Navigation Links
Why humans choose running over walking
Date:1/5/2012

Other than Olympic race walkers, people generally find it more comfortable to run than walk when they start moving at around 2 meters per second about 4.5 miles per hour.

North Carolina State University biomedical engineers Dr. Gregory Sawicki and Dr. Dominic Farris have discovered why: At 2 meters per second, running makes better use of an important calf muscle than walking, and therefore is a much more efficient use of the muscle's and the body's energy.

Published online this week in Proceedings of the National Academy of Sciences, the results stem from a first-of-its-kind study combining ultrasound imaging, high-speed motion-capture techniques and a force-measuring treadmill to examine a key calf muscle and how it behaves when people walk and run.

The study used ultrasound imaging in a unique way: A small ultrasound probe fastened to the back of the leg showed in real time the adjustments made by the muscle as study subjects walked and ran at various speeds.

The high-speed images revealed that the medial gastrocnemius muscle, a major calf muscle that attaches to the Achilles tendon, can be likened to a "clutch" that engages early in the stride, holding one end of the tendon while the body's energy is transferred to stretch it. Later, the Achilles the long, elastic tendon that runs down the back of the lower leg springs into action by releasing the stored energy in a rapid recoil to help move you.

The study showed that the muscle "speeds up," or changes its length more and more rapidly as people walk faster and faster, but in doing so provides less and less power. Working harder and providing less power means less overall muscle efficiency.

When people break into a run at about 2 meters per second, however, the study showed that the muscle "slows down," or changes its length more slowly, providing more power while working less rigorously, thereby increasing its efficiency.

"The ultrasound imaging technique allows you to separate out the movement of the muscles in the lower leg and has not been used before in this context," Farris says.

The finding sheds light on why speed walking is generally confined to the Olympics: muscles must work too inefficiently to speed walk, so the body turns to running in order to increase efficiency and comfort, and to conserve energy.

"The muscle can't catch up to the speed of the gait as you walk faster and faster," Sawicki says. "But when you shift the gait and transition from a walk to a run, that same muscle becomes almost static and doesn't seem to change its behavior very much as you run faster and faster, although we didn't test the muscle at sprinting rates."

The research could help inform the best ways of building assistive or prosthetic devices for humans, or help strength and conditioning professionals assist people who have had spinal-cord injury or a stroke, Sawicki and Farris say.


'/>"/>
Contact: Mick Kulikowski
mick_kulikowski@ncsu.edu
919-515-8387
North Carolina State University
Source:Eurekalert

Related biology news :

1. Mineral oil contamination in humans: A health problem?
2. Escherichia coli bacteria transferring between humans and mountain gorillas
3. Pigs and dogs can bridge gap between mice and humans in developing new therapies
4. Snails and humans use same genes to tell right from left
5. As super-predators, humans reshape their prey at super-natural speeds
6. Researchers genetically link Lou Gehrigs disease in humans to dog disease
7. Ecologists report quantifiable measures of natures services to humans
8. Early humans had jaws of steel
9. Ancestral genome of present-day African great apes & humans had burst of DNA sequence duplication
10. Genetic differences between yeasts greater than those between humans and chimpanzees
11. Social support during breast-feeding helps humans have more children
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/18/2017)... 18, 2017  Socionext Inc., a global expert in SoC-based imaging ... server, the M820, which features the company,s hybrid codec technology. A ... Tera Probe, Inc., will be showcased during the upcoming Medtec Japan ... at the Las Vegas Convention Center April ... Click here for ...
(Date:4/13/2017)... According to a new market research report "Consumer IAM Market by ... Service, Authentication Type, Deployment Mode, Vertical, and Region - Global Forecast to ... USD 14.30 Billion in 2017 to USD 31.75 Billion by 2022, at ... ... MarketsandMarkets Logo ...
(Date:4/11/2017)... 11, 2017 No two people are ... the New York University Tandon School of Engineering ... found that partial similarities between prints are common ... mobile phones and other electronic devices can be ... vulnerability lies in the fact that fingerprint-based authentication ...
Breaking Biology News(10 mins):
(Date:6/22/2017)... ... June 22, 2017 , ... Ovation Fertility supports the American ... bringing new hope for prospective parents who are challenged with costs of treatment. ... World Health Organization’s designation in hopes of changing the way health insurers, governments ...
(Date:6/22/2017)... ... June 22, 2017 , ... RURO, Inc., a ... version 6.5, a content-packed update to the Limfinity® framework. , LimitLIS® and other ... more diverse base of customers among labs and other businesses. Limfinity® 6.5 adds ...
(Date:6/20/2017)... ... 20, 2017 , ... HorizonScan is providing food and ingredient ... likely threat to their products at the annual IFT conference in Las Vegas, ... expo attracts over 20,000 attendees representing food science professionals from over 90 countries ...
(Date:6/20/2017)... ... June 20, 2017 , ... GigaGen Inc ., ... immune repertoires, announces launch of its new Surge(TM) Discovery service at ... of GigaGen, will present on Surge at the conference. , Surge is the ...
Breaking Biology Technology: