Endorphin Speed 4
The Endorphin Speed 4 is the most versatile shoe on the market, combining a winged nylon plate for stability with PWRRUN PB (PEBA) foam for elite-level energy return. It bridges the gap between a daily trainer and a racing flat.
Ingredients & Purity
The PWRRUN PB foam is a proprietary PEBA formulation that is 40% lighter than standard EVA. The 'winged' nylon plate adds torsional rigidity without the stiffness of carbon.
Scientific Evidence
SPEEDROLL technology is biomechanically engineered to reduce ankle flexion and improve turnover efficiency, backed by Saucony's Human Performance Lab data.
Brand Transparency
Saucony is transparent about stack heights and offset (36mm/28mm), though they are less vocal about specific foam density measurements compared to ASICS.
Value Assessment
For $170, you get a shoe capable of both 5k races and marathon training, effectively replacing the need for a two-shoe rotation.
Why Not Alternatives?
Unlike the Nike Vaporfly which is fragile and expensive, the Endorphin Speed uses a more durable nylon plate and a thicker outsole, making it suitable for 300+ miles of training rather than just race day.