Core muscles. Why do we need them, and how to train?

A no-nonsense 5-minute article on how to train your core muscles — and why it matters.

Core muscle training is the foundation of how professional athletes train today. Physiotherapists prescribe core exercises to people with back pain. Fitness trainers include them in almost every workout.

Let's figure out in this 5-minute article what the trick actually is.

This article is for coaches and thinking athletes. It also contains the answer to why my back hurt badly after performances — and how I fixed it. It's based on the NASM Essentials of Sports Performance Training and personal experience.

What Are the Core Muscles?

Imagine the human body as a LEGO construction. The central part — the core — includes three segments:

• Lower back
• Pelvis
• Hip

Together they form the LPHC (lumbo-pelvic-hip complex). The core works as a link between other parts of the body.

Simplified: Hands + core. Legs + core. Arms + core + legs.

I imagine the center of the body as a keg that we carry through space using arms and legs. The more solid the keg, the easier everything else becomes.

Try to throw a soda bottle as far as possible. Then try to throw a condom filled with water as far as possible. Feel the difference.

If your limbs are strong but your core is weak, the force transmitted through that connecting link gets dissipated. Movements become inefficient — or worse, dangerous.

Strong core muscles provide ideal efficiency for the whole body: better acceleration, deceleration, and stabilization during all movements.

Physical training coaches of sports teams have increased the emphasis on core training because they've documented the direct connection between core strength and improved athletic performance.

By "strong core muscles," I mean the balance of tone and optimal tension in all three areas, specifically:

• Flexibility — balanced length and tension between paired muscles.
• Strength — optimal tone between paired muscles.
• Mobility — maintaining optimal ratios of length and tone, giving joints agility and stabilization during movement.

The core muscles are maximally involved in resisting all the forces that emerge in sport and in life: bending, compressing, twisting, moving, pushing.

Basic sports movements — swinging, kicking, throwing, jumping, sprinting — all require strong core muscles because the energy for those movements is generated in the center of the body and transferred to the limbs.

At Cirque du Soleil training camp, we did bio-impedance analysis — a test measuring body composition. I took the test on the first day of camp and every three months throughout preparation. By the third month, the results showed I had gained 2 kg of pure muscle mass — of which 1.3 kg came specifically from the core area.

What's interesting: I wasn't specifically targeting my abs. I was mostly doing gymnastics and working on the performance routines. This confirms the theory: any functional movement either arises from or passes through the core muscles.

Weak core muscles are a fundamental problem that creates inefficient movement and the risk of many injuries. But a properly designed comprehensive training program helps eliminate this problem quickly. By strengthening your core, you increase the results of your entire musculoskeletal system — all movements, all indicators.

Functional Anatomy of the Core Muscles

To build a great training program, a coach must understand the functional anatomy and stabilization mechanisms of the LPHC. The main stabilization mechanisms are divided into three systems.

1. The Local Stabilization System

These are the muscles attached directly to the vertebrae. Mostly type I muscle fibers — slow, red, resistant to fatigue. These deep muscles are primarily responsible for intervertebral stabilization.

They resist: compression of the vertebrae, shifts of vertebrae relative to each other, and excessive rotation. They also support proprioception — control of body position in space and posture maintenance.

Main muscles of the local stabilization system:

• Transverse and internal oblique muscles of the abdomen — Watch
• Multifid lumbar muscles — Watch
• Pelvic muscles — Watch
• Diaphragm — Watch

Watch the overview video here

2. The Global Stabilization System

These are the muscles attached from the spine to the pelvis. They transfer loads between the upper and lower parts of the body.

Main muscles: square muscle of the lower back, iliopsoas, rectus abdominis and external oblique, gluteus medius, adductors.

These muscles provide stabilization and control over the core during movement and in static exercises — twisting, squats, planks.

Watch video 1 | Watch video 2

3. The Movement System

These are the muscles attached from the spine to the limbs. They're primarily responsible for dynamic movements — generating and absorbing force.

Main muscles: latissimus dorsi, anterior thigh muscles, posterior thigh muscles, buttocks.

These muscles generate driving force — acceleration, throws, jumps (concentric contractions). They also reduce force — stopping during running, receiving impact, landing (eccentric contractions).

Watch video 1 | Watch video 2

How Does Stabilization Actually Occur?

The core is stabilized during movements by two main systems.

System 1: The Tent System (thoracolumbar stabilization mechanism)

A structure of "ropes" stretched in different directions, stabilizing the lower back under good tension.

The spinal extensor tendon is the base, with the latissimus dorsi fascia pulling up and the glute fascia pulling down. When I had lower back pain exacerbations, I found in rehabilitation books that the weaker the glutes and latissimus dorsi, the more the lower back hurts. I didn't understand at first what the latissimus dorsi had to do with the lower back — but I trusted it, trained actively, and the pain eventually disappeared. Now I understand exactly how it worked. This system resists extreme twisting and bending.

System 2: The Balloon System (intra-abdominal pressure mechanism)

A balloon-like structure where the diaphragm is the top, the transverse abdominal muscle wraps around the circumference, and the pelvic muscles form the bottom.

Watch the video here

On inhalation, the diaphragm dome drops. If at the same time you pull in the stomach and clamp the glutes, you create strong intra-abdominal pressure — and your body becomes like a Coca-Cola bottle after shaking and dropping it. Twisting or bending you under those conditions becomes almost impossible. This system resists excessive compression and uncontrolled sliding of the vertebrae.

This technique is widely used in weightlifting, gymnastics, and throwing sports. I perform complex elements on inhalation. Strengthening the core muscles is the best prevention of non-contact spinal injuries.

This is the first of three articles on the topic of core muscles. The next article shares research connecting weak core muscles with back and knee injuries, plus my personal experience with it — read it here: Core Muscles and Low Back Pain.

If you want to put this into practice right now, the Core Challenge is a structured daily program that trains all three stabilization systems step by step. If back pain is part of your picture, the Back Mobility Challenge is the right companion.

FAQ

What exactly are the "core muscles"?

The core is the central segment of the body — lower back, pelvis, and hip — collectively called the LPHC (lumbo-pelvic-hip complex). This includes not just the visible abdominals but deep stabilizers, the diaphragm, the pelvic floor, and the muscles connecting the spine to the limbs.

Why do all sports movements require a strong core?

Because all force generated in athletic movements — throwing, kicking, jumping, sprinting — passes through the core. If the core is weak, that force leaks out or gets distributed unevenly, making movements both less powerful and more dangerous.

What's the difference between the three stabilization systems?

The local system stabilizes the vertebrae directly and handles proprioception. The global system transfers loads between upper and lower body and controls movement. The movement system generates and absorbs force during dynamic athletic actions. All three need to work together and be trained together.

Can core training actually reduce back pain?

Yes — this is well-documented in research and confirmed in personal experience. Weak core muscles create inefficient movement patterns and increase spinal loading. Strengthening the core distributes force better, reduces strain on the passive structures of the spine, and can eliminate the root cause of many types of back pain.

Keep Reading

• Core Muscles and Low Back Pain — part 2: research on how weak core creates a pain trap, and how to break it
• How to Use Core for Handstand Balance — the core in its most demanding role: controlling your whole body through your palms
• Why Your Body Hurts — And How to Fix It With Movement — the bigger picture of core, posture, and pain
• The Back Mobility Vitamin — daily mobility to complement core strength work
• The Best Training Algorithm — where core training fits inside a complete training session