The backpack is a type of bag that may be carried on the back by two straps that pass over the shoulders. The person wearing a backpack is usually called a backpacker.
The use of backpacks is often preferred in the place of bags to carry heavy loads over long periods of time, because the shoulders can bear loads better than the hands. Larger backpacks convey most weight to a belt surrounding the hips, leaving the shoulder straps with only the function to stabilize the load. This allows to carry heavy loads because the hips are even stronger than the shoulders and improves agility and balance because the burden lies near the center of the body’s mass. In addition, this allows to relief the backbone of the load that can damage it.
The backpack has its origin in prehistory, when the man needed to transport his belongings on his back. Over time this item evolved from the need to carry more and heavier objects. The wars have been large driving forces behind its development, both in design and materials.
There are different models of backpacks, depending on the specific objective: climbing (here’s on the climbing essentials), hiking (here’s on the best daypack for hiking), travel, military and carrier, to name a few. There are also the so-called hydration backpacks, which are specially manufactured to carry a water container. These have a hose that goes over the shoulder; so, the carrier of the backpack can hydrate easily.
Classification and characteristics
If classified by their function, backpacks can be divided into three main groups:
- Up to 40 liters: these are used for activities of one day or to attack.
- 40 to 65 litres: their most common use is for activities that will involve a night out, where it is necessary to bring sleeping bag, tent, stove, etc.
- Over 65 litres: this type of backpack is used for several days or activities or for logístics.
Cordura, a derivative of polyamide, is the most common material used today for the construction of backpacks/rucksacks, since it has excellent low weight and resistance to abrasion and tear. The most recommended thicknesses range from 500 to 1000 denier.
Through coating with polyurethane, waterproofing of the backpack is achieved, though the seams will always be the favorite waterways to make forays into clothes, sleeping bag and other things that we carry inside. Some light, large and medium capacity backpacks use fabrics such as Kevlar, a fiberglass with great abrasion resistance, for their construction.
Currently, backpacks have replaced the classic school bags in the transportation of books by children. The backpacks are used to carry to school both the textbooks and notebooks, and also other school supplies: boxes, pens, markers, etc. They also serve to carry lunch and other elements such as robes, clothing for gymnastics, sports, etc.
Backpacks are considered a better option than school bags since they allow to evenly distribute weight on the back of the child. It is recommended for them to have symmetric shoulder straps adjustable to fit the height of the child. Both the straps and the part of the pack that rests on the back must be padded to prevent damage to the body of the carrier. The backpack should always be lifted a few inches above the waist of the child. We should likewise avoid adopting forced positions that could cause muscular injuries. The problems that today’s children suffer from are caused by the misplacement of the backpacks and the excessive weight that schools require them to transport every day.
Mountain, hiking and sea backpack
These bags or backpacks are those that exceed the capacity of 40 litres and are made of durable material, polyamide. These backpacks are made up of several parts:
- The backpack body: most backpacks consist of one main compartment closed with zippers, but this can also be divided into two compartments. To the sides of the body there usually are pockets.
- Lid: this “cap” is located on the top of the body of the bag and covers the opening of the body, has a pocket at the top and sometimes another on the inside.
- Frame: the most important part. It consists of a coating of foam that protects the back from the rigid structures holding the backpack, a pair of shoulder straps which stabilize the backpack and stick it to the back, and a belt with padding to close above the waist that supports the weight.
Some incorporate solar panels, and are called in this case solar backpacks.