One of the most common differences between world class distance runners and recreational distance runners is ground contact time. Top level runners spend much less time on the ground. How do your decrease your ground contact time? Start by running with quick, light strides. Add some plyometrics or explosive strength training exercises to your weekly training routine. The explosive strength training will improve the resiliency of your muscles. Not only will you decrease your time on the ground but you will also improve your running efficiency.