Researchers at Northeastern University today announced that they have demonstrated that, contrary to previous research, swinging the limbs during the act of running requires a significant fraction of energy. In contrast to the established hypothesis, which asserted that force produced when the foot is on the ground (stance-phase) is the only determinant of the energy cost of running, Northeastern researchers observed that a significant fraction energy was used to fuel muscles that move the limb while it is off the ground (swing-phase).
In the study, the researchers estimated energy use by measuring blood flow to the hind leg muscles of guinea fowl in an effort to better explain the energetics of walking and running. In contrast to C. Richard Taylor’s “force hypothesis,” which suggests that swing-phase costs were low enough to be ignored, the researchers were able to demonstrate that the swing-phase muscles, in fact, consume 26 percent of the energy used by the limbs when running while the stance-phase muscles consume the remaining 74 percent of the energy. These findings represent the first time anyone has been able to look directly at the muscles during running and suggest that the force hypothesis needs modification. The swinging motion backwards is,indeed, the researchers assert, expensive energy-wise. Results of the study were published in the January 2nd issue of Science.
“The pioneering effect of this research is that by looking directly at blood flow to all of the individual muscles during running we were able to establish more directly the consumption of energy during the swing-phase,” said Marsh. “Taylor’s force hypothesis tried to unify the mechanics and energetics of running and explain the effects of body size and locomotor speed on the energy cost of running. Not everyone was necessarily convinced of all of the details of this hypothesis, but no one had been able to prove otherwise because most research on running has been based externally observable phenomena. By being able to estimate the energy use by the individual muscles, we were able to account to for energy consumption during swing-phase. Our work maintains Taylor’s emphasis on using energetics to understand terrestrial locomotion, but our findings suggest the force hypothesis will need to be modified to account for a more detailed partitioning of the energetics among muscles used during running.”
Desert ants cannot be fooled
23.11.2017 | Max-Planck-Institut für chemische Ökologie
Bacteria as pacemaker for the intestine
22.11.2017 | Christian-Albrechts-Universität zu Kiel
Heat from the friction of rocks caused by tidal forces could be the “engine” for the hydrothermal activity on Saturn's moon Enceladus. This presupposes that...
The WHO reports an estimated 429,000 malaria deaths each year. The disease mostly affects tropical and subtropical regions and in particular the African continent. The Fraunhofer Institute for Silicate Research ISC teamed up with the Fraunhofer Institute for Molecular Biology and Applied Ecology IME and the Institute of Tropical Medicine at the University of Tübingen for a new test method to detect malaria parasites in blood. The idea of the research project “NanoFRET” is to develop a highly sensitive and reliable rapid diagnostic test so that patient treatment can begin as early as possible.
Malaria is caused by parasites transmitted by mosquito bite. The most dangerous form of malaria is malaria tropica. Left untreated, it is fatal in most cases....
The formation of stars in distant galaxies is still largely unexplored. For the first time, astron-omers at the University of Geneva have now been able to closely observe a star system six billion light-years away. In doing so, they are confirming earlier simulations made by the University of Zurich. One special effect is made possible by the multiple reflections of images that run through the cosmos like a snake.
Today, astronomers have a pretty accurate idea of how stars were formed in the recent cosmic past. But do these laws also apply to older galaxies? For around a...
Just because someone is smart and well-motivated doesn't mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.
That is the implication of a new study which shows for the first time that there is a broad range of differences in people's visual ability and that these...
Computer Tomography (CT) is a standard procedure in hospitals, but so far, the technology has not been suitable for imaging extremely small objects. In PNAS, a team from the Technical University of Munich (TUM) describes a Nano-CT device that creates three-dimensional x-ray images at resolutions up to 100 nanometers. The first test application: Together with colleagues from the University of Kassel and Helmholtz-Zentrum Geesthacht the researchers analyzed the locomotory system of a velvet worm.
During a CT analysis, the object under investigation is x-rayed and a detector measures the respective amount of radiation absorbed from various angles....
15.11.2017 | Event News
15.11.2017 | Event News
30.10.2017 | Event News
23.11.2017 | Earth Sciences
23.11.2017 | Physics and Astronomy
23.11.2017 | Power and Electrical Engineering