Is it possible to be the captain of two teams? Can a participant register for more than one participation type in the same TeamRaiser?
A constituent can only register once for a given TeamRaiser. This means they can't have more than one participation type or captain more than one team. If a constituent needs to do either of these things, they would need to register as a new constituent with a different email.
In some cases, an organization may want to enable people to both volunteer at the TeamRaiser and participate. In this situation, it would be best to create a separate volunteer event using the event module.