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Last Sunday, a penalty kick helped Tottenham Hotspur rescue a 1-1 draw against fierce rivals Arsenal in the Premier League. But, video replays revealed that Spurs striker Harry Kane had actually been in an offside position when he was fouled in the box, and the penalty should never have been given.
Afterwards, Arsenal manager Unai Emery suggested that in future, technology would have prevented such an injustice. Video Assistant Referees, or VAR, are in the process of being rolled out throughout world football – they’ve been used in the World Cup, the Champions League and some domestic cup competitions, and will make their debut in the English Premier League from next season.
But VAR is hugely controversial. Purists argue that it fundamentally changes the game, and point to long delays in making decisions, as evidenced by Tuesday’s Champions League game between Ajax and Real Madrid, when it took VAR almost four minutes to determine whether a ball had gone out for a throw-in in the lead-up to Ajax’s third goal.
VAR may not be perfect, but it is necessary. Football is getting faster and more intense. When Germany won the World Cup in 2006, each player spent an average of 2.9 seconds in possession each time they got the ball. By 2014, that had fallen to 0.9 seconds. Referees desperately need help, and the science backs that up.
“It can be tough, especially when the ball is pinballing around,” says one FA referee, who says there’s a noticeable increase in difficulty as you move up the levels. “Players are more technically skilled so the quality of play improves, and that means that the play moves faster,” he says. “That means a referee will be making more decisions in a game.”
The biggest challenge for officials is that they must keep track of multiple objects at a time – including the ball, and the positions of various players. This is a hugely difficult skill. Take offsides for example. Research has shown that it takes the brain’s visual system at least 160 milliseconds to process information about four moving objects (two defenders, an attacker, and the ball) by which time everyone will have moved.
To compensate, referees and linesmen develop strategies for where to look. A 2016 study using eye trackers found that elite referees are more likely than lower level officials to look at the parts of players bodies most likely to be involved in a foul. This mirrors research with elite athletes, who tend to use their eyes differently to amateurs.
Instead of trying to look at the key points of action, officials tend to look at a mid-point from which they can see everything they need to keep track of in their peripheral vision. But our eyes are designed to have the best resolution at the focal point, where the highest concentration of rod and cone cells are located on the retina. “Your periphery isn’t designed to be able to discriminate fine detail,” says sports psychologist Zoe Wimshurst, director of Performance Vision. From the corner of your eye, you might be able to tell that two players have collided, but it will be difficult to know who has fouled who.
It’s not just that the game is getting quicker. “The challenges facing the referees haven’t changed that much over the years,” says Wimshurst. “It’s just that we’re able to scrutinise them in more detail than we could before.” Viewers at home now enjoy high-definition, slow motion replays from multiple angles. On the other hand, without VAR, referees must make snap decisions based solely on a low-angle, eye-level view of the action – often while they’re running themselves.
For linesmen, the job is nearly impossible – they must keep track of both the position of the attackers relative to the last defender, and the exact moment when the ball is kicked. If they try and shift their gaze from the ball to the defensive line after a pass has been played, they’ll get an inaccurate picture. A brief study by Dutch researchers published in Nature in March 2000 highlighted a further enemy of the linesman: perspective. It tested three professional linesmen across 200 offside situations, and found that they were more likely to incorrectly flag the attacker offside when the play was on their side of the pitch, and more likely to incorrectly wave play on when the action was on the far side.
The following year, the Football Association began experimenting with ways to help linesmen. They installed technology from Norwegian company Reference Point System, which consisted of a series of lights at 1.2m intervals along the side of the pitch which were only visible when the linesman was directly opposite them. Tests in Norway found that providing linesmen with a reference point like this could reduce offside errors by as much as 50 percent. Cathy Craig, CEO and founder of INCISIV, suggests that instead of VAR, it could be AR (augmented reality) that helps eliminate offside errors. “It’s about the patterning of information and how the angles between players are perceived by the brain,” she says. “AR could draw in parallel lines on the pitch to help support decisions.”
Wimshurst thinks that instead of spotting errors after the fact, we should be focussing on making our referees better. She points to research indicating that 18 per cent of officials in the Portuguese league had not had an eye test in the last three years.
Training their vision could be the answer. There's a wave of new training tools that athletes are using to train their visual abilities. The German football club Hoffenheim, for example, have installed a room-sized wraparound screen called the HELIX to train their squad’s peripheral vision. They claim it’s increased the visual field of some of their players from 180 to 200 degrees.
The Premier League has conducted trials with a training technology called EyeGym EyeGym, a computer and tablet based programme which has also been used by the England rugby team, and Premier League teams including Southampton, Wolves, and Tottenham. “With 22 players on the field, there is a lot of action taking place around the referee at any one time that he needs to be aware of,” said Simon Breivik, head of sports science for Professional Game Match Officials Limited, the body which organises match officials in the English game, in 2017. “Some of the guys feel it really improves their attention and focus and want to bring the laptops with them on matchday to prepare.”
According to Sherylle Calder, who developed the EyeGym programme, it’s about improving the ‘fitness’ of the visual system - training the eye muscles and the brain to look in the right place and extract information more quickly to support better decision making. That’s what makes the best athletes stand out, and it’s equally relevant for referees. “If the eyes take in information slowly and the brain processes it too slowly your decision is going to be either too late or not accurate,” she says. “We need to get a referee to be fit enough to handle all that decision making - we’ve found a way of training the decision making.”
The referees trained with the software for three months, and there was an improvement in their on-field decision-making abilities, says Calder. But you have to keep using the software to maintain that edge, and the Premier League is no longer using EyeGym for its officials. “It’s like any fitness system,” says Calder. “You’ve got to maintain it - you’ve got to maintain the edge.”
Referees clearly need help – but instead of using technology to catch their mistakes, perhaps we should focus on preventing them from happening in the first place.
This article was originally published by WIRED UK
