Humans running in place on water at simulated reduced gravity

Alberto E. Minetti, Yuri P. Ivanenko, Germana Cappellini, Nadia Dominici, Francesco Lacquaniti

Research output: Contribution to journalArticle

8 Citations (Scopus)

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.

Original languageEnglish
Article numbere37300
JournalPLoS One
Volume7
Issue number7
DOIs
Publication statusPublished - Jul 18 2012

Fingerprint

Hypogravity
gravity
Running
Gravitation
Lizards
Water
lizards
water
Body Size
Hydrodynamics
hydrodynamics
body size
Muscle
Gerridae
Earth (planet)
muscles
prediction
water birds
Muscles
gait

ASJC Scopus subject areas

  • Agricultural and Biological Sciences(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • Medicine(all)

Cite this

Humans running in place on water at simulated reduced gravity. / Minetti, Alberto E.; Ivanenko, Yuri P.; Cappellini, Germana; Dominici, Nadia; Lacquaniti, Francesco.

In: PLoS One, Vol. 7, No. 7, e37300, 18.07.2012.

Research output: Contribution to journalArticle

Minetti, Alberto E. ; Ivanenko, Yuri P. ; Cappellini, Germana ; Dominici, Nadia ; Lacquaniti, Francesco. / Humans running in place on water at simulated reduced gravity. In: PLoS One. 2012 ; Vol. 7, No. 7.
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