(Ivanhoe Newswire) -- As swimmers lined up for the 2008 Olympic Games in
Beijing, former Olympic swimmer and NBC Sports commentator Rowdy Gaines quipped
that swimmers keep getting bigger, with the shortest one in the current race
towering over the average spectator.
What may have been seen as an off-hand remark turns out to illustrate a trend in
human development -- elite athletes are getting bigger and bigger.
A
new theory by Duke University engineers has shown that not only have Olympic
swimmers and sprinters gotten bigger and faster over the past 100 years, they
have grown at a much faster rate than the normal population.
The researchers were quoted as saying that this pattern of growth can be
predicted by the constructal theory, a Duke-inspired theory of design in nature.
(www.constructal.com). In a new analysis, Jordan Charles, an engineering student
of the class of 2009, who was also a varsity breaststroke swimmer during his
time at Duke, collected the heights and weights of the swimmers (100 meters) and
sprinters (100 meters) who set world records since 1900. He then correlated the
size of these athletes with their winning times.
"The trends revealed by our analysis suggest that speed records will continue to
be dominated by heavier and taller athletes," Charles was quoted as saying, who
worked with senior author Adrian Bejan, engineering professor who came up with
the constructal theory 13 years ago. "We believe that this is due to the
constructal rules of animal locomotion and not the contemporary increase in the
average size of humans."
While the average human gained about 1.9 inches in height since 1900, Charles'
research showed the fastest swimmers have grown 4.5 inches and the swiftest
runners have grown 6.4 inches.
The theoretical rules of animal locomotion generally state that larger animals
should move faster than smaller animals. In his constructal theory, Bejan linked
three forms of animal locomotion -- running, swimming and flying. Bejan argues
that the three forms of locomotion involve two basic forces: lifting weight
vertically and overcoming drag horizontally. Therefore, they can be described by
the same mathematical formulas.
Using these insights, the researchers can estimate running speeds during the
Greek and Roman empires, for example. "In antiquity, body weights were roughly
70 percent [of what] they are today," Charles said. "Using our theory, a
100-meter dash that is won in 13 seconds would have taken about 14 seconds back
then."
"In the future, the fastest athletes can be predicted to be heavier and taller,"
Bejan said. "If the winners' podium is to include athletes of all sizes, then
speed competitions might have to be divided into weight categories. Larger
athletes lift, push and punch harder than smaller athletes, and this led to the
establishment of weight classes in certain sports, like boxing, wrestling or
weight-lifting.”
SOURCE: Journal of Experimental Biology, July 17, 2009
