Düsseldorf, April 17, 2023 – The Puma Fast-FWD NITROTM Elite is an ultra-lightweight shoe that offers mechanical support to propel the wearer forward. It is designed as a race-day shoe for distances of around five kilometers. The maximized energy transfer can be attributed to a new technique developed by Puma for midsoles combining a carbon-fiber-reinforced plastic plate – or PWRPLATE as it’s called – and a foam layer. The PWRPLATE is made of a material variant of the Tepex dynalite product family from Envalior. This thermoplastic composite has a polyamide 12 matrix, in which a woven textile fabric of continuous carbon fibers is embedded.
“Thanks to its high rebound elasticity, the plate – which is made from our highly stiff, high-strength carbon composite – returns the midsole quickly to its original shape after every step. This generates a momentum, with which energy is then returned. As a result, the rolling motion of the runner’s foot is supported, which generates additional forward propulsion,” says Dr. Dirk Bonefeld, Head of Global Product Management and Marketing for Tepex at Envalior.
High stiffness in the fiber direction
Featuring Puma’s NITRO Elite technology, the thermoformed carbon-fiber plate is embedded in a foam made of polyether block amide (PEBA), which is foamed with infused nitrogen as a propellant. The foam not only absorbs shocks that can generate dynamic forces up to three times the runner’s bodyweight during forward motion but also, thanks to its rebound elasticity, supports optimal energy transfer as the runner’s foot rolls over the ground.
The reinforced continuous fibers in the plate extend across the entire length of the shoe. This makes the plate exceptionally stiff, which helps to stabilize the foam. And with a density of just 1.35 grams per cubic centimeter, the composite is also extremely lightweight (ISO 1183-1). “In combination with the foam, this ensures that the shoes are very light. For example, a size 43 shoe weighs only around 200 grams,” says Bonefeld.
Highly stable mechanical properties
Another benefit of this composite for the PWRPLATE is that it adheres very strongly to the foam. This ensures not only that the entire structure exhibits highly stable dynamic and mechanical properties but also that the midsole and shoe are extremely durable. And as a thermoplastic system, the composite can be easily recycled.
You can find more information about Tepex and its applications here.
Embedded inside the foam midsole of the Puma Fast-FWD NITROTM Elite road racing shoe is a plate made of the carbon-fiber-reinforced composite Tepex. This ensures that the midsole returns to its original shape after every step thanks to the high rebound elasticity.
