Upper-body Backpack

Many here find that for loads under 25 pounds that a hipbelt is not needed. Take a look at some of the cottage manufacturers offerings.

I always leave the hip belt off my Swift and keep my load below 22 lbs. I dont have any trouble with shoulder pain so long as I keep things light.

I always use a hipbelt even if the loads are under 20lbs. It simply affords me the stability I require and as well, allows me to adjust fit on the trail over long days. It has nothing to do with strength (I can still squat significant amounts – >300lbs – and my abdominals are rock hard).

Like David, I too always use a hip belt. Minimally, it does stabilizaton if adding little for support, but I tend to loosen the shoulder harness over time.

"Are there packs that strap in very snuggly and hug the chest and ribs and back adequately enough that (for people with strong abdominal muscles) a hip support is unnecessary for light loads?"

That sounds difficult to breath in.

trick question, right?

It is a personal preference that depends on your pack's carry weight being light enough for you to be comfortable.
I personally find that if I keep my carry loads 14 lbs or lower, then a hip belt is superfluous.
If my carry loads are 20 lbs or higher, then a hip belt is a definite necessity.

I generally tuck my mason jar bear canister under my arm like a football, and go sans hip belt.

If I find I need more support, I use my catheter as a make shift belt.

If I need even more support, I use the lean back wall of my tent to beef up my pack frame.

For even more frame, I put my SAW vertically against my back like a stay.

If I need more support than that I inflate my back country lazy boy to stiffen the pack to the max.

If I don't have a unflatable lazy boy, or, saw, or catheter, I just bring a pack with a hip belt.

"Are there packs that strap in very snuggly and hug the chest and ribs and back adequately enough that (for people with strong abdominal muscles) a hip support is unnecessary for light loads?"

Actually, Gossamer Gear makes one. What they call the "Big Bag." It works really well for biking. But I find the lower strap a bit high for support. It also works as a stabilizer to some degree.

Man, I laughed so hard at Cameron's response. Read it while I was breaking in some used leather boots. Macadamia, what a nut!