The Boston Marathon Is A Race. But It's Also A Goal, And A Training Plan And All The Days It Stays On Your Mind Before The Big One. The Adizero Boston 12 Shoes Are Built For Mid-To Long-Distance Running. They Bring A Race-Day Feel To Training With A Propulsive Feel That Comes From The Glass-Fiber Infused Energyrods 2.0, Which Limit Energy Loss Underfoot. They're Fast, But That Does Not Come At The Cost Of Durability — The Midsole Layers Ultra-Light Lightstrike Pro Cushioning With A New Version Of Durable Lightstrike 2.0 Eva.