High school senior Amanda Kautzer’s favorite activity was once an alternative training exercise for the Norwegian military.

Few athletes can say they’ve competed on the national stage. Soccer player Addison Clark has had the honor of competing with the top players in the nation on the U.S. Under-15 Girls’ National Soccer Team—and she’s only 14 years old.

Very few people know what it takes to compete at the highest level of any given thing. Certainly it’s a combination of commitment and passion, fortitude and hard work—sometimes with very little reward.

Endorphins make you happy. In fact, they are said to cause a sense of euphoria. Although their release can occur in a variety of states, perhaps most notable is during a strenuous and prolonged period of exercise.