What are some barriers to participation?

I think that some of the most important and relevant barriers to participation, on any king of activity, be it physical, political, social, etc., are the perceived disabilities, be them physical, or mental.

Explanation:

Whenever you look at scenarios like sports, or political arenas, as well as working arenas, one thing that will always become a barrier for people's participation in them, is their physical and mental capacitites. The reason is that these people, whatever others want to say, are perceived as less able, or less capable. They are measured by their capacities as perceived by others, and not their potentials, even with their discapacities, or disabilities. It is true, however, that a physical or mental disability can pose a limitation, and not all people are built to have the same capacitites, not even those whose physical and mental abilities are what is considered "normal" or "average". But these two incapacities do form a lot of barriers for participation, especially in sports.