In computer animation, the motion adaptation or motion retargetting problem consists of optimally mapping the body configuration and the motion parameters from one graphics character to the configuration of another character with different structural characteristics. Therefore, an animator can reuse motion capture data to create a variety of animations. In this thesis, we examine and implement a method for motion retargetting using Transom Jack and MATLAB. In particular, we focused on adapting the motion parameters obtained from an actor to virtual characters with different anthropometric dimensions. Our objective was to create adaptations that preserve desirable qualities of the original motion. In particular, the method first identifies specific features of the motion as constraints that must be maintained throughout the motion. Then, a space-time constraints' solver is employed to compute the adapted motion. We demonstrate our approach using a variety of motion capture data.