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.
When you think of science, the first thing that probably comes to mind is images of atrophied, goggle-wearing weaklings in white coats. Bulging muscles and inhuman strength are certainly not part of your mental image!