Scientific Stretching (Your Brain On Yoga series)

[Originally published on US News Health, 30 October, 2013]

When I began the practice of yoga, I did not yet have a solid and balanced exercise routine. My physical workouts consisted of bouts of jogging, weight lifting and rowing. These activities were inconsistent and generally resulted in increased tightness of muscles all around. I began the practice of yoga asana (the physical postures) by exploring various standard poses (side angle, triangle, warrior, forward bends, etc.), patiently letting the body gradually enter the poses over time in a passive manner. As I entered a more formal era of personal yoga training, I learned that yoga is about how we engage our lives. How can we engage our activities in a more complete manner, bringing online more of our body, mind and spirit in a conscious manner? It was when I began my yoga training with Skanda Yoga in Miami, Fla., that I learned to actively engage the simple practice of stretching in a way that exponentially deepened the limits of what I imagined was possible on a physical level.

Stretching our muscles is an essential component of any healthy workout. Before and after a run, we sink our weight into a forward bend to lengthen our hamstrings, increasing the chances of muscular strain. Muscle tension is a natural function of the body that maintains tendon, and thus joint, stability, by monitoring and protecting the range of muscle extensibility. This tension is maintained in part by the Golgi tendon organ (GTO), an innervated organ made of collagen that connects muscle fibers to the tendons, which then attach to the bone. The nerves in the GTO conduct electrical signals from the muscles through the spinal cord to the cerebellum, a part of the brain near the brainstem that regulates movement, initiating a reflexive contraction that prevents excessive and potentially dangerous elongation of the muscle. A muscle strain or pull happens when, despite the best efforts of the nervous system to maintain muscle tension, overstretching occurs. This is the most common athletic injury, and the most common in yoga asana.

Fortunately, it is possible to hack the stretch reflex of the GTOs in order to stretch more deeply and safely. Normally, we approach stretching in a passive manner, resulting in a rather slow increase in flexibility. By applying an understanding of how this stretch reflex works, we can actively engage stretching in a way that strengthens and stabilizes neuromuscular patterns and memories. We can use a technique called Proprioceptive Neuromuscular Facilitation (PNF) that achieves safe musculotendenous lengthening by first applying a strong contraction to the muscle that is to be stretched. For instance, in trying to stretch the hamstrings, instead of going immediately into a passive stretch, the hamstrings (agonist muscles) are first contracted by actively resisting the stretch for at least six seconds, the minimum time required to offset the GTO stretch reflex. Then one would relax the hamstrings and engage the quadriceps (antagonist muscles) as the hamstrings are lengthened and stretched. This technique can be exemplified by a leg split (also known as Hanumanasana), in which the front knee is initially bent as the foot is pressing into the ground in order to engage the hamstrings, followed by relaxing the hamstrings and gradually straightening the knee and pushing the leg forward. This technique works to retrain the nervous system by activating conscious awareness during stretching and increasing the capacity of the muscles to utilize and store bio-energy.

In my previous post on the Complete Breath, we learned that the inhalation naturally stimulates the sympathetic nervous system and that the exhalation stimulates the parasympathetic nervous system. If we combine constant mild muscle engagement as we stretch, along with conscious breathing, we have what in Skanda Yoga is termed Active Dynamic Stretching. Combining the inhalation with engagement of the agonist muscles (resisting the stretch) and drawing them concentrically toward the core of the body will signal the GTO that there is adequate muscle tension, and that it is therefore safe to stretch. Subsequently exhaling while eccentrically (towards the periphery of the body) lengthening the muscles as we maintain some engagement relaxes the nervous system as a whole and results in a deeper stretch more safely and quickly than if the stretch were simply passive, or without agonist engagement prior to stretching. This technique can be done vigorously with strong muscle energy for gross and observable results, or it can be applied to a softer degree as we enter poses by skillfully pruning the strength of muscular tension. The degree of strength applied should depend on the context and desired results. At first it is useful and motivating to feel the overt physical results of these techniques, and gradually one can apply them more subtly. The Sanskrit language has a term called the spanda that refers to the pulsation or throbbing of consciousness on every level. This is observed in the constant play of opposites – the polarities of inhaling and exhaling, of contracting and lengthening, of engaging and disengaging. Eventually, the stretching techniques can reveal in experience the more subtle principle of the pulsation of consciousness underlying thought, emotions, desires, time and life itself.

Actively stretching in this way is a powerful way to bring greater flexibility into your yoga practice and any athletic activity. It is generally recommended to avoid vigorous stretching before a workout, as it will decrease strength output during the workout and increase susceptibility to injury. It is important to honor our limitations, understanding that persistent and patient discipline rather than rushed pushing paves the way for progress in yoga, whether physical or otherwise. Performing PNF and/or Active Dynamic Stretching after a workout will result in a greater release of muscular tension. It adds greater awareness to the process of stretching by utilizing the biophysical properties of the neuromuscular system to one's advantage, and by creating a deeper link between the physical body, the breath, the nervous system and conscious awareness. Actively approaching our stretching methodology from a scientific and functional perspective becomes a way of more completely and consciously engaging our physical activity. This is our yoga.