Smooth, sleek and responsive, the Altra Rivera 4 will take you to new places. Whether you are traveling to a new city or working hard to reach your running goal, the Altra Rivera 4 can keep up with your active lifestyle. The Rivera 4 has all of Altra’s signature characteristics—a wider toe box lets your toes splay and a zero heel-to-toe drop promotes natural, balanced running. It also features Altra’s slim FootShape™ Fit which gives it a sleeker appearance and tighter fit compared to other Altra shoes. With a springy feel and stylish look, the Altra Rivera 4 knows no limits. Details: Upper: An updated upper gives you a more contemporary look and a better fit through the forefoot. There is also a revamped heel collar to give your foot a better lockdown. Midsole: Altra’s Ego™ midsole provides a responsive ride, while the Innerflex™ grooves give you plenty of flexibility to run as naturally as possible.Outsole: Altra’s Footpod™ technology encourages natural movement underfoot.