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

August 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.

“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: Running shoes may cause damage to knees, hips and ankles

Related Stories

Running shoes may cause damage to knees, hips and ankles

January 4, 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

Chimpanzees shed light on origins of human walking

October 6, 2015

A research team led by Stony Brook University investigating human and chimpanzee locomotion have uncovered unexpected similarities in the way the two species use their upper body during two-legged walking. The results, reported ...

How much for that Nobel prize in the window?

October 3, 2015

No need to make peace in the Middle East, resolve one of science's great mysteries or pen a masterpiece: the easiest way to get yourself a Nobel prize may be to buy one.

The dark side of Nobel prizewinning research

October 4, 2015

Think of the Nobel prizes and you think of groundbreaking research bettering mankind, but the awards have also honoured some quite unhumanitarian inventions such as chemical weapons, DDT and lobotomies.

Who you gonna trust? How power affects our faith in others

October 6, 2015

One of the ongoing themes of the current presidential campaign is that Americans are becoming increasingly distrustful of those who walk the corridors of power – Exhibit A being the Republican presidential primary, in which ...


Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.