It’s an overused but misunderstood word. The core doesn’t really have a medical determined set of muscles hat categorically define it. For me it’s everything that is not arms or legs. Whatever your definition it should definitely include the deep muscles of the Psoas, Quadratus Lumborum and all of the pelvic floor. It should also include the group of muscles known as erector spinae.


A huge amount of back problems could be avoided by focusing more on building these deep core muscles. Abdominal work is often included in a workout programme but is usually movement based. The deep core muscles are predominantly fixator muscles. This means they are responsible for holding you in a fixed position. They do this through Isometric contraction.




isometric contraction


Muscles work in three ways. Concentric when the muscle is shortening, think of the bicep as you lift a weight towards yourself. Eccentric the same motion but in reverse: As you lower the weight back to it’s starting position the muscle controls the descent but is lengthening, this is an eccentric movement. If you stop but keep the weight held up, the muscle is working to hold it in position. This is an Isometric contraction.

The deep core muscles are working isometrically all the time to keep you upright but also to transfer the weight as you move, keeping you upright through motion.

isometric core contraction


If you spend all day sitting at a desk, your deep core muscles; especially in the front are not working. The majority of the work is being transferred to the lower back? Back ache? No wonder!

Working these deep core muscles isometrically, strengthens them which helps them work fro longer before becoming fatigued. It also helps the rest of the muscles become more actively recruited and work together.

If you work in a office, the best thing you can do ….is leave! The next best thing is to get up and move around, making sure you engage as many muscles as possible, whilst allowing the fatigued ones to switch off.

More information is contained in the video. Bruce Lee was an advocate of isometric training Here are some excellent examples of some deep core exercises


Every condition is different, for a full assessment and advice on what you can do to improve your pain, stiffness or flexibility come and see me.

Jason 07980 339 864