Neutral Running Shoe Glossary

Drop and stack: difference versus total height

Heel-to-toe drop is the difference between the sole height beneath the heel and forefoot. Stack height describes the amount of shoe beneath a specified location. Two shoes can share a drop while placing the foot at very different heights above the ground.

Do not compare measurements without checking how they were reported. A manufacturer specification and a separately measured figure may use different methods. More height also does not tell you exactly how soft the foam feels.

Rocker, heel bevel and toe spring: parts of the curve

A rocker is curvature intended to influence the transition through stance. A heel bevel is the angled or rounded rear edge, while toe spring describes the upward shape toward the front. These features relate to one another but are not interchangeable names.

Brooks describes different rocker designs for different experiences. That is why simply marking two shoes as rockered does not mean they roll forward at the same point or suit the same pace.

Last and upper volume: shape beyond the size number

The last is the form around which the shoe is constructed. It influences shape, while upper materials and the way they are assembled also affect the usable space. A width label cannot fully describe a narrow heel, tall instep or the outline around the toes.

Plate and flexibility: construction rather than permission

A plate is a stiffening element within a shoe. Materials and shapes vary; Saucony’s Endorphin Speed 5 uses a nylon plate, for example. The presence of a plate alone does not establish racing suitability, comfort or how the whole shoe bends.

Resilience and softness: different foam descriptions

Softness concerns how readily a material deforms under load. Resilience concerns its rebound after deformation. Marketing descriptions can blur these ideas, so avoid interpreting either word as a guaranteed improvement in running performance. The complete shoe and the runner still matter.