The heel drop refers to the height difference between the midsole at the heel and the toe. Most hiking boots have an 8mm or higher heel drop, while typically trail runners have a 3mm to 5mm heel drop. Heel drops serve heel strikers well as they help to cushion their foot and absorb some of the impact that would otherwise go up their leg. For midfoot and forefoot strikers, on the other hand, high heel drops can unnaturally alter their gait. As the Outdoor Life gear team learned first-hand, going from a high-drop shoe to a low-drop or zero-drop shoe like the Altra Lone Peaks is one of the biggest changes you can make in your footwear. For some people, this switch can reduce pain and open up their stride; for others, it’s the complete opposite and can actually result in more pain than they had in their previous footwear. But one thing we know for sure is that your first day wearing a backpack with a zero-drop shoe should not be your first day on the PCT. If you’re interested in switching to a zero-drop shoe, Brosnihan has some advice for you: “It's recommended that you have at least 16 weeks of loaded use in them before you bring them on trail,” she says, noting that going from a traditional hiking boot to the Altra Lone Peak is a “dramatic end of spectrum switch.”