Puma Nrgy Neko Knit Mens Running Shoes. Puma NRGY Neko-knit mens running shoes use custom Neko needles to create a memorable and attractive design. Puma’s unique NRGY midsole uses thousands of ultra-elastic thermoplastic polyurethane (TPU) pellets to reduce shock and improve efficiency. The synthetic fabric upper has a flexible air mesh that allows natural, full movement, retards dust and enhances airflow for a well-ventilated interior. The laces are fused to the overlay for a very secure, no-slip hold.