[pct-l] Backpack Packing strategies...

[Yoshihiro Murakami]

Dear Glen

The oxygen consumption is widely used as an energy cost among
Ergonomics professionals, because it is valid and reliable index.

This article clearly indicated that the energy cost significantly
decreased during walking with load than without load, and the load on
the upper back condition was more energy saving than lower back
condition.

The contradictory result, that the with load condition was energy
saving,  may be perplexed you. But, these result may be well
interpreted by the recent dynamic walking model ( inverted pendulum
analogy). That is, if the pendulum movement  might be facilitated by
the pack weight, energy expenditure will decrease.

I have uploaded the excerpt from a recent Ergonomic article at my
site. http://bit.ly/iSnVzl

The very classic book "Complete Walker IV"(2002) page.34  stated that

The maximum for backpacking as an enjoyment is perhaps one-third of
body weight. A well-conditioned body can handle more weight, if
necessary, and training routines can help. A reasonable load would be
one-fourth or one-fifth of body weight. Unbearable Lightness would
kick in down around one-eighth.

I think many people can walk up to 20 % body weight without an
increase of energy by using  inverted pendulum movement. The
description of Complete Walker is easy to understand by the recent
dynamic walking model.










2011/5/13 Glen Hoshizaki <hoshizaki at ca.rr.com>:
> On page 37 of the paper the investigators defined energy cost as oxygen consumption rate per walking speed, all normalized over total mass (body mass plus mass carried). So for any given walking speed (at least within a certain range) even though oxygen consumption increased with increasing load, it did so less than proportionately.
>
> Or am I completely confused?
>
> Glen
>
> -----Original Message-----
> From: pct-l-bounces at backcountry.net [mailto:pct-l-bounces at backcountry.net] On Behalf Of CHUCK CHELIN
> Sent: Thursday, May 05, 2011 8:31 PM
> To: Yoshihiro Murakami
>
> Good evening, Yoshihiro,
>
> I have a question about your Interesting Point No. 1:  If more force is
> necessary to move a large mass compared to a small mass; and if energy is in
> terms of force applied over a distance, how can it be as you say that moving
> a large mass over a distance requires less energy than moving than a small
> mass over that same distance?
>
> Steel-Eye
>
>



-- 
Sincerely
--------------- --------------------------------------
Hiro    ( Yoshihiro Murakami  村上宣寛 )
Blogs http://completewalker.blogspot.com/
Photo http://picasaweb.google.co.jp/CompleteWalker/
Backpacking since about 1980 in Japan
2009 JMT, the first America.
2010 JMT, the second America.
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