Filling a travel backpack is not to throw all the items into the backpack, but to carry comfortably and walk happily.
Generally heavy items are placed on the top, so that the center of gravity of the backpack is higher. In this way, the backpacker can straighten his waist while traveling, and part of the center of gravity must be lower, so that his body can bend and bounce between trees, or travel in the climbing terrain of bare rock avalanche. During climbing (rock climbing backpack), the center of gravity of the backpack is close to the pelvis, that is, the center point of body rotation. This prevents the weight of the backpack from moving to the shoulder and during hiking, The center of gravity of the back packing can be higher and close to the back.
Heavy equipment shall be placed at the upper end and on the back, such as stove, cooker, heavy food, rain gear, and water bottle. If the center of gravity is too low or far away from the back, the body will bend and walk. The tent shall be tied to the top of the backpack with umbrella straps. Fuel oil and water shall be placed separately to avoid contamination of food and clothing. Secondary heavy items shall be placed at the center and lower side of the backpack, For example, spare clothes (which must be sealed with plastic bags and marked with different colors so that they can be easily identified), personal appliances, headlights, maps, north arrows, cameras, and light articles should be tied underneath, for example, sleeping bags (which must be sealed with waterproof bags), camp posts can be placed in side bags, and sleeping pads or backpacks placed behind backpacks should be equipped with long straps to bind some articles, such as tripods, camp posts, or placed in side bags.
The backpacks suitable for men and women are not the same, because the upper torso of boys is longer while the upper torso of girls is shorter but the legs are longer. Be careful to choose your own suitable backpack. The weight of boys should be higher when filling, because the weight of boys is close to the chest, while girls are close to the abdomen. The weight of heavy objects should be close to the back as much as possible, so that the weight is higher than the waist.