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The scissors is a style used in the athletics event of high jump.〔G.H.G. Dyson, ''High Jumping'', Amateur Athletic Association, London, 1956, p. 15.〕 ==Description of the technique== As it allows jumpers to land on their feet, it is the style most often used by junior athletes where the landing surface is not deep or soft enough to meet full competition standards. The approach (or run-up) in the scissors is a straight line at 30 to 50 degrees to the bar, jumping over the lowest point of the bar which is usually the centre. Speed is brisk, simply to ensure horizontal travel over the bar, but not a full out sprint, as there is little chance to resolve forward motion into vertical motion at take-off. Horizontal acceleration should be complete by take-off, with the shoulders held high and the take-off leg (the outside leg in the case of the scissors style) flexing to launch the jumper into the air. At take-off the leg nearer the bar (the lead leg) is held straight and swung into the air to clear the bar. At exactly the same time the hips and body are driven into the air by the take-off leg. As the jumper crosses the bar, the trailing or take-off leg has to be quickly swung up to clear the bar. If this occurs as the lead leg crosses and clears the bar, the lead leg can be driven downwards, helping to keep the athlete's centre of mass closer to the bar (in other words, enabling clearance of a higher bar). This up-down/up movement of the legs can best be described as a scissoring action. Once the take-off leg has left the ground (but not before) the athlete should attempt to pull the upper body face down towards the knee, also to keep the centre of mass as close as possible to the bar. Care must be taken not to hit the head against the knee. Driving or swinging the arms into the air at take-off provides additional upwards momentum. The arms can be brought back to the sides during clearance, as a further measure to keep the centre of mass as close as possible to the bar. Even with these measures, it is clear that the bar remains considerably below the centre of mass, so the scissors is far from an optimal clearance technique. Landing from the scissors is usually on the feet, but a landing area of soft matting or sand is desirable to reduce foot impact. No high jumping should be performed without regard to this and other safety issues. 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Scissors jump」の詳細全文を読む スポンサード リンク
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