In your stomp walking animation video you switch to the graph editor to adjust the z location of the head during the up's and downs, and you use the period key to zoom in to the z location keyframes.
When I do that I noticed the vertical scale of the z location changes to some very small number like .00000000001. Took me awhile to figure out why I could not get the figure eight by adjusting my heights of the keyframes in the graph editor, because when i adjust the keys head only goes up by a fractional amount.
How do I avoid very small scales in the graph editor or this problem in general? Sorry if I missed the answer in another video.