For speediest athletes, it's all in the center of gravity

July 12, 2010

DURHAM, N.C. - In the record books, the swiftest sprinters tend to be of West African ancestry and the faster swimmers tend to be white.

A study of the winning times by elite athletes over the past 100 years reveals two distinct trends: not only are these athletes getting faster over time, but there is a clear divide between racers in terms of body type and race.

Last year, a Duke University engineer explained the first trend - athletes are getting faster because they are getting bigger. Adrian Bejan, professor of engineering at Duke's Pratt School of Engineering, now believes he can explain the second trend.

In a paper published online in the International Journal of Design and Nature and Ecodynamics, Bejan, and co-authors Edward Jones, a Ph.D. candidate at Cornell University currently teaching at Howard University, and Duke graduate Jordan Charles, argue that the answer lies in athletes' centers of gravity. That center tends to be located higher on the body of blacks than whites. The researchers believe that these differences are not racial, but rather biological.

"There is a whole body of evidence showing that there are distinct differences in body types among blacks and whites," said Jones, who specializes in adolescent obesity, nutrition and anthropometry, the study of body composition. "These are real patterns being described here -- whether the fastest sprinters are Jamaican, African or Canadian -- most of them can be traced back generally to Western Africa."

Swimmers, Jones said, tend to come from Europe, and therefore tend to be white. He also pointed out that there are cultural factors at play as well, such as a lack of access to swimming pools to those of lower socioeconomic status.

It all comes down to body makeup, not race, Jones and Bejan said.

"Blacks tend to have longer limbs with smaller circumferences, meaning that their centers of gravity are higher compared to whites of the same height," Bejan said. "Asians and whites tend to have longer torsos, so their centers of gravity are lower."

Bejan and Jones cite past studies of the human body which found that on average, the center of gravity is about three percent higher in blacks than whites. Using this difference in body types, the researchers calculated that black sprinters are 1.5 percent faster than whites, while whites have the same advantage over blacks in the water. The difference might seem small, Bejan said, but not when considering that world records in sprinting and swimming are typically broken by fractions of seconds.

The center of gravity for an Asian is even more advantageous to swimming than for a white, but because they tend not to be as tall, they are not setting records, Bejan said.

"Locomotion is essentially a continual process of falling forward," Bejan said. "Body mass falls forward, then rises again. Mass that falls from a higher altitude falls faster. In running, the altitude is set by the location of the center of gravity. For the fastest swimmers, longer torsos allow the body to fall forward farther, riding the larger and faster wave."

The researchers said this evolution of body types and increased speeds can be predicted by the constructal theory, a theory of natural design developed by Bejan that explains such diverse phenomena as river basin formation and basis of animal locomotion (www.constructal.org).

Jones said that the differences in body densities between blacks and whites are well-documented, which helps explain other health differences, such as the observation that black women have a lower incidence of osteoporosis than white women because of the increased density of their bones.

Jones notes that cultural issues can play a role in which form of athletic competition someone chooses, and therefore might excel in.

"When I grew up in South Carolina, we were discouraged from swimming," said Jones, who is black. "There wasn't nearly as much encouragement for us as young people to swim as there was for playing football or basketball. With the right encouragement, this doesn't always have to be the case - just look at the Williams sisters in tennis or Tiger Woods in golf."
-end-
This analysis was supported by the National Science Foundation.

Duke University

Related Athletes Articles from Brightsurf:

51% of Americans agree paying college athletes should be allowed
More Americans than not believe that college athletes should be allowed to be paid more than what it costs them to go to school, a new national study of nearly 4,000 people suggests.

Menstrual dysfunction is more common among young athletes than among non-athletes
Menstrual dysfunction is more prevalent in young Finnish athletes than it is among non-athletes of a similar age, but athletes experience less body weight dissatisfaction than non-athletes do.

Athletes don't benefit from relying on a coach for too long
Athletes increasingly relying on a coach over the course of a season may be a sign that they aren't progressing in their development, according to new research from Binghamton University.

Olympic athletes should be mindful of their biological clocks
Biological clocks have sizeable effects on the performance of elite athletes.

Female athletes at risk for nutritional deficiencies
Two decades of research among female athletes over the age of 13 years shows that a lack of nutrition knowledge about what they need to eat to stay healthy and compete may contribute to poor performance, low energy and nutrient intake, and potential health risks, according to a Rutgers Robert Wood Johnson Medical School study.

Electrocardiogram shows value in college athletes' screens
Research published today indicates that screenings that incorporate an ECG are more effective at detecting cardiac conditions that put athletes at risk, and more efficient in terms of cost-per-diagnosis of at-risk players, than screenings involving only a physical exam and patient history.

How kirigami can help us study the muscular activity of athletes
Scientists devise an elastic and durable skin-contact patch for measuring the electromyographic activity of the palm muscle inspired by ancient Japanese paper crafts.

Study examines attitudes toward transgender athletes
As several states draft legislation that would force student-athletes to play as their gender identified on their birth certificate instead of on a team that matches their gender identity, a team of political scientists investigated underlying factors that drive public opinion on transgender athletes.

The mind-muscle connection: For aesthetes, not athletes?
The 'mind-muscle connection.' Ancient lore for bodybuilders, latest buzz for Instragram fitness followers.

Sudden cardiac arrest in athletes: Prevention and management
It's marathon season, and every so often a news report will focus on an athlete who has collapsed from sudden cardiac arrest.

Read More: Athletes News and Athletes Current Events
Brightsurf.com is a participant in the Amazon Services LLC Associates Program, an affiliate advertising program designed to provide a means for sites to earn advertising fees by advertising and linking to Amazon.com.