[pct-l] footwear weight, was UL danger

[Yoshihiro Murakami]

Thanks Len

You had corrected my misunderstandings.

> Yoshihiro, IMO your interpretation (spelled out in an earlier post) of
> figure 4 is not correct. You have to look at how Cw is computed.  The
> Cw values include the added mass of the ankle weights as part of the
> calculation.  Let's say I walk 80m/min with no additional weight, and
> the Cw value is 'x'.  Next, I walk with 1.5kg attached to each ankle.
> My VO2 goes up in proportion to the added weight, so the computed Cw
> value remains the same - 'x'. The body mass of the test subjects was
> 62kg, 1.5 kg is 2.4% of that, so in reality oxygen consumption
> increased by 2.4% when 1.5kg were added.  I think.


This paper is difficult to understand for me. I had simplified their results.
Cw = netVO2/v, where net VO2 is defined ml/[BM+L]/m
Let  VO2= 100 in 0 kg condition, and the values of Cw are equal in 0
kg and 1.5 kg condition,
100/(62+0)= x/(62+1.5), then x=102.4

You are right!

But the increase of energy consumption is smaller than the expected.
Is  there any significant difference? I do not know. They did not
calculated.  Generally speaking, the largeness of 2 or 3 % is
statistically non significant level. This difference may be very
small.

>  Those shoes were not part of the ankle
> weight, so the free lunch for carrying weight on the feet would be
> even higher, by perhaps .7kg or so.

Yes, I know.


> How all this relates to 'one pound of weight on the foot equals five
> (or whatever) pounds on the back', I dunno.


I don't know the  'one pound of weight on the foot equals five on the
back' theory. This might be applicable only to the climbing as like
Everest expedition. I will study in near future.

This experiments were carried out on the level treadmill, so the
results are applicable only to the level walking. If you think PCT and
JMT are predominantly level walking, these results are more applicable
than the 'one pound equal five pounds' theory. (I think JMT is
predominantly level walking, many switchbacks! )

This paper also revealed that the economical walking speed with no
load was between 70 and 90( 4.2Km/hr-5.4Km/hr). Their recent article
which appeared in Applied Ergonomics 2008, 392-398. also indicated
3.6-4.8Km/hr speed was economical when carried 15% load on the back.


 A two-minute search
> turned up this study:
>
> http://www.informaworld.com/smpp/content~content=a779402900&db=all

Yes, I had ordered the copy of this paper yesterday.

>
> I looked at Ryan Jordan's book 'Lightweight Backpacking and Camping'
> under 'Footwear'.  A 1906 book, 1953 Everest expedition, and the
> chapter author's own experience are cited with regard to the impact of
> footwear weight.  I also looked at 'The Complete Walker IV' and it has
> the same 1906 and 1953 references.

Thanks very much Len

Now, I must go back to my job.

-- 
Sincerely
--------------- --------------------------------------
Hiro    ( Yoshihiro Murakami )
HP:http://psycho01.edu.u-toyama.ac.jp
http://picasaweb.google.co.jp/CompleteWalker/
Backpacking for 30 years in Japan
2009 JMT, the first America.
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