澳门金沙网页游戏:Get stuck in

日期:2019-03-08 08:17:04 作者:闾鲥 阅读:

By Matt Walker FOOTBALLERS should be able to get off the mark faster thanks to boots equipped with a new type of stud. The new boots, launched this week by sportswear maker Mitre, have pyramid-shaped studs with a flat edge perpendicular to the toes. Mitre claims the studs give the boot a better grip than conventional round studs and can increase acceleration over the first five metres of a player’s run. This could give players a crucial edge when they are racing to get to the ball. The stud, which is made of moulded plastic, has a hexagonal metal head that can be gripped by a spanner to screw it into the sole of the boot. The new stud was the brainchild of biomechanics expert Jenny Mitchell, a member of Mitre’s research team. She realised that traditional cone-shaped studs lack grip when players drive themselves forward. “Round studs are the worst you can have,” she says. Because soft ground is essentially fluid, the studs cut through the soil with the minimum of drag, she explains. And drag equates to grip. “So we looked at putting in a flat edge to increase the drag,” she says. Mitre has shaped the stud so that it only increases grip when players are going forwards. Too much grip on the outside edge of the boot could lead to players twisting their ankles when turning, Mitchell says. Initial tests with amateur players showed that the studs improved acceleration by an average of 13 per cent, equivalent to a half-metre head start over the first five metres, Mitre says. The company then commissioned engineers at Imperial College, London, to conduct an independent investigation into the studs’ performance. Peter Lindstedt and Fred Marquis modelled the forces acting on the studs using computational fluid dynamics. There are two main components of the force affecting an object in a fluid: form drag, which depends on the shape of an object, and viscous drag, which depends on its surface area or size, says Lindstedt. “The new stud produced a much greater form drag,” he says. The engineers spent two weeks modelling the behaviour of the studs over a range of pitch conditions. They found that Mitre’s design could theoretically boost initial acceleration by up to 40 per cent. “The softer the pitch the greater the improvement,” says Lindstedt (see graph). Mitre has patented the design, which has been accepted by football’s governing body, FIFA, and English Premier League referees. However, Steve Haake, an engineer in the sports engineering group at the University of Sheffield cautions that new boot designs may not have a significant impact on player’s performance. “The fact that conventional studs have been around for 40 or 50 years means there is not much wrong with them. All you can really do is tinker with the design,