Science seeks the limits of performance

Athletes: Records are being broken less often - and by slimmer margins.

Athens Olympics 2004

August 18, 2004|By Michael Stroh | Michael Stroh,SUN STAFF

Since 1896 the motto of the modern Olympics has been Citius, altius, fortius - Swifter, higher, stronger. But with the Athens games now under way, some scientists are asking: For how long?

The world pole vault record - 20 feet, 1 3/4 inches - hasn't budged for a decade. The shot put mark is 14 years old. Nobody has managed to hurl a hammer farther than Yuriy Sedykh of Russia since his 284 1/2 -foot toss in 1986. That's the same year the discus record last fell.

Even in less stagnant events such as the 100-meter sprint, athletes are advancing by ever-finer margins. Tim Montgomery's current world record of 9.78 seconds is just 11 percent faster than Archie Hahn's winning time at the 1904 Olympics. Montgomery had a tailwind.

FOR THE RECORD - A graphic in yesterday's editions listing world records for shotput incorrectly labeled the distance in feet. The distance should have been labeled in meters.
The Sun regrets the error.

Yes, records will crumble in the coming days. Michael Phelps set a world mark of 4:08:26 in the 400-meter individual medley Saturday. That's one of six Phelps and his swimming teammates have set since January.

But one thing also appears certain: Even for the world's elite, it isn't as easy as it used to be. And this, in turn, has led to renewed speculation in many sports, particularly track and field events - are athletes approaching fundamental physiological barriers that ultimately limit how much faster and stronger humans can become?

"I think we're already there - or at least very close to being there," says Peter Snell, an exercise physiologist at the University of Texas Southwestern Medical Center and fastest miler in the world from 1962 to 1964.

Breaking barriers

Predictions, of course, are always dangerous. Fifty years ago, nobody thought a humans could run a mile in less than four minutes - until a 25-year-old British medical student named Roger Bannister clocked 3:59.4.

And advances in training and technique over the decades have helped athletes maintain a steady march of record-breaking performances.

High jumper Dick Fosbury won the gold and unwittingly advanced his sport by leaping backward, rather than forward, over the bar at the 1968 Olympics in Mexico City. Physicists later determined that the "Fosbury flop" shifted the athlete's center of mass outside his body, allowing him to clear greater heights. Now Fosbury's flop is standard fare.

Technology has also played an important role. At the first modern Olympics in Athens, a bamboo pole was used to set the vaulting record of 10 feet, 10 inches. When fiberglass poles emerged in the 1960s, vaulters soared to unheard-of heights.

This Olympics will be no different. Phelps and sprinter Maurice Greene are just two of many athletes in skintight body suits engineered to cut drag and slice split-seconds from their times.

But most scientists agree that better training and equipment can contribute only so much: Ultimately, it comes down to what the body can do.

"It's difficult to imagine that a man will be able to run as fast as a horse," says Francois Peronnet, an exercise physiologist at the University of Montreal. "There should be a ceiling somewhere."

But where? Will someone ever run a 3:30 mile? Or a chuck a 16-pound hammer more than 300 feet?

Scientists have spent more than a century attempting to map the body's biological limits. The lessons they've learned are complex and far from complete. But basically they boil down to this: Athletes are ultimately limited by how much energy they can produce.

For endurance runners, performance is mainly a question of how efficiently the body can take in and burn oxygen. In landmark experiments during the 1920s, British physiologist A.V. Hill outfitted runners - including himself - with rubber hoses and airtight bags to collect their breath as they circled Manchester University's grass track.

By measuring the percentages of oxygen and carbon dioxide left behind in the bags after each lap, Hill and his assistants calculated the maximum amount of oxygen the human body burned. Hill dubbed this measure "VO2 Max." Today it's recognized as a crucial gauge of athletic potential and progress.

"Nobody can be an elite endurance athlete if they don't have a high VO2 Max," says Michael Joyner, a researcher at the Mayo Clinic who studies circulation and exercise.

There are other factors. For example, "running economy," a measure of much oxygen endurance athletes burn for a given distance. Joyner compares this to miles per gallon in a car. Scientists also track tolerance to lactic acid, a byproduct of exercise that contributes to muscle fatigue.

For sprinters and power lifters, it's a different story, says David Bassett Jr., a University of Tennessee researcher who studies the body's energy expenditure.

Watch world-class sprinters and you barely see them draw breath between the time they explode from the starting block and when they burst through the tape.

"They're certainly not sucking in air like a marathoner," says Bassett. These athletes rely less on oxygen intake than the composition of their skeletal muscles, he says.

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