Backpacking and hiking enthusiasts know all too well the importance of loading a backpack for optimal weight dispersion. The most critical part of the loaded pack, however, is the waist belt. This apparatus is what evenly distributes the weight on your hips when adjusted appropriately. All backpacks are constructed differently, and all backpackers' hips are different in proportion. To improve your waist-belt to fit your hips, you must first know how to tighten it properly, and make adjustments here and there to improve the belt's efficiency. The tightening and adjusting process is the most critical to ensure comfort, especially over longer treks or extended hiking trips into the backcountry.
Put the backpack on your back and position the waist belt so that your top hip bones are centred within the waist belt, then buckle the belt.
Tighten the waist belt adjustment straps by grabbing the straps and pulling forward. Some backpacks may have two waist belt adjustment straps on both sides, but typically there is only one strap per side. Tighten the straps securely, but do not over-tighten. You shouldn't feel any stress on your diaphragm, but the belt must be snug around the waist.
Look for any gaps between your body and the waist belt. Gaps are what cause improper weight dispersion, and over longer treks the gaps will cause significant discomfort.
Obtain Velcro padding from a backpacking outfitter, and apply it to the waist belt. Typically the padding is placed right onto the belt where the belt meets the pack frame--around the back--and the Velcro is adjusted to fit. Try the backpack on and check for any gaps. You should notice a significant improvement with comfort once the gaps are filled by the padding.
If you need to improve your weight dispersion while out on the trail, take a fleece or sweatshirt and fold it up flat, then tie it around your waist. Put the pack on and adjust the waist belt over the fleece or sweatshirt. This should fill any gaps that may be causing discomfort.