These are rapid back-and-forth shuttles with one step in between direction changes. Go two steps to the right, then two to the left.
This really focuses on lateral change of direction, and it's a great way to improve coordination and leg strength/power while building structural integrity in the lower body. Higher reps will scorch your quads and lungs.
Back in December, Coach Thibaudeau introduced T-Nation to Pendulum Training, his particular style of non-linear periodization, then he applied this effective approach to bodybuilding. Now, the big bald Canadian is tackling powerlifting. This should be interesting!