What is Discus?

So, you've chosen to learn about the sport of discus throw in track and field. Awesome choice! Perhaps one of the most iconic events of track and field, the discus throw has been a staple of the Olympics since the ancient Greek pentathlons in 708 BC. Let's take a closer look.

We'll first discuss the dimensions and the boundaries of the field, the surface upon which all the jumping and throwing events are held. Afterwards, we'll break down the process of the discus throw into six steps, and explore the rules and strategies for each one.

Discus Glossary Terms

Here are all the terms we will be covering related to the sport of the discus throw in track and field.

• Discus Throw
• Standard Competition Area
• Arena
• Track
• Field  
• Infield
• Throwing Circle
• Protective Cage
• Landing Sector
• Throwing Sector
• Impact Area
• Implement
• Discus
• The WIndup
• The Turn
• Pivot Leg
• The Power Position
• The Release
• Foul Throw
• Fair Throw

History of Discus

Though discus can be traced back to approximately 800 BCE, the event was only officially added to the Ancient Greek pentathlon as a part of the 708 BCE Olympics, along with the javelin throw, the long jump, the standion (a footrace), and wrestling.

When the Olympic Games were reinstated in 1896, men’s discus came with it. Every modern Olympics since then has had the men’s discus event.

The International Amateur Athletic Foundation (IAAF), which was created in 1912, is now the ruling body for all track and field athletic events, including the discus throw, and holds its own World Championships every two years.

Throwing The Discus

The goal of the discus throw is for the competing athlete to throw his or her discus as far as possible. The technique used in throwing the discus is very specific and makes use of a specific rotation as the athlete usually completes a 540-degree spin on his or her way to launching the discus.

A participant’s attempt is only legal if he or she remains within a 2.5 meter-diameter circle during the throw and until the discus lands. The discus must also land inside the specified landing sector, which is a zone that extends outward from the center of the aforementioned circle at an angle of 34.92 degrees.

The Discus Throw Facility

The discus throw facility is made up of three components:

1. The Throwing Circle

2. The Protective Cage

3. The Landing Sector

The Throwing Circle

The throwing circle is the concrete circle of diameter 2.5 m, bordered by a rim with a thickness of 6 mm, within whose boundaries the discus must be thrown from.

The Protective Cage

The protective cage is the net surrounding the throwing circle in a U-shape, designed to protect the spectators and the officials from an inadvertent throw by the athlete into their direction. Thus, this net is strong enough to stop, without rebounding, the flight of a 2 kg discus travelling at 25 m/s, and its height is no lower than 4 m.

The Landing Sector

The landing sector, also known as the throwing sector or the impact area, is the wedge-shaped area with a soft, even surface, upon which the implement in a throwing event must initially land in order for the throw to be considered valid. For the discus throw, the landing sector is centered with respect to the throwing circle, and has an angle of 34.92 degrees and a length of 80 m.

Furthermore, the surface of the landing sector is typically made of a soft, even material, such as cinders or grass, which can absorb the impact of the discus as it lands, and prevent it from rolling or bouncing away, ensuring that the most accurate distance can be measured by the event officials.

The Number of Competitors

Only one competitor at a time is allowed to attempt the discus throw. This means that only the eligible competitor may be in the discus throw facility at any given time. All other athletes who have finished their attempts, or are awaiting their turn, must ensure that they are not in contact with any part of the throwing sector, the protective cage, or the landing sector.

The Throwing Circle

The throwing circle is the concrete circle of diameter 2.5 m, bordered by a rim with a thickness of 6 mm. Although the competitor is allowed to make contact with the inner part of the rim, he may not touch the top surface of the rim or the area outside the throwing circle with any part of his body or clothing during the course of the throw. In addition, the competitor may not leave the throwing circle before the discus has fully landed. Disregarding the boundaries of the throwing circle, even if it is accidental, will result in the attempt being declared an invalid foul throw.

The Discus

The discus is a metal disc that varies in weight and diameter. In the men’s event, the disk weighs two kilograms and is measured at 22 centimeters in diameter. Women, however, use a disc that weighs one kilogram and is 18 centimeters in diameter.

The discus is the implement that is thrown for distance by the competitor during the discus throw.

The Construction

The discus is a symmetrical, lens-shaped disc, whose outer surface is constructed of plastic, wood, fiberglass, carbon fiber, or metal. The body may either be solid or hollow, but must contain a metal core, which contributes to the majority of the discus' weight. Furthermore, the entire outer edge of the discus is rimmed in smooth metal, which must be free of any roughness, unevenness, or potential finger holds.

The Weight

In elite international competitions, the discus that is used for the men's discus throw has a weight of 2 kg and a diameter of 22 cm, while the one that is used for the women's discus throw has a weight of 1 kg and a diameter of 18 cm.

Discus Types

There are four main types of discus that a competitor can use, depending on his individual preference and level of performance:

1. Very High Spin Discus: In this discus, 85 - 92 % of the total weight is from the rim alone. It is used mostly by top athletes, who are able to generate a significant level of spin.

2. High Spin Discus: In this discus, 80 - 84 % of the total weight is from the rim alone. It is used mostly by advanced athletes, who are able to generate a high level of spin.

3. Low Spin Discus: In this discus, 75 - 80 % of the total weight is from the rim. It is used mostly by intermediate  athletes, who are able to generate a moderate level of spin.

4. Center-Weighted Discus: In this discus, 60 - 70 % of the total weight is from the rim. It is used mostly by beginning athletes, who are able to generate a low level of spin.

Although a discus with a higher concentration of its weight in the rim will be more difficult to throw, it will also be able to travel a greater distance, if thrown properly, by producing greater angular momentum, which results in a more stable flight.  

The Discus Grip

In order to properly hold the disc, the non-throwing hand must first be placed beneath the discus for support. The fingers and thumb of the throwing hand must then be evenly spread on the top side of the discus.

There are two ways that the fingers and thumb of the throwing hand can be arranged on the top side of the discus:

1. Slide the throwing hand up towards the edge of the discus, so that the knuckles of the fingers, excluding that of the thumb, are aligned with the rim and the fingertips are hanging off the side.

2. Move the index and middle fingers of the throwing hand close together, then evenly spread out all the remaining fingers. However, unlike the grip strategy above, do not move the throwing hand towards the edge. No finger should be hanging off the discus.

The Number of Attempts

Every competitor is given three attempts to throw the discus as far as possible from within the throwing circle onto the landing sector. Although all fair throws of a competitor will be recorded by the officials, only the one with the greatest distance will be used to determine the athlete's standing in the event.

The Time Limit

For each attempt, the competitor is typically given a total of 1 minute to start his wind up for the throw. If a competitor fails to initiate his attempt before 1 minute has passed, the attempt will be declared a foul throw.

The Throwing Circle

Unlike the foot racing events of track and field, there is no official start line for the discus throw. Instead, competitors are free to initiate their approach run at any point within the boundaries of the throwing circle. However, keep in mind that an attempt in which the competitor either leaves the throwing circle before the discus has fully landed, or touches the top surface of the rim or the area outside the throwing circle during the course of the throw, will result in the attempt being declared an invalid foul throw.

The Start Point

The athlete typically initiates the discus throw from the edge of the throwing circle furthest away from the landing sector.

The Start Position

Once the athlete has determined his start point at the very back of the throwing circle (assuming that the front of the throwing circle is the part closest to the landing sector), he must first make sure that his body is completely facing away from the landing sector. In other words, the athlete must be 180 degrees away from the landing sector.

Next, the athlete must assume a half-squat position, with the legs shoulder-width apart and the knees and waist slightly bent.[4] The athlete can either distribute the weight evenly on both legs, or put the majority on the non-throwing leg (the leg that is on the same side of the body as the non-throwing arm). The upper body must also lean forwards slightly, so that the chest is over the knees. Furthermore, both arms should be held out straight onto either side of the torso, and raised almost up to shoulder-height.

Note that the discus must be gripped single-handedly by the throwing hand, without support from the non-throwing hand. There are two ways that the fingers and thumb of the throwing hand can be arranged on the top side of the discus:

1. Slide the throwing hand up towards the edge of the discus, so that the knuckles of the fingers, excluding that of the thumb, are aligned with the rim and the fingertips are hanging off the side.

2. Move the index and middle fingers of the throwing hand close together, then evenly spread out all the remaining fingers. However, unlike the grip strategy above, do not move the throwing hand towards the edge. No finger should be hanging off the discus.

Do not make the mistake of gripping the discus single-handedly by placing the throwing hand on the underside of the discus. The throwing hand must always be on the top side of the discus.

Windup Objectives

The objective of the wind up is for the athlete to establish a steady swinging rhythm from one side of the body to the other. This is essential to building up the necessary power and momentum for the discus to travel the greatest distance possible.

The Wind Up Strategy

From the start position, the athlete must begin to swing the throwing arm, keeping it straight and outstretched, towards the opposite side of the body. The trajectory of the throwing arm's swing must be as horizontally straight as possible, and not resemble that of a parabola.

Note that the non-throwing arm must also continue to be held out straight onto either side of the torso, and raised almost up to shoulder-height. As the throwing arm swings over, the throwing hand and the discus will naturally fall into the non-throwing hand.

The athlete, now with both hands gripping the discus, must then swing both arms back towards the side of the throwing arm. Again, note that the trajectory of the swing must be kept as horizontally straight as possible, and not resemble that of a parabola.

Depending on the personal preference and level of performance for each athlete, it may also be advantageous to shift the weight distribution from side to side during the swing, as this will help build up momentum even further.

This two-armed, horizontal swing is then repeated for as many times as the athlete feels necessary to build up sufficient momentum and establish a rhythm.

The Turn Objectives

Once the athlete has built up sufficient power and momentum from the wind up, he must move on to the next step - the turn. This stage of the discus throw acts as a transition between the wind up and the release of the discus through a series of two half-revolutions.from the back of the throwing circle to the front.

The Turn Strategy

The turn can be divided into three steps:

1. The Position

2. The Initiation

3. The Completion

The Turn Position

Immediately after the athlete feels that his wind up is complete, he must begin rotating the head and torso towards his throwing side. Simultaneously, both arms must be separated, with the throwing arm single-handedly holding the top side of the discus again. The throwing arm must then be stretched back beyond the torso, at about a 90-degree angle with the shoulders, while the non-throwing arm is stretched out into the opposite direction. The athlete's weight must also be shifted onto his throwing leg, while on the non-throwing side, the knee must be bent and the heel raised off the ground.  

The Turn Initiation

The athlete must now start shifting his weight back onto the non-throwing leg, while further rotating the head and torso towards the throwing side to face the landing sector. At the same time, the athlete must also pivot about the non-throwing foot to swing the throwing leg over the non-throwing leg, towards the center of the throwing circle. This is the first half-revolution.

The Turn Completion

If the above step was performed correctly, the throwing foot (the foot on the same side of the body as the throwing leg) should land mid-center on the throwing circle. However, just before the throwing foot makes contact with the ground, it is critical that the athlete pushes off on his non-throwing foot to continue pivoting towards the front of the throwing circle. Thus, the athlete will momentarily be slightly air-borne. This is the second half-revolution.

Transitioning to Power

By the end of the two half-revolutions, the athlete's non-throwing foot will have been brought to the edge of the throwing circle closest to the landing sector, while the throwing foot remains planted mid-center.

As soon as the non-throwing foot lands on the edge of the throwing circle, the athlete must immediately assume the power position, which will allow for the greatest transfer of power and momentum that have been built up through the wind up into the flight of the discus.

The Power Position Strategies

Firmly plant the non-throwing foot on the ground, as it lands on the edge of the throwing circle closest to the landing sector. The throwing foot, which should have remained planted mid-center, must now be raised off the heel and up onto the toes, while carrying the majority of the athlete's weight.

The non-throwing arm must also be pointed forward towards the landing sector, while the throwing arm is fully outstretched high behind the athlete. The discus, held single-handedly by the throwing hand, must be held at about hip-height.

Finally, to transfer as much power and momentum as possible into the flight of the discus, the head should be thrown back, facing upwards into the sky.

The Release Objective

The objective of the release is to launch the discus into flight at precisely the height, angle, and velocity that will allow it to retain as much power and momentum as possible, and thus travel the maximum horizontal distance through the air.

The Release Strategies

From the power position, continue pivoting the hips towards the throwing side, while increasingly shifting the weight forward towards the non-throwing leg. This is the third and final half-revolution that a competitor will make in the discus throw.

While pivoting, simultaneously raise the throwing arm from hip-height up to an angle of 35 degrees above the shoulders. Note that the throwing arm must continue being held directly outstretched to the side of the body, not angled in front or behind.

At this point, the athlete must now release the discus into the flight stage. While stretching up onto the balls of the throwing foot, the athlete must gently relax his grip on the discus. If the discus had been held properly, it will smoothly slide off the index finger and enter flight.

But we're not done yet! The follow through is another crucial step in ensuring that the competitor's attempt is a valid fair throw.

The Follow Through

The competitor may not leave the throwing circle at any point during the course of the throw, or before the discus has fully landed. Disregarding the boundaries of the throwing circle, even if it is accidental, will result in the attempt being declared an invalid foul throw.

Therefore, in order to eliminate the possibility of losing his balance and inadvertently stumbling out of the boundaries of the throwing circle, the athlete must immediately initiate the follow through after the discus has been released.

The Follow Through Strategies

Both feet must immediately be fixed onto the ground and remain firmly in place, while the throwing arm continues on its swing trajectory across the torso. At the same time, the athlete must also twist his torso to follow the path of the throwing arm, rotating the upper body from the throwing to the non-throwing side. Doing so ensures that the athlete retains his balance and does not commit a foul throw.

The Completion of the Attempt

Every competitor is given three attempts to throw the discus as far as possible from within the throwing circle onto the landing sector. A competitor is deemed as having completed an attempt at the instant when the discus makes contact with the ground.

Fair Throw

A fair throw refers to an attempt in which the discus throw competitor has abided by all the boundary rules throughout and after the course of the throw, and the discus has landed within the boundaries of the landing sector.

Foul Throw

A foul throw refers to an attempt in which the competitor has broken one or more of the event rules. The distance thrown by the athlete in a foul throw will not be recorded or considered in determining the winner.

A foul throw is declared when the one or more of the following occurs:

1. The competitor has failed to initiate the attempt before the appropriate amount of time has elapsed.

2. The competitor has made contact with the top surface of the rim or the area outside the throwing circle during the course of the throw.

3. The competitor has left the throwing circle before the discus has landed.

4. Upon landing, the spot that the discus made initial contact with was on or beyond the boundaries of the landing sector.

Disqualification

Every competitor is given three attempts to throw the discus the greatest possible distance onto the landing sector. A total of three failed attempts or foul throws will result in the elimination of the competitor.

The Distance Measured

The distance travelled by the discus is measured in a straight line from the inner circumference of the throwing circle to the nearest mark left on the landing sector by the discus.  

The Winner

The winner of a discus throw  event is the competitor whose discus has travelled the greatest distance. Note that although all fair throws of a competitor will be recorded by the officials, only the one with the greatest distance will be used to determine the athlete's standing in the event.

Dispute Resolution

In the rare event that the greatest distance thrown by two or more athletes is exactly the same, the event official will then examine the second-greatest distances that have been thrown by the tied competitors. The individual with the greatest second-greatest distance will then be declared as the winner.