PWRRUN HG Explained
In brief: PWRRUN HG (High Grade) is Saucony's premium PEBA foam, manufactured using supercritical nitrogen infusion. With a claimed energy return of around 95 percent, it was Saucony's highest-performing foam prior to incrediRUN. PWRRUN HG is firm yet highly responsive and more stable than softer PEBA foams, which made it a favourite for elite racing models such as the Endorphin Elite and Endorphin Pro 4.
What is PWRRUN HG?
PWRRUN HG, with the HG standing for High Grade, is Saucony's premium PEBA-based racing foam. PEBA (the polymer family that includes Pebax) is prized in performance running for its lightness and high energy return, and PWRRUN HG is Saucony's most refined expression of it before the arrival of incrediRUN. It is made using supercritical nitrogen infusion, a process that forces nitrogen into the molten polymer under pressure to create an extremely light, energetic foam structure. The headline figure is a claimed energy return of around 95 percent, which made PWRRUN HG Saucony's highest-performing foam at the time of its launch and a foundation for their fastest race-day shoes.
How supercritical nitrogen infusion works
Supercritical nitrogen infusion is a modern foaming technique used across the top tier of running. Nitrogen is held in a supercritical state, behaving partly like a gas and partly like a liquid, and driven into the polymer under high pressure. When the pressure releases, the gas expands to form a fine, uniform cell structure throughout the foam. The benefit is a midsole that is exceptionally light yet highly resilient, returning a large share of the energy a runner puts into each stride. This is the same broad approach used by other elite super foams, and it is what allows PWRRUN HG to feel both feather-light and powerfully springy.
Firm, responsive and stable
What sets PWRRUN HG apart from many PEBA foams is its character. Rather than being soft and bouncy, it is tuned firm yet highly responsive. Some super foams trade away stability for a plush, energetic feel, which can feel unstable at speed. PWRRUN HG keeps things more controlled, giving a planted, stable platform that works well in fast, plated racing shoes. For competitive runners pushing the pace, that combination of firmness and responsiveness translates to confident, efficient propulsion rather than a sensation of sinking. It is a foam built for performance under pressure, not for casual cushioned comfort.
Where you will find it
PWRRUN HG lives at the sharp end of Saucony's range, in their elite racing models. It featured in the Saucony Endorphin Elite prior to 2025 and in the Endorphin Pro 4, paired with the carbon plates and rocker geometry that define those shoes. These are race-day tools designed to help competitive runners chase personal bests over distances from 5K to the marathon. The foam's light weight and high energy return complement the propulsive design of the Endorphin platform, where every gram and every percentage point of return counts.
Superseded by incrediRUN
In 2025 Saucony introduced incrediRUN, a Saucony foam developed to take over the top-tier role for their newest elite racing shoes. That positions PWRRUN HG as the foam that defined Saucony's racing performance in the years before it, still a genuinely high-performing compound that earned its place in the brand's fastest models. If you are looking at a Saucony Endorphin Elite from before 2025 or an Endorphin Pro 4, PWRRUN HG is the engine inside, and it remains a serious race-day foam in its own right.
PWRRUN HG at OD's Designer Clothing
At OD's Designer Clothing we stock Saucony elite racing models from the Endorphin family that put PWRRUN HG to work, built for runners who want genuine race-day performance. Our footwear team can explain how Saucony's plated racers and their nitrogen-infused PEBA foam are designed to deliver speed, and help you decide if they suit your goals. We offer next-day delivery and free click and collect, and you can visit our St Helens store to try the Endorphin range on and feel the firm, responsive ride for yourself before you buy.