Walking involves a repeated process referred to by scientists as 'crash, vault, push' – landing ('crashing') on the heel, vaulting over the stationary leg and then pushing off with the toes. This is the most economical way of walking and, as research published today in the Journal of the Royal Society Interface shows, the force exerted on the ground is the same for people walking normally or in high heels and for ostriches.
Dr Tatjana Hubel from the Royal Veterinary College explains: "Despite vastly differing arrangements of joints and hip wiggles, humans walking normally, women in extremely high heels and ostriches all produce strikingly similar forces when walking. This is the most mechanically economical way of walking. We do everything we can to make the forces follow the same pattern, which is why for example women wiggle their bottoms when they're in high heels. The question for us is, why is the human foot shaped the way that it is and not, say, like an ostrich's?"
When scientists model how the leg moves, they tend to simplify the movement and view the leg as a stick with a block on top (the body) which moves in an inverted pendulum motion. In this simplified model, the shape of the human foot does not make sense. But in fact, the human leg is more complicated than this; it contains muscles that likely evolved out of a tension between being optimised for walking and being more efficient at running. As humans are intelligent and able to plan and use tools, being able to move quickly to catch a prey or to evade a predator is not essential.
The shape of the human foot means that when the foot is flat on the ground, all the force goes through the ankles, allowing the muscles to support the weight of the body whilst being largely unloaded during the 'vault' stage. When muscles bear a load, they get tired easily, even if they are doing no work. For example, if we hold our arms outstretched, after a few minutes they will grow tired; by comparison, a JCB digger can extend its arm indefinitely.
The researchers believe this finding may have implications for the design of better prosthetic limbs for above-knee amputees and for the legs of humanoid robots. These might be improved by bearing more resemblance to an ostrich leg than that of a human.
Dr Jim Usherwood, a Wellcome Trust Senior Research Fellow at the Royal Veterinary College, explains: "If you want to make a good prosthetic foot but don't care what it looks like, you should put the motor – in this case, the ankle – as far up the leg as possible, where it can provide the power without making the feet heavy and hard to swing backwards and forwards. There's no point in putting the motor at the end of the foot, where it makes the leg more difficult to swing forwards – important in both walking and running.
"Some clever prosthetics copy the ankle and are very human-like, which is fine for prosthetics to replace the foot, but for above-knee amputee, a typical prosthetic leg which is very human-like is heavy and hard to move around. It's much better to have an ostrich foot at the end of a very lightweight leg.
An example of this kind of prosthetic already in use are the blades used by Paralympic athlete Oscar Pistorius – the 'Blade Runner'. These blades are light, springy and without a heel, similar to an ostrich's legs, which are optimised for running from predators rather than for walking.
Jen Middleton | EurekAlert!
Tiny implants for cells are functional in vivo
19.03.2018 | Universität Basel
Scientists develop new tool for imprinting biochips
09.03.2018 | Advanced Science Research Center, GC/CUNY
Satellites in near-Earth orbit are at risk due to the steady increase in space debris. But their mission in the areas of telecommunications, navigation or weather forecasts is essential for society. Fraunhofer FHR therefore develops radar-based systems which allow the detection, tracking and cataloging of even the smallest particles of debris. Satellite operators who have access to our data are in a better position to plan evasive maneuvers and prevent destructive collisions. From April, 25-29 2018, Fraunhofer FHR and its partners will exhibit the complementary radar systems TIRA and GESTRA as well as the latest radar techniques for space observation across three stands at the ILA Berlin.
The "traffic situation" in space is very tense: the Earth is currently being orbited not only by countless satellites but also by a large volume of space...
An international team of researchers has discovered a new anti-cancer protein. The protein, called LHPP, prevents the uncontrolled proliferation of cancer cells in the liver. The researchers led by Prof. Michael N. Hall from the Biozentrum, University of Basel, report in “Nature” that LHPP can also serve as a biomarker for the diagnosis and prognosis of liver cancer.
The incidence of liver cancer, also known as hepatocellular carcinoma, is steadily increasing. In the last twenty years, the number of cases has almost doubled...
In just a few weeks from now, the Chinese space station Tiangong-1 will re-enter the Earth's atmosphere where it will to a large extent burn up. It is possible that some debris will reach the Earth's surface. Tiangong-1 is orbiting the Earth uncontrolled at a speed of approx. 29,000 km/h.Currently the prognosis relating to the time of impact currently lies within a window of several days. The scientists at Fraunhofer FHR have already been monitoring Tiangong-1 for a number of weeks with their TIRA system, one of the most powerful space observation radars in the world, with a view to supporting the German Space Situational Awareness Center and the ESA with their re-entry forecasts.
Following the loss of radio contact with Tiangong-1 in 2016 and due to the low orbital height, it is now inevitable that the Chinese space station will...
Fraunhofer Institute for Organic Electronics, Electron Beam and Plasma Technology FEP, provider of research and development services for OLED lighting solutions, announces the founding of the “OLED Licht Forum” and presents latest OLED design and lighting solutions during light+building, from March 18th – 23rd, 2018 in Frankfurt a.M./Germany, at booth no. F91 in Hall 4.0.
They are united in their passion for OLED (organic light emitting diodes) lighting with all of its unique facets and application possibilities. Thus experts in...
A new scenario seeking to explain how Mars' putative oceans came and went over the last 4 billion years implies that the oceans formed several hundred million...
23.03.2018 | Event News
19.03.2018 | Event News
16.03.2018 | Event News
23.03.2018 | Materials Sciences
23.03.2018 | Agricultural and Forestry Science
23.03.2018 | Physics and Astronomy