Hello, I’m making a large battle scene with multiple characters fighting at once and figured I’d use the action editor to make a bunch of cycles, running, sword swinging, blocking, stabbing, ect… and then use the NLA editor to easily make the fight sequences between characters. I am new to the NLA editor and am coming up with problems as I go.
First Question: I’ve made a run cycle where the character runs in place. Now I’m making the movement actions, simply moving the root bone of the rig forward. In the NLA editor, I put the run cycle track in and the movement track above it and I can get the run cycle to cycle by adjusted the “repeat” value. I can’t figure out how to get the movement, (y position of the bone) to extrapolate from a single track so that position continues to increase as the run cycle repeats. Is this even possible?
What I do is create one keyframe of forward movement on the root bone, so that the stride lines up, with constant interpolation of course. Then go to the graph editor for the root action, select each curve that’s needed and add a modifier>cycles>repeat with offset (probably on the after: section)
Then freeze that stride action in the NLA editor and set its action extents to the length you need.
It is still a bit fiddly but with some experimenting it can do the job. I recommend the ‘Blender 2.5 Animation Cookbook’ from Packt for a good overview of Blender animation techniques. Well that’s where I got started on the NLA 
Good luck.
Sorry for the late reply. Worked like a charm! Thanks a ton!
I’ll post back if I encounter more problems (highly likely).
Hey glad it helped 
Ok, it’s been a while but I return with another question. I have an action of him falling a certain distance, just an animated z position. I want to have the fall occur while I’m using the forward movement action to simulate jumping off little ledges while running.
The problem is that the action with the vertical movement must be place directly over or completely outside of the forward movement action. If it is overlapping, the character’s position suddenly snaps back to where it was near the begging of the forward motion action clip before falling.
I have the position set to add for both actions and the only animated channels on the actions are just the y position for the forward action and the z for the vertical position.
How can I get it so that mid fall his forward position stops?
EDIT: I solved it, turns out that the blending between actions was messing everything up, I turned off the blending and it worked.