[pct-l] Backpack Packing strategies...

Thu May 5 22:41:23 CDT 2011

Dear Steel-Eye

I don't know. There may be many parameters to consider. I will search
more experimental data.

The truth is very complex. The walking is a very complex locomotion.
Our Intuitive thinking sometimes goes wrong way.

2011/5/6 CHUCK CHELIN <steeleye at wildblue.net>:
> 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
>
> Hiking the Pct since before it was the PCT - 1965
>
> http://www.trailjournals.com/steel-eye
>
> http://www.trailjournals.com/SteelEye09
>
> 2011/5/5 Yoshihiro Murakami <completewalker at gmail.com>
>>
>> Dear treerings
>>
>> There are ergonomic experiments concerning load carriage: I found the
>> article( Abea et al. 2007, Applied Ergonomics) last year. Now, his
>> article is converted into PDF file and open to access.
>>
>> Interesting points:
>>
>> 1. The energy cost of walking significantly decreased during walking
>> with load than without load at slower speeds. This means that the
>> energy cost does not increase as the load increase, contrary to the
>> expectation:
>>
>> 2. A significant decrease in the energy cost of walking was also
>> observed while carrying the load on the upper back than on the lower
>> back at 60-80 m/min. The load on the upper back is superior to the
>> lower back load.
>>
>> You can read PDF file at http://bit.ly/jkAinW  . Please see Fig.2
>>
>>
>> Abstract
>> We examined the effects of load carriage position on the energy cost
>> of walking defined as the ratio of the 2-min steady-state oxygen
>> consumption to the speed and economical speed. Fourteen healthy men
>> walked on a treadmill at various speeds without and with load on the
>> lower and upper back, which corresponded to 15% of their body mass.
>> The energy cost of walking significantly decreased during walking with
>> load than without load at slower speeds. A significant decrease in the
>> energy cost of walking was also observed while carrying the load on
>> the upper back than on the lower back at 60-80 m/min. The economical
>> speed significantly decreased when carrying the load on the upper and
>> lower back, and it was significantly correlated with body height.
>> These findings suggest that an optimal carrying method is evident to
>> reduce physical stress during walking with loads.
>>
>>
>>
>>
>>
>>
>>
>> 2011/5/6  <treerings at gmail.com>:
>> > I think the video author misses the fact that as the center of gravity
>> > lowers it becomes less important to place the pack load vertically over
>> > the
>> > weight-bearing hips. In other words, packing all the heavy stuff in the
>> > bottom doesn't necessitate leaning over at a right angle just to keep
>> > the
>> > load vertically over the hips. That seems a little silly.
>> >
>> >
>> > On Fri, Apr 29, 2011 at 10:21 PM, John Abela <
>> > pacificcresttrail2011 at gmail.com> wrote:
>> >
>> >> Hello,
>> >>
>> >> First, spend 8 minutes of your life and watch this video:
>> >>
>> >> http://www.youtube.com/watch?v=2wuwNnRfrG4
>> >>
>> >> I would not be able to comment on this overall too much. I have gone
>> >> from using a 4,200 cubic inch (68.8 liters) backpack to a 2,600 cu in
>> >> (42.6 liters) and I have just placed an order for a 1,000 cu in (16.3
>> >> liters) backpack that I am hoping beyond all hope I will be able to
>> >> get my gear into. However what I can comment on is that a good deal of
>> >> it depends upon the design of your bag. These days with things like
>> >> Backpack lids/brains, it is just totally screwing up how to properly
>> >> go about packing a backpack. Best thing I ever did was order a custom
>> >> made backpack with no outside pockets (except for two shoulder
>> >> pouches). Not only does it force me into properly packing a backpack -
>> >> and not having to counter balance with outside pocket weight - but it
>> >> results in zero snags with trees and bushes.
>> >>
>> >> I think there are so many different "suggestions" out there on the
>> >> internet that it just really makes most people lost in what is
>> >> 'right'. Watch the video and stop and think about everything you might
>> >> be reading on the internet about this issue. It will so totally
>> >> disprove the vast majority of what you are probably reading.
>> >>
>> >> Not a lot of info I can share on this fact beyond what I have. I am
>> >> sure if you provided some further details on the pack you have and the
>> >> amount of gear you have and what your big-three are, it could help
>> >> some folks help you with some initial suggestions!
>> >>
>> >>
>> >> John B. Abela
>> >> www.RedwoodOutdoors.com
>> >>
>> >> On Fri, Apr 29, 2011 at 9:58 PM, Guthrie Nutter
>> >> <guthrie.nutter at gmail.com> wrote:
>> >> > *sheepish look*
>> >> >
>> >> > Having a bit of an 'adventure' with my amateur attempts to pack a
>> >> backpack
>> >> > properly.  Maybe doing a better job than anticipated, but need the
>> >> > extra
>> >> > confidence booster.
>> >> >
>> >> > Anyone know of any good articles I can read on about how to actually
>> >> > visualize the layout of where to put everything?  Ideally I would
>> >> > prefer
>> >> to
>> >> > see a hands-on demo at ADZPCTKO, but it's not possible.  Starting
>> >> > 5/17.
>> >> >
>> >> > If there's anyone on this list serv in the NYC area, holla in this
>> >> > direction, and we can get a conversation going.  See you on the
>> >> > trail!
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>>
>>
>>
>> --
>> 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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>
>

-- 
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.
------------------------------------------------------