I was recently asked by one of my clients why core strengthening is a key part of my training repertoire. Thinking about that question and how to answer it without getting into a clinical explanation, I came back with the most honest answer - because the core is the foundation of the body - when you build a house, the stronger the foundation the stronger and more stable the house.
Now, to a more involved response as to the necessity of training your core. An individual's core consists of the lower back (lumbar spine), mid back (thoracic spine), and neck region (cervical spine), as well as the hips and the pelvis. Essentially, the core is the torso minus the arms and legs and as a result of it's position in the middle of the body, the core serves as a link that allows for the transfer of energy between the upper and lower extremities (arms and legs). When the core is functioning optimally, it allows the individual to produce strong, functional movements of the extremities. The lack of a strong core results in inefficient movement, limiting the client who may experience loss of balance which can lead to injury.
The musculature of the core is divided into two categories: The stabilization system and the movement system. Although it is key to strengthen the muscles of both systems, it is important to first strengthen the stabilization system as this will help you to move most efficiently.
Stabilization system exercises involve little motion through the spine and pelvis such as various plank exercises. Movement system exercises involve movement of the spine through a full range of motion like a ball crunch or cable rotations. A core workout will involve more than one muscle group, thus showing results that much faster. Remember, it is key to improve your core, creating a natural corset that supports your spine and body and ultimately strengthens your entire body.