For the strength-based events of track & field, the Saucony Unleash SD is built to handle it all. Athletes competing in shot put, discus, and hammer throw will appreciate the improved fit thanks to Saucony's ISOFIT technology. The built-in cross strap helps to lock down the midfoot during intense power movements where stability is important. Upper: Adaptive ISOFIT system provides stabilizing support. FLEXFILM upper provides lightweight comfort and support. Flat laces reduce irritation and pressure points. Padded heel collar enhances comfort. Midsole: Internal EVA offers underfoot cushioning. Midfoot cross strap locks foot down to the platform. Outsole: Nylon forefoot plate and high-density rubber outsole enhance spin and glide techniques.