Many of my patients have worked with trainers or used workouts found on the internet to help them strengthen their core muscles prior to seeing me for back pain.  Sit-ups on the slant board, crunches, and Roman Chair back extensions are popular core exercises.  Certain yoga poses seem to engage the core to a degree and can offer a kind of introduction to core strengthening as well.  But perhaps the most commonly promoted exercise for strengthening the core is the plank.  Planks are performed by getting into a push-up position (putting your weight either on your hands or elbows) and then holding the legs and torso in a straight line above the floor for a protracted period of time.  

The core can be thought of as having four separate quadrants: front (rectus abdominus), back (lower back and buttock muscles), and left and right sides (obliques and transversus abdominus).  Unlike sit-ups, crunches, and back extensions which each work only one of the four quadrants of the core, planks, when done correctly, engage three of the four quadrants (front and sides).  In this way, planks are a more comprehensive core exercise than sit-ups, crunches, or back extensions.  But there is a bit more to the story and before we rate planks as a core exercise we need to discuss the differences between exercises that involve motion and those that do not.

Exercises that cause muscles to shorten as they contract are referred to as concentric exercises, while exercises that cause muscles to lengthen as they contract are referred to as eccentric exercises.  When you do a push up, the part where you move upward from the ground is powered by concentric contraction of chest (pectoral) and triceps muscles which become progressively shorter the higher up you go.  If you then lower yourself quite slowly to touch your chest back down to the floor, those same muscles progressively lengthen while contracting, resulting in eccentric work.  Planks do not involve movement, so there is neither shortening nor lengthening of muscle fibers.  Exercises that involve muscle contraction without motion (shortening or lengthening of muscle fibers) are referred to isometric exercises.  

Of the three forms of exercise (concentric, eccentric, and isometric), isometric conditioning is the least effective for building muscle strength.  Isometric exercises such as planks are often used in clinical practice as the first phase of rehabilitation because they are a gentler form of exercise and carry less risk of injury when patients are de-conditioned and particularly vulnerable.  Following surgeries or prolonged immobilization, planks, yoga poses, and other forms of isometric exercise can be very useful for establishing base stability safely.  But base stability is insufficient for back health and will not provide a sculpted, chiseled mid-section. 

Kore Power Trainer offers three levels of workouts: Core Stabilization, Basic Workout, and Advanced Workout.  The Core Stabilization routine engages each of the four quadrants of the core in isometric exercise for one minute.  This makes it more effective than planks which do not engage the back quadrant.  Once Core Stabilization becomes easy to do, we recommend that you move to the Basic Workout which involves both concentric and eccentric work.  Four minutes of the Basic Workout, 3-5 times per week, can build sufficient core strength to reduce, eliminate, and prevent many forms of chronic back pain as well as help give a chiseled appearance to the mid-section.  

Though popular in the fitness world (for now), planks actually rank quite low as a core strengthening exercise.  For a truly powerful core and a sculpted mid-section, you must do concentric and eccentric work.  We invite you to try 4 minutes on a Kore Power Trainer.  

The 'core' is a term used to describe several different muscles in the lower back buttocks, abdomen, and sides which function together during bending, lifting, straining, pushing and pulling.  Broad, full-body activities such as these require coordinated work between the upper and lower body with the low back as the connection between them.  Strong core muscles not only help power many of these activities working in conjunction with the arms, legs, chest, and shoulders, but they also support the lower spine.  When core muscles are weak and de-conditioned, the physical stress of lifting, pushing, pulling, etc., can overwhelm them, causing microscopic tearing known as a 'strain' injury.  Even more harmful is the effect that a weak core has on the discs and joints of the lower (lumbar) spine.  When core muscles are strong they act to bolster and support the spine.  In a sense they act like a weight-lifter's belt, encircling the lower back, keeping it strong and tight and absorbing some of the burden of forces applied through the back during heavy activity.  

When core muscles are weak, those forces are transferred exclusively to the small joints and discs of the lumbar spine.  However, these structures are not well designed to bear extreme loads and over time, they too can become overwhelmed.  When a joint is overwhelmed, the ligaments holding them together get stretched and torn.  This is called a 'sprain' injury.  When a person with a de-conditioned core tries to lift a heavy object the forces applied to the lower back can result in both overwhelmed muscles and joints.  We call this a lumbar strain and sprain.  Repeated lumbar strain and sprain injuries take their toll on discs.  Each episode causes microscopic tearing and over time, multiple tiny tears begin to coalesce and form larger tears that ultimately lead to disc herniations.  

Disc herniations occur when the softer material inside the disc (called the nucleus) is squeezed out through tears caused by repeated lumbar sprain and strain injuries.  This nuclear material can wind up trapping nerves causing pain, numbness, and/or weakness down the leg sometimes referred to as sciatica.  Sciatica caused by a pinched nerve is a more serious condition and once discs have herniated, the nuclear material can never be put back inside the disc.  

Ever wonder why people shrink in height as they age?  The most common reason is repeated injury to the intervertebral discs.  Discs act as weight-bearing shock absorbers for the spine, and when they herniate, they lose height.  This diminishes their ability to absorb forces and makes us shorter.  Discs normally bear twice as much weight as the smaller lumbar facet joints, but when they herniate and loss their height more of the weight-bearing function gets shifted to the smaller lumbar facet joints causing them to undergo excessive wear and tear as well.  Osteoarthritis is the body's response to excessive wear and tear.  It consists of thickening of joints to compensate for weakened muscles and damaged ligaments and discs.  A sedentary lifestyle leads to a weak core and a weak core sets the stage for recurrent lumbar strain and sprain injuries, disc herniations, and ultimately, chronic degenerative osteoarthritis.  This is why a core routine is so vitally important!  A four minute core workout on your own bed, 3-5 times per week using Kore Power Trainer can promote and maintain sufficient core strength to support the spine, prevent many lumbar strain and sprain injuries, and slow or halt this process.  Think about it.  Can you commit to 4 minutes of exercise every other day?