The recurve bow, featuring limbs that curve away from the archer to increase power is the only type of bow allowed in Olympic competition. The lever effect created from a recurve bow can propel arrows in excess of 150 miles per hour.
Archery is an ancient sport that is really making use of modern technology. In the early 1900s, archers used wooden bows with a string. In the old days, string material was not very consistent. So when an archer found a string that shot well they would save it for major competitions or only use it when the competition got tough. They did not want to shoot it too much and take the chance of breaking it. So they would shoot their second or third string until it was critical and then they would put on their "first string".
Modern bows are made of aluminum, carbon, titanium, graphite and fiberglass. The modern Olympic bow has a machined aluminum handle (riser), and limbs (the flexible ends) made from carbon, syntactic foam and fiberglass. The bowstring is high tech too being made from spectra fiber, commonly used in bullet proof vests and many other applications where its light weight and stronger than steel properties are needed. Sights are used on bows for accuracy and stabilizers give a little weight and balance to the bow.
The use of carbon in arrows has been one of the biggest changes in modern archery equipment. The most high tech arrow of modern times is the Easton X10, barreled in shape and consists of a carbon/aluminum composite tube. The shaft has a polycarbonate nock, usually Mylar fletching and a ballistic grade tungsten point. A dozen of these arrows cost approximately $500.
In a typical tournament of four days, men lift and draw their 50-pound bow more than 300 times, which is equivalent to a total of 15,500 pounds or nearly eight tons. An elephant weighs anywhere from 8,800 to 15,500 pounds. Women use a 34-pound bow, pulling for more than 10,200 pounds or nearly five tons.
The average bow weight for women shooting in the Olympics is 39 pounds. The average bow weight for men shooting in the Olympics is 47 pounds.