Finally, i did it. The run cycle is complete. This time, i added the arms movements. I'm pretty happy with the results for a first try. It's a little jerky because the character is moving a little bit too much back and forth. It should be fine when i'll move it forward on my rail on each frame instead of trying to make it run on a steady position. (My rail isn't appropriate for that).
Here's the video test.
I should (i hope) improved smoothness while doing the sequence 0:28-0:31. I shall begin it this week-end. Until then, i'll work on my camera movements fluidity.