As the United States running boom (initiated in the ’70s) advanced, athletes’ footwear needs evolved and diversified. These realities paired with a greater understanding of over-pronation (the foot rolling inward upon ground strike) led Nike to answer a call for a running shoe with greater stability. The Nike Air Structure, Nike’s most stable silhouette, debuted in 1991.

Since its introduction, the Nike Structure line has earned legions of fans ranging from elite athletes — like long-distance champion Galen Rupp, who has worn iterations of the shoe for the past 16 years — to everyday runners to off-duty athletes who are drawn to the silhouette’s distinctive style. With the dawn of its 20th iteration, the Nike Air Zoom Structure 20 compiles insights from past

The Nike Air Structure (1991)