Today I’m going to go through in detail about the 3 different types of muscle fibres and their characteristics and hopefully that can help you understand how to recruit the core muscles when doing exercise. We are also going to find out how to distinguish between the deep stabilizer muscles compared to the other types of muscles that we use. Very often, we mistake our core muscles for our abs or some muscle that’s deep in our pelvis but our core muscles are essentially everywhere in our whole body and their job is to stabilize and support our skeletal system (bones).
3 groups of functional classification in muscles – Level 1, 2 and 3
Level 1 a.k.a Local Stabilizers
These are what our core muscles are, our deep stabilizers or level 1 muscles. They are predominantly Type 1 fibres which means that they are slow-twitch and great for long, low level endurance work and usually cross a single joint. They lie deepest to the joint/bone not just in the abs/pelvis but everywhere! They are highly anticipatory and should work/fire before any action of the muscle occurs. In other words, they should turn on as you prepare to move. They are also active through any movement regardless of direction and they control shearing and translation of forces acting on your joints.
An example of this muscle is your Transverse Abdominis.
To activate these muscles, ideal conditions of the exercises include:
1. Being in close kinetic chain, meaning that your hands and feet should touch the floor.
2. Low load, no resistance or weights.
4. Slow speed
5. Close to a neutral position of your spine.
Level 2 a.k.a Global Stabilizers
These muscles lie superficial to the Level 1 muscles and they are best understood as movement stabilizers. Their activity is dependent on the direction of movement of the muscles. Their job is to hold the big chunks together i.e. connecting the rib cage and the pelvis in a functional relationship and to control deceleration and load transfer. They usually consists of Type 2a muscle fibres and work best at a moderate level load or moderate speeds of movement. They can take load but can’t control segmental movement by itself.
Examples of Level 2 muscles include the obliques and the VMO.
To train global stabilizer muscles, the initial phase should involve isolation and disassociation, meaning keeping one part of the body still and stable while moving another part of the body.
Ideal conditions to recruit these muscles are:
2. Low to moderate load
3. Slow to moderate speed.
4. Close to neutral joint position.
5. Proprioceptive challenge.
6. Isometric or eccentric contraction of muscles.
Level 3 a.k.a Global Mobilizers
These muscles are your big strong, power and speedy muscles that is most superficial in the body. They consist of predominantly fast twitch type 2x muscle fibres and usually cross multiple joints and perform multiple functions. However, they fatigue more easily than Level 1 muscles. Because of the size and length, they are capable of producing more force, more quickly and can be recruited under high load and high speed of movements.
Examples of Level 3 muscles are your Gluteus maximus, pectoralis major, rectus abdominis.
Ideal conditions in exercise to promote global mobilizers are:
1. Open kinetic chain – for example feet in the air in tabletop or long diagonal
3. High load – adding weights
4. More complicate coordination
Now that we know the difference between the 3 muscle types and what they do, it’s really important to now recruit them in the correct order and to make sure they are doing its job accordingly. In a dysfunctional system, the local stabilizers/Level 1 typically switch off, the global stabilizers/Level 2 will have decreased force production and the global mobilizers/Level 3 will try to do everything from stabilizing to moving the joints when they are not meant to stabilize. This will cause spasm, trigger points and knots, and muscle tightness leading to an injury or an overworked muscle.
So now at the start of every exercise, slow down and take the time to really recruit those deep stabilizers/Level 1 muscles first. Always do a warm up – breathing and exercises on the foam roller/Bosu/Fitball will assist with core activation and anything that will warm up and move the spine. Keep checking back for more specific pilates exercises that you can try at home to wake up those deep stabilizers/core muscles that will help you move better and prevent injuries and I hoped that this helped you understand what core muscles really mean.