sentences:  This system is also used by some hockey skaters as it pitches the foot slightly forward.A few aggressive skate frames (most notably Rollerblade's Switch Frame, Ground Control's Bullet Frame, and Oysi Frame) are designed so that there are two big outer wheels, and two small inner wheels, rockered so that they all touch the ground.This gives the benefits of a flat setup, while giving the rollerblader more space to grind on the H-block between the wheels.