Preliminary Philmont Pain Index

Date: Fri, 05 Jan 2001 22:20:31 -0800
From: "Dr. Bob Klein" <>
Subject: [Philmont] The Philmont Pain Index - A Proposal

A constant issue of discussion (and contention) in this forum is a topic which I will term the "Philmont Pain Index" - that being, how can you determine <a priori> how challenging a specific trek will be for an individual trekker? As we all know, this involves many factors, including pack weight, the length and difficulty of the trek, the age, weight, experience level, general physical condition, and mental and emotional strength of the trekker, the quality of his/her equipment (and depth of knowledge of its use), and the extent of physical preparation conducted by the trekker prior to his/her arrival at the Ranch. Unfortunately, only 4 of these 10 criteria (pack weight, length of trek, age and weight) can be formally measured - the other 6 are all highly subjective. So it's no particular surprise that everyone constantly argues about them. This is an effort to meld the objective and subjective criteria into something measurable. To my knowledge, no-one has ever proposed anything like this before (but I'm sure someone will enlighten us if I'm wrong!)

It is my hope that Philmont will someday see fit to use this or a similar formula in their preparatory literature.

The Philmont Pain Index Formula

The formula requires the following data input: pack weight (PW), weight of the trekker (TW), Philmont recommended weight (RW), length of the trek (TL), an age factor (AF), a physical prep factor (PPF), and a prior Philmont experience factor (PPEF). These parameters and several needed assumptions are explained below. The formula is as follows:

X = [PW/(PW +TW)] x (TW/RW) x TL x AF x PPF x PPEF

Comments and Assumptions:

X = Pain Index Value

PW - Complete pack weight when leaving Basecamp on Day II, including 3 liters of water and all requisite equipment, food and fuel.

TW - Trekker's weight upon arrival at Basecamp.

RW - Philmont's Recommended Weight for a trekker's height (listed below; note that the listed values are the straight averages of the ranges provided by Philmont). The term (TW/RW) is a weight correction, adjusting for those who are above the recommendations. The (TW/RW) value is significant ONLY if it's OVER 1.00; values less than 1.00 default to 1.00:

Philmont Recommended Weights

5-0     118
5-1     122
5-2     126
5-3     130
5-4     134
5-5     138
5-6     143
5-7     147
5-8     152
5-9     157
5-10    160
5-11    165
6-0     170
6-1     175
6-2     179
6-3     184
6-4     189
6-5     194
6-6     199
6-7     205

It is appreciated that these average values do not take body physiology into account. However, physiology IS taken somewhat into account in the pack weight percentage subequation, since the Trekker Weight is in the *denominator* (that is, [PW/(PW + TW)]).

TL - Scheduled (or Planned) Trek Length In Miles. Since mileage roughly correlates to level of difficulty (that is, typical, rugged, strenuous, or superstrenuous), the latter factor is assumed to be "built in." Not perfect, but reasonable.

AF - Age Factor - a means for guesstimating overall experience, general physical condition, and mental and emotional ability to handle a trek. Participation in at least one long-term, "heavy-duty" wilderness backpacking experience (defined as a minimum of 5 days/50 miles/2,500 feet elevation change) within the previous 5 summers (EXCEPT Philmont, which is handled separately) is a reduction element in the Age Factor. The multipliers are as follows:

Long-Term Backpacking Experience?       None     At Least 1

      14 or 15 years old                 1.25        1.20
      16 - 21 years old                  1.00        0.95
      22 - 30 years old                  1.15        1.10
      31 - 40 years old                  1.25        1.20
      41 - 50 years old                  1.35        1.30
      Over 50 years old                  1.50        1.45

PPF - Physical Preparation Factor - a means for estimating how much effort a trekker has put into physically preparing for Philmont. The multipliers (and explanations) are as follows:

Extensive     1.00
Moderate      1.15
Minimal       1.35
None          1.50

Extensive prep is defined as everyday or nearly everyday backpacking, carrying a heavy pack, for a minimum of 1 hour per day for at least 2 months prior to the trek start date, plus a minimum of 2 "realistic" backpacking shakedown events (10 miles minimum, including at least 2,000 feet of elevation change), during the 2 months prior to the trek.

Moderate is everyday or nearly everyday aerobic exercising (hiking, running, cycling, high-activity sports, treadmill, etc.), with occasional backpacking practice (1 - 2 per week), for a minimum of 1 hour per day for at least 2 months prior to the trek, plus 1 realistic backpacking shakedown event, during the 2 months prior to the trek.

Minimal is occasional (3 - 5 per week) aerobic exercising, for a minimum of 1 hour per day for at least 1 month prior to the trek.

None is anything less than the Minimal category.

PPEF - Prior Philmont Experience Factor - Previous treks WITHIN THE PAST 5 SUMMERS reduce the challenge level. "Knowledge is Power." This implies CREDIBLE understanding AND CORRECT PRACTICE of basic Philmont backpacking protocols, such as the caterpillar technique, dawn-to-dusk scheduling, early hiking, equipment use, etc., etc., etc. The multipliers are as follows:

0                      1.00
1                      0.95
2                      0.90
3 or more              0.85

X Factor Evaluation Chart

Based on my personal experiences and observations, the values derived from the Pain Index Formula may be evaluated as follows:

< 15        Great Job! - Lightly Challenging - Easy Trekking.
15 - 20     Somewhat Challenging
20 - 25     Moderately Challenging
25 - 30     Highly Challenging
30 - 35     Extremely Challenging
35 - 40     Hellish
> 40        Potential Darwin Award Winner

Let's look at some real and simulated values. In 2000, my pack weight started out just under 40 pounds. I weighed 154 pounds when I left Arlington, but after 3 days of chowing down big time in Colorado, I was probably nearer 160 when I hit the Ranch. I'm 5-6 (on a good day), so my recommended weight was 143. I was 44 years old, and had done a serious non-Philmont backpacking trek within the previous 5 summers. We took an enhanced version of Trek 30, equalling about 85 miles total. My physical preparation level was "Extensive." I had been to Philmont 3 or more times within the previous 5 summers 1995 - 1999. Thus:

X = [40/(40 + 160)] x (160/143) x 85 x 1.30 x 1.00 x 0.85 = 21.0
(Low end of Moderately Challenging)

...which is truthfully about the way I felt.

Let's also look at Joe Scouter, who also went in 2000, for the second time (but his first time was 37 years ago). His starting pack weight was 54 pounds. He was 5-11, weighed 191 pounds, was 51 years old, had done 2 serious non-Philmont backpacking treks within the previous 5 summers, did a moderate level of physical preparation, and took a trek of 58 miles:

X = [54/(54 + 191)] x (191/165) x 58 x 1.45 x 1.15 x 1.00 = 24.7
(Upper end of Moderately Challenging)

However, if Joe had taken my trek (85 miles), his Pain Index Value would have ballooned to 36.2 - Hellish. On the other hand, if he reduced his pack weight from 54 to 40 pounds (matching me) to help compensate, he would have dropped to 28.4 - "only" Highly Challenging.

Let's also look at Year 2000 first-timer Johnny Scout, whose pack weight started at 49 pounds. Johnny was 5-8, weighed 140 pounds soaking wet, was 15 years old, had never done any serious backpacking before, did a minimal level of physical preparation, and took a 69 mile trek:

X = [49/(49 + 140)] x (Default = 1.00) x 69 x 1.25 x 1.35 x 1.00 = 30.2
(Low end of Extremely Challenging)

However, if young Johnny had reduced his pack weight from 49 to 39 pounds, and bumped his personal physical preparation up to the "moderate" level, his Pain Index Value would have fallen all the way to 21.6 - only Moderately Challenging - a huge drop! - and obviously worth the effort.

Final Thoughts and Comments - I suppose this could start a lively debate on the relative merits of my numbers and cutoff values, but I sincerely hope no one will so engage. The intent is to show which factors cannot be controlled (age, recent Philmont experience, and (to a lesser extent) trek length) versus what factors can be adjusted (pack weight, personal weight, prior serious backpacking experience, personal physical preparation, and (again) trek length), and the relative impacts of all those criteria. Viewed dispassionately, the results will give at least a qualitative sense for the relative merits of changes in the adjustable parameters.

Please note that this formula is designed to gauge the AVERAGE trekker, and exceptions to the rule are just that! Obviously, this cannot properly gauge trekkers with significant physical, mental, or emotional problems, ridiculously poor equipment, or crappy attitudes; nor can it handle Joe Stud Ranger, his female equivalent, or their real-world compatriots - in all such cases, a little common sense has to be employed.

I hope everyone finds this exercise to be useful. I also hope no-one feels the need to give a mighty Tarzan yell, beat his naked chest with his fists, and crow about what a macho guy he was for enduring a Pain Index Value of 42.7 (or whatever) on his last trek. No Pain = No Pain; this is a GOOD thing!

Yours in Scouting, Dr. Bob Klein, SM-111, Arlington, VA

Note: The content of this Web page is preliminary. A finalized version eventually will be provided on Troop 111's Web pages.
See also:

The content of this Web page was provided by Dr. Bob Klein. Please contact him at <> for more information.

This Web page is maintained by Selden Ball at Wilson Lab.
Please send any comments or corrections to