Celebrity Trainers Dish on Their No. 1 Ab Exercise

Tone It Up trainers Karena and Katrina have the beach-babe thing down. Self shares their favorite move for bikini-worthy abs here.

Tone It Up

The Tone It Up trainers whipped our hair into shape last week with a tutorial on how to create the perfect beachy waves. (They should know since they practically live on the beach!) Now they're here to make sure our abs are in equally hot form.

The one exercise they swear by: the Tone It Up Tummy Toner. "This move tones up your lower abs, sculpts those beautiful lines down the sides of your tummy and strengthens your entire core," Katrina tells SELF.

Here's how to do it: Begin in plank position with your shoulders over your wrists, abs tight and spine in a neutral position. Exhale and slowly bring right knee to meet right elbow (as shown). Imagine you're squeezing your obliques and lower abs to lift knee. Inhale and return right foot back to start. That's 1 rep. Do 3 sets of 20 reps, alternating sides with each rep.

Whatever your summer weekend has in store, consider your abs and hair, toned and ready.

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