Taller people run faster than shorter people. The biomechanics in this theory shows that speed is equal to stride length times stride rate. In other words, if the step length can be increased along with speeding up leg turnover, the runner will go faster. Visit http://www.livestrong.com/article/232563-do-taller-people-run-faster/ for more details.
It is because they have longer legs and can cover more distance quicker and in less strides. So a short person might have to take 20 steps to cross a room, but someone who is tall might only take 13 steps.