The sprint is one of the easiest running drills you can do with an agility ladder. The sprint "one foot in" means that only one foot will enter each square as you are running. The sprint also makes a great warm up for more advanced ladder drills. It is advised to practice all drills at half speed at first. Once you are comfortable with the drill, you can increase your foot speed. Ultimately, your aim should be to do the drill as quickly as possible.
To do this exercise, simply run straight through the ladder. As previously mentioned, only one foot should enter each square as you are running. Be sure to stay on your toes at all times. This is a plyometric drill. You are trying to develop muscular power in order to generate maximum force quickly. Thus, a useful visualization tool is to pretend the ground is a fiery hot surface. In order to avoid danger, you must minimize time on the ground and move quickly.