The Science of Running: Follow the Bouncing Ball

ScienceDaily (Aug. 2, 2012) — Muscle size, genetics and training are among the countless factors that separate Olympic sprinters from the average person. On a fundamental level, however, the mechanics of running are the same for all humans. In fact, they’re basically identical for animals too.

Researchers examined the biomechanics of running and why the joints in the hips, knees and ankles “talk” to each other. (Credit: Image courtesy of Georgia Institute of Technology)

“Science has shown that running is very similar to a bouncing ball,” says Young-Hui Chang, an associate professor who oversees Georgia Tech’s “running lab,” officially called the Comparative Neuromechanics Laboratory. “When humans, horses and even cockroaches run, their center of mass bounces just like a pogo stick.”

This bouncing effect, Chang explains, means that the hip, knee and ankle joints all flex and extend at the same time when the foot hits the ground. Many of the leg muscles are turned on simultaneously, creating force and propelling the runner into the air.

“The greater the force, the greater the speed,” said Chang. “Sprinters and coaches are constantly studying ways to move leg muscles and joints as quickly as possible so that a runner can hit the ground as hard as possible.”

Elite runners and weekend joggers are able to consistently land with the same force, step after step. However, Chang’s research reveals that a stride is just like a fingerprint: no two are exactly alike. The torque generated by each joint is never the same. As a result, your legs have a mind of their own.

“Your knee, for example, automatically adjusts its own torque, each step, based on what the ankle and hip do,” said Chang. “All of this happens without your brain getting directly involved. Your joints ‘talk’ to each other, allowing you to concentrate on other things, like having a conversation or watching for cars.”

By studying how joints adapt to one another, Chang and his team will soon work with amputees to hopefully improve movement for people with prostheses. The researchers are also using their running studies to understand how people walk.

“It may seem backwards to fully understand the nuances of running before we study walking, but walking mechanics are actually more complex. Different muscles are activated at different times in a gait cycle. Joints don’t move in unison. There is no ‘bouncing ball’ phenomenon for walkers.”

Chang is an associate professor in the School of Applied Physiology in the College of Sciences.




Georgia Institute of Technology (2012, August 2). The science of running: Follow the bouncing ball. ScienceDaily. Retrieved August 4, 2012, from­ /releases/2012/08/120802111336.htm

Go-Fast ‘Dimples’ May Be the Secret to Running Success

ScienceDaily (July 20, 2012) — In the run-up to London’s 2012 Olympic Games, research revealed by a sports science expert at Birmingham City University has highlighted how the design of running shoes could boost an athlete’s performance.

You may not be able to beat the world’s fastest man, Usain Bolt — but research led by Birmingham City University has revealed that a more aerodynamic running shoe could give an athlete a competitive advantage.

In the run-up to London’s 2012 Olympic Games, research revealed by a sports science expert at Birmingham City University has highlighted how the design of running shoes could boost an athlete’s performance.

Alongside colleagues from other Midlands universities, Professor Robert Ashford, Director of Postgraduate Research Degrees at Birmingham City University’s Faculty of Health, and his team have examined the drag on models of middle to long distance running shoes by running a series of wind tunnel tests.

The ground-breaking work has been published in the International Journal of Sports Science and Engineering and highlighted in a special Research Councils UK report entitled: ‘Supporting a UK Success Story’.

Shoes tested by Professor Ashford’s team were a Nike Zoom, Nike Free, Nike 100km and a Reebok DMXRIDE. The researchers concluded that the aerodynamics of a running shoe, both in terms of upper shoe design and the overall composition of the frontal aspects of the shoe, could potentially affect a runner’s performance.

According to Professor Ashford shoes that simulate the texture of a golf ball — eg featuring “dimples” — did well in the tests and proved to support better aerodynamic performance.

“If looking at differences in wind conditions, these small differences over a long period of time may actually affect energy consumption and ultimately the finishing time for an individual athlete — whether they are a professional or an amateur,” said Professor Ashford.

Sixteen-year-old Ellis Sabin, an up-and-coming middle distance runner with West Midlands based Tipton Harriers, helped to put the researchers’ theories to the test on the running track.


The team set four different wind speeds to observe and measure how the shoes reacted to certain speeds in terms of their drag properties. The research revealed that the drag on the shoes varied.

Until now, say the research authors, the sports shoe industry has focused much more on the aesthetic appeal of running shoes rather than their aerodynamic qualities. With manufacturers expressing strong interest in the research, Professor Ashford expects the design of running shoes to change accordingly in time for the next Olympic Games.

Professor Ashford added: “Very little research to date has been done on the material of running shoes and there is great potential here for the future.”


Journal Reference:

  1. Robert L. Ashford, Peter White Clive E. Neal-Sturgess, Nachiappan Chockalingam. A Fundamental Study on the Aerodynamics of Four Middle and Long Distance Running Shoes. International Journal of Sports Science and Engineering, Vol. 05 (2011) No. 02, pp. 119-128


Birmingham City University (2012, July 20). Go-fast ‘dimples’ may be the secret to running success. ScienceDaily. Retrieved July 22, 2012, from­ /releases/2012/07/120720083031.htm