There are three main styles people use for the high jump - scissors, straddle and the Fosbury Flop (named for Dick Fosbury, who invented it). At school, people are often taught scissors first, and only go on to the other styles if they show promise. Why do you think good jumpers don't use the scissors style. What do you think is the advantage of the Fosbury Flop?
The answer to this question lies in the position of the jumper's centre of gravity. In the scissors style, all of the jumper passes over the beam at the same time, and so the centre of gravity is above the bar (as in the diagram on the right here). However with the Fosbury Flop, only one part of the jumper passes over the beam at any one time, and the jumper's centre of gravity remains under the beam. This requires less energy, as the centre of gravity does not have to be raised so far, and so people can jump higher using this style.
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