Sport Canada is responsible for athletes at the national level, so the athletes who will be on the committee will be the ones who are active at the national level, or who have been active in the last year. Some are retired, but they are still very active as former athletes.
Evidence of meeting #104 for Canadian Heritage in the 44th Parliament, 1st Session. (The original version is on Parliament’s site, as are the minutes.) The winning word was athletes.
A video is available from Parliament.