This article was originally published in Magnolia Magazine
One of the most misunderstood “terms” in fitness is “The Core”. This is a very complex topic which I will split into two sections within this post. In part 1 we will discuss several ways the core is described and part 2 will cover some general core training concepts.
PART 1
I often see people in the gym doing endless crunches. When asked why they will often say “I’m trying to protect my lower back by strengthening my core”, but in actuality they are really just working their “abs” (primarily the rectus abdominis i.e. “six pack” muscle).
The thing is, you can have a “six pack” and still have plenty of back pain issues. In fact folks who do an overabundance of “crunching” exercises commonly create muscle imbalances which can actually lead to, or in the least, exacerbate lower back issues. In fact I have completely discarded crunching movements both for my own training and for my personal training clients and Boot Campers. I have replaced these with much safer core stability exercises which have eliminated the risk, increased the rewards from a functional standpoint, and yet still give the same basic results aesthetically.
Stuart McGill, a world renowned spinal biomechanist/author from Canada has written extensively about the dangers of too much spinal flexion (such as “crunching” movements), on the intervertebral discs. These discs are like cushions located between each of the vertebrae of your spine. Injuring one’s discs can lead to debilitating and long term physical issues often requiring surgery. The last thing we should ever do is risk damaging these critical structures through bad choices in our exercise program!
In fact, not only are spinal flexion movements a bad choice but also exercises that force rotation on the lumbar spine (i.e. lower back). The lumbar spine’s total rotational degrees are around 13 from top to bottom according to well known Professor of Physical Therapy Shirley Sahrmann. Therefore, placing rotational shear forces on it is a very bad idea. Twisting crunches, a very popular exercise, should be especially avoided since they combine both spinal flexion and rotation.
So what IS the core?
That is actually a very good question because there is no one clear cut definition. I wanted to share several of the diverse descriptions one may encounter from various reputable resources. What follows will illustrate the complex nature of trying to define the core and the need to have a well rounded training program to properly develop it (i.e. not just “bunches of crunches”).
According to ACE (American council on Exercise) Personal Trainers Manual 4th edition, the term “core” generally refers to the muscles of the lumbo-pelvic region, hips, abdomen, and lower back.
The NASM (National Academy of Sports Medicine) Essentials of Personal Fitness Training 3rd edition, describes the core as the lumbopelvic-hip complex, the thoracic and cervical spine, where the body’s center of gravity is located and all movement begins.
It further states that there are 29 muscles that attach to the lumbo-pelvic-hip complex.
Mike Robertson, well known Corrective Exercise/Performance Enhancement specialist, describes the core as a BOX with:
· The diaphragm on the top
· The pelvic floor on the bottom
· The abdominals (rectus abdominus, transversus abdominis) in the front
· The back muscles (spinal erectors, multifidi) in the back
· The lateral stabilizers (quadratus lumborum, internal and external obliques) on the sides.
He also mentions how muscles like the gluteals and lats play an integral role in stability as well.
Mark Verstegen, world class strength and conditioning coach and author of the “Core Performance” book series refers to “the pillar”. This includes the muscles of the front and back of the torso plus the shoulders and hip musculature (imagine a statue missing the arms and legs, what remains would be “the pillar”).
Ground breaking fitness author/teacher Paul Chek long ago wrote about the core as having an “inner” unit and “outer” unit. He uses a helpful visual image of the mast of a ship.
The Inner Unit (the “stabilization system” of the pelvis and spine) are the deeper core muscles and function like the small “guy wires” that run along the mast and connect it from segment to segment (like the small muscles of the spine that connect vertebrae to vertebrae along with other deep spinal muscles). Without those smaller wires creating intersegmental support it would be very difficult for the larger wires to withstand strong forces.
The Outer Unit are the larger abdominal and back musculature, which are closer to the surface of the body (i.e. “superficial” muscles). These function like the larger guy wires which are connected from the top of the mast, run diagonally, and are anchored a distance from the mast.
These muscles are sometimes referred to as the “movement system”. However this is somewhat misleading since the “outer unit” muscles contribute significantly to stabilization. In fact, the muscles of the core, even the “abs”, primarily function as stabilizers in day to day life and actually resist various forces in order to protect the spine as opposed to creating movement.
PART 2
Now I'd like to explain some ways of training the core that work from the standpoint of core stabilization. We will focus on exercises that actually resist spinal extension, lateral flexion, and rotation. Having this ability will go a long way towards keeping your spine safe. This will also provide a stable base that will allow the extremities to produce force in order to carry out various activities. When working efficiently, the deep muscles of the core should activate before the muscles of the extremities.
Exercises (I will post some links at the bottom that have demonstrations of core exercises)
Bird-dog (anti-rotation/anti-flexion): The Bird dog is performed starting on all fours. This is called the Quadruped position. The basic execution of this exercise is to extend the opposite arm and leg away from the center of your body. Your head and neck should remain in line with your spine.
This exercise can be modified by first just lifting one hand and then one leg at a time. You can then progress to just barely lifting the opposite arm and leg, eventually working up to the full expression of the exercise. The idea is to extend the limbs without allowing the torso to rotate or collapse into a forward flexed position. This exercise also works the muscles of the back, hips and shoulders, which are all technically part of the core.
Forearm Plank (anti-extension): The idea of this exercise is to keep your body straight like a plank of wood. It is performed by placing your forearms on the ground with the hands in a “thumbs-up” fist position. You want to make sure your elbows are lined up directly below your shoulders.
The full version of this exercise would be performed on your toes. You can also modify the plank by performing it on your knees. The idea of this exercise is to keep the belly from sagging downwards which would place your lower back into an overly extended position. You also want to make sure you don’t arc your hips upwards which would remove much of the stabilization challenge to the core musculature while also reinforcing bad postural positioning.
The muscles of the shoulders and hips should be strongly engaged as well. A good cue is to squeeze your gluteals in the back and contract the hips and thighs in the front (this is called a “co-contraction). Keep your head and neck in line with your spine at all times. Typically you will hold this position statically for time. Start with 8-10 seconds eventually working up to 60 seconds. When you reach this point, you can make the exercise more advanced by lifting one leg at a time to increase the stabilization requirements.
Side Plank (anti-lateral flexion): The Side Plank works the lateral (side) flexors of the torso and abductors of the hip (which are the muscles that lift your leg to the side). It is performed by first lying on your side with your elbow bent with your hand in a thumbs-up fist position. Your shoulder should be directly in line with your elbow. You then lift upwards bringing your legs,hips and torso off of the ground. Make sure you keep your head and neck in line with your spine and do not allow your torso to rotate forwards or backwards.
The full version of the side plank would be to have your feet stacked one upon the other. Modifications include having both knees bent, the bottom leg bent with the top leg straight, or both legs extended straight but with the top leg staggered in front of the bottom leg.
Like the Forearm Plank start with 8-10 seconds and work up to 60 seconds over time. Side planks can also be performed for repetitions by lowering down and back up again. Ideally, try not to lower completely to the ground between each repetition.
GROUND BASED EXERCISES
Unilateral rows and presses: There are many ways to work the core in combination with other muscles. Two of my favorites are Standing Rows and Presses using anchored elastic resistance (my favorite) or a cable machine. By standing in a Split Stance Position (one foot in front of the other), and performing pressing and rowing movements you engage your entire kinetic chain from the feet through the hips and torso, along with the primary mover muscles.
You can perform these exercises bilaterally (both arms at the same time) or unilaterally (one arm at a time) which impacts the stabilization requirements of the core in a different manner. Bilateral Pulling (i.e. rowing) movements will work the core in anti-extension, Bilateral Pushing movements (presses) will work the core in anti flexion, and both unilateral pulling and pushing movements will work the anti-rotation function of the core as well.
This type of training approach was briefly introduced in my article on Functional Training where I discussed the concepts of “Ground Based Training” and “Stabilization Limited Training”. This is a great way to get more “ bang for your buck” in your training program by training several strength components at one time.
One is only as strong as their weakest link. If that weak link is one’s core then that will always limit how safely and effectively you will be able to perform various activities whether in daily life or recreational/athletic activities.
LINKS TO VIDEO OF CORE EXERCISES
Craig Ballantyne: Plank, Side Plank, and Bird Dog
Split Stance Cable Row (Mike Robertson)
Split Stance Cable Push (Mike Robertson)
Stuart McGill: Core Values (Note: this has an advertisement before playing the featured video, it also shows several other excellent core exercises)
Scott Fishkind/Time4You Fitness
http://www.time4youfitness.com