Three types of trekking bags
Internal frame backpacks: These make most sense on treks as they’re tight and less bouncy, and provide a good amount of internal storage. They also allow a reasonable amount of airflow to your back.
External frame backpacks: These are broad, do not stay close to your body and strain your back. So it becomes difficult to move around with them.
Frameless backpacks: These are used mostly for climbing and are without frames or have detachable ones, so they adjust to the shape of your back. Frameless bags are useful only if you plan to carry lighter goods.
How to pick a bag
Pick a bag that allows easy access and has multiple zips to the main compartment. Outer pockets are also very helpful. The waist belt should have compartments for things like sunscreen and chocolates.
Get a bag with a padded waist belt so that it rests on your hips and the weight is evenly distributed waist-down. You should be able to adjust the shoulder straps so the bag stays on compactly without swinging.
Rucksacks usually have capacities in the range of 65-90 litres. Before buying one, put some weights in it, walk around the store and climb up and down stairs to decide if the size is okay.
Chest and compression straps are also helpful. Chest straps keep the bag from tilting backwards and compression straps make sure the contents fit snugly.
Ensure the weight is borne by the pelvic girdle and not the shoulders. If a bag doesn’t suit your body structure, it’ll pull back outwards when fully loaded and put too much pressure on your shoulders.
Front opening backpacks are preferred over top opening ones, as they allow a complete overview of the contents of the bag. With top opening ones you will have to unload everything to take out stuff kept at the bottom.
The cardinal rule is to have easily at hand all the things that you may need in an emergency. This is when the side pockets and supplemental pouches come in handy.
If you’re carrying a tent, be sure to place it along your back, and secure the poles with the shoulder straps.
Place any other gear you have on top of the clothes, and then place the food items you’re carrying.
If you’re worried about damaging expensive electronic gadgets, you could either place them in between the clothes so they get proper cushioning or carry them around your neck in a separate shockproof bag.
Things that you will need throughout the trek — such as water, map, snacks — should be packed in the topmost pouch.
Pack sleeping bags, sheets in the bottommost compartment so that you can set up base easily without having to unpack entirely.
Put heavy objects at the bottom so the weight centres around your spine.
Line the inside of your backpack with a giant plastic bag or a sheet. Make sure the plastic bag is thin and soft so it doesn’t take too much space inside the backpack.
You can use a waterproof backpack cover. It should big enough, so it can be tied together and sealed around the items of the backpack. But this method won’t work if you’re going to open your bag often, especially in places where water could enter.
Wear a poncho raincoat that has long sleeves, a hood and enough space to allow both you and the backpack to move around with ease.