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4 Essential Exercises for a Stronger Core 

BY Jack McCormick

What does it mean to have a strong core? Is it six-pack abs? Doing 500 crunches in one go? Holding a plank for 10 minutes? True core strength goes beyond aesthetics and endurance. It’s about understanding the function of your core muscles and choosing exercises that effectively enhance those functions.

Defining the Core

Years in the industry have taught me that “core” is a term as ambiguous as “functional.” Ask five different people to define it, and you’ll likely get five different answers. So, how can you be sure you’re training your core effectively?

Let’s clarify what the core muscles actually are. Once you understand this, choosing exercises to strengthen your abs becomes straightforward (and no, it doesn’t involve 500 daily crunches).

Core Anatomy & Functions

Mike Boyle (2010) defines core stability as:

“…the ability to create movement in the legs and arms without compensatory movement of the spine or pelvis, and in the broadest sense allowing force to move from the ground through the hips, spine or scapulothoracic joints without energy leaks (p. 85).”

In essence, your core muscles both create and resist motion at the spine. The primary muscle groups and their functions are:

  • Rectus abdominis: Flexes the vertebral column and tilts the pelvis posteriorly.
  • Transverse abdominis: Compresses abdominal contents.
  • External and internal obliques: Laterally flex and rotate the vertebral column.
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How to Develop Real Core Strength

While textbooks highlight muscles creating movement by acting concentrically (shortening), true core strength lies in their ability to resist movement. This resistance is crucial for effective energy transfer and injury prevention.

To build real core strength, focus on exercises that strengthen the muscles around your spine (especially your lumbar spine) and resist movement. By understanding the main patterns of spinal movement—extension, flexion, lateral flexion, and rotation—you can tailor your exercises to resist these forces and develop a stronger, more stable core.

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Core Strengthening Pattern 1: Resisting Flexion

Flexion involves bending forward or rounding the back excessively. Anti-flexion can be trained with carries and isometric holds in the double kettlebell front-racked position.

Holding a kettlebell on each side of a front-rack position creates a flexion force on the spine in which the weight pulls your torso down and forward. Getting into the double front-racked position, squeezing your armpits, and focusing on just “being tall” effectively engages your core musculature.

Double Kettlebell Front-Rack Carry

  1. Choose two light-moderate kettlebells. If you can’t perform a double kettlebell clean comfortably, set them on a box to safely get into position. Hold both kettlebells on the tops of your shoulders with your elbows up in the front rack position. 
  2. Squeeze your armpits to engage your lats, creating a triangle from hand to elbow to shoulder. The kettlebell rests between the shoulder and hand, pressed against your body.
  3. Keep your wrists neutral.
  4. Think “stand tall” and walk slowly as if balancing a glass of water on your head.
  5. Breathe shallowly, maintaining the stiffness in your abdominal brace.

I recommend starting with stationary holds. This helps you feel the activation of your core musculature as you maintain a tall posture. Start with 20-30 second holds or a 40-yard walk. Walking is more challenging because you’re introducing a reflexive contralateral (opposite) hip stability demand with each step.

Core Strengthening Pattern 2: Resisting Extension

Extension of the spine involves bending backward or creating an excessive arch. A great exercise to resist this is the dead bug with a stability ball. This creates an “extension moment” on your spine as your extremities lengthen and shorten. Contracting your abdominals and creating stiffness resists extension.

Contralateral Dead Bug

  1. Lie on your back with hips and knees bent at 90 degrees, heels level with your knees in the air. Raise your arms straight up.
  2. Create a neutral spine by “bringing your ribs down toward your pelvis” and bracing your midsection.
  3. Place the ball between your knee on one side and the opposite hand.
  4. Gently squeeze to engage your abdominal muscles.
  5. Inhale deeply, then exhale forcefully as if blowing out candles through a straw to engage the transverse abdominis.
  6. As you exhale, raise the non-engaged arm overhead and extend the non-engaged leg toward the floor without resting them.
  7. Control the motion, keeping your spine neutral. The lower your extremities reach, the more your abdominal muscles will resist spine extension.

Start with 8 reps on each side.

Core Strengthening Pattern 3: Resisting Rotation

Resisting rotation is often overlooked in core training. This pattern engages deeper muscles than standard planks or sit-ups. The tall kneeling anti-rotation press out is highly effective.

Start in a tall kneeling position for this exercise. This takes your feet and lower legs out of the equation and forces you to activate your glutes to extend your hips and keep a neutral spine. 

Tall Kneeling Anti-rotation Press Out

  1. Position a cable column at chest height while kneeling.
  2. Align so the column is straight to your side.
  3. Use a light weight (10-20 lbs).
  4. Grab the handle with your outside hand, covering it with your inside hand.
  5. Pull the handle to your chest and make yourself tall.
  6. Anti-shrug your shoulders.
  7. Inhale deeply, then exhale as you press the handle out in front. Hold briefly before bringing it back.

Start with 8 reps on each side.

Core Strengthening Pattern 4: Resisting Lateral Flexion

Lateral flexion is the spine bending to the side. Suitcase carries are excellent for resisting this movement and also strengthening the shoulders. The key to suitcase carries is to stand tall with level shoulders instead of letting the weight “rest” on your side. 

Suitcase Carry

  1. Hold a light to moderate weight in one hand, heavy enough to feel your obliques on the opposite side.
  2. Hold the weight slightly off your side without resting it on your leg.
  3. Maintain a neutral spine and tall posture, breathing shallowly while keeping your torso braced.

You might feel your quadratus lumborum (a muscle at the side of your low back) active on the opposite side of the weight — this muscle assists with lateral flexion. 

Start with 15-20 second static holds or 20-30 yard walks.

Approach Core Work Differently 

Understanding core strength and how to train it effectively is key. Resisting spinal patterns builds a strong, stable core that reduces injury risk and enhances performance.

Try these exercises for a well-rounded, stronger core:

  • Core-engaged contralateral dead bug: 2 sets of 8 reps on each side
  • Double kettlebell front rack carry: 2 sets of 20-30 second holds or 40-yard walks
  • Suitcase carry: 2 sets of 15-20 second holds or 20-30 yard walks on each side
  • Tall kneeling anti-rotation press out: 2 sets of 8 reps on each side


Biel, Andrew, et al. Trail Guide to the Body: A Hands-on Guide to Locating Muscles, Bones and More. 5th ed., Books of Discovery, 2014.

Boyle, Michael, et al. Advances in Functional Training: Training Techniques for Coaches, Personal Trainers and Athletes. On Target Publications, 2010. 

Cholewicki, Jacek, et al. “Effects of External Trunk Loads on Lumbar Spine Stability.” Journal of Biomechanics, vol. 33, no. 11, 2000, pp. 1377–1385.,

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Jack Mccormick
About Jack McCormick

Jack McCormick is a coach and trainer with nearly 14 years of experience in fitness settings from college sports performance to tactical strength and conditioning.

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