Deadlocked football matches often end in penalty kicks, most recently in Sunday’s World Cup match between Costa Rica and Greece.  

With penalty kicks playing such a key role in the competition, a British scientist advises football teams to look into the science behind them.

In the 1994 World Cup, a missed penalty kick by Roberto Baggio dashed the hopes of the Italian team in the final match against Brazil.

Team psychologists and strategists have long studied the emotions of both the kicker and the goalie, trying to find strong and weak points.

Ken Bray, a sport scientist at the University of Bath, says to be successful the kicker must aim for the area outside the goalkeeper’s maximum reach.

“If you can place the ball outside of his diving envelope you should be successful almost 100 percent of the time,” Bray said.

Studies have shown that shots inside the envelope were saved 50 percent of the time, which is the same as flipping a coin. But shots aimed at the so-called ‘unsavable zone’ were more than 80 percent successful.

Bray, who wrote the book, "'How to Score," also says anxiety issues dictate that the team’s coach should not let his best shooter make the first kick because the less experienced player might have more anxiety.

“Less experienced first, more experienced last, produces a better result on average,” Bray said.

Goalkeepers also employ their own strategies to distract kickers.

“When the player's walking up, I'll have the ball in my hands before, so then they'll have to come and get it off me, so then as they're walking back, I step out a little bit, so the ref has to tell me to step on my line," said goalkeeper Nick Croucher. "Just get into the players' heads.”

Bray says coaches should not choose penalty kickers on a volunteer basis but rather carefully analyze which of their players is best suited for the nerve-wracking task.