Packing your Backpack for Hiking
When packing your backpack, the major considerations on weight distribution is what type of terrain you're hiking on. Is it flat or steep? When on relatively flat ground your main weight items should be higher in the pack, close to the top. The heaviest items need to be packed so that they are between the shoulder blades.
For steep or extremely rough terrain, you need to carry the weight lower for better balance. This keeps the items from easily throwing you off balance and falling while moving uphill. The heaviest items need to be situated so that they are packed at the middle of your back.
Generally, women have lower centers of gravity than men, therefore, heavier items should often be placed lower in the pack and closer to the body (similar to the steep hiking style). A pack specifically modeled for women often times compensates for this by having the pack itself built lower on the frame.