[1] (shot put) Why is the weight of the shot put 7.257kg, and why do you want to keep three decimal places? This has to start with the origin of shot put. 1340, the world's first artillery appeared in Europe, using gunpowder guns. The shell is made of iron and looks like a ball. The weight of a shell is 16 pounds, or 7.257 kilograms. When soldiers are resting, they push shells around to play, which gradually developed into a physical exercise method and was later included in track and field events. However, some people think that the iron casting ball is too big and inconvenient to use, so they change the lead in the iron shell to become the shot put, and the weight is still the shot put.

It's 7.257 kilograms. Because the specific gravity of lead is greater than that of iron, the volume of shot put is much smaller than that of iron ball under the condition of constant weight, so it is much more convenient to use. But now the shot put of 7.257 kg (rounded to 7.26 kg) is only used in men's competitions. The shot put in the women's competition is 4 kg, but the decimal number is no longer reserved. Shot put is a traditional event of track and field in the world. In ancient times, faced with the harsh natural environment and primitive low-level productivity, in order to survive on the earth, human beings not only had to run fast, or quickly jump over obstacles to chase all kinds of animals, or avoid the harm of wild animals, but also learned to use tools to throw stones, harpoons, harpoons and so on. In order to hit prey and get food. During the period of slavery, with the evolution of human beings and the progress of society, throwing heavy stones has become an important way of fighting. In order to improve their respective combat effectiveness, throwing heavy stones is regarded as an important training means. In ancient Greece, there was a stone-throwing competition, which was regarded as an important criterion for selecting Hercules. According to legend, around the year 1 150, a massive stone-throwing competition was held in Athens, Greece. According to the regulations, Hercules held the boulder high and threw it into the distance, and the victory or defeat was determined by the throwing distance. This can be said to be the predecessor of shot put. Around AD 1340, artillery began to appear in Greece. Shells are made of round lead. In order to make gunners skillfully, quickly and agilely load shells in battle and improve the combat capability of the army, the Greeks let soldiers practice with stones with the same weight as shells in daily training and compete. Later, abandoned lead bullets were used instead of stones for simulation training, which is the direct origin of modern shot put. After that, this kind of training changed from the army to the people, and gradually became a game of shot put. It quickly spread and became a popular sports competition. 1896, shot put became the official event of the first modern Olympic Games. Since its birth, it has always been the darling of Hercules, enabling Hercules around the world to show its glory.

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Originated from ancient human activities of hunting animals or defending attacks with stones. launch

Modern shot put started from 65438 to 2004, when European artillery pushed and threw shells in their leisure time in the 1940s, and gradually became a sport. The production of shot put has experienced the process of using iron, lead and lead in external iron. In the official competition, the weight of men's shot put is 7.26 kg, and the diameter is 1 1~ 13 cm. The women's shot put weighs 4 kg and has a diameter of 9.5 ~ 1 1 cm. There is no fixed way to put the shot in the early stage, and it can be put in place or run-up; Can be pushed with one hand or both hands; There are also competitions classified by weight [2]. At first, the shot put technique was used in situ, and then it gradually developed to lateral push and upper push. In 1950s, American athlete O 'Brien invented the back sliding shot put technique, which was called "a revolution in the history of shot put". In 1970s, the Soviet athlete Barry Sinkov invented the spinning shot put technique, but it is difficult to control the body balance after spinning, so far only a few athletes have used it. During the competition, the athlete should use one hand to push the ball from the shoulder and make a circle with a diameter of 2. 135 meters. The shot put must fall within the angle line of the landing area to be effective. Men's and women's shot put were listed as Olympic events in 1896 and 1948 respectively.

Edit this paragraph standard

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The shot put is heavy and round, and it is a metal ball with a smooth surface. In men's competition, the shot put diameter must be between 1 10- 130mm, and for women it must be between 95-1/0 mm. In the shot put competition, the sport is to stand in the throwing circle and start throwing. The periphery of the throwing ring is inlaid with iron, 6 mm thick, and the top is painted white. When throwing, athletes must not touch the top of the iron edge or the ground outside the throwing circle. The diameter of the shot put throwing ring is 2 135 meters, and the inner surface of the ring is cement or anti-slip material with similar hardness, and the height is slightly lower than the ground height. There is a wooden baffle with a length of1.21-1.23m in front of the shot put ring to prevent the athletes from slipping out of the ring. Athletes can touch the inside of the board, but not the top of the board. In the competition, the landing zone is a flat area composed of cinders, lawns or other substances that can leave traces. Each sector is separated by a 5 cm wide white line. In the shot put competition, the sector angle of the landing zone was changed from 40 degrees to 34.92 degrees in 2003.

Edit the stadium equipment in this paragraph.

Throwing area

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In the shot put, discus and hammer throw competitions, athletes all stand in the throwing circle and start throwing. The throwing ring is surrounded by metal edges, 6 mm thick, and the top is painted white. When throwing, athletes must not touch the top of the iron rib or the ground outside the throwing circle. The diameter of the throwing circle of shot put and hammer throw is 2. 135 meters, and the throwing circle of discus is slightly larger, with a diameter of 2.5 meters. The ground in the ring is made of cement or anti-slip material with similar hardness, and the height is slightly lower than the ground height. Put a wooden toe board in front of the shot put ring to prevent athletes from slipping out of the ring. Athletes can touch the inside of the toe board, but not the top of the toe board.

Falling area

In all throwing competitions, the landing area is a flat fan-shaped area composed of lawns or other substances that can leave traces. Each sector is separated by a 5 cm wide white line (this 5 cm wide white line is not included in the landing zone). The fan angle of the shot put, hammer throw and discus throw area is 34.92 degrees, and the javelin throw is about 29 degrees. The shot put used in the Olympic Games and world track and field competitions should be made of solid iron, copper or any other metal with hardness not lower than copper. The shape of the shot put must be spherical and the surface must be smooth.

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During the competition, athletes who commit the following violations will be sentenced to a foul and their results will be invalid: ① exceeding the time limit; (2) The throwing techniques of shot put and javelin do not conform to the rules (the rules require that shot put and javelin must be thrown with one hand on the shoulder); (3) When throwing, no part of the body and apparatus shall touch the ground along or outside the iron ring of the throwing ring and any part of the ground outside the throwing arc, extension line and line of javelin, including the top of the toe board of the shot put, otherwise it will be a throwing failure; (4) Athletes are only allowed to leave the throwing ring or the run-up path after the equipment has landed. Javelin athletes can't completely turn their backs on the javelin before it hits the ground after throwing it. After throwing, hammer throwers, discus throwers and shot putters must withdraw from the extension line of the second half of the throwing circle. Javelin athletes must quit after throwing arcs and extension lines; ⑤ If there is no foul, the competitor can stop the trial throwing action that has already started, leave the throwing area temporarily after putting down the equipment and start again, but the throwing must be completed within the specified time limit; 6. Participants can leave the competition area during the competition, but they must get the permission of the referee and be accompanied by the referee; ⑦ During the competition, athletes are not allowed to use the following electronic devices in the competition venue: cameras, portable tape recorders, radios, CD players, walkie-talkies, mobile phones, MP3 players and similar electronic devices.

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In throwing events, there are usually two referees holding a red flag and the other white flag to show whether the athletes have succeeded in trying to throw. Holding a red flag means that the trial vote failed and the result is invalid; Holding a white flag means a successful and effective result. One of them standing near the throwing area is called infield referee, who mainly judges whether the athlete commits a foul in the trial throw; The other one in the landing area is called the outfield referee, which mainly judges whether the landing point of the instrument is effective.

Edit this paragraph to watch the game etiquette.

Any sport with a long history carries its specific culture, and track and field is no exception. Track and field enthusiasts should watch the game as an act of feeling the beauty of sports and the charm of life. Track and field is the biggest event in the Olympic Games. When watching track and field events, we should generally pay attention to the following points: 1. Sit down in advance when watching the game, so as to respect the athletes and not affect others to watch the game. 2. When awarding prizes, raising flags and playing music, stand up quietly, don't laugh, and don't do anything else to show respect. When the athletes appear, the audience should give encouragement and applause, not only to the country and their favorite athletes, but also to other athletes. 4. When the athlete starts to jump, throw and run up, the audience can applaud according to the rhythm of the athlete's run-up, and be careful not to walk around in the stands at will. In high-altitude events, no matter how high the athletes are, they will eventually reach an unsurpassed height. So we should congratulate the athletes when they successfully cross a certain height. But when the athletes finally failed to cross the higher bar and end the game, the audience should also give the athletes warm applause. 6. In short-distance track events, when the athletes stand behind the starting line and the announcer begins to introduce each athlete, the audience should give warm applause and cheers to show their love and support for the athletes. When the referee gives the password of "take your positions", that is, when the athletes bend down to prepare for the start, the stadium must be absolutely quiet. The audience should not applaud and cheer, but cheer for the athletes silently in their hearts, and don't distract the athletes because of off-court factors. When the starting gun goes off, the audience can fully release their energy and passion and cheer for their idols. 7. In some long-distance events, such as marathon, when the athletes who are far behind insist on the finish line, the audience should give these athletes the warmest applause and applaud their spirit of dedicated participation. 8. At the end of the game, the winning athlete usually goes around the field to thank the audience. Everyone must express their appreciation and encouragement for their wonderful performance with applause and cheers. 9. Take care of the stadium as your home. Smoking is prohibited in the stadium, and the mobile phone should be turned off or set to vibration mute.

Edit this paragraph posture classification

In-situ shot put

Turn your back to the throwing direction, turn your torso and shoulder straps to the right, lean forward (depending on the strength of your legs), load your right leg, and stretch your left arm and shoulders forward and buckle slightly inward. The pushing action is the same as the technical part. Pre-position before sliding: Pre-position once or twice before sliding. When pre-swinging, the left leg bends naturally, the thigh swings upward forcibly and steadily, the right leg straightens, and the upper body bends forward. The left arm is slightly bent forward or drooped and slightly inward, and the head and back are kept in a straight line.

lofty stance

Stand with your back facing the throwing direction, close to the back edge of the circle, and stand with your feet back and forth, with a distance of about 20-30 cm. The tip of the right foot is close to the inner edge of the throwing ring (the foot can also be turned inward slightly), and the left leg is at the back, naturally bending before the sole or toe touches the ground. Your upper body is upright and relaxed, your left arm naturally rises and your weight falls on your straight right leg.

Low posture

Hold the ball with your back to the throwing direction, stand near the back edge of the circle, and stand back and forth with your feet at a distance of about 50-60 cm (depending on your height and squat degree). The left foot is behind, the forefoot or toe touches the ground, and the tip of the right foot points in the opposite direction of throwing near the circle (the foot can also be slightly turned inward). The left arm hangs naturally, the left shoulder is slightly buckled inward, the legs are bent, and the upper body leans forward.

Editing skills of shot put in this slide

★ Method: ★ Out-of-bounds Freehand Slide Exercise: Shot Put

Swing leg swing exercise: pull the left hand to shoulder-high fixture or companion's hand. When the left leg is retracted close to the right leg, it quickly extends in the direction of the toe board. The method is the same as above, but before the left leg swings in the throwing direction, the center of gravity of the body moves later, then the left leg swings and the right leg stretches to push the body to move in the throwing direction. Exercise of pulling the right leg: the legs are upright back and forth (feet are shoulder width apart) and the weight is between the legs. The upper body leans forward slightly From this position, quickly put the calf under the center of gravity to bear the body weight and maintain balance. When the right foot is close to the center of gravity and touches the ground quickly, the left leg quickly retreats to form a posture before the final exertion. Freehand gliding exercise: stand on a high place, swing your legs to a certain height, and gradually bend your right leg to lower your center of gravity during recovery. When the left leg recovers to be close to the right leg, complete the knee flexion, and immediately start the sliding action after the body is stable, and the continuous sliding action can be carried out after the movement is skilled. ★ Slide light shot put: In teaching practice, although students have mastered the technique of freehand slide, it is often difficult to finish it because of the certain weight after holding the ball. In order to ensure the coordination of movements, you can use a lighter ball at the beginning of holding the ball and gradually increase the weight at the later stage. Sliding shot put: Sliding shot put is carried out on the basis of preliminary mastery of sliding and final exertion. ★ At the end of the last hard slide, the right foot landed before the left foot. After the right foot touches the ground, the right leg actively stretches to push the right hip to rotate in the throwing direction. The upper body gradually rises in rotation, while the muscles of the trunk contract actively. The left arm and the left shoulder are higher than the right shoulder, the shot put is kept as low as possible, and most of the weight is still on the bent and compressed right leg. The right leg is extended, and the right hip is further sent out in the throwing direction, and the right arm pushes the ball out quickly and forcefully. When the shot is about to be shot, turn your wrist slightly inward and bend your wrist at the same time, and pull the shot quickly and forcefully to make the shot leave your fingers. After the shot put leaves, the legs bend or exchange, reducing the center of gravity, buffering the forward momentum, maintaining the balance of the body and preventing fouls. ★ In the specific teaching steps of sliding shot put, firstly, we should repeatedly practice the coordinated action of right leg extension and left leg support after sliding to solve the connection between sliding and shot put, and secondly, we should push the ball out of the circle with a lighter shot put.

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Holding the ball ★ Players' fingers are naturally separated, and the ball is placed at the roots of the index finger, middle finger and ring finger, and the thumb and little finger are supported on both sides of the ball (Figure) to prevent the ball from sliding and facilitate the control of the ball direction. Don't touch the ball with your palm. launch

★ After holding the ball, the left side of the body faces the throwing direction, the left and right feet are slightly wider than the shoulders, and the left toe points obliquely forward and is in line with the right foot arch; The right knee is bent, the upper body is tilted and twisted to the right, and the center of gravity falls on the right leg; The left arm is slightly bent on the chest, so that the vertical line of the ball leaves the outside of the right foot, so as to lengthen the exertion distance and tighten the left muscle. When pushing the ball, the right foot pushes the ground quickly and forcefully, the heel is lifted, the right knee is varus, and the right hip is sent forward, so that the upper body is lifted to the left and rotated in the throwing direction. When the left side of the body is vertical to the ground, take the left shoulder as the axis, quickly straighten the right leg, turn the body to the throwing direction, hold your head high, forcibly send the right shoulder forward, and quickly straighten the right arm to push the ball forward and upward at an angle of about 40-42 degrees (as shown in the figure). When the ball leaves your hand, your wrist should be hard and you should stir the ball with your fingers. At the same time of putting the shot, the left leg should be forced upward to increase the forward and upward strength of the shot put. After the ball is released, the right leg is quickly exchanged with the left foot, and the left leg is lifted back, which lowers the center of gravity, buffers the forward force and maintains the balance of the body.

Error correction of shot put when editing this paragraph

★ Improper exertion of fingers and wrists during shot put (sometimes causing contusion) Reason: Fingers are completely relaxed during shot put, fingers and wrists are weak, and the exertion is too strong during shot put. ★ Correction method: It is required that the fingers have a certain tension when holding the ball; Pay attention to developing fingers, wrists and strength; Practice with a light shot put, and pay attention to the order of exertion. ★ When putting the shot, the elbow joint drops, resulting in throwing the ball. Cause: The elbow joint of the ball-holding arm is too low, and the head turns to the throwing direction too early during sliding or shot putting. ★ Correction method: Pay attention to arm movements when holding the ball, do more positive push, and ask the elbow joint to be raised (not higher than the shoulder). When the slide begins to push the ball (lifting stage), the eyes are still looking at the front and the bottom. ★ The sliding distance is too short. Reason: The kicking and swinging strength is not enough, or the combination is not good, or the calf is not pulled actively. ★ Correction method: Repeatedly practice the combination of pedaling and swinging movements with bare hands or holding the ball; Continue to do the exercise of pulling the calf; Draw a sign with two feet touching the ground. Let the students slide on the sign and touch the ground. ★ Reasons for large fluctuation of the body's center of gravity during sliding: kicking the ground or swinging the legs too upward; The right leg is not straight, and the calf contracts prematurely. ★ Correction method: Move the body center of gravity later before sliding; When the left leg swings, it is required to touch the marker in the rear (throwing direction) (the height of the marker is lower than the hip). ★ After sliding, you can't keep the correct posture before throwing, your upper body is lifted too early, and your body center of gravity is between your legs. Reason: The stretching and retracting movements of the right leg are not perfect. First, the leg is slow or jumping. Second, the retraction distance is short and will not fall below the center of gravity of the body. In addition, in the sliding step, the left arm swings to the left or the head rotates in the throwing direction to drive the upper body to move; When sliding, lift the upper body and move the center of gravity in the throwing direction. ★ Correction method: do leg contraction with bare hands or continuous holding of the ball; The teacher pulls the students' left hand on their right side (later), or presses the upper body behind them to practice sliding. ★ Reasons for pause after taxiing: the left leg swings too high and the landing is not active; The strength of the right leg is weak, and the center of gravity drops too much after sliding. ★ Correction method: Turn your back to the throwing direction, open your feet left and right, bend your legs, lean forward, then take a step back with your left foot, and after landing voluntarily, push your right foot to the ground quickly; After sliding with the ball, push the ground with your right leg; Strengthen leg strength training. ★ When pushing the ball, you don't need the strength of your back muscles and lower limbs, just the strength of your arms. Reasons: the throwing arm is forced too early, and the order of force is not clear; The movements of all parts of the body are uncoordinated; Finally, the posture is not correct when exerting force, and the body center of gravity is between the legs. ★ Correction method: The students are ready to put the ball, and the teacher holds the students' right hand in front, or the teacher holds the students' right hand behind, asking the students to kick their legs repeatedly and lift their bodies; The students are ready, the teacher presses the students' left shoulder with his left hand behind his back, and when kicking the students, his right hand pushes his right hip to rotate in the throwing direction; Push the ball in place (front or side), and use the whipping action of lower limbs and upper body to push the ball out conveniently. ★ Causes of hip recoil when pushing the ball: the right leg is not fully pedaled, and the hip fails to turn in the opposite throwing direction; Finally, the distance between the feet before and after the force is too long; The left foot brake is big; Afraid of thigh foul. ★ Correction method: The teacher stands behind and puts his hands on both sides of the students' hips to help turn around and send the hips when pushing the ball; To do the final hard exercise with bare hands, it is required to touch the marker at a certain height and distance above the front with your right hand. ★ The reason why the body leans to the left when pushing the ball: the left arm swings excessively to the left and rear; The position of the left foot is too far to the left, which leads to the excessive interval between the left and right feet and the unstable support of the left side. ★ Correction method: First fix the elbow of the left arm on the side of the body and push the ball into place; Fix the marker in front of the right side, and push the ball in the direction of the marker (or push it by hand); Draw the position of the foot on the ground, and ask the foot to slide and land on the sign; Fix an object with your back. Practice putting the ball back in place with your bare hands. ★ Reasons for low hand angle when pushing the ball: weak left foot support or knee joint bending; Bow your head or turn to the right, back and down when pushing the ball; Push the ball slowly. ★ Correction method: Before throwing, hang a mark at a certain height and distance above, and ask to push out the ball contact mark on the ground; Push the crossbar at a certain height and distance (the height and distance of the crossbar and marker depend on the students' grades).