I did Academic Decathlon all four years in high school, and went to the state competition twice.
Our C students on the team were amazing, and I think competing was really transformative for them. Most had never been "picked" for any academic competition before. The A and B students were totally focused on helping them learn the material (which incidentally was good for the A and B students' learning, I think), and we really competed together as a team.
It was a lot of work, but I would definitely recommend it.
