The 2014 World Cup is full of interesting stories, not all of which are on the sports page. We rounded up some interesting tidbits of soccer (read: football, for purists) science for both the die-hard fan and casual viewer—perhaps humoring the die-hard fan who dragged you out to the local pub at 11 am to catch Mexico versus Cameroon—alike.
Cyborg soccer: breakthrough or hype?
The opening ceremonies for this year’s World Cup (Thursday, June 12) will feature the debut of a robotic exoskeleton developed by Duke University neuroengineer Miguel Nicolelis. The system employs a brain-machine interface that translates electrical signals in the brain, detected by EEG readings, and feeds commands to robotic machinery. When fully realized, Nicolelis hopes that the exoskeleton will allow paralyzed people to walk again. But some experts are skeptical, wondering if the display at the World Cup is more spectacle than scientific demonstration.
Using EEG signals to control movement is still something of a challenge. Scientists haven’t been able to pull a lot of data from EEG wave changes in a short amount of time—just about 5 to 50 bits per minute, which by itself isn’t really enough to direct a complex movement like walking, according to the MIT Technology Review. Nicolelis has written before about a “share control” concept for the exoskeleton where a patient’s brain plays the executive role in deciding how to move, while the robot’s software takes care of working out the lower-level mechanics automatically.
“Without the person there is no movement,” Nicolelis told Scientific American. “The person has to imagine what kind of movement he or she wants to make and that decision triggers what the exoskeleton does—when it stops, when it kicks the ball… We are basically creating a mental language for the patients to have a variety of actions that they can control.”
Just what percentage of the exoskeleton’s control stems from the brain signals is something Nicolelis won’t say yet—a detail sure to spark debate among neuroscientists about the goals of brain-machine interfaces. How much does the brain actually have to be involved in order for something to be truly “mind controlled”? There’s no peer-reviewed data available yet on the exoskeleton that will be on display at the World Cup (though Nicolelis told Scientific American that he expects to publish “many things” in the next few months), so this will be one instance where both the public and the experts will get a first look at the same time.
This year’s ball: redesigned for truer flight
The official 2014 match ball, the Adidas Brazuca, should delight goalkeepers much more than the one used in the last World Cup. 2010′s Adidas Jabulani was made with just eight panels sewn together, as opposed to the traditional 32, under the theory that fewer stitches on the ball’s surface meant it would generate less turbulence and friction as it sailed through the air. But in reality, the Jabulani turned out to be unbalanced; it “knuckled,” or dipped in its flight, at much higher speeds than most balls, making it much harder for goalies to judge where all those free kicks were headed.
The Brazuca has even fewer panels (six) than the Jabulani, but Adidas designers studded the entire ball’s surface with tiny polyurethane nubs that mimic the effect of the stitches on an ordinary ball. This creates a uniform roughness that, ideally, should result in even turbulence and a straighter flight path from foot to goal (or to the goalkeeper’s hands).
A pair of researchers from the University of Tsukuba in Japan subjected the Brazuca and four other soccer balls (including the much-maligned Jabulani) to a series of tests using a wind tunnel and a special kicking robot. The results, published in the journal Scientific Reports, suggest that the Brazuca comes out on top, aerodynamically speaking. It had the lowest “drag crisis regime,” meaning that the drag on the ball tended to remain pretty consistent instead of suddenly changing (the Jabulani scored the highest of the five on this measurement). And when kicked by a robot, the Brazuca’s point of impact was remarkably stable.
Betting strategy: bettering your odds with math
Davidson College mathematician (and 2014 World Science Festival participant) Tim Chartier and a few of his colleagues have created a tool called FIFA Foe Fun that lets you earn some sports statistics bragging rights with just a few clicks. To generate a ranking of the World Cup teams, you set the parameters for a host of variables—a team’s win-loss record, how many points they tend to score, whether records in qualifier games count more than performance in friendly matches, etc.—and the algorithm produces your rankings.
Trying to crunch the numbers for soccer is complicated by unique characteristics of the game, such as the possibility of overtime shootouts. “Unlike football, these happen quite a bit,” Chartier told us. “Do you count them the same as normal wins? We do not. FIFA also sees them as different.”
Whatever your opinion on the value of winning on penalty kicks, the variation of factors that can be plugged into FIFA Foe Fun means that the rankings can vary as well. But patterns do start to emerge.
“It is VERY clear that Brazil is a heavy favorite,” Chartier says. “When you see the same team at the top across various parameters, you begin to see a team’s strength. We find that using scores generally helps, which surprised us. We expected the ‘noise’ of scores to hurt the results but so far we aren’t seeing that!”
(For those who want to delve further into the equations, Chartier has a new book out called Math Bytes that explores the kind of algorithms used to develop FIFA Foe Fun.)
Hi-speed cameras: keeping the refs honest
At the 2010 World Cup, English fans were outraged when a clear goal by midfielder Frank Lampard in a match against Germany was disallowed. To avoid a repeat of this fiasco, FIFA bigwigs agreed to try out a new kind of goal-line technology in 2014 to provide the referees with some additional, impartial eyes on the field to precisely call when a goal has been scored or not.
The setup that will be used in Brazil this year is a German-made system called GoalControl. A semicircle of seven high-speed cameras keeping watch above each goal (and capturing 500 frames per second) automatically alert referees and officials on digital watches if a ball crosses the goal line.
“GoalControl has installed the system at the 12 World Cup stadiums and conducted what it and FIFA said were about 2,400 tests — in wind, in rain and with one or multiple cameras blocked by players or the goalkeeper,” the New York Times reported. As of June 9, “they said that they had yet to have an incorrect decision.”
However, the match referee still makes the final call on whether or not to use GoalControl during the game.
A new noisemaker: easier on the ears (but still banned)
Remember the brassy cacophony emitted by the vuvuzela, the plastic horn that became the bane of the last World Cup? Brazilian musician Carlinhos Brown designed an alternative that’s much less annoying: the caxirola, a plastic maraca-like instrument named after a traditional Brazilian musicmaker called a caxixi. The resulting sound (hear the sound) is a bit like clapping and ocean waves mixed together, and doesn’t drill into your eardrums like the vuvuzela. Acoustic engineers that tested the caxirola have given it a decibel rating of about 80 dBA, equivalent to a telephone dial tone, vs. the vuvuzela’s 109 dBA, close to a lawnmower. “The caxirola wouldn’t pose any danger, any hazard, to the human hearing system, as the vuvuzela did,” Federal University of Santa Maria acoustic scientist Stephan Paul told the Wall Street Journal.
Unfortunately, unruly soccer fans have proved that the caxirola can still poze a hazard: The instrument was banned by Brazil’s sports ministry after fans threw dozens of them onto the field during a match between two local clubs. But if you can’t take it to the game, you can still nab a caxirola online—just avoid the temptation of throwing it while watching the game at the pub.
Image credit: Jarke/Wikimedia Commons
By: Roxanne Palmer
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