[pct-l] Pack weight to body weight ratio...

[stevesgt at effable.com (Steve Sergeant)]

Don Fletcher said:
> Hey : does anyone have any thoughts about body weight to pack weight
> ratios , for optimum physiologic work while hiking??
>  I have tried to find some science on this to no avail ( so far )

About 1994, I remember reading a translation of a Swiss military study on
the effects of backpack weight on fatigue and balance.  I unsuccessfully
Yahoo'd and Googled many times since then for a reprint or follow-up of
that study.  I sure wish I could find the original article, or some
follow-up study.  Other countries must have done similar research.

At any rate, I wrote about this article in a club newsletter at the time.
The excerpt below might be somewhat helpful, though probably not directly.
 In my newsletter article, I wrote:

"A Swiss military report suggests that everyone has a backpack weight
threshold at which they become significantly more encumbered. They
determined this weight by measuring how much it takes for a person's
balance-time to degrade by 20%. You can determine your balance-time
degradation by measuring the time that you can stand on one foot without
your pack, and then compare that to the time you can do so with your pack
on.

"Apparently the Swiss military sought to optimize the performance of
'light & fast' special-forces types. They found that for their typical
soldier, balance degraded by 20% when wearing a pack weight between 8% and
10% of their lean body weight. The degree to which the pack carrier's
balance degrades directly relates to the rate at which they'll become
fatigued.

"This study suggests ways to improve your backpacking experience. The
traditional guideline of 25% to 40% given by some how-to books on
backpacking would seem quite high by these standards, so you should try to
go lighter. Experiment with loading your pack to minimize the degradation
of your balance time."