Frame 1: Contact (right foot forward, left foot back)
In a conventional gait, arms are always in opposition to the legs, to give balance and momentum.
Frame 2: Going Down
The bent leg, absorbing the force of motion
Frame 3: Average Pose or break
Being straight leg in the Middle Pose, pelvis, body and head slightly rise.
Frame 4: Going Up
The thrusting foot bears the pelvis, the body and head to its highest position.
Then, leg stretches to locate in the Pose Contact, lest we fall to the floor of mouth.
Frame 5: Contact (Left foot forward, right foot back)
Frame 6: Going Down
Frame 7: Average Pose or break
Frame 8: Going Up
Run: Always walk, one foot remains on the ground.
Only one foot leaves the ground at a time.
But in a run cycle, at some point, will either foot contact with the ground.
The other way is Liquify filter (Shift-Control-X) and its Forward Warp Tool . With it you can slightly move some part of the body, for example close the eye of the cheetah when it's hitting the ground after big leap, or move its ears during the run (or, in my case, change the head's size that still didn't look OK). The third way is to actually paint something on the frame, like waving fur. These small changes can give more life to the animal, taking away the stiffness made by a bit automatic process of animation. They work the best when they're gradual - starting slightly on one frame, with strong effect on another frame and weakening on the next one.