Definition
In pose-to-pose animation, the animator plans his action, figuring out what drawings will be needed to animate the scene. This technique is a bit complex as you draw the key poses first and then move onto the next stage. The key poses are the actions that will take place at the beginning and end of the animation sequence.
Usage in Animation
For actions to feel life-like Pose-to-pose animation technique is used as it helps maintain the right timing and structure of the characters. To create this animation style, you will need to draw the key poses or keyframes (known as ‘extremes’) first whilst they are in significant points of action and then inbetweening other actions through intermediate frames. This gives the illusion of the character moving from one point to another smoothly, just like a pendulum. By doing this step, the animator gets to keep more control over the animation and its final result.
Animators also save themselves from making an extra effort as they get to view the draft of the specific animation before finishing the actual product. This draft can then be reviewed and edited as early on as needed and as many times as possible. 
Additional Information
Pose-to-pose Animation is used to create an animation that requires good acting, and where poses and timings are very crucial to the video. This animation style is being heavily utilized in traditional and computer-based animation. It’s also a big part of 3D animation. This is because this type of animation is more planned out and charted.
The sizes, volumes, actions, and proportions of characters are better controlled using Pose-to-pose animation. This animation styles’ strength lies in its positive points of being able to communicate story points properly. It is easy to structure, and it is far easier to build a performance using Pose-to-pose animation. This is why it’s a preferred form of animation by many. Furthermore, you will find a majority of the Animators combining the Pose-to-pose technique with the Straight Ahead technique.
When using Straight Ahead, the Animators draw one frame after another, all in order. This is quite different from Pose-to-pose Animation where the frames to be drawn first are the starting and the ending frames. It is believed that a combination of the two approaches can yield much better results in Animation.
