Javelin

Analysis of Throwing Throwing comprises of two phases, the preparatory phase and the throwing phase. Most actions are rotational in the transverse plane and longitudinal axis and the two  joints primarily involved are the elbow and shoulder. The elbow is a hinge joint formed by the humerus and ulna. The shoulder is a ball and socket  joint formed between the humerus and the scapula. Note: The javelin is incorrectly held. See the

Javelin section for more details.

Preparatory phase Joints Articulating involved bones Humerus Shoulder and scapula Elbow

Humerus and ulna

Action

Agonist Muscle

Posterior deltoids Horizontal and latissimus hyperextension dorsi Extension

Triceps brachii

Throwing phase Joints Articulating involved bones Shoulder Elbow

Action

Agonist Muscle

Humerus Horizontal Anterior deltoids and and scapula flexion Pectoralis major Humerus and ulna

Flexion

Biceps brachii

http://www.brianmac.co.uk/moveanal.htm

6. Internal Rotation

This is a rotary movement around the longitudinal axis of a bone toward the midline of the body. It occurs in the transverse plane and is also known as rotation medially and inward rotation. The  joints of the body where internal rotation can occur are listed in the table below as well as an example for each joint; Internal Rotation

Joint Example Shoulder Movement of the humerus in the transverse plane medially along its long axis toward the midline Hip Medial rotary movement of the femur in the transverse plane around its longitudinal axis and towards the midline. Knee Rotary movement of the lower leg medially toward the midline.

Internal rotation is a very common movement in the human body. When we walk or run our hips undergo internal rotation with every stride we take. The run up in javelin demonstrates internal rotation as illustrated in Figures 13 and 14 below. The purpose of this movement is the

production of momentum which can be transferred to the hand and wrist in order to maximize release speed of the javelin. Furthermore the consequence of the internal rotation of the hip is forceful rotation of the trunk which produces momentum which can be transferred to the upper body and used. For these reasons internal rotation of the hip joint is an important factor in the successful completion of a javelin throw.

http://www.quintic.com/education/case_studies/Anatomical_Movements.html

THE JAV  SPEED! TECHNIQUE! SPEED! These are the three basic requirements for obtaining a maximum distance javelin throw. And the word "throw" is not really correct in the classic definition of the word. The javelin is "flung", and, assuming that you have initiated it on the correct trajectory, the faster it is going when you fling it, the farther it will go. This event has much more to do with speed than it has to do with strength. After the athlete has mastered the proper mechanics, the thrower must work to develop increased approach and delivery speed. THE RUN-UP: The reason for the run-up is to develop a large horizontal velocity that is ultimately transferred to the javelin. The athlete should strive for maximum controllable speed that can be transferred through the crossover steps and up through the wrist. THE CROSS-OVER: Proper cross-over step rhythm must be maintained in order to achieve optimum final block and release positions. The basic sequencing through the cross-over (C-O) is left foot strike which begins the C-O, the left foot takeoff, the right foot strike, the right foot takeoff, the final foot strike (left) and then the release of the javelin. During the C-O, every effort must be made to keep the foot/ground contact time to a minimum. Extending the foot contact time slows the body speed and will ultimately slow the delivery speed of the javelin. Some javelin throwers use a technique where they extend the amount of time off the ground during the cross-over stride by jumping off with the left leg. There is no data to support that this action will result in a longer throw. This action will also tend to cause a premature start to the throwing action and shorten the acceleration path of the javelin. RIGHT FOOT STRIKE TO TAKEOFF: This is the delivery stride and the most critical point. The right elbow should be fully extended from right foot strike through to release. The left knee should be fully extended at this point. Keeping the knee extended will cause a higher rate of deceleration of the COM (center of mass) resulting in a better transfer of momentum to the trunk and right arm. The hip and shoulder axis should be closed through this stride. LEFT FOOT STRIKE TO RELEASE: Every effort should be directed at getting the left foot planted as quickly as possible after the right foot has touched the ground. With the extended left knee, this will provide the pivot

point for the left hip and facilitate the transfer of momentum to the upper body. As the right leg comes forward, the right hip should rotate around the left hip. This will cause the trunk to rotate to the left and begin the delivery sequence. The right elbow is kept fully extended upward, trying to hold the  javelin as far from the body as possible. YAW AND RELEASE ANGLES: The release angle should be close to 40 degrees. All other conditions being equal a 40-degree throw will travel farther than a throw at 37 degrees. Yaw, the difference in the direction of the javelin and the direction of the grip at release, will impact distance. Effort should be made to ensure that the javelin is pointed in the same direction as the movement of the wrist. THE FLAIL: The throwing action of the arm is a flailing/lashing action by the arm. There are three "levers" involved in this action. These are the shoulder, the elbow and the wrist. Each pivot point of these "levers" must be as high above the other as possible. This action is started by driving the deltoid/shoulder up into the ear and then continuing this upward motion through the elbow and wrist. Very simply, the longer this lever, the faster and more powerful the force of the throw. KEY ACTIONS: The transfer of momentum from the lower to upper body and the length of the throwing levers are the key ingredients to a successful throw.

A detailed "BIO-MECHANICAL ANALYSIS" was performed on some of the best  javelin throws at the 1995 World Championships with the following conclusions-The elements of good throwing technique include: 

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A right foot strike to begin the delivery stride, with the shoulder and hip axis closed and the left knee extended in preparation for the left foot strike. Maintaining a mass center of velocity of 6m/s and an extended right elbow through to final foot strike. Decelerating the mass center at the greatest possible rate by maintaining an extended left knee to transfer momentum to the upper body.

http://www.coachr.org/jav.htm

Sejarah Rejam lembing (javelin) adalah acara olahraga yang tertua dan dipercayai dimainkan sejak zaman purba lagi. Ketika itu lembing digunakan untuk memburu dan sebagai senjata dalam peperangan. Acara merejam lembing mula di pertandingkan dalam Sukan Olimpik Moden pada tahun 1912. Sejak itu, acara merejam lembing merupakan satu acara balingan dalam semua acara sukan dunia. Acara ini juga dipertandingkan di peringkat negeri, daerah atau sekolah. Prinsip asas merejam lembing Merejam lembing berbeza daripada aktiviti membaling yang lain seperti melontar peluru dan melempar cakera. Ini kerana terdapat perbezaan di antara bentuk alatan yang digunakan dan juga kawasan untuk bergerak bagi ketiga-tiga acara sukan itu. Dalam acara merejam lembing, pelatih menggunakan aksi membaling yang lebih kurang sama dengan tindakan membaling sebiji batu atau bola tenis. Selain itu, pelatih hendaklah mempelajari teknik menggunakan keseluruhan badan mereka untuk menghasilkan tindakan yang berkesan semasa merejam lembing. Latihan ansur maju hendaklah dimulakan dengan mengajar para pelatih tentang cara memegang lembing, berlari dengan lembing, merejam dengan cara berdiri dan seterusnya sehingga mereka dapat berlari sambil merejam lembing. Butiran seperti pentingnya meleding badan sebelum merejam, langkah larian yang licin, keadaan tangan yang lurus semasa membawa lembing dan tindakan tumit untuk membantu pergerakan badan adalah perlu kepada para pelatih. Keselamatan para pelatih Semasa membawa lembing 

Mata lembing biarlah menghadap ke bawah

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Jangan berlari

Semasa latihan 

Pastikan tidak ada orang di kawasan merejam

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Perhatikan pergerakan orang lain di sekitar kawasan

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Para pelatih lain yang masih menunggu giliran mereka mestilah berada di kawasan yang telah ditetapkan oleh jurulatih

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Amalkan dasar semua memungut lembing setelah semua merejam

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Susunan dan organisasi kelas hendaklah diatur rapi bagi membolehkan penyertaan setiap pelajar secara maksimum

BAHAGIAN  – BAHAGIAN LEMBING Lembing biasanya diperbuat daripada besi atau logam campuran. Bahagianbahagian lembing terdiri daripada kepala, grip dan ekor. Terdapat dua jenis gaya rejaman yang boleh digunakan oleh perejam lembing. Kedua-dua gaya ini sering digunakan oleh perejam-perejam amatur mahupun professional. Gaya rejaman tersebut ialah Gaya Rejaman Dari Atas Bahu dan Gaya Rejaman Dari Bawah Bahu.

Gaya memegang lembing Terdapat tiga teknik asas memegang lembing iaitu; Gaya Amerika Lembing dipegang di antara ibu jari dan jari telunjuk serta disokong oleh tiga jari yang lain. Gaya Finnish Lembing dipegang di antara ibu jari dan jari tengah. Gaya Pegangan  – U Lembing dipegang di antara jari telunjuk dan jari tengah. Kawasan rejaman lembing Kawasan rejaman hendaklah bebas daripada sebarang gangguan atau halangan serta tidak membahayakan keselamatan orang ramai. Panjang kawasan larian tidak melebihi 36.5 m dan lebar 4 m, manakala kawasan rejaman yang dilebarkan pada sudut 29  – 30 darjah mempunyai jarak 8 m dari pusat lengkungan ke titik sudut. Panjang kawasan ini tidak mempunyai had asalkan bersesuaian dengan taraf atau prestasi peserta. Teknik rejaman lembing Terdiri daripada empat fasa utama seperti berikut:

Fasa persediaan Fasa lari landas Fasa rejaman Fasa ikut lajak 1. Fasa persediaan Fasa ini memberi fokus kpada persediaan fizikal seperti teknik memegang dan menentukan kedudukan lembing serta persediaan mental. Perkara yang perlu diberi perhatian ialah: 

Berdiri dengan keadaan postur badan yang tegak dan seles

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Pegang lembing mengikut gaya pegangan yang dipilih dengan kemas dan selesa

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Lembing berada pada aras kepala dalam keadaan bersudut 40 darjah

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Bahagian kepala lembing hendaklah menghala ke arah kawasan rejaman

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Pandang kearah kawasan rejaman

2. Fasa lari landas Fasa ini bertujuan untuk mewujudkan kelajuan yang maksimum dan dalam keadaan terkawal. Perkara yang perlu diberi perhatian ialah: 

Mulakan larian sambil memegang lembing pada aras kepala

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Tingkatkan kelajuan mewujudkan daya pecut secara terkawal

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Langkah terakhir lebih besar daripada langkah  – langkah sebelumnya

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Tumit kaki hadapan menekan kuat ke tanah semasa memberhentikan larian supaya kuasa larian dipindahkan ke lembing sebelum memasuki fasa rejaman

3. Fasa rejaman Fasa rejaman memerlukan pemindahan kuasa kaki ke lembing untuk memberi kelajuan yang maksimum pada rejaman. Perkara yang perlu diberi perhatian ialah: 

Dalam keadaan tumit kaki hadapan menekan ke tanah, kilaskan badan ke sisi

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Kilaskan badan ke sisi dan belakang dengan menggunakan tangan bebas dan kuasa rotasi pinggang

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Tolak lembing ke belakang dan tarik ke atas dan ke hadapan untuk melancarkan lembing

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Perlakuan ini memerlukan rotasi di pinggang dan lentikan di belakang untuk menambahkan kuasa rejaman

4. Fasa ikut lajak Penyerapan daya dan stabilkan pergerakan selepas merejam adalah penting. Perkara yang perlu diberi perhatian ialah: 

Sebaik sahaja lembing dilepaskan, langkah setapak ke hadapan dan mendarat dengan sebelah kaki

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Imbangkan badan dengan kaki yang sebelah lagi

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Rendahkan badan bagi mengimbang dan menstabilkan kedudukan badan

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Kawal pergerakan supaya tidak melepasi garisan lengkungan bulatan

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http://olahraga2u.wordpress.com/2010/03/18/merejam-lembing/