Learn all about your core

February 29, 2016

One of the most common requests personal trainers and fitness coaches receive from clients is "I want abs!" I think many of you may realize that this is a pretty vague request, and one that I wish to tackle with this blog.


First, we will go over many of the muscles that make up the "core," along with their function, and then we will go over some myths and mis-truths about the core that I promise, even the most well-rounded fitness enthusiasts out there, will learn something new.


Keep in mind that your core includes your entire torso (minus, of course, your arms and legs). All the muscles that surround your spine - neck, glutes, abs, back, scapular, pecs, obliques, etc. can and should be considered your "core" muscles. However, rather than get into most of the intricacies of every single one of the muscles involved, I figured I would break down most of the primary movers and supporters of your core so that we can better understand its purpose as a whole, and how you can improve it!


So, first of all, let's cover your anterior side of your body:

Source: http://arcphysicaltherapy.com/2014/what-is-the-core/


Serratus Anterior


The serratus anterior (/ˌsɨˈreɪtəs ænˈtɪəri.ər/) (Latin: serrare = to saw, referring to the shape, anterior = on the front side of the body) is a muscle that originates on the surface of the 1st to 8th ribs at the side of the chest and inserts along the entire anterior length of the medial border of the scapula.


Not to many people would consider the serratus anterior part of the core. This muscle helps protract the scapula (antagonist of the rhomboids) for overhead movements, such as in presses or throws. Since our arms perform so many actions, especially in athletic movements overhead, I consider the serratus to be a major player when it comes to core/shoulder stability.


Not only that, but I personally find the serratus anterior to be one of the most under appreciated visual cues of physical fitness.


External Oblique


The external oblique muscle (of the abdomen) (also external abdominal oblique muscle) is the largest and the most superficial (outermost) of the three flat muscles of the lateral anterior abdomen.


Beyond helping stabilize the vertebral column during flexion and rotation, the external oblique helps pull the chest downward an action known as the valsalva maneuver. For those of you who are familiar with traditional strength training should know that the valsalva maneuver is a breathing/stabilization technique used to stabilize the midsection during heavy lifting.


Rectus Abdominis


The rectus abdominis muscle, also known as the "abs and lower abdominals," is a paired muscle running vertically on each side of the anterior wall of the human abdomen, as well as that of some other mammals. There are two parallel muscles, separated by a midline band of connective tissue called the linea alba ("white line"). It extends from the pubic symphysis,pubic crest and pubic tubercle inferiorly, to the xiphoid process and costal cartilages of ribs V to VII superiorly.


Ah yes, the "six-pack" muscle. The one muscle in the entire body that majority of the population wishes to improve. We will get into more of that later, but realize that besides flexing the spine (forward crunches), the rectus abdominis is one of the most over-hyped muscles (in my opinion) in the entire body.


Besides flexing the spine, the rectus abdominis also assists in contracting to increase abdominal pressure (valsalva) during times of heavy lifting or during childbirth. One function that most people do not know about, is that your six-pack also helps respiration by forcefully exhaling.


Internal Oblique


The internal oblique muscle (of the abdomen) is the intermediate muscle of the abdomen, lying deep to (below) the external oblique and just superficial to (above) the transverse abdominal muscle.


Besides aiding in respiration, the internal obliques are a major contributor to side to side flexion of the torso as well as rotational stability.


Transverse Abdominis


The transversus abdominis muscle (TVA), also known as the transverse abdominus, transversalis muscle and transverse abdominal muscle, is a muscle layer of the anterior andlateral (front and side) abdominal wall which is deep to (layered below) the internal oblique muscle.


One of, if not the most important muscle in your core, although located on the anterior side of your body, the transverse abdominis plays a large part in core stability by contracting the midsection to support structures like your spine.

Source: http://timiinengland.wordpress.com/2012/01/03/hard-core-workout/





In human anatomy, the trapezius (/trəˈpiːzi.əs/) is a large superficial muscle that extends longitudinally from the occipital bone to the lower thoracic vertebrae and laterally to the spine of the scapula (shoulder blade). Its functions are to move the scapulae and support the arm.


The trapezius, along with the rhomboids, help retract the scapulae (shoulder blades). How is this related to core? Well, many people have weak upper backs, leading to their shoulders hunching forward giving them a minor "hunchback" look, also known as kyphosis.


Anyways, having a rounded upper back can lead to spine mis-alignment, and can actually throw your entire spine, including the natural arch of your lumbar, out of place. For a lot of people, this is where a lot of their troubles originate. Sure, most people end up having low back pain, but it may very well originate higher up their spine due to misalignment and poor support from lack of muscle tone.




The rhomboid muscles, (/ˈrɒmbɔɪd/) often simply called the rhomboids, are rhombus-shaped muscles associated with the scapula and are chiefly responsible for its retraction. They are supplied by the Dorsal Scapular nerve.


Latissimus Dorsi


The latissimus dorsi (/ˌləˈtɪsɨməs ˈdɒrsaɪ/) (plural: latissimi dorsi), meaning 'broadest [muscle] of the back' (Latin latus meaning 'broad', latissimus meaning 'broadest' and dorsummeaning the back), is the larger, flat, dorso-lateral muscle on the trunk, posterior to the arm, and partly covered by the trapezius on its median dorsal region. Latissimi dorsi are commonly known as "lats", especially among bodybuilders.


Despite being a primary mover for rowing-type exercise (pull-ups), the lats play a large role in spine stabilization.


Erector Spinae


The erector spinæ is a muscle group of the back in humans and other animals, which extends the vertebral column (bending the spine such that the head moves posteriorly while the chest protrudes anteriorly). It is also known as sacrospinalis in older texts. A more modern term is extensor spinae,[2] though this is not in widespread use.


Think of your erectors as support cables for a suspension bridge. They keep you upright, along with help from the other large muscle groups in your back listed here.


Gluteus Maximus


The gluteus maximus (also known as glutæus maximus or, collectively with the gluteus medius and minimus, the glutes) is the largest and most superficial of the three gluteal muscles. It makes up a large portion of the shape and appearance of the hips.


One of the most important muscle groups in your body, not to mention your back, your glutes aid in not only keeping you erect, but bring you back to an erect position from a bent over or squatted position.


Let's go ahead and clear up some common myths or mis-truths about your core.


Working your abs (i.e. crunches) will give you a flat midsection and/or "six-pack."


Without a doubt, one of the most common misconceptions that fitness professionals, strength trainers, and personal trainers come across. This can be explained in 3 parts:

  1. You cannot spot-reduce fat! The truth is, everyone has core muscles, and in fact a "six-pack." If you didn't, you wouldn't be able to sit, stand, walk, climb stairs, etc. Your core stabilizes your midsection, so you have one. The problem people run into is that their muscles don't have any definition because they are covered by layers of body fat (adipose tissue). In order to get a flat stomach and/or visible abs, you need to take a well-rounded approach of eating healthy and exercising regularly in order to lower your body fat percentage.

  2. Core training is not designed to make you lose body fat any faster. Effective core training is designed to make your midsection even more stable than it already is so that the rest of your body can perform better (more functional). If you have a strong, stable core, you can lift more weight, run faster, and just overall train safer and more efficiently.

  3. Doing crunches will work such a small section of your entire core. That is like someone saying that they wish to build big shoulders so they are going to do 20 minutes worth of anterior shoulder raises. Anterior shoulder raises work your anterior deltoids, but in order to have a safe and effective shoulder, there are a wide range of exercises that can, and should, be done to ensure you have healthy, strong shoulders.

All you need to do is squat and deadlift in order to work your core


Yes, research has shown that lifting heavy weights, like the movements used during squats and deadlifts can be extremely effective at activating core stabilizer muscles. In fact, I would argue that deadlifts and squats are far superior to nearly anything else out there in terms of activating your posterior chain.


However, like I mentioned earlier, you are missing out on a lot of effective core strength and stabilization if you are just focusing on squatting and deadlifting. Not only that, but squats and deadlifts are extremely effective at strengthening posterior chain muscles, however, they are less effective at training the entire core, such as those found in the front of the body.


I by no means advocate getting on the ground and doing crunches, in fact, just the opposite. I recommend using a well-designed core training program at least once/week outside of your scheduled fitness regimen to help stabilize and strengthen your core.


Doing crunches is an effective way to develop the core


Well, sort of. Crunches can be one of the ways you work your core muscles. However, they should play a small part when compared to the wide range of exercises used to develop core strength and stability.


Having said that, despite having contracted abs to throw/receive punches, I personally can't think of many sports that require a lot of dedicated rectus abdominis (crunches) work. For most athletes, the relatively small muscle group rectus abdominis acts to stabilize the core and prevent torso/spine over-extension (think of catching an overhead pass), but far more sports utilize rotational strength and power for athletic movements.


Soccer, golf, hockey, and baseball immediately come to mind when thinking about rotational power of the core, but then think about agility sports that may require an athlete to run in one direction while looking and receiving a pass from another direction, such as a football wide receiver.


So, in my opinion, athletes and those of you who wish to exercise and improve your overall health should focus more on core strengthening and training to improve the stability and rotational strength of the core in order to perform better at athletic events which can include exercise itself. And remember, no amount of crunches will ever make your body fat disappear and give you a defined midsection. That requires time, dedication, and a well-designed strength and conditioning program.


Strengthening your core will alleviate back pain


This one may be one of my favourite points on the list for a couple reasons. Not only is this statement so open-ended and vague, but it clearly indicates the common fallacy most people have that when they hear something enough, not only must it be true, but that they can then repeat it to others because of how true it really is.


You may be reading this and have gone through this exact scenario. You tell someone you have back pain and they either a) recommend you take some anti-inflammatories, or b) they tell you to strengthen your core.


I guess be telling you to strengthen your core, they are not entirely wrong by the sense of the word because if we remember back to what exactly makes up our "core," we know that there is more than just the abdominal muscles that make up our core. However, when most people think of alleviating low back pain by strengthening their core, they believe that this means either strengthening their abdominal muscles or their lower back muscles which more than likely won't help.


There are a wide range of factors as to why your back may be sore. Here are just a few of the common examples that affect so many: 

  1. Weak abdominals, glutes, and hamstrings combined with tight hip flexors, quadriceps, and low back muscles can cause what is known as anterior pelvic tilt. This causes a hyperextension (inward rounding of the lower back, butt protrudes) of the the back placing added stress on the muscles and structure of the back. This may be improved by strengthening the abdominals, glutes, and hamstrings as well as improving range of motion (stretching) the low back muscles and hip flexors.

  2. Tight abdominals, glutes, and hamstrings combined with weak low back muscles, hip flexors, and quadriceps can cause a posterior pelvic tilt. This causes a flexion (outward stress on the low back, butt tucks under) of the lumbar spine loading the spine in a way it was not meant to be loaded. This may be improved by strengthening the low back muscles, hip flexors, and quadriceps along with improving the range of motion (stretching) of the abdominals, glutes, and hamstrings.

  3. Individuals may have mild cases of thoracic kyphosis, or a rounding of the upper back. This may be even more present in modern humans due to our penchant for sitting. We sit when we drive, we sit watching television, we are constantly looking down at our smart phones, many of us sit at work for much of the day, etc.

    With a forward head, or a slight thoracic kyphosis, we are mis-aligning our spine, which can have a domino effect causing things like low back pain. Even a slight kyphosis can either cause or exacerbate both anterior or posterior pelvic tilt. This can be remedied by strengthening the posterior chain, including our spinal erectors, latissimus dorsi, rhomboids, trapezius, etc. By strengthening the muscles that make up not only our lower backs, but our upper backs as well, we will have a posture due to a more natural retraction of the shoulder blades, potentially alleviating the rounding of our upper backs.

Ultimately, diagnosing and treating low back pain goes well beyond just doing some crunches and/or holding a plank for 30-60 seconds. A well-trained individual who knows what to look for in postural imbalances will be able to give advice on what to strengthen and where to improve range of motion.


Tyler Robbins
Director of Fitness
Head of CrossFit

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