Celebrity Trainers Reveal Their Top Fitness Secrets

David Kirsch trains some of our most beloved (and ripped) stars such as Heidi Klum and Naomi Campbell. 

Through his custom and challenging workouts, he creates a regimen that combines circuit training, body sculpting and cardiovascular conditioning that works the entire body, head to toe. What many of his bombshell clientele have expressed is that David is not in the business of changing someone's body and letting a woman lose her curves; rather he wants to sculpt, tighten and tone her natural shape *Hint, he got Kate Upton in bomb shape for her Sports Illustrated cover* 

His advice? Go for the glutes to get the booty you've always wanted (it's known to be the ultimate celeb secret to achieving a better bum) - it's called the stability ball prone scissors.

• Lie facedown with your hips resting on a stability ball, hands and feet on the floor for balance.
• Walk your feet out behind you so your legs form a wide V.
• Slowly lift both of your feet about 12 inches off the floor and squeeze them together.
• Lower your toes back down to the floor, spreading them into a V shape at the bottom of the move, and repeat for a total of 15 to 20 reps.

TA-DAAAAA booty POP (J. LO is known to have been 'Kirsched,' FYI)

[Photo via @davidkirsch]