2008年11月19日星期三

Track spikes

Track spikes are shoes used at most track and field events. They are lightweight shoes with spikes screwed into their bottom, or spike plate, in order to maximize traction (and therefore performance) when running, throwing or jumping.

Near the front of the foot, there are usually 3 to 11 threaded holes where the spikes may be screwed using a spike wrench. There are usually no spikes near the heel, except for high jump and javelin shoes. Some shoes have permanent or "fixed" spikes.

While all track and field shoes that contain spiked soles are referred to as "track spikes", there are differences between sprinting, distance running, and field event shoes. Sprint spikes generally have more support, and a stiffer, more aggressive spike plate. They often are built minimalistically, with as little material and hence weight as possible. Some have zip-up covers for laces, to improve aerodynamics. Distance spikes have a more relaxed plate, more heel support, and contain fewer spike points. They are built as much for support as they are for speed. Field shoes are very different, with each shoe configured for the demands of its event.

Most spikes have the toe of the shoe pointing up, not touching the ground. This is called "taper" and is designed to make the runner run on their toes to run faster. The more aggressive a shoe is, the stronger the taper. Sprint spikes are generally the most aggressive, with the shoes becoming less aggressive as the distance of the race that they are intended for increases. Marathons, for example, are run in racing flats, which have no taper.

Notable spike manufacturers include Nike, Adidas, Brooks, Mizuno, Saucony, Reebok, Asics, Puma AG and New Balance.

The spikes of the shoe vary in size. While most range between 3 millimetres (3/16 inch) and 12 mm (1/2 in), with the most common being the 6 mm (1/4 in), there are a number of specialty lengths, as well as minimal "blank" spikes used to cover a spike hole. The three main types of spikes are the pyramid, the needle (or pin), and the compression tier (or Christmas tree) spike. Pyramids are conical spikes that taper to a sharp point. They normally have a maximum diameter nearly equal to the diameter of the threads of the spike. Needles also have a sharp point, but a thinner cone diameter. The purpose of both is to penetrate the track surface and so derive its traction from its position. The alternate variant for synthetic tracks is the Christmas tree spike. It uses a terraced cone shape with a flat end to, instead of penetrate, compress the track below it upon impact, and use the track's reaction force to in fact return energy to the runner, increasing his speed. It also reduces the damage incurred in the event of "spiking" or contact by the spikes with another runner. Spikes also come in either steel or ceramic varieties, as well as multiple colors (or unpainted).


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