Competency-based approaches using information and communication technologies have been the main solution of the organization's expectations in all fields (public and private) to increase the products' quality and employees' capacity. Furthermore, the concept of competency can have several different definitions, which may make it difficult to model. As a result, without a good representation of the knowledge and competency and reusable definitions of competence, an e- Learning system will be unable to adapt to its users, to personalize learning activities. In this paper, we present a view of some important competency definitions and the main competency specifications, like the HR-XML specification (Human Resources XML), and the IMS Reusable Definition of Competency or Educational Objective (IMS RDCEO). Moreover, we suggest a competency model for training and education based on these specifications.