The Mystery of the “Core”
Dr. Bruce Buckman PT, DPT, ART
Dr. Vincent Porta DC
For many, the concept of the “core” is limited to training the six pack abdominal muscles, and while Chuck Norris and The Total Gym as well as many other machines have made millions of dollars claiming to help you achieve a stronger “core”, rectus abdominus and oblique strengthening alone will not reduce your susceptibility for low back pain and or improve your functionality as a human being.
The “core” or inner abdominal unit is a complex group of muscles, some deeper/more superficial/ smaller/larger than others that are incorporated in almost every functional movement of the human body. These muscle stabilize your spine and your pelvis as well as compress your abdominal contents to transfer force from your lower body to your upper body and vice versa. So why then in training core do we perform non-functional exercises such as sit-ups, crunches, planks and side planks? These exercises may be perfect for low level, initiation of core strengthening after injury, but they are not functional, and do not teach you how to properly use your core when moving. The purpose of this article is to identify the core musculature and provide functionally based exercises to help you strengthening your core muscles in order to reduce your risk for injury.
What Muscles are in the Core?
Think of your core as a three dimensional box, or a cube, that has six sides. Each six of these sides represents a muscle that acts as a part of your core. Some of these muscles your will not have heard of, but that does not mean that they don’t exist, nor does it mean that they don’t need to be exercised and strengthened.
Starting at the top of the box, the diaphragm is a dome shaped muscle that separates the thoracic and abdominal cavities. The diaphragm muscle allows for inhalation and exhalation involuntarily. The diaphragm contracts causing negative pressure in the thoracic cavity forcing air into the lungs at the same time as increasing intra abdominal pressure. Thus, breathing becomes an important factor in the activation of the core musculature.
The Pelvic Floor
A group of muscles including the pubococcygeus, illiococcygeus, and ishiococcygeus that makes up the bottom of the box. These muscles, when activated, lift superiorly towards the head and again act to increase intra-abdominal pressure. These muscles, although you may have never heard of them are used every day during urination. Specifically, they activate to assist in empting your bladder and stop the flow of urine out of the urethra.
Deep rotators and stabilizers of the spine, that makes up the back of the box. When activated unilaterally (on one side) rotate spinal segments, when activated together, these 2-4 joint muscles stabilize and aide in the further activation of the larger posterior chain muscles such as the erector spinae and quadratus lumborum. The multifidi have been extensively researched, with findings suggesting that these muscles atrophy and develop fatty deposits by about thirty percent within two days of a low back injury.
The Transverse abdominus muscle plays a key role in the stability of the pelvis and spine acting as the front and sides of the box. Amazingly, this muscle originates on the posterior aspect of the pelvic crest at the lumbar fascia and wraps all the way around the front of the body to the pubic crest and rectus abdominus muscle sheath. This muscle acts as a muscular girdle, or weight belt would around your waistline to increase the stability of your spine through movement.
Diaphragm/ Breathing exercise
While laying flat on the floor, bend at the knees keeping the feet flat on the floor as well. Place one hand over the chest and the other over the stomach. While taking a deep breath in push the stomach out towards the ceiling. While exhaling do the opposite, pushing stomach down towards the floor.
Pelvic Floor Contraction
This exercise is performed by lying in the hook lying position. First place your fingers over the hip bones and rolling the tips of the fingers into the pelvic muscles. Kegels are performed by contracting the pelvic floor muscles, and the most easily described way to perform this exercise is to imagine urinating, and to squeeze as if to stop the flow of urine. This exercise should be held for a period of time (3-10 seconds) depending on tolerance and performed for sets of 3-5.
Bird Dogs For The Multifidi
Starting on all fours, the bird dog exercise, will be performed by raising one arm and the opposite leg in unison. After holding this position for one second the arm and leg will be lowered and the same motion will be repeated on the opposite side.
Side Plank for Transverse Abdominus
The side plank will be preformed by starting out in a side lying positing with the legs extended and the hips stacked. Then with the arm directly under the shoulder he torso will be propped up making sure the spine is in a straight position. This will be held for 20 seconds on each side.
When used in conjunction, during functional movements, the core musculature can reduce risk for low back injury, which as we all know is one of the leading causes of disability in the USA every year. Schedule your appointment today to have your core musculature formally assessed!
DeTroyer A, Estenne M. Functional anatomy of the respiratory muscles. Clin Chest Med. 1988;9:2