Some scenes of the protagonist getting bullied, including threats of violence, pushing him into a lake and trying (but failing) to hit him in the head with a skateboard.
Some scenes of kids falling on skateboards, though in a mostly comedic slapstick way.
At one point one of the bullies is kicked by a Taekwondo instructor during a chase scene. The kick looks like it hits his head, but his reaction afterwards implies he was kicked in the stomach.