Start on the side of the speed ladder facing laterally with a slight bend in the knees and keeping your weight on the balls of your feet.  Step into the first hole with your lead leg and follow with the trail leg, then step back out with the lead leg followed by the trail leg.  Continue this movement pattern down the entire length of the speed ladder moving as quickly as possible while maintaining control.  Perform the next repetition moving in the opposite direction so your lead leg and trail leg are switched.