leg length is really not that important. The most important thing for a runner is weight. The lighter you are, generally the faster you can run. Sammy Wanjiru,

leg length is really not that important. The most important thing for a runner is weight. The lighter you are, generally the faster you can run. Sammy Wanjiru, the guy who won the olympic marathon, is 5'4" and 112 lbs! When you have longer legs it also takes you more energy to move them. Running long distances is all about running as efficiently as possible. Weight also matters in sprinting. If you looked at the NFL combine results, for the 40 yard dash times, the most factor tends to be weight- the lighter you are, the faster your times are. This is why it's such an anomaly to find someone that's really big that can run extremely fast. (BC's BJ Raji for example). It's been estimated that for every lb you use lose, you can lose about 2 lbs on your mile time. Want to improve your mile time by 20 seconds? Lose 10 lbs!