The shape and size of fibreglass sheets and the quantity of fibreglass used is carefully planned to provide required stiffness and length of the pole. While the poles are manufactured various types of fibres are used which includes carbon fibre. This is used in order to give a specific feature and characteristic to the pole. This is also done to promote high jumps. In the recent years, carbon fibre has been included to the commonly used E-glass and S-glass materials in order to create pole with lighter carry weight. Just as in case of high jump, the area of landing originally used to be heap of sand or sawdust where athletes landed on their feet. With the improvement of technology there evolved higher vaults, mats also evolved into bags of huge chunks of foam. Modern day high-tech mats are foam usually 1-1.5 meters (3 ft 3 in-4 ft 10 in) thick, and mats are growing bigger in area as well to decrease risk of injury. The proper technique in landing lies in the back of the shoulder. And landing on the feet must also be avoided, so as to eliminate the risk of injury to the lower extremities, especially ankle sprains. With times and more exposure to the game, the rules keep changing. And the amendment of rules have actually resulted in increased landing area and also added padding of all hard and unyielding surfaces. The pole vault crossbar has actually evolved from triangular aluminium bar to a round fibreglass bar with ends made of rubber. This is then balanced on standards and can also be knocked off when it is hit by a pole vaulter or pole. Rule changes have led to shorter pegs and crossbar ends that are semi-circular. |