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This may be of interest to some, which I 1st heard of through the ABC Science Report
Quote:
Scientists have explained mathematically why the famous 'silly walks' of Monty Python's John Cleese have never caught on.
The giant, leg-twirling strides of silly walks may allow someone to leap around swiftly but are simply too expensive in metabolic energy compared to conventional locomotion, according to a paper published today by the UK's Royal Society.
The research, which appears in the journal Proceedings of the Royal Society A, is potentially useful in biomechanics and robotics, where scientists need to understand mathematically how humans (or their robot mimics) move, and the energy cost of doing it.
Dr Manoj Srinivasan and Professor Andy Ruina, researchers in applied mechanics at New York's Cornell University, drew up a geometrical model of human walking and running.
They found that, in essence, each of your legs is a 'telescoping actuator' that can change its length.
When you walk your body vaults forwards in circular arcs, driven forward by the pendular swing of your legs. Your toe and heel provide the push-off and landing point for each movement.
But when you run your body travels from one parabolic arc to the next, with a bounce in between.
The researchers then factored in the metabolic cost of three drains on energy on both movements.
These are the energy expenditure required to keep your body's basic functions ticking over; the cost of swinging your legs; and the cost incurred when your leg touches the ground.
Their equations show emphatically that walking and running are the most energy-efficient gaits for our species, honed by millions of years of evolution.
"Inverted pendulum walking is energetically optimal at low speeds and step lengths, and impulsive running is energetically optimal at higher speeds," they say.
Silly walks gathered cult status in the UK TV comedy show Monty Python's Flying Circus, when the gangling Cleese, dressed in a pinstripe suit and bowler hat, cavorted around as a bureaucrat in a 'Ministry of Silly Walks'.
Unfortunately only an abstract of the article is available free
Idealized walking and running gaits minimize work
Issue Volume 463, Number 2086 / October 08, 2007
Pages 2429-2446
Authors
Manoj Srinivasan1, Andy Ruina2
1Mechanical and Aerospace Engineering, Princeton University, Princeton, NJ 08544, USA
2Theoretical and Applied Mechanics, Cornell University, Ithaca, NY 14853, USA
Abstract
Even though human legs allow a wide repertoire of movements, when people travel by foot they mostly use one of two locomotor patterns, namely, walking and running. The selection of these two gaits from the plethora of options might be because walking and running require less metabolic energy than other more unusual gaits. We addressed this possibility previously using numerical optimization of a minimal mathematical model of a biped. We had found that, for a given step-length, the two classical descriptions of walking and running, ‘inverted pendulum walking’ and ‘impulsive running’, do indeed minimize the amount of positive work required at low and high speeds respectively. Here, for the case of small step-lengths, we establish the previous results analytically. First, we simplify the two-dimensional particle trajectory problem to a one-dimensional ‘elevator’ problem. Then we use elementary geometric arguments on the resulting phase plane to show optimality of the two gaits: walking at low speeds and running at high speeds.
but an earlier article published in Nature in 2006 is available in full text PDF here with lots of maths equations to keep Kevin happy
__________________ Stephen Tucker Eastern Health
Podiatry Manager
Re: Idealized walking and running gaits minimize work
Quote:
Originally Posted by Tuckersm
This may be of interest to some, which I 1st heard of through the ABC Science Report
Unfortunately only an abstract of the article is available free
but an earlier article published in Nature in 2006 is available in full text PDF here with lots of maths equations to keep Kevin happy
Stephen:
Yes, this article did make my morning read at breakfast enjoyable. This is really not new research; R. McNeil Alexander has done this type of work years before, and much better written, in my opinion. It is a good review article for those who are not familiar with basic walking and running biomechanics gait optimization theory and "forward dynamics simulations". One of the PhD biomechanists at Penn State that I am working with on subtalar joint axis location, Steve Piazza, wrote a review article on forward dynamics simulations for those of you who aren't afraid to learn what is currently happening in the real world of biomemechanics (and aren't afraid of a little math).
__________________
Sincerely,
Kevin
**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
Re: Idealized walking and running gaits minimize work
It is somewhat paradoxical that, on the one hand we consider that the idealised gait is the one that minimises work and on the other hand, the proponents of the instability footwear that increases work is also considered by them to be a good thing .... don't figure
__________________
Craig Payne
Department of Podiatry
La Trobe University
Melbourne, Australia http://www.latrobe.edu.au/podiatry
__________________________________________________ ___________________________________ God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
The views expressed above are those of the author and not that of La Trobe University This is where I am, where are you?
Re: Idealized walking and running gaits minimize work
Quote:
Originally Posted by Craig Payne
It is somewhat paradoxical that, on the one hand we consider that the idealised gait is the one that minimises work and on the other hand, the proponents of the instability footwear that increases work is also considered by them to be a good thing .... don't figure
It's called creative marketing.....sad but true!
__________________
Sincerely,
Kevin
**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
Re: Idealized walking and running gaits minimize work
Quote:
Originally Posted by Kevin Kirby
It's called creative marketing.....sad but true!
The other thing that don't figure is that these people always seem to make more money than you or I
__________________
Craig Payne
Department of Podiatry
La Trobe University
Melbourne, Australia http://www.latrobe.edu.au/podiatry
__________________________________________________ ___________________________________ God put me on this earth to accomplish a certain number of things - right now I am so far behind, I will never die.
The views expressed above are those of the author and not that of La Trobe University This is where I am, where are you?
Re: Idealized walking and running gaits minimize work
I have also seen the claims about the increased work required wearing the MBT (and apparent benefits), but have not actually seen the study which showed this (but i know it is from a well respected researcher).
Perhaps someone better informed than myself can tell me whether the weight of the shoes was taken into consideration... they are not light! I think you could also increase oxygen consumption by strapping a couple of cans of soup to your ankle.
__________________
Craig Tanner
Podiatrist ASPETAR-
Qatar Orthopaedic and Sports Medicine Hospital
Doha
QATAR http://www.aspetar.com/
Re: Idealized walking and running gaits minimize work
Quote:
Originally Posted by Craig Payne
It is somewhat paradoxical that, on the one hand we consider that the idealised gait is the one that minimises work and on the other hand, the proponents of the instability footwear that increases work is also considered by them to be a good thing .... don't figure
Now the latest craze here it Fitflops. These miracle thongs will "make your bum smaller and your legs leaner". Apparently they cause a longer stimulation of gluteus maximus and rectus femoris which leads to an improved gait and toned legs. Cancel your gym membership - all you need to do for toned legs is wear these thongs. They did a story on them on a current affairs program last week. The next day I was in a shoe store and these things were flying out the door at $90 a pair.
Re: Idealized walking and running gaits minimize work
Quote:
Originally Posted by CraigT
I think you could also increase oxygen consumption by strapping a couple of cans of soup to your ankle.
Adding weights to running shoes does increase oxygen consumption rate during steady state running (Catlin MJ, Dressendorfer RH: Effect of shoe weight on the energy cost of running. Medicine and Science in Sports. 11: 80, 1979). This effect is probably not related to energy savings during the stance phase of gait but rather is likely due to the increased moment of inertia of the leg during swing phase that results from adding mass to the shoe of the runner.
__________________
Sincerely,
Kevin
**************************************************
Kevin A. Kirby, DPM
Adjunct Associate Professor
Department of Applied Biomechanics
California School of Podiatric Medicine at Samuel Merritt College
Idealized walking and running gaits minimize work
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