A backpack, also called knapsack, rucksack, Rucksac, Pack, sackpack or backpack, is, in its frameless form simpler, a cloth bag transported on the back and fixed with two strips that go over the shoulders, nevertheless can have an external frame, inner frame , and there are Bodypacks.
Backpacks are commonly used by walkers and students, and the bags are often preferred to carry heavy loads or carry any type of equipment due to the limited ability to carry heavy weights for long periods of time In the hands.
Large Backpacks, used to carry loads of more than 10 kilograms (22 lb), as well as smaller sports backpacks (e.g., running, cycling, hiking and hydration), usually discharging most (up to about 90%) From its weight in padded hip belts, leaving the shoulder straps mainly to stabilize the load. This improves the potential for carrying heavy loads, because the hips are stronger than the shoulders, and also increase agility and balance, as the load is closer to the user’s center of mass.
The backpacks are usually divided into one of four categories: external frame, internal frame and Bodypack. A frame of package, when present, serves to support the package and distribute the weight of its contents in the body more appropriately, transferring much of the weight to the hips and legs. Therefore, most of the weight is removed from the shoulders, reducing the chance of shoulder strap pressure injury (large numbers backpacks equipped only with shoulder straps can affect the posture of a person carrying more than 30 pounds), as well as being Less restrictive of the range of motion of the upper part of the body. Most backpacks can be closed with a buckle mechanism, a zipper or a dry bag-type closure, although some models use a cable with a cable lock for the main compartment.
A balloon is a backpack equipped with one or more pockets that are suspended in the user’s chest and loaded in such a way that the load on the front and the load on the back are close to it. Most of the cargo in a balloon is transported by the hips. The Ideal load transport system should not disturb the natural posture, balance and maneuverability of the user. The load should be spread over the skeletal structure in a uniform manner, and should not produce unbalanced forces in the body.