The foam
The midsole is FF Blast, tuned very soft (5/5 on our cushioning scale). The foam is highly resilient — it gives energy back rather than swallowing it, which is what makes the shoe feel eager when you push. At 45 mm of heel stack this sits in max-cushion territory; legs stay fresher on long efforts, but the platform is tall. Combined, the ride reads as snappy at 4/5 responsiveness.