A Nov. 11 article in Scientific American cites the expert analysis of SMU physiologist and biomechanist Peter Weyand as part of an effort to explore the physics of speed and acceleration.

In a special partnership with NBC Learn, the science magazine set up an imaginary 40-yard dash to present additional information for the video series, “The Science of NFL Football.”

Weyand was posed the question: Imagine a 40-yard dash that races a wide receiver, a safety, an ostrich, an elephant and a pig — who would win?

See the excerpt below for Weyand’s answer.

Read the full story and see the video.

Weyand is an SMU associate professor of applied physiology and biomechanics in the Annette Caldwell Simmons School of Education & Human Development. He lead a team of experts in biomechanics and physiology that conducted experiments on Oscar Pistorius, a South African bilateral amputee track athlete. Pistorius has made headlines trying to qualify for races against runners with intact limbs, including the Olympics.


Scientific American
If you want to be a professional football player, you’d better start practicing your 40-yard dash. It’s the gold standard for assessing a player’s speed and ability to accelerate, as NBC Learn’s segment on kinematics, motion, speed and acceleration shows.

Human beings need about 10 yards to reach maximum velocity, so the 40 is really a test of both acceleration and speed — unlike a longer sprint, such as the 100, which is more about a runner’s ability to maintain maximum speed. Acceleration depends on how much force runners can put into the ground (and thus receive back) relative to their mass. For this reason, the smaller you are the easier it is to accelerate rapidly. That’s why gymnasts, for example, are generally small — they must be able to generate a large amount of force relative to mass to accelerate enough to run and perform multiple flips in a row. Imagine an offensive lineman trying to do that! Wide receivers, running backs and defensive backs are not as massive as linemen, and therefore are very good accelerators, which is one reason they can handily outrun the latter in a 40-yard dash.

At present, no standard method or variable exists to quantify a human or animal’s top acceleration. One reason: the variable changes with every step until top speed is reached, making a tangible value a moving target. As a result, comparing the top accelerations of humans and other animals is difficult. Nevertheless, it’s true that smaller animals are better at accelerating — think of how quickly a squirrel can dart up a tree trunk, for example.

Speaking of squirrels, imagine a 40-yard dash that races a wide receiver, a safety, an ostrich, an elephant and a pig — who would win? “The ostrich wins pretty easily,” says Peter Weyand, a professor of applied physiology and biomechanics at Southern Methodist University. “And then would probably come the wide receiver, the safety, squirrel, the pig and, finally, the elephant.”

The ostrich, although bigger than a human, is built for speed. “The easiest way to explain why the ostrich is fast is that it has long legs,” Weyand says. It also runs on its toes, and what looks like a backward knee is actually its ankle. Most of the bird’s leg muscles reside on short thighbones, so the task of accelerating and maintaining speed is left to long, light limbs.

Read the full story and see the video.

Weyand is an expert in the locomotion of humans and other terrestrial animals with broad research interests that focus on the relationships between muscle function, metabolic energy expenditure, whole body mechanics and performance.

An expert in the scientific basis of gait and movement, his global interests in muscles and movement have made energy and performance central themes throughout his research career. Weyand’s research and expertise on the limits of human and animal performance have led to featured appearances on CNN, NHK Television in Japan, the Canadian Broadcasting Corporation, the History Channel, City TV of Toronto, CBS Boston and others.