So, why have we stuck with our inefficient heel first footfall pattern when the rest of our bodies are honed for marathon running? This paradox puzzled Nadja Schilling and Christoph Anders from the Jena University, Germany, and Christopher Cunningham and David Carrier from the University of Utah, USA, until they began to wonder whether our distinctive heel first gait, inherited from our ape forefathers, might be an advantage when we walk.
The team put young healthy volunteers through their paces to find out why we walk and run heel first and publish their results on 12 February 2010 in The Journal of Experimental Biology at http://jeb.biologists.org.
Measuring the amount of oxygen consumed as their human subjects walked, the team asked the volunteers to walk in one of three different ways: normally, with the heel contacting the ground first; toes first, with the heel slightly raised so that it didn't contact the ground; and up on tip-toes. Then the scientists asked the athletes to repeat the experiments while running heel first and with their heels slightly raised. Calculating the amount of energy required to run and walk, the team found that walking with the heel slightly raised costs 53% more energy than walking heel first, and walking on tip-toe was even less economical. However, there was no difference between the runners' efficiencies when they ran with flat feet and up on their toes.
Our 'heel first' gait makes us incredibly efficient walkers, while both postures are equally efficient for runners. Human walkers burn roughly 70% less energy than human runners when covering the same distance. However, this efficiency would be completely wiped out if we switched to walking on our toes. 'Our ability to walk economically may largely be the result of our plantigrade [heel first] posture,' says Carrier.
But why is heel walking so much more efficient than walking on our toes? To find out, Carrier and his colleagues asked volunteers to run and walk at various speeds in the three postures while recording electrical activity in their muscles to see if the heel first walkers were saving energy by using their muscles differently from toe first walkers. The team also measured the volunteers' metabolic cost of standing on their toes, to find out if increasing stability saved energy, and the forces exerted by the ground on the volunteers' bodies, in case they were reduced in any way that could result in an energy saving.
Analysing the results, the team realised that we lose less energy as our heels collide with the ground than we do when we walk toes first. Landing heel first also allows us to transfer more energy from one step to the next to improve our efficiency, while placing the foot flat on the ground reduces the forces around the ankle (generated by the ground pushing against us), which our muscles have to counteract, resulting in another energy saving.
So we still use our ancestor's heel first gait because it makes us better walkers and Carrier adds, 'Given the great distances hunter-gatherers travel, it is not surprising that humans are economical walkers'.
IF REPORTING ON THIS STORY, PLEASE MENTION THE JOURNAL OF EXPERIMENTAL BIOLOGY AS THE SOURCE AND, IF REPORTING ONLINE, PLEASE CARRY A LINK TO: http://jeb.biologists.org
REFERENCE: Cunningham, C. B., Schilling, N., Anders, C. and Carrier, D. R. (2010). The influence of foot posture on the cost of transport in humans. J. Exp. Biol. 213, 790-797.
This article is posted on this site to give advance access to other authorised media who may wish to report on this story. Full attribution is required, and if reporting online a link to jeb.biologists.com is also required. The story posted here is COPYRIGHTED. Therefore advance permission is required before any and every reproduction of each article in full. PLEASE CONTACT firstname.lastname@example.org
MicroRNA helps cancer evade immune system
19.09.2017 | Salk Institute
Ruby: Jacobs University scientists are collaborating in the development of a new type of chocolate
18.09.2017 | Jacobs University Bremen gGmbH
Using ultrafast flashes of laser and x-ray radiation, scientists at the Max Planck Institute of Quantum Optics (Garching, Germany) took snapshots of the briefest electron motion inside a solid material to date. The electron motion lasted only 750 billionths of the billionth of a second before it fainted, setting a new record of human capability to capture ultrafast processes inside solids!
When x-rays shine onto solid materials or large molecules, an electron is pushed away from its original place near the nucleus of the atom, leaving a hole...
For the first time, physicists have successfully imaged spiral magnetic ordering in a multiferroic material. These materials are considered highly promising candidates for future data storage media. The researchers were able to prove their findings using unique quantum sensors that were developed at Basel University and that can analyze electromagnetic fields on the nanometer scale. The results – obtained by scientists from the University of Basel’s Department of Physics, the Swiss Nanoscience Institute, the University of Montpellier and several laboratories from University Paris-Saclay – were recently published in the journal Nature.
Multiferroics are materials that simultaneously react to electric and magnetic fields. These two properties are rarely found together, and their combined...
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems Holding GmbH about commercial use of a multi-well tissue plate for automated and reliable tissue engineering & drug testing.
MBM ScienceBridge GmbH successfully negotiated a license agreement between University Medical Center Göttingen (UMG) and the biotech company Tissue Systems...
Pathogenic bacteria are becoming resistant to common antibiotics to an ever increasing degree. One of the most difficult germs is Pseudomonas aeruginosa, a...
Scientists from the MPI for Chemical Energy Conversion report in the first issue of the new journal JOULE.
Cell Press has just released the first issue of Joule, a new journal dedicated to sustainable energy research. In this issue James Birrell, Olaf Rüdiger,...
19.09.2017 | Event News
12.09.2017 | Event News
06.09.2017 | Event News
19.09.2017 | Event News
19.09.2017 | Physics and Astronomy
19.09.2017 | Power and Electrical Engineering