One of the most basic elements of learning body awareness for things like posture, injury prevention, and proper movement is learning which muscles perform certain actions. For example, we have fast twitch muscles and slow-twitch muscles.

Fast Twitch muscles are our strength, speed and power muscles. Think pecs, biceps, and triceps. Slow twitch is where it gets interesting. Slow twitch muscles are our fatigue-resistance, high endurance muscle fibers. Fundamentally, every muscle is comprised of a mixture of fast and slow twitch muscles -- the legs are a terrific example of this. But some muscles are slow twitch only! What does that mean?

Slow twitch only muscles are the "core" muscles of our body. Meaning, they should be firing at all times, with every function our body performs. What muscles are they and why is this so important to understand?

The slow twitch only muscles are our Transverse Abdominis (underlying abs), Erector Spinae (lower back), Soleus (lower calf). These 3 muscles are responsible for keep us upright and supporting our posture and functional movements.


  • Transverse Abs -- works with the Erector Spinae to support and stabilize the spine. It is our "natural belt" that helps compress our abdomen.
  • Erector Spinae -- supports our lower back and allows us to extend our back. When they Transverse Abs are weak, the Erectors will attempt to take over -- this is often a major cause for chronic lower back pain.
  • Soleus -- supports the arch in our feet and our gait. A week soleus will often result in flat feet, and increased pressure on the body while walking/running (think shin splints).


My challenge to you this week is, focus on these 3 muscles while doing any physical activity. Can you feel them activating? Can you keep them activated while performing Deep Breathing? As you pay more attention to these muscles, what changes do you notice to your body while you exercise?