What are core muscles? Easily misunderstood, and often overlooked, your core muscles are an intricate and constantly interacting system. “The core is a vast number of muscles that operate together to keep you moving safely and with control,” says health and fitness consultant James Pisano. “This means it's incorporated into almost every exercise on some level.”
If you’ve been hard at work with some of the best abs rollers, then you may be able to spot some of these core muscles – even if visible abs are more down to low body fat than any core strength you possess. And even if you can’t see them, they’re still there working hard to keep you moving as you should.
“The core effectively should be working all day long,” says Pisano (opens in new tab), “as it's part of the cylinder that keeps you together.”
We’ve established the importance of our core, now let’s have a look at what are the core muscles and what they do, with this anatomical breakdown of each core muscle. Learn your muscle fiber types (opens in new tab) or read on for more about your core.
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The deepest of the muscles within your abdominals, the transversus abdominis is considered the most important in preventing back pain. The muscle wraps around the trunk from front to back, extending between the ribs and the pelvis, with the muscle fibers running horizontally, providing posture support and protecting your organs within.
The top layer of your abdominal muscles – and what we commonly refer to as the six-pack – the rectus abdominis runs from between your ribs down to the pubic bone in the front of your pelvis. It helps with a number of bodily functions like urinating and coughing, while also providing general stability around your core.
Obliques (external and internal)
There are two sets of muscle within your obliques muscles (opens in new tab): internal and external – all of which are to the side of the rectus abdominis. The external obliques (shown above) run diagonally down and inward from the lower half of your ribs to the pelvis in a V shape. They are vital for any rotational movements, like a golf or tennis swing, as well as sideways bending.
Your internal obliques (shown above) sit much deeper within the body. They also play a key role in trunk rotation, as well as flexing the spinal column and compressing the abdomen.
Your pelvic floor muscles span the bottom of the pelvis, the area of the body below the abdomen that is between the hip bones. Your pelvis contains the bladder, rectum, and uterus, and your pelvic floor muscles help support these vital organs, with any weakness in the area leading to issues like poor bladder or bowel control. Women and men have slightly different pelvic floor muscles, but the diagram above shows where they are located.
The hip flexors are a group of strong, powerful muscles near the top of your thighs and to the front of your hip. They’re vital for moving your lower body, and allow you to walk, run, bend and kick.
This is just below your lungs, the diaphragm is the main muscle responsible for breathing. Large and dome-shaped, it contracts continually as you inhale and exhale. Besides breathing, the diaphragm also places pressure on the esophagus to prevent acid reflux.
One of the smallest sets of muscles within your core, the multifidus muscles are attached either side of your spinal column. They’re important for taking pressure off the vertebral discs so that your bodyweight is well distributed along the length of your spine, while also helping keep your back straight.
Another set of muscles around our spine, the erector spinae muscles sit on either side of your vertebral, or spinal, column, the central axis of the skeleton. These lengthy muscles extend the length of the column, and can bend and rotate the vertebrae. Strong erector spinae muscles are vital for keeping any lower back pain away, while they also help provide for side-to-side rotation.
The deepest abdominal muscle, the quadratus lumborum is in your lower back on either side of the lumbar spine. It has an important role in stabilizing the pelvis when standing upright, while also helping to support the core of the body when breathing.