Jung Dayeon

The woman who kick-started the "momjjang" (hot body) fad in Korea, Jung Da-yeon.
This young lady transformed herself through exercise, and is known as an expert on physical training and exercise now.
She has released a popular fitness book, a DVD called "Momjjang Diet" and even been in a K-drama (in Korea) called "Aquarius".
Jung played a fitness instructor.
She has her own website, http://jungdayeon.com/ that is in Korean and Japanese.

And here are some clips from her TV show FIGUREROBICS from YouTube: