When the goal is to improve movement and performance, understanding the core muscles and their function is crucial for maximizing your training.
Technically, core muscles include all the muscles of the trunk, pelvic floor, and hips surrounding the spine and abdominals. But we’ll focus on the four core muscles typically associated with the word ‘core.’
The four main core muscles
Rectus Abdominis
External Obliques
Internal Obliques
Transverse Abdominis.

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The core muscles help to provide stability and support to the spine and pelvis and to maintain proper posture.
In addition, each core muscle has an essential role in movement.
The rectus abdominis, aka “six-pack,” is a paired muscle that runs vertically down the front of the abdomen. It flexes the trunk by bringing the rib cage towards the pelvis and vice versa.

Rectus abdominis in action flexing the trunk.
The external obliques are a pair of broad, flat muscles that run diagonally along the sides of the abdomen, extending from the lower ribs to the pelvis. They predominately rotate and laterally flex the trunk, along with the internal obliques.
They also play a part in forced exhalation to breathe. And together with the rectus abdominis and internal obliques, they flex the trunk.

Obliques in action rotating the trunk.
The internal oblique is a paired muscle that sits just beneath the external oblique, running diagonally across the abdomen in the opposite direction. As with the external oblique, it rotates and laterally flexes the trunk and assists in trunk flexion.

Obliques in action laterally flexing the trunk.
Additionally, the internal and external obliques also increase intra-abdominal pressure. For things like forced exhalation, pooping, coughing, or any force output that requires a stable core like a tennis shot.
The transverse abdominis is a deep muscle that runs horizontally across the abdomen, beneath the more superficial rectus abdominis and oblique muscles.
It plays a vital role in maintaining normal abdominal wall tension. It has a protective and supportive role, holding the abdominal organs in place.
As with the other lateral abdominal muscles, transversus abdominis creates compression of the intra-abdominal viscera, increasing the intra-abdominal pressure.
Training the core muscles
Building a strong core requires a program that covers all the core muscles’ functions—flexion, rotation, and lateral flexion.
While variety is the key to training the core muscles, many neglect the importance of breathing for building a strong core.
Our clients use core breathing techniques to ramp up core muscle activation in their training. The beauty of core breathing is that once you learn it, it’s easily transferable to any activity or sport you do to create more power and strength in any position.
Core breathing involves engaging the diaphragm and pelvic floor muscles to create intra-abdominal pressure.
This intra-abdominal pressure can stabilize the spine, trunk, and hips. This allows you to create more force throughout the rest of the body. Whether hitting a tennis ball, doing a roundhouse kick, or jumping to slam a volleyball mid-air.
Learn more about core breathing and build a stronger core
Sign up for our Core Breathing online program. It’s a program where Ian teaches you the basics of core breathing and provides a wide range of exercises to help you improve your core strength and stability.
In addition to learning the basics of core breathing, the Core Breathing program includes video demonstrations of each exercise and detailed instructions on proper technique and form.
With various workouts and progress-tracking tools, you can stay motivated and track your progress as you work towards your fitness goals.
Understanding the anatomy of your core and incorporating core breathing into your training routine can significantly impact your overall fitness and performance.
By learning how to engage your diaphragm and pelvic floor muscles, you can improve your reduce your risk of injury and build a stronger and more stable core that supports your movement and performance goals.