Backpack Size Selection
The maximum length of backpack you are able to fit correctly
will depend on your Individual Torso Length. A backpack is then
chosen that best suits this Torso Length.
White Mountain recommends two methods of determining the correct
In the first method, you can hold the backpack with a straight
frame up to the individual with the hip belt level with the Iliac
Crest (the bone at the hip directly under the bottom rib). If the
backpack does not proceed past shoulder ridge by more than 8 cm
(5cm after Internal Stave reduction in contouring), or not lower
than the shoulder ridge by 2 cm (5cm after Internal Stave reduction
in contouring), then this is a suitably sized backpack for customisation
to the individual.
The second method is to Measure your Torso Length, and compare
this measurement to the recommended Torso Length for each backpack
provided by the backpack supplier, if available. All credible backpack
suppliers will list the recommended Torso Length for each of their
Internal Frame Backpacks with information supplied on each of these
The definition of the Torso is the upper part of the human body
excluding the head and arms. For the purpose of fitting backpacks
we further define the Torso Length, as a point along the spine at
position level with the top of the Iliac Crest, up to the base of
the neck or top of the seventh cervical vertebrae (the prominent
bone or large knuckle at the base of the neck, or when bending the
head backpacks the crease of the neck).
To assist in choosing which size/length of backpack is best for
you, first Measure your Torso Length (This link will open a new
window with instructions and diagram for accurately measuring your
own Torso Length). You can either measure your Torso Length in a
straight line, or measure your Torso Length along the curve of your
spine and subtract 3 cm.
To Measure your Torso Length, begin at a point on the spine level
with the top of the hipbone or Iliac Crest. Measure along the curve
of the spine up to the base of the neck or top of the seventh cervical
vertebrae (the prominent bone or large knuckle at the base of the
neck, or when bending the head backpacks, the crease of the neck).
Typically, you would measure the Torso Length vertically in a
straight line, and not along the curve of the spine. To obtain a
more accurate Torso Length, measure along the curve of the spine
between the two points indicated above and subtract 3 cm. This will
hold true for all Torso Lengths.
All recommendations, all tables, and all tables of specifications
for White Mountain™ Internal Frame backpacks, assume that
you have measured the Torso Length in a Straight Line.
The White Mountain™ Harness Systems incorporate an adjustment
that indicates your Torso Length in a straight line measurement.
f you have instead measured along the curve of the spine simply
subtract 3cm to obtain you straight line Torso Length measurement.
The straight line Torso Length measurements are marked on the backpack
harness, and the Harness Shoulder Straps have a corresponding marker.
To set the Torso length simply align the Harness Shoulder Straps
markers to the Torso Length measurement on the backpack.
White Mountain™ uses the extra small to large length of
Internal Staves with adjustable Torso Length positioning to facilitate
a correct fitting. Each Optimum Torso Length for each Internal Stave
Length can facilitate a variation on this Optimum Torso Length.
That is, each Internal Stave Length can facilitate an adjustment
of 5 cm or 2” either side of the Optimum Torso Length. This allows
a range total of 10 cm or 4” for each Internal Stave Length.
Providing a second lower anchoring position for the Upper Load
Stabiliser Strap, then further facilitates this range and extends
the maximum length by 5cm or 2". We can then fit a backpack to an
individual’s Torso Length of - 5 cm (- 2"), to + 5 cm (+ 2"). The
first anchor position is at the top of the Internal Stave and the
second 5 cm or 2” lower than the first position. By lowering the
anchor position of the Upper Load Stabiliser Strap we are then able
to accommodate the backpack proceeding past the shoulder by as much
as 5 cm (2"), in which case the last 5 cm (2") of frame proceeding
past the shoulders would need to bent away from the head at approximately
30º. This lower position when fitting to a smaller Torso Length
prevents the Upper Load Stabiliser Strap pulling and lifting the
Shoulder Strap from the shoulder and leveraging backwards, which
would place excessive pressure on the chest and lower back.
White Mountain™ recommends, as the most advisable choice
a Maximum Torso Length of no more than - 4 cm (- 1 5/8"), to + 8
cm (+ 3 1/8") either side of the Individual Torso Length (your own
Torso Length) for an acceptable backpack size. For example, if the
Individual Torso Length were 48 cm, the best choice would be a backpack
with a Maximum Torso Range of 44 cm to 56 cm, or a Optimum Torso
Length closest to the length of 48 cm.
The information provided is based on research into the correlation
between White Mountain Backpacks™ Stave Length, Lower Back
Length, Torso Length, and Spinal Curvature. Remember the incremental
adjustments on the White Mountain™ backpack harness systems
assume that you have measured your Torso Length in a straight line.
Regardless of Torso Length, simply subtract approximately 3 cm if
measuring along the curve of the spine to obtain the comparative
figures for the table below.
The Torso Length markings on White Mountain™ backpack harness
systems use the Straight Line Torso Length measurement. For example,
if your Straight Line Torso Length measurement is 50cm then this
will correspond to 50cm on your White Mountain™ backpack harness
system. Alternatively if your Torso Length is measured along the
curve of the spine at 53cm then this will correspond to 50cm (53cm
– 3cm) on your White Mountain™ backpack harness system.
The following table of specifications for Internal Frame backpacks
assume that you have measured your Torso Length in a Straight Line,
not along the curve of the spine.