Here Dr. Shawn Allen of The Gait Guys works with elite athlete Jack Driggs to reduce a power leak in his running form. The Cross-over gait is a product of gluteus medius and abdominal weakness and leaves the runner with much frontal plane hip movement, very little separation of the knees and a "cross over" of the feet, rendering a near "tight rope" running appearance where the feet seem to land on a straight line path.

• penguin walk *
  Glute stance, abdominal squeeze - hold until next step!

Part 2: https://www.youtube.com/watch?v=WptxNrj2gCo