The Altra HIIT XT introduces a new cross-training category to Altra. Designed with CrossFit and HIIT workouts in mind, it features a wrap-around, sticky rubber outsole for rope climbing, multi-surface workouts and lateral traction. More cross-training specific features include the removable insole-without it the stack height goes from 24mm to 18mm-stitch ‘n’ turn stitching underfoot for a comfortable fit with or without the insole, and the stylish, durable upper. Built to perform, the HIIT XT is the perfect choice whether you want to hit the gym or run a lap (or both!). Experience the new shape of strength.