Stability and the Unsung Heroes of Our Body

Last post I wrote about balance. Our human body is a wonder of wonders. And at times I find myself at loss of words to describe the inherent beauty in the co-ordination of muscle work and the fine tuning for nuances in movement patterns. Suryanamaskar in yoga involves alternate spinal movements, synergistic bilateral, and reciprocal movement patterns in a rhythmic symphony, exercising most muscle groups and instilling a sense of overall balance in the body. There, I did it again! (Suryanamaskar enters my posts regularly and with much ease, and well deservingly so). 
Being bi-pedal, trunk stability is key to execution of dynamic movement patterns with less muscular demands and subtle adjustments in small centralized or proximal body movements (for example breathing movements) and greater muscular demands with increasing adjustments needed for movements distally (for example extremity movement in upright postures). In other words, greater the shift of COG of the body during any movement, greater the muscular effort to maintain stability. 
From the perspective of a physical therapist, the abdominals, the back extensors, and the surrounding hip muscles contribute much towards dynamic stability with movement. Hence lumbo- pelvic stability is important to begin any movement and pelvic-hip stability is imperative for weight transfer from the spine to the lower extremity- as in the vrikshasana or standing on one-leg. This ability is very crucial in activities involving single limb stance, such as gait, when weight is shifted from one leg to the other as we move forward. 
When we move, certain muscles have a lower threshold for their activation due to frequent recruitment i.e. muscles that hold us upright in presence of gravity, while others have higher threshold due to infrequent use or activation on demand. Static strength (isometric strength) is to be measured by holding steady in given position and isotonic strength by the ability to lift and move a certain weight. The “seeming paradox” here is that when one holds steady, one moves better. When you look into it, you realize these are in fact complimentary and a steady trunk is a requirement for stable, smooth dynamic movement. Our body is equipped with tonic or postural muscles which support the framework and allow smooth movement through phasic or movement muscles. Postural muscles are closer to the midline or spine and more distally, in the limbs, the joint stabilizing muscles are closely surrounding the joints. These postural or stabilizing muscles are basis of movement and their being in optimal flexibility and tone, enhances the quality of movement. The phasic muscles may have a longer lever arm for efficiency with movement. 
One fresh perspective is that the important muscles are the ones that work involuntarily/ subconsciously and through their health, allow the voluntary muscles to function ideally. Lifestyle, over decades, has been changing steadily and we have begun adopting more seated postures. This employs more of the postural muscles, which we have taken for granted. Those intermittent stretches and change of posture your physical therapist has suggested, are necessary for the health of the postural muscles. What’s more, walking and exercising are necessary also.
The abdominals are big contributors to spinal stability. Wait! Did I not mention earlier that our body is a wonder of wonders? Breathing is an ongoing and involuntary function with the control-center in the brainstem. The diaphragm involuntarily contracts and decreases the pressure in the lungs, thus pulling air in from the atmosphere (inhalation) and when it relaxes, it pushes the air out (exhalation). In upright postures, the lumbar multifidus (LM), being supportive, postural muscle, is active providing posterior inter-segmental vertebral stability. The transverse abdominus (Tr.A), the deepest of the four abdominals, has been scientifically found to be one of the first of the voluntary skeletal muscles to contract when movement is contemplated. And though true in relation to the skeletal, mobility muscles, its contraction intuitively (subconsciously / reflexively) co-ordinates with diaphragmatic and pelvic floor contraction thus forming not only a corset around the abdomen, but also bracing the abdominal organs to provide support. As we all have experienced, this is not something trainable or at voluntary conscious level. Though it may seem sequential, the involuntary-voluntary stabilizing muscle contractions occur with such harmonious synergies, within a few milliseconds that it is mind boggling. This is the wonder of the human body and there are a multitude of speculative articles explaining the sequence in which this occurs, I neither support nor refute any of them. In the true spirit of yoga, we must take charge of the known (voluntary) and leave the results or outcome to that intuitive ability within us. One thing most of the studies agree with is the contribution of the LM, Tr. A, and intra-abdominal pressure regulation through diaphragm in providing stability. Then, it is the support to the spine that must be coordinated with breathing through LM, and Tr. A re-education, by awareness of contraction strength (muscle fiber recruitment speed), isometric holds, positional changes, and functional movement pattern re-education rather than sequence or order of muscle recruitment.
Physical Therapy has not much explored the role of the involuntary muscles and the supportive postural muscles, other than scientifically study its role or actions. I wonder what makes the involuntary muscles work relentlessly to keep us alive ( think of the diaphragm or the cardiac muscle) and the supportive postural muscles work in moving well (LM and TR.A, Obliques). And it is not by chance that the muscles that provide stability are postural muscles that act beyond our conscious awareness! However, we can bring our awareness to these and exercise them at conscious level to make them stronger. What's more, they stay healthy when the voluntary muscles function well. Which is why movement study and re-education is effective in influencing them and making physical therapy interventions effective. Though this is an indirect approach, it does alleviate acute pain and discomfort. Direct approach may be beyond the scope of physical therapy as we currently know it. When one realizes yoga is the root of physical therapy and there is much to explore beyond, one may look into yoga for these answers. For the body is a mere instrument and to explore beyond that, yoga is necessary. 
(To be continued….)

P.S. :- Video edited from following image/video:
https://pixabay.com/…/heart-blood-orga…/
https://pixabay.com/…/lungs-anatomy-me…/