Outsoles – Outsoles, or the bottom of the trainer, should be thick and provide traction to avoid slippage. This type of sole allows for rapid changes between activities, the hallmark feature of cross training.
Midsoles – Midsoles should provided plenty of cushioning, especially for the athlete who spends a good amount of time running or enjoying other high impact activity.  Well-cushioned midsoles are essential for providing sufficient shock absorption for high impact fitness.
Upper – The upper part of the shoe should provide sufficient support to the ankle and breadth of the foot so that the foot doesn’t turn out or inward when working out. For ultimate comfort, the material should be breathable.