The science of running: Follow the bouncing ball (w/ Video)

Aug 02, 2012

(Phys.org) -- 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.

“Science has shown that 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 video is not supported by your browser at this time.
Video: Creating Speed and Force While Running. Georgia Tech Associate Professor Young-Hui Chang discusses the biomechanics of running and why the joints in your hips, knees and ankles "talk" to each other.

This bouncing effect, Chang explains, means that the hip, knee and ankle 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.” 

Explore further: What I learned from debating science with trolls

add to favorites email to friend print save as pdf

Related Stories

Running shoes may cause damage to knees, hips and ankles

Jan 04, 2010

Knee osteoarthritis (OA) accounts for more disability in the elderly than any other disease. Running, although it has proven cardiovascular and other health benefits, can increase stresses on the joints of the leg. In a study ...

Recommended for you

When it comes to how pizza looks, cheese matters

4 hours ago

Most consumers have an idea what they want their pizza slice to look like. Golden cheese with that dark toasted-cheese color scattered in distinct blistery patches across the surface with a bit of oil glistening in the valleys. ...

Freedom and responsibility of science

10 hours ago

Yesterday, the German Research Foundation (DFG) and the Leopoldina National Academy of Sciences presented their recommendations for "The Freedom and Responsibility of Science" in Berlin. Both research organizations appeal ...

What I learned from debating science with trolls

Aug 20, 2014

I often like to discuss science online and I'm also rather partial to topics that promote lively discussion, such as climate change, crime statistics and (perhaps surprisingly) the big bang. This inevitably ...

Activists urge EU to scrap science advisor job

Aug 19, 2014

Nine major charities urged the European Commission on Tuesday to scrap a science advisor position it says puts too much power over sensitive policy into the hands of one person.

User comments : 0