Allow your backpack hang off your body as if you are not wearing it.
I don’t think the type of bag really matters, only how you carry yourself when you carry your bag. The best way to carry something is to stand as if you aren’t carrying anything, it will be easier and you will feel stronger. The more you “try” to carry your bag, the more tension you will develop. In the image I want to show that the figure on the left is working harder than the one on the right.
More on Carrying Your Bag
Video: How to Carry Your Backpack
Article: How to Carry Your Bag.
Video: Bending to Pick Up Your Bag
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