Made for Speed day / race day The Endorphin Speed 5 is built to go fast and feel smooth—whether you're pushing the pace on track night with friends or you're chasing a PR. A newly designed nylon plate and responsive PWRRUN PB cushioning come together for snappy transitions and a fast ride. This is speed you can count on. Origin: The Endorphin Speed 5, a descendant of the 'keystone super trainer' lineage, emerges from the crucible of innovation. Its genesis lies in the pursuit of a versatile performance trainer, designed to excel across various running disciplines. The initial concept prioritized a more flexible, nylon-plated alternative to the carbon-plated Endorphin Pro, thereby carving its own distinct path. Construction: This iteration is meticulously crafted with a single-layer engineered hexagon mesh upper, delivering a snug, breathable fit. The core is built around PWRRUN PB superfoam, a PEBA-based compound, paired with a full-length semi-rigid nylon plate. Further enhancing its design, the outsole utilizes XT-900 carbon rubber, reconfigured for superior durability and traction. Utility: The Endorphin Speed 5 is engineered for the discerning athlete seeking a 'super trainer' capable of handling daily training, tempo runs, intervals, and even race day efforts. Its design philosophy balances speed, efficiency, and comfort, ensuring peak performance across diverse running scenarios. The shoe's construction supports a wide range of use cases, solidifying its place as a cornerstone in the runner's arsenal. Influence: The Endorphin Speed series has become a symbol of performance and innovation in the running world. It has influenced the design of countless trainers, solidifying its place as the 'original super trainer'. Its impact can be seen across the industry, particularly in the adoption of Pebax foam in non-racing footwear. The Endorphin Speed 5 continues this legacy, embodying the spirit of speed training.