During the Civil War, a Union Army doc noticed that the human body was built to support weight on the pelvic girdle, not the shoulders. Putting weight on the shoulders interfers with circulation and in uncomfortable. Putting the same werght on the hips has neither effect.
Guided by these insights, he invented and patented a pack that had diagonal wooden struts to carry the weight of the GI pack down to a broad canvas cartridge belt.
The folks running the military nixed the idea, and the patent expired. (These were the same folks who thought magazine-fed rifles were a bad idea because they allowed the soldiers to shoot too fast. Back to single shot as soon as the war was over and that meddler Lincioln was out of the way.
) It took the military almost 120 years to get the message.
In about 1969, Kelty "discovered" the waist belt. Even by that standard, the frame pack with waist belt is hardly a new idea. Prresnted by this second discovery of the principle, the military stuck with rucksacks. (Let's not get precipitous! We're only a century behind the curve.)
Kids joint ends are still soft and subject to damage. They should carry any significant load for more than a few minutes only in a pack with a frame and padded waist belt -- that fit. Using such a rig, only about 20% of the total load should be on the shoulders, with the balance on the waist. (Lot's of info on the Internet on general topic due to kids injuring themsleves carrying bags of books to/from school.)
The Camptrails line of packs from Johnson Outdoor has good entry-level packs (Adjustable II). Campmor carries a frame pack (2780 cubic inches) for $39.97 (looks like Colemans nylon-framed pack) and gives a discount to Scout units.
Our Troop adults watch house/garage sales and get 6-10 used but perfectly useful packs a year for an average of $12-13 each (latest finds this week were two top-of-the-line Jansport's for $20.00).
The frame for the ALICE system was designed for skiing. It transfers no significant amount of weight from the shoulders. The same sort of farme was used in WWII on a different rucksack. Didn't work then either. (See "Kidney Killer")
More capable packs mean greater repeat participation.
More capable packs means the chance to go in colder weather when more gear needs to be hauled.
More capable packs allow longer trips.
