When Ryan Lochte dives into the London Aquatics Centre today to race Michael Phelps, he'll have to do more than swim fast if he wants to beat the 14-time Olympic gold medalist.

The Spruce Creek High School product will have to overcome a law of physics.

It's long been said that Phelps, with his reported 79-inch wingspan, has the perfect swimmer's body.

And there's scientific evidence to back up that talk.

It centers around the fundamental law of fluid flow, said Charles Eastlake, professor emeritus of aerospace engineering at Embry-Riddle Aeronautical University.

"Ryan is pretty close to the perfect swimmer's body, but Phelps is from another world," Eastlake said. "The fundamental law of fluid flow gives Phelps a little bit of an advantage against almost everyone he swims against."

Phelps and Lochte will open their 2012 Olympics competition with today's 400-meter individual medley. Preliminaries begin at 5 a.m. EDT and the finals are set for 2:30 p.m. It airs on NBC-TV during prime time, according to NBC's Olympic website.

Phelps' long body gives him a higher Reynolds number -- a measurement used in fluid mechanics -- that in swimming terms relates to drag. A higher Reynolds number equals less drag.

"In the case of a swimmer in a swimming pool, a longer body means a higher Reynolds number," said Eastlake, an avid swimmer who follows the rivalry between the world's top swimmers. "And Phelps is really, really long. Lochte's a pretty good size kid (6-foot-2), too. But Phelps is taller. He's 6-4 and has this ungodly arm span."

Phelps' wingspan is 4 inches longer than his height. According to Scientific American, most people have arm spans that correspond closely to their height.

Lochte's dad, Steve, estimates Ryan's wingspan is somewhere in the low 70-inch range. Phelps' body style gives him a slight advantage, but, as Eastlake pointed out, even a slight physics advantage can be the difference in the color of medal won.

What Lochte must have, according to Eastlake, is more muscle to create more power.

"To put it in a NASCAR context, if you have two cars that have the same aerodynamic drag, and you put them on the racetrack, the one that wins is the one that has the more powerful engine," Eastlake said. "In this case with swimmers, we're talking about muscle power. The guy who's a little bit shorter swims in a flow field that's characterized by a lower Reynolds number and will have slightly higher drag, and there's nothing he can do about that.

"That means, to be competitive (Lochte) has to be capable of producing a little more muscle power to keep up with the guy next to him who has slightly lower drag, and apparently Lochte can do that."

Steve Lochte, Ryan's former coach, has seen the results of Phelps' flow-field advantage and more with his own trained eyes.

"Michael has the longer torso and arms," Steve Lochte said. "You look at Michael and his arms are past his knees."

There are other things, too, that weigh in Phelps' favor. Popular Mechanics noted Phelps has relatively short legs -- a 32-inch inseam -- that coupled with his long torso and longer arm span "let him ride high in the water."

The Popular Mechanics article also describes Phelps as "a genetic phenom, built like a fish, with hands and feet like canoe paddles."

Ryan Lochte realized after the 2008 Beijing Games -- where Phelps won an Olympic-record eight gold medals -- that he had to make some training changes and build a better motor within himself, if he was going to beat his rival.

"That's why after Beijing, Ryan said to himself, 'I've got to do something,' " Steve Lochte said. "Obviously, he couldn't stretch out his arms and body. He had to take what he had and make it stronger."

There were two areas where Ryan Lochte made huge changes.

"Number one, Ryan had to stop eating McDonald's morning, noon and night, and two, he had to increase his strength program and get stronger," Steve Lochte said.

That was the correct scientific approach, Eastlake agreed, to counter Phelps' flow-field advantage.

"That's the fundamental physics that everyone lives with -- if you've got higher drag and you want to go just as fast, you need more power," Eastlake said. "Are you capable of creating more power for the required length of time? If it doesn't work, change your training method. Maybe you can do it, maybe you can't. Maybe the guy with lower drag has equal muscle power. Then, you're out of luck."

Ryan Lochte's improved nutrition -- McDonald's and all other fast foods were out -- and enhanced training methods, including the addition of exercises like flipping tractor tires, apparently paid off. He went on a swimming rampage in 2010 and '11, beating Phelps for four gold medals in championship meets on the way to twice being named World Swimmer of the Year.

If dieting and strength training helped Lochte, 27, close the gap on Phelps, 27, his work in the water may have given him a slight advantage.

"(Ryan is) one of the few older guys in the world (who) when he got to a certain point didn't say, 'I don't need to do this anymore,' and he stayed after it," U.S. men's Olympic swim coach Gregg Troy said. "That's why there are a lot of older guys who've leveled off and stayed in the same place. I think he's continued to improve. I think that's allowed him to go by these people."

Phelps, for example, cut back on his training when he was unsure about his future after Beijing.

Through hard work, Lochte has become perhaps the world's strongest underwater kicker. And that was one of his weaknesses when he began swimming at the University of Florida, Troy said.

"Out of high school, he wasn't especially good underwater. He wasn't a tremendous kicker," said Troy, who also coaches at UF. "That's his strength now. He was adequate in all four strokes, and he's worked to refine them.

"He's the complete package now. He still has strengths and weaknesses, but what makes him good is he utilizes his strengths, which is his ability to kick and being compact off walls, and he's addressed his weak areas, things like the breaststroke and the butterfly."

But perhaps, the reason Lochte has been able to dedicate himself for so long is that his earliest coaches -- his parents -- gave him some slack when he was young.

"When he was little, we knew he had natural talent," said Lochte's mom, Ileana "Ike" Lochte, who was Ryan's club coach through age 12. "It was just a matter of how to harvest it, I guess. He just had so much energy, there was no way we could control it in the water."

So while his peers would continue to do sets, he was allowed to leave the pool when he lost focus. And he usually spent the rest of practice sliding in the showers or playing basketball.

At one point, his mother said, Ryan only liked to do the hard sets and goofed off when the swimmers were doing the easier sets.

"It was almost like, 'I'm done competing with myself, now I'm leaving,' " Ike said. "Everybody else came to swim. Ryan just wanted to have fun. If he wasn't having fun, he would have quit (the team) right away. He had a lot of district records (when he was 8, 9 and 10), but he never knew it."

By the time he became a teenager, Lochte's competitive nature took over. After he lost, he worked harder to make sure it didn't happen again. That's a cycle that he's continued into international competition.

After 2008, he set his sights on beating Phelps, and he knew he would have to work harder than he had ever worked before to reach his goal.

"I think we were more lenient with him when he was younger," Ike said. "If we hadn't been, by the time he got to college, he would have burned out. Obviously, it helped him to decide if he really wanted to swim or not."

Now, as the 2012 Olympic swim events begin today, Lochte and Phelps are scheduled to go head to head in just two events in London -- today's 400 IM and the 200 IM on Thursday. It may truly be a case of less being more as these two events could highlight these Olympics.

Will Ryan Lochte be able to overcome the world's most decorated swimmer, one who has the laws of physics on his side?

"Everyone talks about all of these things, and then there's the one thing we seem to forget: heart," Steve Lochte, speaking in coaching and fatherly terms, said.