Attached Link: http://www.auroratrek.com/

My 2 cents: you should only have a keyframe where you need it, and animate each body part indivdually as needed, building your curves in the Graph Editor. Curves are actually fine for human movement, but you need to control them in the Graph Editor to create smoother or sharper movement. In the graph editor, tight curves and sharp verical climbs and drops represent faster/sharper movement, while the looser, flatter curves are smoother  & slower movement. Generally, you shouldn't have many sharp corners in human movement, since even the sharpest movements usually have a little "give."

--Tim