The Puma ELECTIFY NITRO 3 is a progressive design that is a great choice for all runners and any distance, especially younger runners or those getting started.  The two-part midsole is redesigned in our 3rd model to allow for more NITRO in the heel and durable PROFOAMLITE throughout the rest of the midsole. More NITRO means better responsiveness and ride under the foot. This shoe remains light for the cushion offered, and PUMAGRIP enhances safety in the outsole rubber