The purpose of this study was to identify the actions Olympic medalist male swimmers undertake on a competition day that they believe are critical to their success. The secondary purpose was to understand the meaning these athletes gave to these actions.Utilizing constructivist grounded theory the present study identified critical attributes, purposes and by-products and proffered a substantive theory of a competition-day routine of Olympic gold medalist male swimmers. Five Olympic gold medalist male swimmers from the 2008 Beijing Summer Olympic Games participated in a three-stage data collection: a) an initial interview, b) a competition observation at an elite meet, and c) a follow-up interview. Additionally, each of the participants coaches were interviewed regarding the swimmers actions at competition. All interviews were semi-structured and digitally recorded. Interview transcriptions and expanded field notes were analyzed for emergent themes. Field notes from observations provided confirmatory data regarding competition-day activities. Method and data triangulation provided trustworthiness. Constructivist grounded theory coding and analysis strategies were used to analyze data (Charmaz, 2006). Themes were divided into attributes, purposes, and by-products of a competition-day routine. Five attributes emerged: (a) flexibility, (b) adaptation, (c) automaticity, (d) time management, and (e) skill acquisition. Each attribute was significant as an individual characteristic and when interacting together. Comfort and focus were the purposes behind the use of a competition-day routine. The by-products of the participants routine were enjoyment, excitement and fun. INDEX WORDS: routine, grounded theory, Olympic athlete, competition, expertise, automaticity, adaptation, flexibility, skill acquisition