Facilitated stretching is the most powerful method for creating length in muscles and, thereby, depth in yoga poses. It makes use of a nerve receptor that is located at the muscle-tendon junction called the Golgi tendon organ. This receptor senses changes in muscle tension and informs the central nervous system (the spinal cord) when this tension increases. The spinal cord then signals the muscle to relax—a phenomenon known as “the relaxation response.” All of this works like a circuit breaker and serves to protect the muscle tension from rising to a level that might tear the tendon from the bone. The Golgi tendon organ, sensory nerve, spinal cord interneuron, and outgoing motor nerve to the muscle are collectively known as a spinal cord reflex arc (FIGURE 1).
You can use the relaxation response to gain length in the contractile elements of muscles. This increases your flexibility and helps to deepen the poses. This process has several steps:
1. First take the muscle group that you are targeting out to a point where it is fully stretched. This is known as the muscle’s “set length.” Stretching the muscle produces tension at the muscle-tendon junction and stimulates the Golgi tendon organs.
2. Maintain the muscles in a stretched position. Then contract the same muscles that you are stretching. For example, if you’re stretching the hamstrings, attempt to bend the knees to engage them. This creates tension at the muscle-tendon junction from two sources: 1. The biomechanical process of stretching the muscle and 2. The physiological process of contracting the same muscle. This combination stimulates more Golgi tendon organs and produces a powerful relaxation response.
The Golgi tendon organs will signal the spinal cord of this increased tension, and the spinal cord will signal the muscle to relax. Basically, you consciously override the relaxation response for a brief period by contracting the muscle that you are stretching.
3. Then stop contracting the stretching muscle and “take up the slack” created by the relaxation response by going deeper into the pose. Make sure you engage the agonists that stretch the target muscle. For example, if you’re stretching the hamstrings, contract the quadriceps to take up the slack. This extends the knees and has the added benefit of augmenting the relaxation response with reciprocal inhibition of the hamstrings, further relaxing them.
FIGURE 1 Spinal Cord Reflex Arc
FIGURE 2 Try this in Parivrtta Trikonasana by first pressing the hand into the side of the foot to lever the trunk into the twist. Do this by pronating the forearm (pronators teres and quadratus), straightening the elbow (triceps), and pressing against the foot from the shoulder (deltoid). At the same time, externally rotate the back hip by contracting the buttocks (gluteus maximus and medius). A cue for engaging the buttocks is to attempt to drag the back foot away from the front on the mat.
These actions turn the trunk and stretch the lower-side internal oblique, rectus abdominis, upper-side external oblique, upper-side quadratus lumborum, and spinal rotators, taking these muscles out to their set length.
FIGURE 3 Maintain the stretch by pressing the hand against the foot and turning the back leg; then attempt to turn the trunk out of the pose. Do this by isometrically contracting the abdominals and back muscles. Use no more than twenty percent of your maximum force as you attempt to turn the trunk. This engages the muscles that were illustrated as stretching in Figure 2 (shown here in blue for contraction). Hold the contraction for five smooth breaths and then prepare to stretch the same muscles and deepen the pose. This is an example of a kriya (action/activity) in yoga.
FIGURE 4 Next, take up the slack produced by the relaxation response. Do this by re-engaging the same muscles you used to get into the stretch while relaxing the abdominal and back muscles. Note how you can now go deeper into the twist.
Use a variation of this technique by combining poses that stretch similar muscle groups. For example, on the next page, we illustrate using a facilitated stretch in Kurmasana to target the back extensors. Then we take advantage of the increased length in the muscles to deepen Prasarita Padottanasana.
FIGURE 5 Place the arms under the legs in Kurmasana (Tortoise Pose). Engage the quadriceps to straighten the knees. This will hold the arms and trunk in flexion and is an example of connecting the upper and lower extremities. Contract the biceps to maintain a slight bend in the elbows to protect them against hyperextension.
Flexing the trunk takes the erector spinae and quadratus lumborum out to their set length, stretching these muscles and creating tension at the muscle-tendon junction. This is the first part of the facilitated stretch.
FIGURE 6 Now, attempt to arch the back and sit up (while holding your trunk in flexion with the quadriceps). This eccentrically contracts the spine extensors and recruits more Golgi tendon organs to fire. Maintain your attempt to arch the back for five to eight breaths, and then activate the rectus abdominis to flex the trunk (this produces reciprocal inhibition of the back extensors, relaxing them). Contract the quadriceps to straighten the knees and press down on the arms, deepening the pose. Come out and take Dandasana for a few moments to balance this intense stretch with a gentle contraction of the back extensors.
FIGURE 7 Take Prasarita Padottanasana. Pronate the forearms to press the palms into the mat, fixing them there. Then bend the elbows by engaging the biceps. At the same time, attempt to “scrub” the hands forward, as if you were going to raise the arms overhead. This activates the anterior deltoids. Squeeze the abdomen and straighten the knees by contracting the quadriceps. Note how preparing the back extensors with a facilitated stretch in Kurmasana allows you to go deeper into Prasarita Padottanasana.
