I went to a mock interview at U of A medical school and was interviewed by a doctor who is on the admissions committee. He asked me several questions about leadership, so it is obviously important. I noticed that he had a list of qualities that they assess for in the med school interviews at U of A, and leadership was one of them. The thing I didn't like was that he made it seem like the only way to get leadership experience is to be an elected official of a club or organization. I have not had any actual leadership positions, but I have developed leadership skills in my group work at school. Try to think of examples where you demonstrated leadership skills, even if you weren't actually called the president of a club. By the way, are you applying to U of A this year?