Rocker? Last? Drop? What do these terms mean? Here’s a quick rundown of some common running terms that you might come across, both in this piece and on the roads and trails.
Midsole rocker: Many shoes now feature a rocker where the midsole slopes upward at the toe, heel, or both. Rockers encourage a smooth rolling motion for more efficient transitions from heel strike to toe-off, and can help improve both your running economy and comfort.
Carbon/nylon plates: In recent years, we’ve seen more and more brands add plates to their shoes. The main role of a plate is to add stiffness, control, and spring to a shoe’s soft, light, and bouncy foam. Each brand adopts different designs, from spoon-shaped or footlong plates to winged plates. The Adidas Adizero Adios Pro ($250), for example, have what Adidas calls Energy Rods 2.0, with a series of carbon rods under each toe in a bid to create a more flexible, natural ride. Plates are most typically used in faster race shoes or speedy training shoes, but they’ve also been appearing in shoes designed for cruising daily miles and trail running.
Energy return: The amount of bounce or spring that comes back from the midsole from each foot strike. The more energy returned, the bouncier the ride. Faster shoes shoot for higher energy return, but this can come at the cost of stability.
Stack height: This is the thickness of the midsole, measured from the ground to the footbed. You get two measurements, one in the heel and one in the forefoot. Higher stack heights generally deliver increased cushioning and shock absorption, while lower stack heights retain better ground feel and stability. This is also related to …
Drop: Also called heel-to-toe drop or offset, this is the difference between the heel and forefoot stack heights. Drops range from 0 to 12 millimeters, with most shoes in the 6- to 10-millimeter range. Higher-drop shoes shift impact to the heel, offering more cushioning for heel strikers. Lower-drop shoes promote a midfoot or forefoot strike, and tend to put pressure on the calf muscles more. But be aware—and yes, I appreciate this all sounds a bit complicated—rockers can also alter the impact of the drop.
Overpronation: If you overpronate, the foot rolls excessively inward during running, putting extra strain on the arch and inner foot. If you’re new to running, head to a running specialist and ask for an assessment on a treadmill. They’ll be able to see if you’re over- or underpronating, or running neutrally.
Underpronation: Sometimes called supination, an underpronator’s foot rolls outward. This can reduce the shock absorption and put more strain on the body.
Stability: Stability shoes offer more support to under- or overpronators. Features like lower stack heights, firmer midsoles, medial posts, or guide rails align the foot, which helps distribute impact more evenly and reduce strain.
