for: Plymouth Backpack

Backpacks are often preferred to handbags for carrying heavy loads, because of the limited capacity to carry heavy weights for long periods of time in the hands. Large backpacks, used to carry loads over 10 kg, usually offload the largest part (up to about 90%) of their weight onto padded hip belts, leaving the shoulder straps mainly for stabilising the load. This improves the potential to carry heavy loads, as the hips are stronger than the shoulders, and also increases agility and balance, since the load rides nearer the person's own center of mass.

In ancient times, the backpack was used as a means to carry the hunter's larger game and other types of prey as a way of easier transport. In the cases of larger hunts, the hunters would dismember their prey and distribute the pieces of the animal around each one packing the meat into many wrappings and then into a bag which they place on to their back. The bag itself was made up of different animal hide and skin (depending on what sorts of animals were in the area) and sewn together by the intestines of said animals, which were woven together tightly to make a sturdy thread-like material. Fact: date=October 2008

Terminology

The word backpack was coined in the United States in the 1910s. Knapsack and packsack were used before; they now occur mainly as regionalisms in North America. The word rucksack is a German loanword mainly used in the UK: 'der Rücken' means 'the back' (the part of the body) in German. The name Rucksack is cognate with Danish Rygsæk, Norwegian Ryggsekk, Dutch Rugzak, and Swedish Ryggsäck. Alternative names include Haversack, and Bergen (from the manufacturer's name Bergens, used for a backpack supported by an external frame, usually associated with the British Armed Forces).

Backpacks can often simply be referred to as "packs", especially in outdoors contexts; though sometimes ambiguous compared to other bags such as saddlebags and duffel bags, context is generally sufficient for identification.

Backpack designs

Backpacks in general fall into one of three categories: frameless, external frame, and internal frame. A pack frame, when present, serves to support the pack and distribute the weight of its contents across the body more easily (generally by transferring much of the weight to the hips and legs), so most of the weight does not rest on the shoulders, restricting range of motion and possibly causing damage from pressure on the straps. Most are capable of being closed with either a buckle mechanism or a zipper, though a few models use a drawstring for the main compartment.

Frameless

The simplest backpack design is a bag attached to a set of shoulder straps. Such packs are used for general transportation of goods, and have variable capacity. The simplest designs consist of one main pocket. This maybe combined with webbing or cordage straps; while more sophisticated models add extra pockets, waist straps, chest straps, padded shoulder straps, padded backs, and sometimes reflective materials for added safety when the wearer is out at night. In general these packs can be produced inexpensively.