy exchanges energy from the transition stage to the release. The impulse stride is your final cross-over step but with the exaggeration of the right knee drive. The drive of the right knee aids tugging the hips ahead (Rogers, 2000). The athlete being analysed performs the cross-over steps with ease but just has no final impulse stride, which increases explosive energy for the release phase. The lack of an impulse stride means there is no vigorous movement creating no rate and explosion.
Fig 5. The image shows the lack of a knee drive. The leg should theoretically be at 90 degree angle. The lack of leg drive reduces the explosive motion of the impulse stride.
Another major weakness from the athlete is during the block stage. As Rogers (2000) talks about the left aspect of the body should be stored firm and become a stop whilst the drive originates from the right side side, accelerating through the stop. The left knee should be totally extended therefore the right hand aspect can rotate and drive through the kept lower leg. The weakness the athlete shows is the fact that following the impulse stride the left-leg is planted but is flexed. The implications of the are that the right hands cannot drive through the still left side, producing no power for the javelin throw. The flexing of the still left knee causes the sides to sink indicating bodyweight is forced backwards.
Fig. 6 The image shows having less block during the release period. The planting ft. should be firm and almost in a vertical line. The flexing of the front knee causes sides to sink and a lack of drive through this block.
Table 1: illustrates the athletes strengths and weaknesses.
Strengths
Weaknesses
Good good posture in run-up with the javelin stored stable.
Arm drops below aircraft of the shoulder blades when attracted back
Uses 10-15 step run-up.
Lack of exaggeration during the impulse step
Palm faces up-wards and shoulder externally rotated when javelin is attracted back.
Good footwork during the transition period, with 3 well performed cross-over steps.
During block phase left-leg not fully extended, triggers right side unable to drive through the block.
Hips drop and level lost through the block and release, triggered by left-leg not totally extended.
Developing Technique of the Performer
As mentioned in the last section the three key weaknesses have been prioritised. The weaknesses are; the drop of the arm below the airplane of the shoulders when extended back again, lack of exaggeration of the impulse stride and lack of expansion of the remaining leg during the block and release period. Drills now have to be created so strategy of the performer is improved, so subsequently the end outcome of the toss will be upgraded. Drills for increasing these techniques can be put together as well as drills for extension of the arm and lead lower leg culminated along.
The first practice drill will be a standing javelin put. This drill is a warm-up drill but can also focus on technical aspects of the throw (Bowerman and Freeman, 1991). The primary objective of this drill is to stabilise the arm. As stated a weakness of the performer is the dropping of the arm below the plane of the shoulder blades. To simplify this drill the sportsman could use a turbo javelin, this is a lighter javelin aimed at improving specialized aspects or perhaps a rugby ball. The athlete should complete about 30-60 standing up javelin throws therefore the action is stereotyped and the athlete gets the kinaesthetic feel of the throw. During this drill the coach should be giving feedback concentrating on the arm position, ensuring it is above the plane of the shoulders. This drill is focusing on technological aspects so distance and work should not be an issue the coach has to focus on.
The next development of the drill is designed to perform 3 cross-over steps then perform a throw. This drill despite the advantages of the cross-over steps targets the arm position and expansion of the lead calf during the release stage. As seen the athlete through the transition phase let us the javelin drop below the planes of the shoulder blades, triggering an over rotation of the javelin. During this drill the sportsman should begin the throw with the arm fully extended to the rear and above the plane of the shoulder blades. The first stride should then be completed with the left lower leg and then cross-over step and chuck. During the release stage the athlete needs to focus on fully increasing the lead knee allowing the right side to be able to drive through the block (Rogers, 2000). The mentor should prescribe the athlete to shadow perform this drill and pause as the left leg plants. This will indicate whether the athlete is fully extending the lead knee. Originally this drill should be achieved at a slow pace to get used to the rhythm of the movements. Once perfectly the level and pace of this exercise should be increased. Again this step should be repeated so the movements is stereotyped to the performer. This means the action can be repeated without the conscious thought. To increase the difficulty of the drill the athlete should toss towards a goal, making a gate to target the javelin towards. The athlete should then task themselves out of 10 how many times can the athlete successfully land the javelin.
The next drill will focus on the impulse stride. As explained the athlete lacked any exaggeration of the impulse stride therefore lacking explosive power into the release stage. This drill will concentrate on the high leg drive of the right knee. The athlete will perform cross-over steps over a line of SAQ hurdles. The athlete will only drive the right calf in the 12 inch SAQ hurdles. The will be done so the sportsman feels more comfortable with the feel and explosive motion of the impulse stride. The sportsman should now understand the necessity s of the impulse stride so the final practice should be the athlete performing a 7-11 javelin chuck. This will likely replicate the throw in a competition environment. The trainer need to see all the different parts of the javelin if the technique has improved upon.
Summary
The javelin chuck regarding to Rogers (2000) is put into four phases. These stages are; procedure, transition, block and release and follow through. Each period has key aspects which the instructor should compare against a good style of the practice, the model of practice I likened the performer to was Steve Backley. Through the use of video-analysis strengths and weaknesses of the performance could be attracted. For the weaknesses intensifying and technical techniques were drawn up so strategy of the performer could improve, therefore bettering performance. The main element weaknesses of the performer analysed was; falling of the arm below the aircraft of the make when withdrawn in the transition phase, lack of expansion of the lead knee through the release stage and insufficient an impulse stride during the transition period which is the most explosive motion. The progressive techniques focused on one or two tips and are basic and recurring so the strategy can be inserted in the performance. Eventually the techniques developed into a practice javelin chuck replicating what would be done in competition, so improvements is seen.
