This is the best example of a run-on sentence. A run-on sentence occurs when two independent clauses are joined in an improper way. These are complete sentences that can stand on their own. This is the case in this example as "swimming is a good sport" and "it helps build muscle" are both independent clauses.
“I believe a longer spring break will help students perform better in school. After a week away from their studies, students will be refreshed and able to concentrate until the end of the school year”
