Monday, November 8, 2021

Strapping It On or How to Wear a Backpack


OK, I can see where the title of this post could bring a wide range of images to mind, everything from feeding horses (or yourself) to enthusiastic adult play, but don't get your hopes up. Continuing on with the theme of last post's subject, this post is about properly wearing a backpack. Or at least how I wear it, proper or not.

While we have our similarities every human is different so I'm not going to skip down that yellow-brick road of ego and delusions-of-grandeur and tell you how you should be wearing your pack, but I will tell you how I wear mine in the (admittedly grandiose) hope that it might help someone else figure out how to wear their pack more efficiently.

With anything more than the most basic day-pack, which in my opinion really shouldn't be out there on anymore than a paved quarter-mile 'nature trail' anyway, or better yet, left on the shelf in the store in the first place, there are a number of adjustments to consider and unfortunately most are not a set-and-forget proposition, so understanding what each one does and how to use them all in concert is handy.

There are two sets of straps on my pack. The compression straps that stabilize the contents of the pack once it's loaded, and the suspension straps that actually hold the pack on my back and keep it from shifting around back there.

Depending on how how my pack is loaded - bulk, distribution, weight - and the season, which affects how much clothing I am wearing as well as how much personal padding I am carrying, (You know, holiday season and all - - -) these adjustments will change. So unless I've already been carrying it today, before I lift the pack off the ground I loosen all the straps involved with suspension of the pack. 

But I'm actually getting ahead of myself.  Once my pack is loaded and before I lift it to my shoulders, I snug up most of the various load-compression adjustments. (which I loosened before loading the pack)

I start with the upper-pack stabilizers, which are what the blue arrows are pointing at though they are mostly hidden now by the brain-straps. These stabilizers help pull the load in the upper part of the pack closer to my back, where it belongs.

Then I do the cordage in the middle, tightening it from the bottom up like a shoelace to pull the center of the pack in close. After that I fasten the brain down securely - the other two green arrows - so it doesn't flop and shift.

I hold off on the final set of compression straps, the ones at the red arrows that run from the lower-back of the pack, around the sides, and terminate at the rear corners of the hip-belt pockets. If I tighten these now it could affect my ability to get the waist-belt adjusted properly so I won't do them until the pack is on and the suspension adjustments are done.

It's important to note that when tightening any of these compression straps I don't gorilla them. Snug is good, tight to the point of straining doesn't improve the compression of the load all that much, it just wears out straps and stitching unnecessarily.

Now comes the suspension of the pack.

The purpose of my pack is to allow me to efficiently carry a load from one place to another with only the resources of my body.

Essentially this is an engineering issue involving the transfer of a load to ground through, in the case of the human body, a controllable articulated structural support.

The human skeleton is designed to transfer loads to ground from the pelvis down through the legs, some of the body's largest bones, and finally the feet.  In between pelvis and ground that load passes through three articulated joints that are controlled and supported by some of the largest muscles in the body.

Which brings me to step one, and arguably the most important step, of adjusting my pack on my back.

The job of the hip-belt is to transfer much of the load of the pack directly to my pelvis

To accomplish this I want the padded part of my hip-belt resting on my christa iliaca, or to get down off my high horse, the widest points of my hip-bones. Like most people, if I draw a line between these points (Not in indelible ink please!) it crosses about an inch, maybe a little less, below my bellybutton.

Some "experts" say the proper vertical positioning of the hip-belt is to have the middle of it on the hip-bones, others say it should be about a third of the way up from the bottom of the hip-belt.

Rather than taking "expert" advice as gospel each individual should find the spot that works best for them.

For me it happens to be a little below the mid-point  of the hip-belt. I find this provides padding to the skin caught between belt and pelvis but also curls the snugged up belt slightly over the top of my iliatic crests so that I'm not relying entirely on friction but also using gravity to assist in transferring the load from pack to pelvis. In other words the pack doesn't drag my pants down until I'm wearing them like a hipster since the hip-belt is partially hooked over my pelvis reducing that downward drag.

So once I fling my pack up onto my back, using the shoulder-straps at this point just to keep it from falling back to the ground, I buckle the hip-belt, hitch the pack to the right vertical position,  and yank the adjusting straps tight, and I mean tight!

The pelvis is a very strong structure so tight isn't going to hurt it and any organs trailing down that far, such as lower intestines and bladder are protected inside the pelvic 'bowl', so the only thing I'm squeezing down on is fat, which doesn't really mind being squeezed. After all, that's exactly what Spanks do when making it look like there's less of us than there is.

This pulls the wings of my hip-belt firmly around the wings of my pelvis and at the same time snugs the padding at the lower-rear part of the pack against the massive bony structure of the sacrum there at the base of my spine, which not only helps with load transfer, but also keeps the pack from shifting laterally on my back as I move, potentially throwing me off balance.

After about a quart-mile I hitch everything up and tighten the hip-belt again, usually gaining another quarter to half inch since things have settled in as I walked. I will periodically recheck the tightness as the day goes on, because as I said, this is arguably the most important adjustment to the pack suspension.

Now that the hip-belt is tightened up I can snug up those lower compression straps. These pull the lower part of the pack's load in close to my back and prevent the bottom half of the pack from lurching side to side as I move. Both good things!


Now, and only now, is it time to worry about the shoulder-straps. Since my Kestrel has torso-length as well as strap length adjustments this is initially a four-step process. But once torso-length is set it's just a three step process.

Step one:

Once the hip-belt position is established I can work on the torso-length adjustment.

What I don't want is to set that adjustment too low so that the straps wrap over the tops of my shoulders and partway down my back. But I also don't want the adjustment so high it lifts the straps completely away from my back either.

I want the straps to wrap lightly over my shoulders. With this pack that's about when the upper cross-strap (the red arrow on the right) is on top of my shoulder and the upper stabilizing strap (yellow arrow) is pretty much horizontal.

To get this finicky adjustment right I first fully loaded the pack, since if full is comfortable, half-full will be too, and went to work. I ended up making a number of attempts over many miles and several days of hiking at tweaking this adjustment before I got it just right.

Fortunately once this pesky adjustment is set I don't have to mess with it again until my spine shrinks or my hump grows. Either of which will change the distance from my pelvis to my shoulders.

At this point I wouldn't be surprised if some of you are thinking I should let the straps wrap over my shoulders farther, more like the left image, in order to spread the load over a greater area and reduce the risk of sore-spots. You have a point but here's why I don't do that.

While the pelvis and leg-bones are superb load-bearing structures, the spine is more like a slinky with water-balloons between the coils.

When it comes to load-bearing this creates two issues.

Unlike leg-bones which are rigid and can support vertical loads all by themselves, (think thick concrete column holding up the roof) the spine is designed to be flexible and relies on muscles to keep it in column, or vertical. (think multiple layers of guy-wires - muscles - holding up a tall, thin antenna tower) If I add additional load to the top of the spine it requires those muscles to use more energy in order to keep it vertical, energy which I could have used for humping myself over that last ridge-line instead.

The structure of the spine consists of a rigid element, a vertebra, stacked on top of a squishy disk, essentially a water-balloon, repeated many times. While the vertebrae themselves are bony and capable of transferring quite a bit of load, the disks - not so much - and in fact they can compress and pinch nerves or even rupture, blow-out completely, when stressed too far.

Step two:

So this brings me to the second step of adjusting my shoulder straps. Tightening them down over my shoulders.

Some people see this as the primary means of carrying a pack and the hip-belt as an accessory. Also many "experts" in those 'how to adjust your pack' videos put out by big sporting-goods chains and pack manufactures will tell you that you should be carrying 40% of the pack's weight on the shoulder-straps and 60% on the hip-belt.

Well the first group has it backwards, the hip-belt is primary and the shoulder-straps secondary, and I don't know about these so-called experts, but I don't carry a scale around with me to figure out the proper 40/60 split. Besides, because of the limitations of the human spine and the amount of hiking I do, I disagree and want as much weight on the hip-belt as I can get there. If that turns out to be a 10/90 split that's great! But I'll take what I can get.

In fact, since the internal frame of my pack is designed to transfer the load of the pack down to the hip-belt anyway, all I really need the shoulder straps to do is keep the pack from tipping backwards and slamming me down on the mat like the loser in a pro-wrestling match.

That's why, when I'm adjusting my shoulder-straps I want to feel weight on the front of my shoulder and not on the top. In fact, if you look at this photo closely you can see that my shirt is compressed under the green arrow where I want to feel the load, but from the red arrow on down my back the strap is riding lightly.

I actually fiddle with this adjustment during a hike more than any other. What I'm looking for is that point where, as my pelvis sways as I take each step (yes guys, our hips sway when we walk too!) and the hip-belt transfers that alternating, side-to-side shift to the pack's internal frame which transfers it up to the top of the pack, is to feel the pack almost, but not quite, shifting side to side against my upper back. If the shoulder-straps are too tight there's no hint of shift and that means I'm carrying too much load on my shoulders. If the straps are too loose there is actual shiftage which not only means the pack is not riding as close to my natural center of gravity as it could but might also result in chafing over the course of a long hike.

Another thing I keep in mind to ensure proper load distribution, especially then going up-hill or late in the hike when I'm tired and tend to want to stoop over into each step, is to stop leaning forward into the shoulder-straps and stand up straight instead. 

From an energy expenditure standpoint this is more efficient. Leaning forward forces my back muscles to tighten up in order to keep my spine from flopping so far forward my forehead connects with the ground. And then there's that whole compressed spine thing to consider as well since leaning forward transfers load off of my hip-belt and up onto my shoulders then back down my spine to my pelvis.

Step three:

While I'm on this photo I'll go over a sometimes obscure but very impactful step in shoulder-strap adjustment.

Just to the right of the red arrow in the photo above you can see a small strap running horizontally between the top of the shoulder-strap and the top of the pack. These are called load-adjuster straps and their job is to pull the top of the pack forward which shifts the balance point of the pack closer to my body's center of balance. The amount of shift may only be an inch, or even less, but it makes a big difference!

Unfortunately sometimes I have to be a contortionist to reach the too-short free ends of these straps, and if I over-tighten them I have to resort to taking the pack off, loosening the load-adjuster straps, and starting all over again. Very frustrating so I tighten these straps up in small increments with stretches of hiking in-between to reduce the likely-hood of overshooting the mark.

Finally! The last adjustment is the sternum-strap which is used to hold the shoulder-straps in place on the chest.

I have come across some that never use this strap, claiming it restricts their breathing, but personally I've never noticed that with a properly fitted pack.

What I do is adjust the ends of the sternum-strap up or down the shoulder-straps (On decent packs there always some way to adjust this, on the Kestrel the strap ends in a kind of semicircular claw-like fitting that rides up and down a rail or bead attached to the shoulder-strap) until they are opposite where the  outside of the shoulder-straps dive under my arms.

Because my pack is well fitted, now all I need to do is adjust the length of the sternum-strap to apply a very light cross-chest pressure to the shoulder-straps. Just enough to keep them from shifting outwards and chafing the crease under my arms as I move.


Alright, this took way too long to write about, much longer than it takes to actually do it, especially after a little practice, so now it's time to shut this damn computer down and go hiking!


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