In principle, javelin is a very simple sport. Javelin was first introduced to sports as a part of the pentathlon in the Ancient Greek Olympics. The most simple rule is that competitors take turns throwing a spear as far as they possibly can. The person who throws the spear, which is called a javelin, the farthest is the winner. Javelin has been a part of the modern Olympics since 1908 for men and 1932 for women. The basics of the competition have remained the same over the thousands of years since the Greek Olympics.
Today, there are highly specific rules for the measurements of the javelins that athletes use. Traditionally javelins were made of wood. Now, they can still be made of wood but for the most part they are metal or a fiberglass material. Javelins have to fit specific measurement requirements. For men the javelin has to be between 2.6 and 2.7 meters (approximately 8 feet 6 inches to 8 feet 10 inches) and has to weigh at least 800 grams (1.8 pounds). For women the javelin has to be at least 600 grams (1.3 pounds) and between 2.2 meters (7 feet 3 inches) and 2.3 meters (7 feet 6 inches) long.
When throwing a javelin there are rules you must follow in your physical motion. The first is that the athlete cannot turn their back on the throwing area at any time. This makes sure that while you throw the javelin with as much strength as you can you have to still be under control to stop your body from rotating all the way around. On top of that you cannot leave the throwing area. If any part of your body crosses the line at the end of the runway, your throw is not valid. This line is also called the foul line and the scratch line.
When throwing, you have to throw the javelin above your shoulder, and your arm and the javelin have to remain above the shoulder throughout the entire throwing process. You can only grip the javelin with one hand, and that hand has to stay on the grip of the javelin. You cannot use a glove or tape on your throwing hand unless you are using tape to cover an open wound and have been approved by an official, but you are allowed to chalk up your hand to reduce slipping.
Once you let go of the javelin it can't just land anywhere. The runway in javelin has to be at least 33 yards but cannot be longer than 37 yards. At the end of that runway is the field where the javelin can land. This pitch of grass widens out at a 29 degree angle. There is no limit on its length, though obviously it depends on the arena and the level at which you're playing. In that area the javelin has to hit the ground front tip first. Because of this, the javelin almost always sticks in the ground. If your throw lands on the end of the javelin inside the proper area then you're scored on how far your throw goes, measured from where the tip hits the ground.
What happens if you don't follow all the rules of javelin? During most javelin competitions you have a set number of throws that you get per round. For a majority of competitions that number is four to six. If you cross the foul line or your throw does not land in the 29 degree pitch, or if any part of the javelin hits the ground before the front tip, your throw will not be scored. You can still have your other throws though and if one of those is the best of the day you can still win. If you are caught using something to help you throw like a glove or tape, it becomes up to the discretion of officials. For the most part you will receive a warning and if you already threw, it may be invalidated. If you commit several violations, you may be removed from the competition.
In javelin the furthest throw wins. Usually every athlete gets four to six throws per competition. If the throw lands on the front end of the javelin, inside a specifically marked zone, and the thrower hasn't landed beyond the throwing line, then that throw is scored. However far the throw is from the foul line is that person's score. The farthest throw no matter the attempts is the winner. If there is a tie, the person who's next best throw went the farthest wins.
There are a few fouls you can commit in javelin that will cause a throw not to count. If you cross the foul line with your body or if you turn your back on the throwing field your throw will not count. Additionally, the javelin has to land on its front tip. If any other part of the javelin hits the ground first then the throw is also invalid. If the throw lands outside of the 29 degree area in which it can land the throw also won't be scored.
When you throw a javelin there are specific rules you have to follow. First of all, you can only throw the javelin with one hand. You must keep that hand above your shoulder and throw it in an above the shoulder fashion. The javelin has a grip on it in the middle that you have to use to throw, you cannot use any other part. You can't use anything to help you throw the javelin like a glove or tape. The only exception is if you have any open wounds on your hand you can use band-aids or tape. You can use chalk for grip but that is it.