Editing - Super speed

To achieve a supernatural feel to my film i wanted to give these supernatural creatures a power in which humans do not so i made them both have super speed to show the incredible powers. To achieve the effect i went into after effects and took a screenshot of the body of the character as shown below and then cut the clip to the point where i want it to start and stop. I took a clean plate shot of the location and framing of the shot. i used this to create the background. I then masked the screenshot and set keyframes on after effects to allow the image to move from one side of the shot to the other. i made this moving of the clip really fast and used directional blur on the screenshot to give a super speed effect. I then got rid of the screenshot as it lined up to another shot with the same framing and made it look like he super speeds in and then stops mid way and runs normally.