A Strong Core, Explained: Why It Matters and How to Build One

When most people hear “core,” they think “abs.” You know, the six-pack or some obliques, and the exercises that go with them, e.g., crunches, sit-ups, planks. But the truth is, the core is way more than just your abs.

From a professional or therapeutic perspective, the core includes everything from your chest down to your knees. It’s all the muscles that stabilize your trunk, support your spine, connect your hips, pelvis, and rib cage, and help transfer force from the ground up or from your limbs outward.

That means the deep muscles like the transverse abdominis and multifidus, but also the “superficial” abdominals, back extensors, lateral trunk muscles, hip-spine linkers, and even the multi-joint muscles that connect your limbs through the trunk. In short, the core is really your body’s central support structure—not just abs.

What the Core Does

A strong, well-coordinated core is about more than looking good. Functionally, it:

• Stabilizes & transfers force: When you lift, squat, throw, push, or pull, your core stiffens the trunk so forces from your legs or arms aren’t wasted or dangerous to your spine.

• Protects your spine: A stable core keeps your spine from “buckling” under load, reducing your risk of injury.

• Controls movement: Before your arms or legs move, your core stabilizes them for safer, more precise motion.

• Prevents injury: Weak or poorly coordinated cores can lead to back, shoulder, hip, knee, or ankle injuries more than weak limbs alone.

• Boosts performance: Stability, balance, posture, and overall movement efficiency all improve with a strong core.

  
  

Experts Weigh In

Stuart McGill, a leading spine biomechanics researcher, explains that core muscles aren’t usually about creating movement, they’re about stabilizing the trunk so forces from your hips or shoulders move safely through the body. McGill emphasizes whole-core bracing instead of isolating one deep muscle. A strong core allows the power generated by your legs or arms to flow efficiently through the trunk for safe, powerful squats, deadlifts, presses, and other athletic movements.

Craig Liebenson, a chiropractor and rehab-performance specialist, also emphasizes function over aesthetics. He points out that what’s “functional” depends on your individual needs, movement patterns, posture, and mobility. Not everyone needs the same core exercises; it’s about strengthening the system your body actually uses.

Do Core Exercises Outperform General Strength Training?

The research is a little mixed. Core-specific training improves stability, balance, and endurance—great for back health and injury prevention. Sport-specific performance or maximal strength doesn’t seem to improve more from isolated core exercises than from general resistance training.

Therefore, it would seem that the best approach is to combine functional core work with compound lifts and progressive overload. That way, your core and your stronger limb muscles adapt together.

Indirect Core Development Through Load and Movement

1. Progress Slowly

As your mobilizer muscles (quads, glutes, lats) get stronger, your core stabilizers need time to adapt. If they lag behind, injuries happen: the core fails before the bigger, more powerful muscles. By gradually increasing load, duration, or difficulty, you allow your core to keep up with your growing strength.

2. Focus on Safe, Functional Technique

Perfect textbook form isn’t always necessary, and sometimes it can even be disadvantageous. Life doesn’t move in perfect, symmetrical patterns. Sports, lifting groceries, or shoveling snow all involve asymmetry and momentum. The goal is safety, control, and force transfer, not being a robot.

Targeted Core Training

The core works across four main roles:

1. Flexion: Controls forward bending and resists excessive spinal flexion.

2. Extension: Counters flexion forces and maintains upright posture.

3. Lateral stabilization: Controls side-bending and frontal-plane stability.

4. Medial (rotational/anti-rotational) stabilization: Resists rotation and maintains transverse-plane control.

   
   

Here’s how some key exercises fit in:

Modified Curl-Up (McGill Big 3)

• Flexion: Trains controlled forward bending without stressing the lumbar spine.

• Extension: Teaches your core to resist collapse into extension.

Side Plank (McGill Big 3)

• Lateral stabilization: Main focus—resists side-bending.

• Medial stabilization: Anti-rotation challenge to prevent torso rolling.

Bird Dog (McGill Big 3)

• Extension: Keeps spine neutral while limbs move.

• Lateral stabilization: Resists side-shifting from unilateral support.

• Medial stabilization: Anti-rotation as opposite arm and leg move together.

Dead Bug (Progressions)

• Flexion: Keeps anterior core engaged while lowering limbs.

• Lateral stabilization: Prevents pelvic shift during unilateral limb movement.

• Medial stabilization: Anti-rotational control during alternating limb patterns.

Pallof Press

• Lateral stabilization: Prevents side-shifting under resistance.

• Medial stabilization: Anti-rotation is the main focus.

  
  

Progression Tips

Some of these exercises can be quite technical, so working with a personal trainer, physical therapist, chiropractor, or other qualified professional may be beneficial. The progressions below allow you to gradually build strength and control, even if you’re not yet able to perform the full movements.

Before starting the exercises, it’s important to understand a key concept: lumbar bracing. This involves activating the lumbar multifidus and transverse abdominis simultaneously (the muscles we discussed earlier). Learning to engage these muscles properly is essential for performing the Curl Up, Bird Dog, and Dead Bug exercises safely and effectively.

Why Learning the Transverse Abdominis Tuck and Posterior Pelvic Tilt Matters

Before jumping into more challenging core exercises, it’s important to learn two foundational skills: the transverse abdominis tuck and the posterior pelvic tilt (referred to as lumbar bracing).

The transverse abdominis is a deep abdominal muscle that acts like a natural weight belt, helping stabilize your spine before and during movement. Learning how to gently activate this muscle teaches your body how to support your low back without excessive tension or stiffness.

The posterior pelvic tilt adds another layer of control by teaching you how to manage your pelvic and lumbar spine position. This helps reduce unnecessary stress on the low back and allows your spine to stay in a safer, more neutral position during exercise and daily activities.

When you can perform both together—gently drawing in the abdomen while controlling the position of your pelvis—and hold that position while breathing normally, it shows that your nervous system understands how to stabilize your spine without compensating or over-bracing.

Once you can do this reliably, your body is ready for more advanced core exercises. Skipping this step often leads to poor technique, increased strain, and slower progress.

Transverse Abdominis Tucks (Abdominal Drawing-In)

Starting Position

·         This exercise can be performed lying on your back, sitting, or standing.

·         Most people find it easiest lying on their back on a semi-firm surface (such as the floor or a firm bed), as the surface provides helpful feedback.

·         If lying down, bend your knees and place your feet flat on the floor.

·         Place one hand on your chest, and the other over your belly button.

How to Perform

1.      Relax your body and breathe normally.

2.      Slowly draw your belly button inward toward your spine, as if gently tightening a belt one notch.

3.      Keep your pelvis and rib cage still—your back should not flatten or arch.

4.      Continue to breathe normally while holding the contraction.

5.      Hold for 8 seconds, then fully relax.

Key Cues

·         Think: “Gently tighten, not suck in.”

·         Imagine lightly zipping up snug pants or gently tightening a corset.

·         The contraction should feel deep and subtle, not hard or forceful.

·         Placing one hand on your chest, and one over your belly button, and not letting the chest move insures you’re not performing a hollowing maneuver.

Common Mistakes to Avoid

·         Holding your breath

·         Bracing too hard or pushing the belly outward

·         Tightening the glutes, thighs, or upper abs

Repetitions

·         Perform 8 repetitions, holding each for 8 seconds

·         Complete 1–2 sets, once or twice per day

Posterior Pelvic Tilt

Starting Position

·         Lie on your back on a semi-firm surface

·         Knees bent, feet flat on the floor

·         You may place your hands under the small of your back for feedback

How to Perform

1.      Relax and breathe normally

2.      Gently tilt your pelvis backward, flattening your low back toward the floor (your low back should be “squashing” your hands).

3.      Imagine tucking your tailbone slightly underneath you

4.      Hold the position while breathing normally

5.      Hold for 8 seconds, then relax

Common Mistakes to Avoid

·         Holding your breath

·         Over-squeezing the glutes

Repetitions

·         Perform 8 repetitions, holding each for 8 seconds

·         Complete 1–2 sets, once or twice per day

Lumbar Bracing (Transverse Abdominis + Posterior Pelvic Tilt)

Starting Position

·   Can be performed lying on your back, sitting, or standing

·   Most people find it easiest lying on their back on a semi-firm surface (floor or firm bed)

·   Knees bent, feet flat on the floor if lying down

How to Perform

1. Relax your body and breathe normally

2. Draw your belly button inward toward your spine (Transverse Abdominis activation)

3. Tilt your pelvis slightly backward, flattening your lower back gently toward the floor

4. Keep your rib cage still

5. Hold this contraction while breathing normally

6. Relax and return to neutral

Repetitions

·         Perform 8 repetitions, holding each for 8 seconds

·         Complete 1–2 sets, once or twice per day

Sets and Reps

There are general guidelines for core exercises, but no strict number of sets or repetitions. Typically:

• Active range-of-motion exercises (like bird dogs, dead bugs, or modified curl-ups) are often performed for 10–30 repetitions per side or 1–3 sets.

• Isometric holds (like side planks or lumbar bracing) are usually held for 8–30 seconds, repeated 1–3 times.

A better approach is to focus on quality over quantity: choose a version that challenges you, keep the workout under 10–15 minutes, and perform the exercises with proper form. Follow this approach consistently, and you’ll get effective results.

McGill Modified Curl-Up

Starting Position

·         Lie on your back

·         One knee bent, the other leg straight

·         Hands placed palms-down under the natural curve of your low back

·         Head and neck relaxed

How to Perform

1.      Do the LUMBAR BRACE

2.      Lift your head and shoulders slightly—just enough to clear the floor

3.      Keep the neck neutral, or chin slightly tucked, and eyes looking upward

4.      Hold for 1-2 seconds, breathing normally

5.      Lower with control and relax

Common Mistakes to Avoid

·         Pulling the head forward

·         Large or jerky movements

Repetitions

10 - 30 reps

Side Plank (From Knees, Beginner)

Starting Position

·         Lie on your side

·         Knees bent, elbow under shoulder

·         Body in a straight line from shoulders to knees

How to Perform

1.      Brace the core gently

2.      Lift hips off the floor

3.      Keep head, ribs, and pelvis aligned

4.      Hold while breathing normally

5.      Lower slowly

Common Mistakes to Avoid

·         Letting hips drop or rotate

·         Shrugging the shoulder

·         Holding breath

Repetitions

5–10 second holds, 5–10 reps

Side Plank (From Ankles, Intermediate to Advanced)

Starting Position

·         Lie on your side

·         Legs straight, feet stacked

·         Elbow under shoulder

How to Perform

Same steps as knee version, maintaining a straight line from head to ankles.

Repetitions

5–10 second holds, 5–10 reps

Bird Dog – Arm Only (Beginner)

Starting Position

·         Hands and knees

·         Neutral spine

·        Do the LUMBAR BRACE

How to Perform

1.      Slowly extend one arm forward

2.      Keep hips and spine still

3.      Hold for 2-3 seconds

4.      Lower and switch sides

Common Mistakes to Avoid

·         Shifting weight or twisting

·         Arching the back

Repetitions

10 - 30 reps

Bird Dog – Leg Only (Intermediate)

How to Perform

1. Do the LUMBAR BRACE

2. Extend one leg straight back

3. Keep pelvis level (maintain your brace)

4. Hold 2-3 seconds

5. Switch sides

Repetitions

10 - 30 reps

Full Bird Dog (Arm + Leg) (Advanced)

How to Perform

1.      Do the LUMBAR BRACE

2.      Extend opposite arm and leg

3.      Hold 2-3 seconds

4.      Switch sides

Common Mistakes

·         Overextending

·         Rocking side to side (shifting weight)

·         Rotating the pelvis

Repetitions

10 - 30 reps

Dead Bug – Arm Only (Beginner)

Starting Position

·         Lie on back

·         Knees bent, feet on floor

·         Arms straight up

How to Perform

1. Do the LUMBAR BRACE

2. Lower one arm overhead

3. Keep ribs down and back neutral

4. Return and switch

Repetitions

10 - 30 reps

Dead Bug – Leg Only (Intermediate)

How to Perform

1. Do the LUMBAR BRACE

2. Lift one foot slightly off floor

3. Lower it back down slowly

4. Keep pelvis still

5. Alternate legs

Repetitions

10 - 30 reps

Dead Bug – Arm and Leg (Intermediate)

How to Perform

1. Do the LUMBAR BRACE

2. Extend opposite arm and leg

3. Keep low back neutral

4. Return slowly

5. Switch sides

Repetitions

10 - 30 reps

Dead Bug – Knees Up (Advanced)

Starting Position

·         Knees and hips bent to 90°

·         Arms up

How to Perform

1. Do the LUMBAR BRACE

2. Perform arm, leg, or arm+leg movements while keeping knees elevated and spine stable.

Repetitions

10 - 30 reps

Pallof Press

Starting Position

·         Stand or kneel sideways to a resistance band or cable

·         Band held at chest level

How to Perform

1.      Brace core

2.      Press hands straight out

3.      Resist twisting

4.      Hold 2–5 seconds

5.      Return and repeat

Repetitions

10 - 30 reps

Hip Abduction (Bonus Exercise)

Purpose

Strengthens the glute medius - keeps the pelvis level during single-leg activities like walking, running, and climbing stairs. Without proper activation, the pelvis can drop or tilt, which puts stress on the lumbar spine.

Starting Position

·         Side-lying

How to Perform

1.      Keep pelvis stable

2.      Move leg out to the side, do not rotate leg, keep toe pointed forward

3.      Keep ankle, knee, hip, shoulder all in a straight line

4.      Breathe normally

Common Mistakes

·         Leaning or rotating

·         Using momentum

·         Letting the leg drift forward and pointing toe point away (becomes a hip flexor exercise)

Repetitions

10 - 30 reps

Summary

So there you have it: first, focus on learning to brace properly. Once you’ve mastered that, you can choose from up to six exercises for a complete core workout. (Important: don't do the beginner, intermediate, and advanced labels altogether—simply perform the version you can do correctly and that provides a meaningful challenge).

Increase duration, range of motion, repetitions, or add light resistance gradually and intentionally to keep your core stabilizers strong and adapting safely. Your core is your body’s central hub, keeping you strong, resilient, and ready for real-world movement. Treat it well, and it will take care of you.

Take-Home Message

• Your core isn’t just abs—it’s everything from your chest to your knees.

• Its main job is stabilization, force transfer, and injury prevention, not just movement.

• Progress slowly and intentionally to keep your stabilizers in step with your stronger mobilizers.

• Technique should be functional and safe, not perfect.

• Functional core exercises like the McGill Big 3, Dead Bug, and Pallof Press are excellent tools when combined with resistance training.

References

1. McGill, S. (2010). Core Training: Evidence Translating to Better Performance and Injury Prevention. Strength and Conditioning Journal, 32(3), 33–46.

2. Liebenson, C. (2015). Rehabilitation of the Spine: A Practitioner's Manual. Lippincott Williams & Wilkins.

3. Kibler, W. B., Press, J., & Sciascia, A. (2006). The Role of Core Stability in Athletic Function. Sports Medicine, 36(3), 189–198.

4. Behm, D. G., & Anderson, K. (2006). The Role of Core Stability in Athletic Performance. Current Sports Medicine Reports, 5(1), 39–44.