What Muscles Make Up the Core? - CrossFit in Bedford, NH

What Muscles Make up the Core

What Muscles Make up Your Core?
Photo Credit: Charlotte Agenda

When you hear the word core you probably think of your rectus abdominis muscles, otherwise known as a “six pack,” but your core is made up of many more important muscles than that. In fact your core is made up of numerous types of muscles all working together to help you with your daily functions such as breathing and providing posture and stability.  This is to help you with things like not falling over when walking, tipping over backwards or swaying side to side uncontrollably.  Your abdominal muscles are located in the front of your body between your pelvis and ribs and some muscles from your back combine with these to create your core. Obtaining a strong core is more beneficial than just having a beach body, it allows you to be able to function and live freely without a continuous struggle to keep moving.

What Muscles make up your core?


Your trapezius muscle runs lateral to your shoulders and vertical from your head to the lower back and connects laterally to the clavicle, the abdomen, and scapular spine. It gives you the ability to look at the world around you as it assists with rotating your neck and head. Your trapezius also helps with whole body lateral flexion, allowing you to move from side to side. It is important to exercise this muscle because a lack of strength and range of motion can lead to kyphotic postural deviation. The kyphotic postural deviation is when your spine will start to curve inward, making your upper back rounded and results in poor posture from the lack of stability and will create pain in your back.


Latissimus Dorsi

Your latissimus dorsi, otherwise known as your “lats”, is a sheet of muscle that covers your back connect to your vertebrae column.This muscle helps with extension, adduction and internal rotation of your arm.  Your latissimus dorsi also helps connect your spine to your humerus.  The main function of your latissimus dorsi is to provide mobility for your shoulder joints allowing you to rock climb or simply do some pushups. You can engage with these muscles by performing exercises such as pull-ups, or lat pull downs to help strengthen them. Injury to this muscle is quite common and can cause chronic shoulder and back pain if overworked. If the muscles become too tight, feeling upper back, neck and shoulder pain are all also common.

Rectus Abdominis

Your rectus abdominis muscles are long, flat and run opposite to one another along the front of your abdomen, in front of your pelvis between your ribs and pubic bone. These are the muscles commonly referred to as your “abs” or a “six pack.” These muscles not only help by making you appear more attractive but actually, serve the purpose of providing posture to your body from compacting your organs with pressure. These muscles keep your organs in place by applying pressure when you are performing exercises that involve heavy weight lifting. While you are performing a workout, such as crunches, you are engaging these muscles in flexing the lumbar spine. You also use your rectus abdominis after you complete a workout in the cool down process. These muscles help assist the process of respiration when you have to forcefully exhale.

External/Internal Obliques

Your oblique muscles are divided into two categories; internal and external. Your external obliques are located lateral to the interior abdomen and run parallel to your rectus abdomens. They work to compress your abdominal cavity by pulling downwards on your chest. This pulling allows you to twist and rotate your torso. One external oblique will perform the movement required for the twist, while the opposite will contract to create the twisting movement. Your internal obliques are located underneath your external obliques but above your transverse muscles. These muscles cover from inside your hip bones all the way up to under your ribs. The internal obliques also help with trunk rotation by pulling the rib cage to the hip and lower back when you twist. These muscles can also assist with respiration as they act as an opponent to your diaphragm.


Your diaphragm is the sheet of muscle across the thoracic cavity. This muscle is the reason why you can take long deep breathes in yoga, or quick forceful breathes after a hard run.It resembles a dome like a shape and attaches itself the muscles inside your thorax cavity. Your diaphragm is part of the respiration system. When you inhale, your diaphragm contracts and creates a higher volume of the thoracic cavity. The diaphragm muscles work as a vacuum and suction up air into your lungs. When you exhale, your diaphragm releases the tension from when you inhaled and covers the thoracic cavity once again. The diaphragm is a vital muscle to maintain healthy because with a weakened or unhealthy diaphragm you will suffer from respiratory failures.

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Transverse Abdominis

Your transverse abdominis works to compress your abdominal contents giving you stability. It is a sheet of muscle located underneath your internal obliques on either side of your abdomen. Your transverse abdominis muscles help with pelvic and thorax stability by compressing the ribs and viscera. They also provide stability to your trunk and regulate the pressure applied to your organs. When you are weightlifting, these muscles act as a natural lifting belt as they provide the stability you need in your core to perform your exercise. If exercised correctly, they can help with back pain because the muscles support your lumbar spine. If this muscle is over worked, it can lead to injuries such as hernias, hemorrhoids, and digestions disorders.

Serratus Anterior

Your serratus anterior muscle is located underneath your ribs and chest and outlines your scapula. This muscle helps pull your arm to a further extension. This helps you when you lift weights overhead because it pulls down your scapula and works with your trapezius to give your shoulder rotation. The primary function of your serratus anterior is to protect your scapula and to give you the ability to use your arms. This muscle is nicknamed the “boxer’s muscle” because it gives you the ability to perform athletic motions with your arms such as punching. This muscle helps with your everyday functions as it works with the rhomboids to raise and lower your arms, allowing you to simply reach for things on shelves, or raise your arms in absolute victory after crossing the finish line of a race.

Pelvic Floor

Your pelvic cavity is lined with a strong muscle called your pelvic floor. Your pelvic floor is a very important muscle to keep healthy and strong, as it serves the important function of supporting your pelvic organs. Your pelvic floor both supports and controls your bladder, and if it is weakened can cause uncontrolled urine leaking from sneezing, laughing or even double unders. Your pelvic floor also supports your bowel, intestines, and in females it supports the uterus. The pelvic floor and assist in child birth, but after pregnancy can become weak. Doing exercises, such as squeezing and then releasing these muscles, can help strengthen the tissues in your pelvic floor to prevent serious damage to these muscles and your pants.

Erector Spinae

Your erector spine is made up of the muscle groups, your iliocostalis, longissimus, and spinalis. These long and thin muscles originate from your lower back and climb all along your spinal column along the lumbar, cervical, and thorax sections. Each muscle group serves a different purpose to help your body function properly. The spinalis group works along with the trapezius muscle to rotate your head, giving you the ability to look around at your surroundings. The iliocostalis and longissimus groups straighten your back and give you the ability to rotate from side to side. These muscles allow you to bend forward, backward, left, and right. Your erector spinae lets you bend over to pick up something you dropped, or stretch in your yoga class. If these muscles become injured back spasms are a common side effect.

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