Javelin

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Analysis of Throwing

Throwing

comprises of two

phases, the

preparatory phase

and the throwing

phase.

Most actions are

rotational in

the

the transverse

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.

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Javelin section for

more details.

Preparatory phase

Joints

involved

Articulating

bones

Action

Agonist Muscle

Shoulder

Humerus

and

scapula

Horizontal

hyperextension

Posterior deltoids

and latissimus

dorsi

Elbow

Humerus

and ulna

Extension

Triceps brachii

Throwing phase

Joints

involved

Articulating

bones

Action

Agonist Muscle

Shoulder

Humerus

and scapula

Horizontal

flexion

Anterior deltoids and

Pectoralis major

Elbow

Humerus

and ulna

Flexion

Biceps brachii

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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

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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.

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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

cross-over 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

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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:

 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.

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S

ejarah

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

 Jangan berlari

Semasa latihan

 Pastikan tidak ada orang di kawasan merejam

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 Para pelatih lain yang masih menunggu giliran mereka mestilah

berada di kawasan yang telah ditetapkan oleh jurulatih

 Amalkan dasar semua memungut lembing setelah semua merejam

 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. Bahagian-bahagian 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

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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

 Pegang lembing mengikut gaya pegangan yang dipilih dengan

kemas dan selesa

 Lembing berada pada aras kepala dalam keadaan bersudut 40

darjah

 Bahagian kepala lembing hendaklah menghala ke arah kawasan

rejaman

 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

 Tingkatkan kelajuan mewujudkan daya pecut secara terkawal

 Langkah terakhir lebih besar daripada langkah_– langkah

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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

 Kilaskan badan ke sisi dan belakang dengan menggunakan

tangan bebas dan kuasa rotasi pinggang

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

melancarkan lembing

 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

 Imbangkan badan dengan kaki yang sebelah lagi

 Rendahkan badan bagi mengimbang dan menstabilkan kedudukan

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 Kawal pergerakan supaya tidak melepasi garisan lengkungan

bulatan