The science behind the art of taking penalties in football

As it is, keepers can expect to save about one penalty in four. Not good odds, and they get worse during major tournaments, dropping to about one in five.
UAE  midfielder Theyab Awana scores an audacious penalty against Lebanon in a friendly match in July.
UAE midfielder Theyab Awana scores an audacious penalty against Lebanon in a friendly match in July.

The UAE midfielder Theyab Awana may well be glad the spotlight of world football is off him now the new season has kicked off in Europe.

For a few days last month, his penalty kick against Lebanon was the focus of worldwide attention.

Some hailed his back-heeled goal one of the greatest penalties of all time. Many others sided with his own manager and the match referee, seeing it as egregious showboating that deserved the booking and substitution that followed.

But at least it was a successful bit of showboating, unlike the Manchester City striker Mario Balotelli's shameful display against LA Galaxy a few days later. And in any case, Awana has added fuel to perhaps the most vexed debate in football: how to take a successful penalty.

Penalty kicks have long been the bane of players and fans - just ask the US women's team and their fans after their defeat on penalties to Japan in their World Cup final last month.

Whoever devised the rules of the penalty in 1891 seems to have had a fiendish understanding of human abilities.

If the penalty spot had been placed much further out, goalkeepers could make their saves with ease. Had it been put much closer, they would never have a hope.

As it is, keepers can expect to save about one penalty in four. Not good odds, and they get worse during major tournaments, dropping to about one in five.

It is a statistic that reflects the huge psychological pressure that haunts keeper and penalty-taker, driving both to do better.

Yet studies suggest many football teams ingore the issue, making little effort to improve their success rates through regular practice.

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This is even harder to understand given that there is now a wealth of hard scientific evidence on the fine art of dealing with penalties.

The hardest fact of all is that unless the keeper can anticipate where the ball is going before it is kicked, the chances are it is going straight to the back of the net.

Top penalty-takers such as Frank Lampard of Chelsea are capable of shooting the ball in at more than 100kph with deadly precision. At those speeds, a goalie who hesitates is doomed.

Studies of elite goalkeepers show they typically make their first move about 100 milliseconds before the ball is struck.

Eye-monitoring studies by the sports scientist Dr Mark Williams of Liverpool John Moores University in England have shown goalkeepers ignore everything but the legs and feet of the striker, looking for clues on the direction of the final kick.

This makes good sense. Research has shown strikers usually plant their non-striking foot in the direction of the final kick, and then line their hips up in a way that reveals the direction of the final kick.

Video analysis of penalties in international competitions has shown that this "watch the other foot" rule holds true about 80 to 85 per cent of the time.

Better still, it buys the keeper as much as 200 milliseconds to prepare before the kick is taken. For a ball struck at more than 70kph, that translates into half a goalmouth's worth of distance - and the difference between victory and defeat.

Another ruse keepers can use was recently revealed by a team of researchers led by Dr Rich Masters, of the University of Hong Kong.

Strikers can unwittingly be fooled into aiming their shot to the left if the goalkeeper stands just slightly to the right of the centre of the goalmouth, or vice versa.

The displacement doesn't have to be very big - just 6cm to 10cm will do - but it's enough to unconsciously convince the striker there's a bigger area in which to aim, while giving the keeper some idea of the most likely direction of the shot.

It's not always the goalkeeper we want to succeed, though, so what can penalty-takers do to boost their chances? Not surprisingly, many strikers opt for sheer brute force, which certainly helps.

A ball travelling at more than 100kph not only gives keepers little chance of reaching it, but also minimises the chances of him holding on to it or deflecting it away from the goal.

A bit of subtlety works better still. A team at Liverpool John Moores University analysed footage of penalties from cameras inside the goal, and found the best chance of scoring came from kicking the ball at high speed at a point about 50cm under the crossbar and just inside either one of the goalposts. Easier said than done, of course, and nerves play a huge role in penalty-taking. And for the player trying to score, this only increases the chances of failing.

Researchers at the University of Exeter, England, found nervous players tend to focus on the goalkeeper rather than where they are going to aim.

This makes them more susceptible to distracting antics and more likely to give away their intentions. The result is a doubling in the risk of failing to score.

As Awana showed last month, penalty-takers can also turn the tables, performing their own antics in front of goal. And it can even work sometimes.

But to judge by his experience, the only thing it guarantees is substitution by an irate manager - and the enmity of all true fans of the Beautiful Game.

Robert Matthews is a visiting reader in science at Aston University, Birmingham, England

Published: August 21, 2011 04:00 AM

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