What Is Cushioning in Running Shoes? | The Soft Layer Explained

Cushioning is the layer of material—usually foam, gel, or a brand’s proprietary structure—between your foot and the pavement that softens that landing. Understanding what cushioning actually does (and doesn’t do) matters more than chasing the thickest sole, because the right amount depends on how you run and what you want underfoot.

How Cushioning Works

Cushioning lives primarily in the midsole. When you land, that material compresses under load, spreading the impact over a slightly longer moment. Instead of a sharp jolt, you feel gradual deceleration. Salomon’s guide describes this as absorbing impact during the landing phase while making ground contact feel less abrupt.

The materials do the heavy lifting. Most shoes use EVA foam, a lightweight, springy plastic that compresses and rebounds. Newer options include ETPU and PEBA, which tend to be more responsive and durable. Some brands engineer structural elements instead. On’s CloudTec® uses hollow pods that collapse independently on contact, which On says delivers adaptive cushioning and a smooth push-off. ASICS uses GEL™, a silicone-based material the company says disperses vertical impact forces and cuts vibration.

Stack height—the total thickness between your foot and the ground, usually measured at the heel and forefoot—is the quickest way to compare cushioning between models. A higher stack generally means more cushioning, but foam density and geometry matter just as much. A thick slab of firm foam feels completely different from a thick slab of soft foam.

What Cushioning Is Not

Cushioning softens vertical impact; it does not control side-to-side motion. That job belongs to support features—arch structure, medial posts, or stiffer heel counters—which keep your foot stable as you push off. Mixing the two up leads runners to buy a plush shoe expecting stability and ending up with a wobbly ride on uneven ground.

Cushioning also does not guarantee injury prevention. Runner’s World notes that more cushioning has not clearly reduced annual injury rates across the running population. A soft shoe can feel pleasant while still transmitting meaningful ground reaction forces through your body. Perceived comfort is real, but it is not armor.

Here’s the catch that surprises most runners: softer is not always more stable. A very tall, very soft platform can compress unevenly on corners or cambered roads, making the shoe feel unstable even though it feels plush on a straight line. That is why brands warn that cushioning exists on a spectrum and interacts with overall geometry.

Choosing the Right Amount of Cushioning

There is no universal rule for how much cushioning you need, which is why categories online—maximal, traditional, minimal—are not industry standards. One guide defines cushioned shoes by a heel stack over 30 mm; another labels anything at or under 16 mm as minimal. These are private categorizations, so treat them as rough guidance rather than hard rules.

Choose more cushioning for a softer feel, extra comfort on long runs, or more impact absorption on hard roads. Choose less for a firmer, lighter shoe with more ground feedback for speedwork or trail running. Your pace, body weight, and surface all factor in, and many runners rotate between a cushioned daily trainer and a firmer speed day shoe.

When comparing models, check three things: stack height, midsole material, and geometry. Brand terminology is inconsistent, so trying shoes on beats reading spec sheets. When ready, our roundup of the best cushioning running shoes tested this season breaks down what each pair actually feels like.

Common Cushioning Materials and Their Characteristics

Fit still overrides every material choice. The most advanced foam cannot save a shoe that is too narrow, too long, or rubbing your heel. Match the cushioning to your body, pace, and terrain, and let the midsole do its one honest job: making every landing a little gentler.