About "Piggyback"
I'm pretty sure you all know what a backpack is, but since there's Wikipedia out there, let me put the nice definition here:A backpack (also called rucksack, knapsack, packsack, pack, Haversack, or Bergen) is, in its simplest form, a cloth sack carried on one's back and secured with two straps that go over the shoulders, but there can be exceptions. Light weight types of backpacks are sometimes worn on only one shoulder strap, or in the hand liken an ordinary bag.
Backpacks are often preferred to handbags for carrying heavy loads, because of the limited capacity to carry heavy weights for long periods of time in the hands. Large backpacks, used to carry loads over 10 kg, usually offload the largest part (up to about 90%) of their weight onto padded hip belts, leaving the shoulder straps mainly for stabilising the load. This improves the potential to carry heavy loads, as the hips are stronger than the shoulders, and also increases agility and balance, since the load rides nearer the person's own center of mass.
I peronally LOVE backpacks, I've gotten so used to mine that I wear it everyday. To Uni, to work, downtown shopping - it fits so much :). Of course I do still like handbags, but if I have something heavy to carry I prefer my Deuter backpack.