Rather than being open to all, the stages are separated into age groups; competitors range from junior high school runners to fully-fledged professional athletes.
As the local community grows, these groups may put on events which attract dealer attention or significant fan activity and which become recognized as fully-fledged conventions.
In other words, the player can play through two stories; while they may share common events and environments, the stories are largely unique and in essence are fully-fledged games.