Core Training and Ab Exercises

Trainers’ Favorite Exercises for a Flat Belly

We asked trainers for their personal favorite ab move of all time to help you sculpt a killer core

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Trainers’ Favorite Exercises for a Flat Belly // plank with bent knees c Beth Bischoff

Image: Beth Bischoff

Jessica Matthews, ACE-certified personal trainer and certification director for the American Council on Exercise in San Diego

Favorite ab move: Side plank with bent knees

How you do it: Lie on your right side with your knees bent and legs stacked one on top of the other in a comfortable position. Engage your core muscles as you raise your hips and torso off the mat, supporting yourself on your right forearm. Your right elbow should be directly under your shoulder and your head should be aligned with your spine. Exhale, keeping the abdominals engaged to brace the spine. Inhale and gently return to the start position. Hold this position for 5 to 20 seconds, and then switch sides. You can increase the exercise intensity by increasing the duration (holding up to 60 seconds on each side) or by extending the legs straight and stacking one foot on top of the other. Do 3 sets.
Why it works: “Research has shown that the side plank not only effectively activates several key muscles of the core (the obliques, transverse abdominis, and quadratus lumborum), but also that this combination of muscle recruitment actually helps to ensure stability in the spine,” she says.

More: How to Go from Lifting to Lifting 2.0

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