Aki Salo is almost always on the track when the British sprint relay teams are competing — but the scientist's job is to analyze the race, not run it.

It's a basic tenet of the four-man relay: having speed is great, but it's those tricky baton exchanges that can put a team on the podium or send them home with a disqualification.

An expert in sport biomechanics at the University of Bath, Salo has been working with elite British sprinters for a decade, scrutinizing their performances at the last few world championships and the Beijing Olympics.

"Aki is pretty much our fifth man on the team," said Harry Aikines-Aryeetey, a British sprinter hoping to be named to the U.K. Olympic squad. "He films all our (baton) exchanges and then goes off to calculate how much faster we could go if we did things differently."

"Getting his feedback gives us confidence we're doing the right things and everything possible to win a medal," the sprinter added.

At the London Olympics that begin July 27, Salo will be filming the British men's and women's heats to see if they can make any time-saving tweaks to their technique before hopefully running in the finals. For now, he is focused on helping them at training camps to refine their baton hand-offs. The baton is light — only 50 grams (1.76 ounces) — but fumbling it has cost teams top medals at previous championships.

Even in the 4 x 100 meter relay, which involves the fastest athletes on the planet, Salo emphasizes that winning isn't just about speed.

"This is a race where you have this interaction between two people which is not always so slick," he said. "You can have the fastest runners in the world, but if they drop the baton or make a mistake in the exchange, it's over."

The baton exchange takes place in a 20-meter (nearly 66-foot) section where the baton must be passed by an incoming runner to his outgoing teammate. Sprinters can mark their preferred spot on the track with tape to show them where to start running once their teammate hits that mark. But that doesn't always happen.

"I look at how accurate the runners are to see if they leave too early or too late when the incoming athlete comes in," Salo said. He also calculates runners' speed to determine what the quickest exchange possible would be if everything went perfectly, usually around the 15-meter (49-foot) mark.

At the 2007 world championships in Japan, Salo noticed that two baton exchanges in the men's heat happened a bit early, so he recommended a slightly later handoff. The British team used his strategy for the finals and shaved 0.43 seconds off their time. Salo estimates about half that improvement came from his advice while the other half came from runners simply sprinting faster from the pressure of being in the final. They won a bronze medal.

Since the 4 x 100 meter relay was introduced at the Olympics and major championships in 1912, the U.S. has dominated the medals. But in recent years, both the U.S. men's and women's teams have been plagued by baton mistakes.

At the Beijing Games, the U.S. men dropped their baton while the British men were disqualified for passing it over too late. When U.S. sprinter Tyson Gay started running towards the finish line, he reached back for the baton but never got it from teammate Darvis Patton.

"By the time I went to grab it, there was nothing," Gay said at the time. "I feel like I let my teammates down."

British runner Aikines-Aryeetey said most relay teams don't take the kind of scientific analysis Salo does seriously enough.

"Most teams just rely on their flat speed to get them where they need to go," he said.

Salo acknowledged that teams with someone like Usain Bolt could probably afford to have a bad exchange and still win.

"Science is never a real substitute for performance, but we try to minimize any possible errors to maybe leapfrog the faster runners," he said of the British strategy. "But, of course, the starting point is that it's always best to just have the fastest runners on your team."