What does this mean? What exactly is Core?


The area of the body, which is commonly referred to as the core, is your midsection and it involves all your muscles in that area including the front, back and sides. A weak core can lead to injuries. As a Physiotherapist, I see this daily. It often amazes me how people can move when their core is not working. Our body and brain are so smart! A person can function and work with an inefficient core! However, not for long. Injury is extremely prevalent and often inevitable when the core is not working efficiently. Along with this, a weak core can also leave you susceptible to poor posture, and lower back pain. If you’re suffering from these pains, see our services page to learn more about how Restorative Touch Physiotherapy Hamilton can help you. 


How does lower back pain occur?  Abdominal muscles deactivate (or stop working) with low back pain. This does NOT ONLY mean your back is weak and needs strengthening but in many cases, the low back is already overworked and needs support from surrounding muscles.  (Dr. Stuart McGill, 2015). If you’re interested to learn more see our article on lower back pain


The Core is comprised of OUTER and INNER units. 



Outer Unit


The outer unit includes muscles that have an important stability function when the body is under load (lifting weights) or during high-speed movements.


Essentially, the outer unit controls the range of motion, generates movement, and provides gross stability of our spine.

The muscles comprising the OUTER UNIT are:


  • Rectus Abdominus
  • Internal and External Oblique
  • Erector spinae
  • Latissimus dorsi
  • Gluteus muscle group
  • Quadratus lumborum
  • Adductors and hamstring


Inner Unit


These muscles have their origin or insertion at the spine (along the vertebrae) and generate little or no movement during activation. Contraction of these deep core muscles provides segmental stabilization of the spine.


Muscles of the INNER UNIT are:


  • Transverse abdominus (deepest abdominal muscle)
  • Diaphragm (a muscle that assists in breathing),
  • Multifidus (deep back muscle along spine),
  • Pelvic floor (deep muscle helps to prevent urine flow). 



It is important to make note of the importance of the Transverse Abdominus Muscle. Contraction of the Transversus abdominis plays a very important role in inner unit stabilization for the following reasons:


  1. The drawing in of the abdominal wall on Transversus abdominis contraction increases the intra-abdominal pressure.
  2. The Transversus abdominis and internal Oblique are connected to the thoracolumbar fascia. The contraction of these muscles tightens the thoracolumbar fascia like a weight-belt fashion, which offers greater stability. The thoracolumbar fascia attaches to the spinous and transverse processes of each lumbar vertebra. The generated power causes stabilization of each vertebra.


These UNITS work together to provide stability for the entire body. 


What does this mean?


It is important to strengthen both the OUTER and INNER units to obtain maximal stabilization and reduced incidence of injuries, as well as provide a strong system able to handle daily life tasks. 


Here are some exercises of OUTER and INNER core strengthening.