Humans Running in Place on Water …

… at Simulated Reduced Gravity

journal.pone.0037300.g001
Abstract

Background
On Earth only a few legged species, such as water strider insects, some aquatic birds and lizards, can run on water. For most other species, including humans, this is precluded by body size and proportions, lack of appropriate appendages, and limited muscle power. However, if gravity is reduced to less than Earth’s gravity, running on water should require less muscle power. Here we use a hydrodynamic model to predict the gravity levels at which humans should be able to run on water. We test these predictions in the laboratory using a reduced gravity simulator.

Methodology/Principal Findings
We adapted a model equation, previously used by Glasheen and McMahon to explain the dynamics of Basilisk lizard, to predict the body mass, stride frequency and gravity necessary for a person to run on water. Progressive body-weight unloading of a person running in place on a wading pool confirmed the theoretical predictions that a person could run on water, at lunar (or lower) gravity levels using relatively small rigid fins. Three-dimensional motion capture of reflective markers on major joint centers showed that humans, similarly to the Basilisk Lizard and to the Western Grebe, keep the head-trunk segment at a nearly constant height, despite the high stride frequency and the intensive locomotor effort. Trunk stabilization at a nearly constant height differentiates running on water from other, more usual human gaits.

Conclusions/Significance
The results showed that a hydrodynamic model of lizards running on water can also be applied to humans, despite the enormous difference in body size and morphology.

Citation: Minetti AE, Ivanenko YP, Cappellini G, Dominici N, Lacquaniti F (2012) Humans Running in Place on Water at Simulated Reduced Gravity. PLoS ONE 7(7): e37300.

Read more at http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0037300

Stephen Hawking performs Big Bang Theory theme song …

… in surprise Comic-Con appearance

My hero! Jim Parson's Sheldon gets to meet Stephen on the Big Bang Theory back in April

My hero! Jim Parson’s Sheldon gets to meet Stephen on the Big Bang Theory back in April

He’s the one man on the planet who science geek Sheldon Cooper is really impressed by.
Renowned theoretical physicist Stephen Hawking made a surprise appearance at Friday’s Big Bang Theory panel at Comic-Con in San Diego, California.
And the 71-year-old genius – who is idolized by Jim Parson’s character on the hit show – even apologized to the gob-smacked audience that he could not be there in person during his pre-recorded video segment.

Hawking – who has made cameo appearance on the show playing himself – started his message by saying: ‘Sorry, I couldn’t be there. I got a flat tire – that was a joke. Ha ha!’
And the amazing Oxford born physicist and cosmologist joked that he enjoyed playing games with Sheldon.

‘When I’m not playing Words With Friends with Sheldon, I like to think about the universe,’ he revealed.

Then, much to the delight of the assembled fans, Hawking decided to explain the Big Bang theory in 17 words by singing the show’s theme song.

Read more: http://www.dailymail.co.uk