First released way back in 1983, the Nike Pegasus has undergone massive development in recent years, culminating in this latest edition, the Air Zoom Pegasus 37. For this incarnation, Nike transitioned from a full-length Zoom Air bag to a forefoot Zoom Air bag that is twice as thick a the previous Pegasus 36 model. Additionally, Nike top-loaded the Air Zoom technology into React foam for the midsole. This makes for lighter weight and a more responsive and durable foam for your run.