The origin of the backpack goes back to prehistory, when the human began to move, he had to carry his few belongings on his back. The evolution of the backpack has gone hand in hand with the human need to transport more and heavier things. Wars have been what have driven, especially since the eighteenth century, the different advances, both in materials and in forms and capacities. Nowadays, our backpacks have nothing to do with those made of heavy canvas, since they are made of waterproof and light synthetic fibers, the resistance being conditioned by the use of one or another material. The shape and structure of backpacks have also evolved to adapt much better to the human anatomy, with the appearance of modern suspension and regulation systems. The activity that we are going to carry out will determine the type of backpack that we must acquire (climbing, hiking, skiing...)
Cordura, a derivative of polyamide, is the most widely used material today for the construction of backpacks, as it is endowed with an excellent weight ratio and resistance to abrasion and tearing.
The load capacity of a backpack (volume) is calculated in liters. It should also be taken into account that the pockets add volume to the backpack, so the formula should be applied to them and add the result to the volume of the backpack By means of a coating finish, resin or induced, of polyurethane, the impermeability of the backpacks, although the seams will always be the preferred pathways for water to make inroads into the clothes, bags and other things that we carry inside. Some medium and large capacity hyperlight backpacks use fabrics such as Kevlar, a fiber with high resistance to abrasion, for their construction.
Backpacks can be divided into three large groups depending on their capacity:
Up to 40 liters These are used for activities of a day or for attack.
From 40 to 65 liters Its most common use is for activities in which you are going to spend at least one night out, since it is necessary to carry a sleeping bag, coat...
More than 65 liters This type of backpack is the most hated by everyone, since it is almost never empty and is usually tremendously heavy. It is used for activities of several days or to carry out portages.
In general, the backpacks are going to be of many different shapes and they are going to have a series of details that will be more or less appropriate for the activity that we want to carry out. Next, we list the following characteristics:
Possibility of increasing its capacity thanks to additional extensions in the upper part of the backpack, which must be accompanied by a cover not attached to the back In medium and high capacity backpacks, independent direct access to the lower part of the backpack is highly recommended. backpack, by means of an external zipper, with the possibility of communication with the rest of the useful space. The shoulder, back and belt padding is usually made with closed-cell polyurethane foam of different densities.
The straps are very necessary when carrying crampons, ice axes, trekking poles...
Exterior pockets add potential extra cargo and selective access to gear, but they tend to unsettle the wearer and, by Murphy's law, they tend to snag everywhere possible and impossible. In the case of having them, it is advisable that they be of the bellows type so that when they are not needed they can be integrated into the sides of the backpack.
The fanny packs on the belt make it possible to carry some snack food while we are walking, without having to stop. The bottle holders that some backpacks incorporate are also very useful, to leave the liquid more at hand.
The seams are the ones that join the different parts of a backpack, therefore, being the most common part of breakage. To be durable, the thread must be of high resistance (polyamide thread) and those that are going to withstand greater effort must be double or triple or include an effective reinforcement system.
In cargo and porterage backpacks, it is very important to adapt them to our back. facilitating a correct distribution of weight and volume on shoulders, back and hips.
While the small backpacks provide simple padding, the medium ones incorporate an anatomical back, reinforced with high-density synthetic materials that give them a certain rigidity as well as channels in the contact areas to facilitate rapid moisture evaporation. Cargo backpacks have different regulation systems so that the user adjusts the backpack to their anatomical characteristics. It is very important that the systems are as simple as they are effective.
Although it seems that any backpack is suitable for anyone, this is not the case. Nowadays we can choose within the same model the size that best fits our shoulder, avoiding that the height of the user and that of the backpack are very disproportionate Models for women usually have shorter backs, wider hips and preformed shoulder pads to avoid the typical discomfort in the breasts.
Lid height adjustment: Incorporated in some models, it is another way of adapting the different load requests to which we submit the backpack.
Lifting handle: With it we will handle the backpack more easily when we do not have it loaded on our backs.
Upper shoulder straps or back stabilizer: They allow the shape of the backpack to be adapted to the user's sword depending on the weight of the load.
Anatomical shoulder pads: They will adapt to the back shoulder-thorax shape, reducing the indirect support of the shoulder pads on the neck. Models designed for women are intended to relieve the load from above the breasts. They improve when they are wide and padded.
Padded back. Essential when transporting a lot of weight or loads with edges that can dig into the back.
Chest adjustment. Keeps the shoulder pads in place, improving overall stability.
Shoulder Pad Tensioners Adjust the shoulder pads from their base to different thoracic capacities
Waist adjustment. This belt will prevent the backpack from jumping when walking.
Belt sway girders: Reduce lateral sway, especially when the backpack is high.
Lumbar padding: Improves the comfort of the place where the greatest weight of the set will fall
Height adjustment: Adapts the backpack to the different heights of the users' backs.
Anatomical crosspiece: The beginning of the shoulder pads is designed to distribute the load directly to the center of the clavicles, freeing the neck and supporting between the shoulder blades.
Pocket on the lid: To keep the small accessories that we will use continuously at hand
Material carrier: They will allow you to load material on the outside of the backpack in a safe way (insulation, crampons, etc.).
Once carried on the back, the cross formed by the beginning of the shoulder pads must coincide between the shoulder blades of the back (fig.1). In models that do not have stabilizers, this area may be a little higher, depending on the morphology of each user. We will close the belt (fig 2). Its position will correspond to the upper part of the pelvis. We will tighten in such a way that there is contact all around the waist. We will tighten the lateral adjustments of the belt (fig.3), until there is no rocking of the bottom of the backpack.
We will tighten the shoulder straps (fig 4) until we notice that there is contact in the entire area of the chest, shoulders and preferably also the beginning of the back. We will tighten the upper straps of the shoulder pads (stabilizers), in such a way that the swaying of the upper part of the backpack is canceled and taking care that it does not interfere with the turning of the head (fig.5). To improve the immobilization of the load, the chest strap is very useful.
Because of the seams, it is impossible for a traditional backpack to be completely watertight. The use of watertight inner bags or the use of a waterproof outer cover (backpack cover), will guarantee to keep your contents dry. Distributing the material in plastic bags of different colors improves the layout inside the backpack and facilitates quick location.
On certain occasions (in the event of an avalanche or falling into the water), systems that allow you to quickly get out of your backpack can be very useful. The removable metal rods that some models of backpacks have on their backs can be used in an emergency to improvise an immobilizing splint in case of breaking a bone in a limb.
At the time of loading, we must take into account which will be those elements of the equipment that we may need during the march (availability) and which are the heaviest (weight), According to this, the lightest and least necessary should go in the bottom (sleeping bag, bivouac cover, spare clothes, etc). The heaviest will preferably be installed in the upper two thirds of the backpack (kitchen and gas, food, material). This detail will facilitate better control of the load and greater stability of the load as the center of gravity of the backpack and the person are aligned. The objects with the greatest possibility of use (headlamp, sunglasses, creams , maps, etc) will be placed in the upper part of the backpack.