But be aware that while frames may spare your back, they don't necessarily protect your shoulders. Too heavy of a load across the neck and shoulders can cause nerve pressure and damage. For this problem, it's advised to find a backpack with adjustable and padded shoulder and sternum (across the chest) straps.

The idea is to prevent the straps from pulling your shoulders too far back and down from your normal posture. This kind of position can put traction on the nerve with the same risk for nerve palsy.

A waist support is essential to prevent the risk of nerve pressure. This is especially true for anyone carrying a heavy load while using your hands to climb. Finally, even the best backpack won't prevent neck, back, and arm pain or palsy if it's too heavy and/or carried for too long. How much you pack into a good backpack is just as important as the backpack design and features.