Energy Optimality in Novel Movement: Sideways Walking

The Ohio State University Department of Mechanical and Aerospace Engineering Honors Theses
November 2012
date available 2012-11-09T20:34:17Z
http://hdl.handle.net/1811/53177

Matthew Handford

Abstract

The theory of energy optimality states that humans naturally move in a manner that minimizes the energy that their bodies use. This theory has been shown to be approximately true for natural gaits but it has not been tested on many unnatural gaits. To test if this theory would work on novel gaits, we conducted an experiment to compare people’s natural preferred speed to their energy optimal speed as they walked sideways. Subjects were asked to choose a comfortable speed using while walking sideways which was then recorded as the preferred velocity. Then, using a portable metabolic measurement system (the Oxycon Mobile VO2 device), their metabolic energy usage was recorded at a variety of speeds. Using this data, energy optimal velocities were found and compared with preferred velocities. While these quantities didn’t match exactly, a person’s preferred speed could be predicted by the population’s optimal speed with an average absolute error of 0.117 m/s. With the caveat that the subject pool was small with high data variability, the mean optimal speed (0.592 m/s) differed from the preferred speeds by only about an average of 0.041 m/s. In future experimentation, we hope to investigate the effects of perception and prior experience and the length of time it takes to reach the energy optimal speed with the subjects’ natural movement.

Keywords

Human Locomotion; Energy; Walking; Optimality

http://hdl.handle.net/1811/53177

http://kb.osu.edu/dspace/handle/1811/53177

Chasing maximal performance: a cautionary tale from the celebrated jumping frogs of Calaveras County

J Exp Biol 216, 3947-3953
November 1, 2013
doi: 10.1242/​jeb.090357

H. C. Astley [1*], E. M. Abbott [**], E. Azizi [**], R. L. Marsh [2] and T. J. Roberts [1]

[1] Brown University, Department of Ecology and Evolutionary Biology, Providence, RI 02912, USA
[2] Northeastern University, Department of Biology, Boston, MA 02115, USA
[*] Author for correspondence at present address: Department of Physics, Georgia Institute of Technology, Atlanta, GA 30332, USA
[**] Present address: Department of Ecology and Evolutionary Biology, University of California Irvine, Irvine, CA 92697, USA

Summary

Maximal performance is an essential metric for understanding many aspects of an organism's biology, but it can be difficult to determine because a measured maximum may reflect only a peak level of effort, not a physiological limit. We used a unique opportunity provided by a frog jumping contest to evaluate the validity of existing laboratory estimates of maximum jumping performance in bullfrogs (Rana catesbeiana). We recorded video of 3124 bullfrog jumps over the course of the 4-day contest at the Calaveras County Jumping Frog Jubilee, and determined jump distance from these images and a calibration of the jump arena. Frogs were divided into two groups: ‘rental’ frogs collected by fair organizers and jumped by the general public, and frogs collected and jumped by experienced, ‘professional’ teams. A total of 58% of recorded jumps surpassed the maximum jump distance in the literature (1.295 m), and the longest jump was 2.2 m. Compared with rental frogs, professionally jumped frogs jumped farther, and the distribution of jump distances for this group was skewed towards long jumps. Calculated muscular work, historical records and the skewed distribution of jump distances all suggest that the longest jumps represent the true performance limit for this species. Using resampling, we estimated the probability of observing a given jump distance for various sample sizes, showing that large sample sizes are required to detect rare maximal jumps. These results show the importance of sample size, animal motivation and physiological conditions for accurate maximal performance estimates.

http://jeb.biologists.org/content/216/21/3947

Venturi didgeridoo

United States Patent
Publication number US8466361 B1
Application number US 13/554,713
Publication date Jun 18, 2013

Charles Adams Eaton

Corrales, NM

Claims

The invention claimed is:

1. A musical instrument played by blowing air in a first end in the manner of an Australian Aboriginal Didgeridoo, the musical instrument comprising: a body comprising two or more un-tapered venture cylinder segments that can be nested or telescoped for portability; wherein each segment closer to a second end of the musical instrument, opposite the first end, has a diameter smaller than a diameter of any preceding segment closer to the first end.

2. The instrument of claim 1, further comprising: terminal sections of various lengths to provide different fundamental frequencies.

[...]

UTILIZATIONS

The “Walkabout Didgerido”

The 48″ Venturi-Didgeridoo, when made of fiberglass and resin, weighs only 9 ounces. If the rubber tip for a cane is inserted into the distal opening (FIG. 2) and a cap with a strap is put over the proximal opening (FIG. 3), it is converted into a walking stick—or “Walkabout Didgeridoo”. If the base of the cap is drilled and tapped, a properly threaded bolt will convert the “Walkabout Didgeridoo” into a monopod for camera stabilization (FIG. 3).

http://patft.uspto.gov/netacgi/nph-Parser?Sect2=PTO1&Sect2=HITOFF&p=1&u=/netahtml/PTO/search-bool.html&r=1&f=G&l=50&d=PALL&RefSrch=yes&Query=PN/8466361

Humans Running in Place on Water at Simulated Reduced Gravity

PLoS ONE 7(7): e37300
DOI: 10.1371/journal.pone.0037300
Received: August 1, 2011; Accepted: April 19, 2012; Published: July 18, 2012

Alberto E. Minetti
Department of Human Physiology, University of Milan, Milan, Italy

Yuri P. Ivanenko, Germana Cappellini, Nadia Dominici, Francesco Lacquaniti
Laboratory of Neuromotor Physiology, IRCCS Santa Lucia Foundation, Rome, Italy

Nadia Dominici, Francesco Lacquaniti
Center of Space BioMedicine, University of Rome
Tor Vergata, Rome, Italy

Francesco Lacquaniti
Department of Systems Medicine, Neuroscience Section, University of Rome
Tor Vergata, Rome, Italy


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.

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

Walking with coffee: Why does it spill?

Phys. Rev. E 85, 046117
volume 85, issue 4, pages 046117
Published 26 April 2012
DOI: http://dx.doi.org/10.1103/PhysRevE.85.046117

H. C. Mayer and R. Krechetnikov

Department of Mechanical Engineering, University of California, Santa Barbara, California 93106, USA

Abstract

In our busy lives, almost all of us have to walk with a cup of coffee. While often we spill the drink, this familiar phenomenon has never been explored systematically. Here we report on the results of an experimental study of the conditions under which coffee spills for various walking speeds and initial liquid levels in the cup. These observations are analyzed from the dynamical systems and fluid mechanics viewpoints as well as with the help of a model developed here. Particularities of the common cup sizes, the coffee properties, and the biomechanics of walking proved to be responsible for the spilling phenomenon. The studied problem represents an example of the interplay between the complex motion of a cup, due to the biomechanics of a walking individual, and the low-viscosity-liquid dynamics in it.

http://journals.aps.org/pre/abstract/10.1103/PhysRevE.85.046117

A woman's history of vaginal orgasm is discernible from her walk

The Journal of Sexual Medicine
Volume 5, Issue 9, pages 2119–2124, September 2008
DOI: 10.1111/j.1743-6109.2008.00942.x

Aurelie Nicholas MA [1], Stuart Brody PhD [2], Pascal De Sutter PhD [1] and François De Carufel PhD [3]

[1] Université Catholique de Louvain, Institut d'études de la famille et de la sexualité, Louvain-la-Neuve, Belgium;
[2] Division of Psychology, School of Social Sciences, University of the West of Scotland, Paisley PA1 2BE, UK;
[3] Unité de sexologie fonctionnelle, Hôpital Braine l'Alleud-Waterloo, Braine-l'Alleud, Belgium

The goddess was discovered by her gait.
(Virgil)

Introduction

Research has demonstrated the association between vaginal orgasm and better mental health. Some theories of psychotherapy assert a link between muscle blocks and disturbances of both character and sexual function. In Functional–Sexological therapy, one focus of treatment is amelioration of voluntary movement. The present study examines the association of general everyday body movement with history of vaginal orgasm.

Aim

The objective was to determine if appropriately trained sexologists could infer women's history of vaginal orgasm from observing only their gait.

Methods

Women with known histories of either vaginal orgasm or vaginal anorgasmia were videotaped walking on the street, and their orgasmic status was judged by sexologists blind to their history.

Main Outcome Measure

The concordance between having had orgasms triggered by penile–vaginal intercourse (not orgasm from direct clitoral stimulation) and raters' inferences of vaginal orgasm history based on observation of the woman's walk was the main outcome measure.

Results

In the sample of healthy young Belgian women (half of whom were vaginally orgasmic), history of vaginal orgasm (triggered solely by penile–vaginal intercourse) was diagnosable at far better than chance level (81.25% correct, Fisher's Exact Test P < 0.05) by appropriately trained sexologists. Clitoral orgasm history was unrelated to both ratings and to vaginal orgasm history. Exploratory analyses suggest that greater pelvic and vertebral rotation and stride length might be characteristic of the gait of women who have experienced vaginal orgasm (r = 0.51, P < 0.05).

Conclusions

The discerning observer may infer women's experience of vaginal orgasm from a gait that comprises fluidity, energy, sensuality, freedom, and absence of both flaccid and locked muscles. Results are discussed with regard to previous research on gait, the effect of the musculature on sexual function, the special nature of vaginal orgasm, and implications for sexual therapy.

http://onlinelibrary.wiley.com/doi/10.1111/j.1743-6109.2008.00942.x/full

A comparison of jump performances of the dog flea, Ctenocephalides canis (Curtis, 1826) and the cat flea, Ctenocephalides felis felis (Bouché, 1835)

Veterinary Parasitology
Volume 92, Issue 3, 1 October 2000, Pages 239–241

Marie-Christine Cadiergues [a], Christel Joubert [a], Michel Franc [b]

[a] Unité de Dermatologie-Parasitologie, Ecole Nationale Vétérinaire de Toulouse 23, chemin des Capelles 31076, Toulouse cedex 3, France
[b] Unité Associée INRA de Physiopathologie et Toxicologie expérimentales, Ecole Nationale Vétérinaire de Toulouse 23, chemin des Capelles 31076, Toulouse cedex 3, France

Abstract

Jump performances of Ctenocephalides canis and Ctenocephalides felis felis have been measured and compared on unfed young imagos. The mean length of the C. felis felis jump was 19.9±9.1 cm; minimum jump was 2 cm, and the maximum was one 48 cm. The C. canis jump was significantly longer (30.4±9.1 cm; from 3 to 50 cm). For height jump evaluation, grey plastic cylindric tubes measuring 9 cm in diameter were used. Their height was increasing from 1 to 30 cm by 1 cm. Groups of 10 fleas of the same species were deposited on the base of the tube. The number of fleas which succeeded in jumping above the tube was recorded. The mean height jump carried out by 50% of fleas was calculated after linearisation of the curves: it was 15.5 and 13.2 cm for C. canis and C. felis, respectively. The highest jump was 25 for C. canis and 17 cm for C. felis.

Keywords

Ctenocephalides canis; Ctenocephalides felis felis; Jump performance

http://www.sciencedirect.com/science/article/pii/S0304401700002740