We love when stars share their go-to secrets for getting killer bods. These 4 sought-after celebrities reveal exclusively how they achieve such body envy. We always find it really cool when they share exactly what types of training they enjoy. Hilary Duff Hilary attributes her fit physique to yoga and Muay Thai, a combat sport from Thailand that combines stand-up striking and strong mental discipline. The sport builds leg strength and improves cardiovascular performance. The rotational movement in the sport makes it an amazing core strengthener. Jessica Alba The toned mama of two is in to self-defense classes as her go-to workout. She takes female focused self-defence which are great at building confidence, encouraging safety and getting in shape. Self-defence classes consist of intense warm up exercises followed by learning techniques. Jessica likes kicking butt in boxing, CrossFit and kickboxing as well. Rosie Huntington Whitely Victoria Secret Angel Rosie is praised for her supermodel frame, but it doesn't come without work. Rosie uses stability-ball exercises to stay in lingerie-ready shape. These workouts increase muscle endurance, balance, muscle tone and keep weight controlled. Demi Lovato Demi digs SoulCycle as her fitness secret. The fine-toned singer enjoys cycling for it's cardiovascular benefits along with the increase in flexibility it provides. Cycling can reduce stress, decreased body fat levels and keep anxiety at bay. Not to mention it's one of the simplest and most fun forms of exercise!