Hiking in the Great Smoky Mountains National Park
About the Authors
Ranking of Trails by the Energy Mile Theory
When setting out on a hike,
clearly every hiker would love to know how hard the hike will be. This is
particularly true for hikes that include substantial elevation gain (or
substantial changes in elevation).
Unfortunately, there is very little empirical evidence telling us how
to judge the difficulty of a hiking trail.
I have sought out the best information available to help with rank
ordering the trails in this book relative to difficulty level. Initially, I
considered the trails relative to the slope of the line based on distance and
elevation gain. Then, I learned of “Petzoldt’s
Energy Mile” theory (Petzoldt 1976) and started
looking into it. Based upon years of hiking experience, Petzoldt
considered the energy mile to represent the amount of energy burned when
hiking one mile on flat terrain. He then suggested that it also requires two
energy miles to hike up 1000 feet of elevation gain. Thus for a 1-mile hike
on level ground, the energy burned would be 1 energy mile, and if there was
also a 1000-foot climb, the total energy burned would be 3 energy miles.
Troy and Phipps (2010)
tested this theory using male and female college students walking 2 miles on
flat terrain and 2 miles with a 1000 foot gain, with and without 44 pound
packs. Their findings showed that the caloric cost of a 1000-foot climb for
women was 1.34 and 1.32 energy miles with or without a pack, respectively.
For males, the energy equivalent was 2.02 and 1.92 energy miles, with or
without a pack, respectively. Combining the data for both sexes, their
findings showed that the energy equivalent is 1.69 miles and 1.64 miles with
or without a pack, respectively, for a 1000-foot elevation gain.
These values based on caloric cost seem to justify
the conservative use of Petzoldt’s 2 energy miles
per 1000 foot gain. An additional reason to use the 2 miles/1000 foot gain is
that the Troy and Phipps study examined college students walking on a stable
terrain. For the purpose of this book, I’m targeting a very diverse
population of men and women who might be carrying a wide variety of packs and
supplies and who will be encountering all manner of trail and weather
conditions. There is a valid thought that energy is expended when going
downhill also, but there is no research or anecdotal information to date, so
I have not been able to include a caloric cost for hiking downhill.
Follow this link to the table that lists the hikes in each area and
their order of ranking based on energy (NRG) mile equivalent. It gives the
hike name and number, the page it appears on, the actual miles hiked, the
total elevation gain, and the NRG mile equivalent based on estimated caloric
cost. The latter two values are incorporated into Tables 2 – 10 in my 4th
Edition of Day Hikers Guide to all the
Trails in the Smoky Mountains. ”
Petzoldt, P. K. 1976. Petzoldt’s Teton Trails. Wasatch Publisher’s Inc., Salt Lake City, Utah (as
cited in Troy and Phipps, 2010).
Troy, Maridy M. and
Phipps, Maurice. 2010. The Validity of Petzoldt’s Energy Mile Theory. J. Outdoor
Recreation, Education, and Leadership. Vol. 2, No. 3, pp. 245-259.