Doc talk:Walk Cycle
Motion Capture - Another tool available for creating motion is biovision or motion capture data rendered as images. BVH files are created by recording 3d spatial data of each joint as a person/figure moves (walking, dancing, fighting, etc.) BVH files are used to animate 3d models, but you can view BVH data rendered on 'stick figures' without a 3d program. Viewing BVH data may help you to create motion imagery in synfig. Some bvhplayers can export images of the the BVH sequence - useful for importing to Synfig as a template layer.