By eliminating extra fabric, with all its unnecessary weight, the SpeedForm Apollo from Under Armour makes you a lighter and more mobile runner. Featuring a full-length Micro G® midsole, allowing for a run that's far more responsive to the terrain -- and to your needs. The seamless heel cup features a silicone grip, making for a much tighter fit. It's almost as though the SpeedForm Apollo is an extension to your foot.