Clark, 40, appeared with four other finalists in the contest on NBC's "Today" show Wednesday and was picked the winner live on the air.
Thousands of women applied for the opportunity to win the title, which was determined by online voting and a panel of judges.
As the winner of the contest, Clark -- a mother of two who runs the fitness business Tiger Athletics in Plymouth with her husband, Chris -- will get the opportunity to star in an upcoming DVD fitness series from Women's Health.
According to the magazine, Clark's fitness mantra is "burn calories, not time."
See Clark give her fitness philosophies in the video below.