Torso Length FAQ's
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.
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 backpack length.
In the first method, you can hold the backpack 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 4 cm, or not lower than the shoulder ridge by 8 cm, then this is a suitably sized backpack for that 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 products.
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 Backpacks™ Internal Frame backpacks, assume that you have measured the Torso Length in a Straight Line.
When measuring and adjusting the White Mountain Backpacks™ SSS or SHS Harness System, 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). Then simply set the Torso Length indicator to that measurement. The White Mountain
Backpacks™ Harness Systems incorporate an adjustment that indicates your Torso Length straight line measurement. If you have measured along the curve of the spine simply subtract 3cm to obtain you straight line Torso Length measurement.
White Mountain Backpacks™ 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 individuals 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 60 degrees. 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 Backpacks™ 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 Medium Torso Length closest to the length of 48 cm.
The Torso Length Tables will assist you in determining the correct backpack size for your Individual Torso Length.