| What it is | Cushioning thickness underfoot (mm) |
| High stack | More cushion/protection; less ground feel/stability |
| Low stack | More ground feel & stability; less cushion |
| Relation to drop | Drop = heel stack − forefoot stack |
Stack height is the thickness of material between your foot and the ground, measured in millimeters, usually given at the heel and forefoot. Higher stack (‘maximal’) shoes offer more cushioning and protection but can feel less stable and reduce ground feel; lower stack shoes give better ground feel and stability but less cushioning. The drop is the difference between heel and forefoot stack.
Cushion underfoot
Together with heel-to-toe drop it defines a shoe’s platform; rocky-terrain protection also comes from a rock plate. A spec of trail running shoes.
Frequently asked questions
What is stack height?
Stack height is how much shoe material sits between your foot and the ground — essentially the thickness of the cushioning (midsole plus outsole and any plate), measured in millimeters and often listed separately for the heel and forefoot. It indicates how cushioned and built-up a shoe is underfoot, independent of the heel-to-toe drop.
Is higher or lower stack height better?
Neither universally. Higher (maximal) stack gives more cushioning and protection for long distances and rocky terrain but can feel less stable and dull ground feel; lower stack offers better stability, ground feel, and agility but less cushioning and protection. The best choice depends on distance, terrain, and personal preference.
How does stack height relate to drop?
Drop is the difference between the heel stack height and the forefoot stack height. So a shoe can have a high stack but low drop (lots of cushion, level platform) or a low stack with higher drop. Stack tells you total cushioning; drop tells you the front-to-back slope — two separate specs worth considering together.
Sources
- Shoe cushioning — American Council on Exercise
- Trail shoe anatomy — American Trail Running Association