Im not very sure but, from the vids it looks like gatlin and blake legs movement are faster than bolt; but Bolt being taller gets and advantage for all the steps he gives.
This is one of the biggest misconceptions that's repeated over and over by the media as an attempt to somehow describe Bolt. Yes, Bolt's strides are longer than the other athletes. But his advantage in stride length is largely a result of his superior power that he applies to the track and not simply because he is taller. Ryan Bailey is pretty tall as well... how come he doesn't have this advantage over Tyson Gay?
Bolt's main advantage is his otherwordly top-end speed. If you watch any major final (2008,2009 worlds, etc) you will notice that when the athletes hit max V (around 65-70m) Bolt seems to pull away from the entire field. If it was simply larger steps as a result of being taller then he would maintain an incremental advantage after each step that would grow linearity throughout the race... Instead Bolt is incredibly elastic and able to continue to apply force despite extremely small ground contact times and reach a just ridiculous speed that nobody else can match. The next two guys who come closest to applying this force and hitting high max V are two of the shorter athletes (gay and blake [gay was injured but watch 2009]), the other tall athletes (Bailey, Powell actually have pretty poor max V).
Stride frequency (legs movement) really has little bearing on sprinting speed. Obviously shorter guys will have to reposition their legs at a faster rate than tall guys when moving at the same speed... but most world class sprinters have stride frequency which isn't much better than an amateur runner. A simple towing drill really proves this: attach a band to a stretched resistance band to a low level athlete and pull them forward as they run and they will have a stride frequency much greater than that of any elite athlete.... The problem isn't that they can't reposition their legs fast enough it's that they can't create enough force to get them going fast enough to need to reposition their legs that fast!
***Note, while the point of this post is that Bolt's advantage isn't stride length as a result of his height.... that's not to say that those extremely long lever arms don't help him generate force... Additionally, remember that this is true largely for the short distance sprints. In the 400m and especially 800m where ground forces have to be limited to avoid fatigue, exaggerated stride lengths of taller runners may provide an advantage.
If you really interested heres a paper:
http://www.ncbi.nlm.nih.gov/pubmed/11053354
