What happens when Cheryl goes to lift her backpack and set out on the hike in Chapter 3: “Hunching in a Remotely Upright Position”?

When Cheryl reaches down to pick up her backpack, which stands as tall as her waist, she is unable to lift it off the ground. Unable to leave any supplies behind, Cheryl musters all of her strength and is finally able to somewhat stand with her backpack. As she staggers around the room, she wonders if this is what it's like to be a backpacker.