The Definitive Guide that You Never Wanted: Fitting and Adjusting Your Backpack
When HL and I wandered out into the backcountry of the Canadian Rockies several years ago, I knew very little about backpacks. The 60L pack I had on me was poorly padded and not well-fitted for my body. Younger Geoff didn’t realize what a massive difference a quality backpack that was properly adjusted would have made on his shoulders and his back. So here are some tips for how to make your 35-lb pack feel much lighter.
Keep in mind that most of this applies to adventure backpacks for hiking or backpacking. Your everyday carry work or school bag may not have a lot of these features. If you need a refresher on all the terminology around the straps, check out our definitive guide on backpack anatomy.
Choosing the Right Bag — Torso Length
Before playing with all the straps of the backpack, you’ll need to make sure that the backpack is actually the right size for you.
- Determine your torso length — the distance from your 7th cervical vertebra (C7) down to the top of your iliac crest along your spine. If you bend your head downward and feel the back of your neck, that bony part on your spine that sticks out a little bit around the base of your neck is where the C7 is. The iliac crest is the top of your hip bone. This is easiest to measure if you have someone helping you.
- Use that torso length to choose a backpack size — 15–17 inches is an XS backpack, 16–19 is S, 18–21 is M, and 20–23 is L.
- Before you purchase the backpack, it’s a good idea to stop by a store to try it out. If you go to outdoor stores like REI, they have sand bags that you use when trying on a backpack to see what it would feel like under the weight of a full load.
Once you have a backpack that is the right torso size, you can then adjust it to your body further with the straps.
Many trekking backpacks, like the Deuter ACT Lite series, have adjustable torso lengths. These still have limited range, so it’s still possible for a backpack with an adjustable torso to not fit your body size. Making sure the torso fits is vital to having an enjoyable hiking experience as the adjustable straps will not be enough to compensate for an ill-fitted backpack.
Adjusting the Backpack for Your Body
Once you have the right pack, you’ll need to know how to properly adjust all those straps to optimize comfort and support. You should do this every time you put the backpack on after you’ve modified the strap lengths. For example, if you were out camping in the backcountry and you loosened the straps when you took the bag off, you’ll need to readjust them in this order when you put your bag back on. If you didn’t change any of the straps and just plopped the bag off, you should be good to go, but it certainly wouldn’t hurt to readjust.
If you’re just testing out a backpack and adjusting the straps, the backpack should be weighted down to properly simulate how it would feel in the field. Start with all the straps fairly loose and go through these steps in order:
- Put the backpack on — You don’t need to tighten the shoulder straps perfectly yet; just loosely wear the bag.
- Waist belt — Buckle the waist belt and adjust the position so that the padding rests on top of your hip bones. You can adjust the shoulder straps to get the proper height. Tighten/loosen the waist belt so that it fits snugly but doesn’t pinch you. It should be secure but comfortable. The waist belt should provide padding to the top of your hip bones and reach around toward the front of your stomach, but the padding should not completely wrap your stomach. There should be several inches between the two front tips of the padding so that there is room to adjust the tightness of the hip belt.
- Shoulder straps — Tighten the shoulder straps so that the straps wrap and hug your shoulders and upper back closely, but doesn’t pinch your armpits. Much of the weight should still be on your waist belt, otherwise you will strain your back and neck muscles. The shoulder straps should attach to the backpack a couple inches below the top of your shoulders. If there is too much space between your shoulders and the shoulder straps, or if the anchor point of the shoulder straps is to high or low even though the hip belt is in the right position, the backpack may be the wrong size or the torso length needs to be adjusted.
- Load-lifter straps — Tighten the load-lifter straps to bring the upper part of the backpack a bit closer to your back. The load-lifters should form an approximately 45 degree angle with the back panel of the backpack and with the horizontal plane that is tangent to the top of your shoulders. If you feel like the shoulder straps are starting to pinch your armpits or shoulders, you probably just over tightened the load-lifters. Like with all the other straps, aim for comfortably snug, not so tight that it’s inflexible.
- Sternum strap — Lastly, put on the sternum strap. The sternum strap height should be about an inch below your collarbone. Its purpose is to relieve the stress on your shoulders by pulling the shoulder straps slightly closer together and should allow your arms to move freely, and to keep the shoulder straps from slipping out of place. Make sure you don’t tighten the sternum strap so much that it feels too tight on your chest or constrict breathing in any way. It should just pull the shoulder straps slightly closer together.
The order is key so remember — Waist, Shoulders, Loads, Sternum. WSLS. Make a mnemonic device. Why Stop Licking Skittles? Walruses Slap Like Sissies.
On the Move
After you’ve properly fitted everything, get moving. You may need to make minor tweaks here and there to stay comfortable, but the key is comfort. As you move most of the weight should rest on your hips. Theoretically, if you take off the shoulder straps and sternum strap, the waist belt should still be holding up your entire backpack. Your quadriceps and all those leg muscles are much stronger and can endure the weight of the backpack longer than your back and shoulder muscles.
A couple last things to look out for and tips when you’re out and about:
- Backpacks shift your center of gravity backward a bit, so leaning forward slightly will help you keep balance as you trek. Just enough so that you can easily maintain balance. Too much will cause back strain and the backpack’s weight will fall on your back though.
- One way to make sure the waist belt is on top of your hips is to shrug your shoulders while wearing the backpack. While shrugging, tighten the waist belt so that it’s snug. Then release your shoulders. The backpack should come down on top of your hips.
- When you’re on the trail and you take a break, take the backpack off. Give your muscles a break and stretch out.
- If you feel your shoulders getting overly exhausted, shift more weight onto the waist belt (tighten slightly) and loosen the shoulder straps slightly). Then later on, tighten the shoulder straps and loosen the waist belt slightly. Alternate back and forth for a bit.
As mentioned earlier, this is mainly just for the outdoors adventure pack where you might be lugging 35 lbs of gear for many days. It’s less applicable for EDC bags where the torso lengths are usually not adjustable and only in one size. But for those backpacks, the idea is still the same — keep the shoulder straps snug. Use the sternum strap to keep your shoulder straps in place and ease off on your armpits. If the waist belt is just a strap of nylon, its purpose is just to prevent the backpack from slinging around, not to hold the weight of the pack. But the key is still to make sure you can walk for an hour and still feel comfortable and without straining any muscles.
Thanks for reading. Hope this helps you fit your bag on any adventures! Please comment if you have any other tips and tricks or if you know of something that we missed!
A few more shots now that I’m feeling nostalgic and restless…
