[pct-l] Backpack Packing strategies...

Thu May 5 23:53:47 CDT 2011

Dear Tortoise

I am not a professional researcher and have no professional knowledge.
I think your question is difficult to answer. The professionals
simplify experimental condition to clarify the parameters. Best way is
to carry out the field experiment, but it costs high and difficult to
execute, and many parameters must be controlled:

A field experiment : Some group of hiker hike for example ten miles in
two different conditions (light weight, heavy weight: pack weight must
be controlled) and measure their oxygen consumption. And if we compare
two different results of energy consumption, we can conclude something
in a limited condition (walking speed must be controlled). At present,
I cannot find those field experiments.

My imagination is:
The energy consumption will not increase within some pack weight. And
if the pack weight is over some weight, the energy consumption will
increase.  But, the proportion of increase of energy consumption might
be unpredictable. I think our imagination will fail.

The truth is not simple.

2011/5/6 Tortoise <Tortoise73 at charter.net>:
> Interesting findings. The load carried was about a  light weight pack load.
> However I have a couple of questions -- what would the results be on a
> moderate upgrade or downgrade comparable to typical trail conditions.  what
> would result if the test continued for some time (typical of hiking), or did
> the tests after the subjects had hiked a good distance -- say 10 miles?
>
> Tortoise
>
> <>  Because truth matters.<>
>
>
> On 05/05/11 18:26, Yoshihiro Murakami wrote:
>>
>> 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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