Ask any instructor and she/he will tell you that Essentrics is a "full-body rebalancing workout." While "full-body" is obvious "rebalancing" may be abstract for some. So what exactly does the latter mean?
Strength vs. Flexibilty
When we think of "balance" we think of equilibrium; we think of equal weight or evenness between two sides. In terms of muscles, "balance" means evenness between strength and flexibility:
"If strengthening were the masculine side of fitness, then stretching would be the feminine; they would be the alpha and omega or each other. As the two most basic forces in nature, one cannot exist without the other." - Miranda Esmonde-White, Essentrics co-creator
While this makes intuitive sense, some of us might still wonder: what does it mean physically to balance between strength and flexibility? Let's look at this question in more concrete details.
Muscles are stretched even at rest
The human skeleton is a structure that provides support, but it doesn't move. Our skeletal muscles move and carry it by contracting and extending, producing motions. These skeletal muscles have a resting length, the length when there is no movement - no contraction, no extension.
By default, skeletal muscles are all stretched even at rest, whether we are simply standing or lying in bed. This is because skeletal muscles are striated and attached to bones via tendons at opposite ends. There is always a degree of stretched tension in our muscle fibers at resting length, which allows us to contract and produce force, or to extend and lengthen further - think of a rubber band that is moderately stretched. It can go either way by extending or contracting further.
Best resting length allows for maximum strength and flexibility
This degree of tension at resting length determines how much skeletal muscles can shorten or lengthen when we move. As mother nature would have it, when our skeletal muscles are normal and healthy this tension at resting length generates maximum strength and flexibility. More precisely, at this length and tension our skeletal muscles can contract as much as 25% and extend as much as 60% to 75%. This is our best resting length, the length we target in muscle rebalancing. Any length above or below best resting (due to bad posture, muscle habits, or injury) will compromise our strength as well as our flexibilty.
Best resting length means optimal overlap of protein filaments
For most of us, the explanation above would probably suffice. For those of us who wish to dig deeper, we can look at muscles on a microscopic level. Muscles comprise of sarcomere bundles which consists of millions of myosin and actin protein filaments.
At ideal length, there is some overlap between myosin and actin filaments (as shown above). This allows myosin to attach to actins and pull them closer, producing contraction and force. Conversely, when actins slide away from myosin, overlap decreases and muscles extend/stretch.
If there is too little or too much overlap between our myosin and actin at rest, then our muscles are imbalanced. Our strength and flexibility are compromised.
Muscle rebalancing - restoring muscles to optimal length and tension
The best resting length of our skeletal muscle fibers is what we address in Essentrics. We use dynamic stretching movements and various techniques to gradually and effectively restore and rebalance our skeletal muscles to their ideal length so we gain maximum strength and flexibility.
Restoring and maintaining this length-tension relationship involves our central nervous system. We therefore incorporate neuromuscular techniques in our workouts. When every muscle fiber reaches its ideal resting length, the result is not only a balance between strength and flexibility, but a distinctive, wonderful feeling of simultaneous looseness and strength. This is why we work every muscle in every Essentrics workout!