Backpacks are used by by hikers and anyone wishing to carry kit from one place to the next. Backpacks are now the preferred mode to carry books from home to college and almost everyone has backpack in the home. This type of bag would be around 16 to 20 litres size, quite small but adequate for boots or some work items.
Small Rucksacks and backpacks are usually used to carry loads up to and over10 kilograms as well as sports backpacks for running, cycling, hiking, usually balance the load, about 90% of the weight
onto heavily padded hi[ straps, leaving the shoulder straps mainly for keeping the load stable. This greatly improves the ability to carry larger loads as the hips are better for this function than the shoulders and will allow for better balance and movement as the load is lower down the body.
The internal frame rucksack started to become popular in the 70s before that most rucksacks had no frame or an external frame. A rucksack with an internal frame pack has a frame,usually light alloy, that is covered by padding and fabric and sometimes can be removed.
This type of bag can be adjusted with various adjustment straps that allow the user to make fine adjustments to spread the load and keep the load safe and stable. It will fit snugly to the user and make sure the load will not move around when being involved in hill walking or scrambling.
The better quality bags can have a ventilation system to keep the back from getting too warm as the back will be snug against the back of the rucksack.
The internal design of the internal frame will allow for a large storage compartment with accessory loops and sleeping bags securing points. It is always best to keep larger items such as sleeping bags and tents on the outside of the bag to save room on the inside.