Backpacker Tip: Measure Your Torso
Before you even start shopping, determine your torso length, so you can find the proper size pack for your body. Nothing is more important in fitting a large-capacity backpack because without the proper measurement, your shoulders, back and hips will not bear the load correctly, causing discomfort and, potentially, injury. To do this, you'll need a friend and a soft tape measure or a length of string. Follow these three steps:
Tilt your chin down so that the C7 vertebra at the base of your neck protrudes. This is the starting point of your measurement.
Put your hands on your hips and use your thumbs to feel for the top of the iliac crest. Draw an imaginary line between your thumbs. Where this line intersects your spine is the end point of your measurement.
Have your friend drape the string or tape measure along the contours of your spine between the two points. You now have your torso length. (Most adults have torso lengths that fall between 16 and 22 inches.)
A Note on Women's Packs
These aren't just smaller men's packs in pretty colors. Good women's packs have subtle but important fit differences that can really improve comfort for women: shoulder straps that are closer together, thinner, and more tapered to meld with narrower shoulders, and hipbelts that are canted to better cup women's hips.