bigmac
13/09/2005, 1:51 PM
I'M IN Dunfermline, the ancient capital of Scotland. The town is home to a beautiful old abbey and royal palace, the final resting place of Robert the Bruce, and the birthplace of Andrew Carnegie, the man behind Manhattan's Carnegie Hall and Pittsburgh's Carnegie Mellon University. But I'm not here for the tourist attractions. For me the big draw is a large corrugated iron shack on the edge of town. It's not exactly an architectural gem, and you'd struggle to describe it as historic. But it does house what is arguably the leading biomimetic technology in the world.
East End Park is the home of Dunfermline Athletic football club. In March this humble stadium became the proud owner of Europe's most advanced artificial grass pitch - around 7000 square metres of verdant plastic which, its manufacturers claim, is the closest you can get to the real thing. If they are right, it puts this unassuming local landmark at the vanguard of a global sporting revolution.
From August FIFA, soccer's world governing body, and its European counterpart UEFA, will allow competitive games to be played on artificial grass. The surfaces have been outlawed for competitive soccer since the early 1990s because they ruined matches (see "Turfed out"). But things have changed, apparently. "The quality has reached a level where it is comparable to or even better than some of the natural turfs," said UEFA chief executive Lars-Christer Olsson when he announced the decision in November 2004. Since soccer is the most popular spectator sport in the world, that's a major coup for artificial turf, and marks the pinnacle of its achievements so far. But soccer is only the latest in a long line of approvals. In 2003 the International Rugby Board (IRB) decided to allow rugby union matches to be played on artificial surfaces, and last year rugby league was played on plastic for the first time. The International Tennis Federation has also given its approval to the stuff. Artificial turf is suddenly springing up all over the place.
“The grass might be artificial, but the match is the genuine article”That's not to say that sport wants to turn its back on the real thing. FIFA, UEFA and the IRB all say that "well-manicured natural grass" is the ideal playing surface. Problem is, good grass pitches are difficult and expensive to maintain, especially in today's dark, cavernous stadiums. The Amsterdam Arena in the Netherlands, for example, has to be relaid up to four times a year. Many big stadiums already use an expensive hybrid system in which the light-starved grass is bound into a plastic mesh to stop it uprooting. For small, indebted clubs like Dunfermline, a low-maintenance artificial pitch can be a godsend. The club won't reveal how much it cost - UEFA footed the bill as part of an experiment that has seen artificial turf installed at five grounds across Europe, including Moscow's Olympic stadium - but it says that going back to real turf would cost about £200,000 a year. The artificial pitch, in contrast, is expected to last up to 10 years and can be hired out, with no risk of damage, when the club isn't using it. Dunfermline earns about £1000 a week this way.
“To small, indebted clubs, a low-maintenance artificial pitch can be a godsend”Economics aside, however, the club is taking a big risk: last month the board of the Scottish Premier League, of which Dunfermline is a member, voted to outlaw the use of artificial surfaces. Dunfermline says it will challenge the decision in court and has the backing of UEFA and FIFA. But whatever the stance of football's big governing bodies, getting the pitch accepted by those that matter is proving an uphill struggle. "There has been a lot of adverse publicity," says Paul Atkinson, Dunfermline's first-team physiotherapist.
Watching a match from the East End Park stands, it's hard to see why. I can tell that the grass, manufactured by Swiss company XL Generation, is not the real thing. But that doesn't seem to affect the game. The ball behaves itself, the players are wearing regular boots, and no one is pulling out of tackles. The pitch might be artificial, but the match is the genuine article.
Given the history of artificial turf, that's quite an achievement. Previous grass substitutes have proved nothing short of disastrous. They were very hard, which affected the way balls bounced, restricted the players' movements and prevented them from wearing their normal footwear. The nylon fibres didn't exert enough friction on the ball, so it would zip across the surface like a pebble across a frozen pond. The nylon was also abrasive, so anyone who slid across the surface risked getting burns. Soccer authorities banned the stuff in the early 1990s.
Surface tension
Since then, turf engineers have realised they can't just create a look-alike surface. They have to know everything about the properties of natural turf, then design an artificial surface with the same attributes. "We performed a lot of tests on natural turf," says Frederic Vachon, a former biomechanics researcher at the University of Montreal in Canada who is now R&D manager of XL Generation. They also studied how players moved around the pitch, and the behaviour of the ball. And then they went back to the drawing board.
The main challenge was to get the interaction between the ball and the pitch right - particularly the "angled ball behaviour", which is what happens when a fast-moving, airborne ball glances off the surface. A good grass pitch will modify the ball's flight in a characteristic way: a football travelling at 14 metres per second and striking the ground at an angle of 25 degrees will continue its journey at a slower pace, around 10 metres per second, and a reduced angle of 17 degrees. Anything else just doesn't feel right.
It turns out that this behaviour depends on two factors: rebound, which determines how high the ball bounces, and friction, which affects the way it rolls. On a natural pitch, a football dropped vertically will bounce back to 60 to 84 per cent of its starting height. A rolling ball, meanwhile, slows down at a well-defined rate, losing 0.5 to 0.8 metres per second for every metre it travels. Get these two properties right, and you've cracked the angled ball problem.
East End Park is the home of Dunfermline Athletic football club. In March this humble stadium became the proud owner of Europe's most advanced artificial grass pitch - around 7000 square metres of verdant plastic which, its manufacturers claim, is the closest you can get to the real thing. If they are right, it puts this unassuming local landmark at the vanguard of a global sporting revolution.
From August FIFA, soccer's world governing body, and its European counterpart UEFA, will allow competitive games to be played on artificial grass. The surfaces have been outlawed for competitive soccer since the early 1990s because they ruined matches (see "Turfed out"). But things have changed, apparently. "The quality has reached a level where it is comparable to or even better than some of the natural turfs," said UEFA chief executive Lars-Christer Olsson when he announced the decision in November 2004. Since soccer is the most popular spectator sport in the world, that's a major coup for artificial turf, and marks the pinnacle of its achievements so far. But soccer is only the latest in a long line of approvals. In 2003 the International Rugby Board (IRB) decided to allow rugby union matches to be played on artificial surfaces, and last year rugby league was played on plastic for the first time. The International Tennis Federation has also given its approval to the stuff. Artificial turf is suddenly springing up all over the place.
“The grass might be artificial, but the match is the genuine article”That's not to say that sport wants to turn its back on the real thing. FIFA, UEFA and the IRB all say that "well-manicured natural grass" is the ideal playing surface. Problem is, good grass pitches are difficult and expensive to maintain, especially in today's dark, cavernous stadiums. The Amsterdam Arena in the Netherlands, for example, has to be relaid up to four times a year. Many big stadiums already use an expensive hybrid system in which the light-starved grass is bound into a plastic mesh to stop it uprooting. For small, indebted clubs like Dunfermline, a low-maintenance artificial pitch can be a godsend. The club won't reveal how much it cost - UEFA footed the bill as part of an experiment that has seen artificial turf installed at five grounds across Europe, including Moscow's Olympic stadium - but it says that going back to real turf would cost about £200,000 a year. The artificial pitch, in contrast, is expected to last up to 10 years and can be hired out, with no risk of damage, when the club isn't using it. Dunfermline earns about £1000 a week this way.
“To small, indebted clubs, a low-maintenance artificial pitch can be a godsend”Economics aside, however, the club is taking a big risk: last month the board of the Scottish Premier League, of which Dunfermline is a member, voted to outlaw the use of artificial surfaces. Dunfermline says it will challenge the decision in court and has the backing of UEFA and FIFA. But whatever the stance of football's big governing bodies, getting the pitch accepted by those that matter is proving an uphill struggle. "There has been a lot of adverse publicity," says Paul Atkinson, Dunfermline's first-team physiotherapist.
Watching a match from the East End Park stands, it's hard to see why. I can tell that the grass, manufactured by Swiss company XL Generation, is not the real thing. But that doesn't seem to affect the game. The ball behaves itself, the players are wearing regular boots, and no one is pulling out of tackles. The pitch might be artificial, but the match is the genuine article.
Given the history of artificial turf, that's quite an achievement. Previous grass substitutes have proved nothing short of disastrous. They were very hard, which affected the way balls bounced, restricted the players' movements and prevented them from wearing their normal footwear. The nylon fibres didn't exert enough friction on the ball, so it would zip across the surface like a pebble across a frozen pond. The nylon was also abrasive, so anyone who slid across the surface risked getting burns. Soccer authorities banned the stuff in the early 1990s.
Surface tension
Since then, turf engineers have realised they can't just create a look-alike surface. They have to know everything about the properties of natural turf, then design an artificial surface with the same attributes. "We performed a lot of tests on natural turf," says Frederic Vachon, a former biomechanics researcher at the University of Montreal in Canada who is now R&D manager of XL Generation. They also studied how players moved around the pitch, and the behaviour of the ball. And then they went back to the drawing board.
The main challenge was to get the interaction between the ball and the pitch right - particularly the "angled ball behaviour", which is what happens when a fast-moving, airborne ball glances off the surface. A good grass pitch will modify the ball's flight in a characteristic way: a football travelling at 14 metres per second and striking the ground at an angle of 25 degrees will continue its journey at a slower pace, around 10 metres per second, and a reduced angle of 17 degrees. Anything else just doesn't feel right.
It turns out that this behaviour depends on two factors: rebound, which determines how high the ball bounces, and friction, which affects the way it rolls. On a natural pitch, a football dropped vertically will bounce back to 60 to 84 per cent of its starting height. A rolling ball, meanwhile, slows down at a well-defined rate, losing 0.5 to 0.8 metres per second for every metre it travels. Get these two properties right, and you've cracked the angled ball problem.