The best captain is the one who notices the kid who stopped talking at practice.

Leadership is mostly noticing. Anybody can run the warm-up and raise their voice; what holds a team together is the person who registers that the quiet kid got quieter, that somebody has not been picked all week, that a teammate is taking it harder than they are letting on. It is attention rather than charisma. The loud version of captain is far easier and does much less.

Look around at the next practice, find whoever has gone quiet, and talk to them about something other than performance. Ask if they are all right and mean it. Do it away from the group, which is what makes it safe to answer.