“. . . according to the Yoga Sutra (3.1), the term [Bandha] refers to the ‘binding’ of consciousness to a particular object or locus (desha), which is the very essence of concentration.”
Georg Feuerstein

The Mind—Body Connection in Yoga

Many of the benefits of practicing yoga cannot be explained by modern Western science—especially the mystical aspects. Nevertheless, an advantage of approaching yoga scientifically is that we can often identify elements of the practice that produce a benefit and then use our knowledge of science to amplify the effect. 

In today’s post we’ll take a look at the neuroscience behind the way the brain “sees” the body. Our video illustrates the “motor homunculus.” This is a visual map of the proportionate representation of the body in the brain. It is derived from the work of Dr. Wilder Penfield, a renowned Canadian neurosurgeon. He developed this map by stimulating regions of the brain in epileptic patients during surgery and then documented what parts of the body were affected. Dr. Penfield’s work was a pioneering contribution to medical science. It was original, elegant in its simplicity, and has stood the test of time.

How to Lengthen the Hamstrings in Janu Sirsasana

In our previous post, we discussed how tight hamstrings can produce hyperflexion of the lumbar spine in forward bends such as Uttanasana. We also illustrated how releasing the hamstrings can aid to prevent this problem. Today we’ll show you a simple, yet powerful technique for using a spinal cord reflex arc to create length in the hamstrings.

Spinal Cord Reflex Arcs 
Spinal cord reflex arcs are composed of a sensory nerve receptor located at or near the muscle, its connection via a nerve to the spinal cord, an interneuron within the spinal cord, and an afferent nerve back to the muscle. The reflex arc we want to use to gain length involves the Golgi tendon organ. This receptor is located at the muscle-tendon junction and senses changes in muscle tension. The Golgi tendon organ signals the spinal cord when tension increases. The spinal cord then tells the muscle to relax. In essence, this reflex arc creates “slack” to relieve tension at the muscle-tendon junction and helps to prevent the tendon from tearing.

Golgi tendon organ spinal cord reflex arc

Proprioceptive Neuromuscular Facilitation (PNF)
Sports medicine experts long ago perceived that this particular reflex arc could be carefully manipulated to lengthen muscles. Using this knowledge, they invented a technique called proprioceptive neuromuscular facilitation (PNF), or facilitated stretching. It is the most powerful method for gaining length in muscles to improve flexibility. Yoga uses stretching, so why not use PNF in our practice to deepen the asanas?

How Tight Hamstrings Affect Your Lumbar Spine

Hello Friends,

Here's a quick 2016 update from the science literature on your hamstrings...

Biomechanically speaking, tight hamstrings can affect the position of your pelvis, especially in forward bends. This can, in turn, affect your lumbar spine because tight hamstrings produce a pull on the ischial tuberosities and tilt your pelvis back (as shown below in figure 2).

Adjacent joints move in what is known as a “coupled” fashion. When the pelvis tilts back, the lumbar vertebrae flex forward. This means that if the hamstrings are tight and we bend forward in Uttanasana, more of the flexion comes from the lumbar spine. Conversely, when the hamstrings are flexible, the pelvis can tilt forward, allowing the forward bend to come from the hip joint, rather than the lumbar spine.

This interaction is known as spino-pelvic rhythm and is how the pelvis and lumbar spine move in relation to each other. Ideally, we want to have have a forward bend come predominantly from pelvic movement (pelvic dominance) rather than from the lumbar (lumbar dominance).

To this end, I wanted to share a couple of articles from the recent science literature relating to how tight hamstrings affect your pelvis and lumbar spine. The first one discusses spino-pelvic rhythm in relation to the hamstrings. These researchers investigated forward bends (essentially Uttanasana) in subjects with tight hamstrings vs flexible hams.

What they found was...

"The lumbo-pelvic-rhythm comprises 2 patterns—lumbar dominant and pelvis dominant. In flexible subjects, pelvis movement was dominant. In conclusion, improving tight hamstrings may reduce lumbar loading thereby reducing low back pain."

And in a subsequent article they concluded that:

"Dynamic stretching could change the spino-pelvic to a pelvis-dominant motion, indicating that flexible hamstrings are important for preventing low back pain."

Yet another article reported that:

Hamstring stretching exercises performed in the working place are effective for increasing hamstring muscle extensibility. This increase generates a more aligned thoracic curve and more anterior pelvic inclination when maximal trunk flexion is performed."

(click on the references below to read the articles)

Figure 1 shows what happens with flexible hamstrings...

hamstrings releasing in uttanasana
Figure 1: This illustrates how stretching the hamstrings releases the pull on the ischial tuberosities,
permitting the pelvis to tilt forward into anteversion. This is known as femoral pelvic rhythm.

Figure 2 illustrates what happens when your hamstrings are short or tight...

tight hamstrings in uttanasana
Figure 2: Uttanasana: tight hamstring drawing pelvis into retroversion and
coupled movement of lumbar spine into flexion. This is lumbar pelvic rhythm.

As the research demonstrates, stretching your hamstrings can help take the strain off of the ligaments and disks of the lumbar spine. Click here to read more on this subject. Click here to read about the role of the thoracolumbar fascia and the core muscles in protecting the lumbar. Click here for some cool information on gaining flexibility in your hamstrings as well as the myofascial connections between your hammies and your feet. (This shows how everything is connected...)

Figure 3 illustrates the intervertebral discs bulging during lumbar flexion.

bulging lumbar intervertebral discs
Figure 3: Lumbar spine in hyperflexion illustrating bulging discs.

Here's a quick review of the anatomy of your hamstrings...

The hamstrings comprise three separate muscles—the semimembranosus, semitendinosis, and biceps femoris. The biceps has a long and short head. The semimembranosus, semitendinosis, and long head of the biceps originate from the ischial tuberosities (sitting bones). The short head of the biceps originates from the back of the femur (thigh bone). The semimembranosus and semitendinosus insert on the inside of the tibia (lower leg). The two heads of the biceps join into one tendon that inserts onto the head of the fibula at the outside of the knee. The main action of the hamstrings is to flex the knee. Secondary actions include extending the hip and rotating the knee.

An excerpt from "Yoga Mat Companion 1 - Anatomy for Vinyasa Flow and Standing Poses".

An excerpt from "Yoga Mat Companion 1 - Anatomy for Vinyasa Flow and Standing Poses".

Thanks for stopping by. Click here to browse through our books for more key information on anatomy, biomechanics and physiology related to your yoga practice! See you later this week for a QuickQuiz on your hamstrings...


Ray Long, MD

1Hasebe K, Sairyo K, Hada Y, Dezawa A, Okubo Y, Kaneoka K, Nakamura Y. “Spino-pelvic-rhythm with forward trunk bending in normal subjects without low back pain.” Eur J Orthop Surg Traumatol. 2014 Jul;24 Suppl 1:S193-9.

2) Hasebe K1,Okubo Y, Kaneoka K, Takada K, Suzuki D, Sairyo K. "The effect of dynamic stretching on hamstrings flexibility with respectto the spino-pelvic rhythm." J Med Invest. 2016;63(1-2):85-90.

3) Muyor JM1, López-Miñarro PA, Casimiro AJ. “Effect of stretching program in anindustrial workplace on hamstring flexibility and sagittal spinal posture ofadult women workers: a randomized controlled trial.” J Back Musculoskelet Rehabil. 2012;25(3):161-9.

How to Use the Abdominals to Release the Back in Uttanasana

I used to quote the writer, Emily Dickenson, as saying, “See the world in a grain of sand…” Then a friend of mine explained that, actually, the quote was by William Blake.
So much for this surfer dude acting cultured . . .

Anyway, the point is that many of the things we learn in one pose can be applied to another.  Similar muscles work in Paschimottanasana as in Uttanasana (with variations).  Physiological principles, such as reciprocal inhibition between agonist and antagonist muscles, also apply across the board for other skeletal muscles. I find that when we approach learning in this way, it makes what appears to be a daunting subject like anatomy more manageable.
reciprocal inhibition in uttanasana
Abdominal muscles contracting to produce reciprocal inhibition of the erector spinae.

For example, let’s look at using the abdominals in Uttanasana. The abs are composed of four muscles. Moving from the surface inward, we have the rectus abdominis in the front and the external obliques on each side. Deep to these are the internal obliques, with the deepest layer being the transversus abdominis. Contracting these muscles flexes the trunk forward and increases intra-abdominal pressure (by squeezing the abdominal organs). Bending forward from the trunk stretches the erector spinae of the posterior kinetic chain. The erector spinae comprise three columns of muscles that lie parallel to the spine. From medial to lateral, these are the spinalis, longissimus, and iliocostalis.

How to Use Nutation to Refine Uttanasana, Part III—A Fringe Benefit

In our last post, Part II of this series on Uttanasana, we gave a trick for engaging the tensor fascia lata (TFL) and gluteus medius. Contracting these muscles allows us to access movement at the sacroiliac joint and aids to protect against hyperflexion of the lumbar spine.

gluteus medius and tensor fascia lata in uttanasana
Countering external rotation of the
 femurs with the gluteus medius
and tensor fascia lata.
Now, when we do a forward bend from the hips, the gluteus maximus stretches. This produces a pull on the femurs that can externally rotate them and turn the kneecaps slightly outwards. Ideally we would like the kneecaps to face directly forward. An added benefit of engaging the TFL and gluteus medius is that it internally rotates the thighs. The gluteus minimus contributes to this action when the hips are flexing. This counteracts the pull of the stretching gluteus maximus and brings the kneecaps to face forward—the optimal form of the pose. Access this fringe benefit by fixing the feet on the mat and gently attempting to drag them apart.  Feel how this internally rotates the thighs.

How to Use Nutation to Refine Uttanasana, Part II—the Tensor Fascia Lata and Gluteus Medius

In the last post, I talked about how masters of various disciplines are continuously refining their art—even though they are masters. I followed the anecdote with some background information on sacral nutation. In this post I will give you a tip on how to use the tensor fascia lata and gluteus medius muscles to create some opening for movement that can incrementally deepen your forward bends, especially Uttanasana.

freeing the sacroiliac joint in uttanasana
Freeing the sacroiliac joint using
the gluteus medius and
tensor fascia lata.
The tensor fascia lata (TFL) and gluteus medius are muscles at the sides of the pelvis. The TFL originates from the front of the iliac crest and inserts onto the iliotibial band and from there onto the outside of the front of the tibia. The gluteus medius originates a bit farther back on the iliac crest and inserts onto the greater trochanter at the top of the femur (thigh bone). The main action of these muscles

How to Use “Nutation” to Refine Uttanasana—Part I

Many moons ago I had the privilege of spending an extended period studying yoga at the Ramamani Iyengar Memorial Yoga Institute in Pune, India. During my time there I made it a point to watch Yogacharya Iyengar practice whenever possible. I not only observed the form of his body but also the way he practiced, how he moved from one pose to another, and the way he worked in the individual asanas. I was fascinated by how he continued to refine his art. Bear in mind that B.K.S. Iyengar is the author of Light on Yoga, and he had been practicing for over 50 years at the time. Still, like a master artist, he polished his poses as if his body were a dynamic sculpture.
sacral nutation
Sacral nutation - exaggerated for effect.

One day, as fate would have it, I was the only other person in the practice hall and Master Iyengar was going through his backbend sequence (picture the most advanced backbends from Light on Yoga to get an idea). I sat on the staircase and watched. He finished, and as he was getting dressed asked if I would like to go with him to visit some people around the city. The next thing I knew, I was in the back of a car speaking with Mr. Iyengar. I mentioned that he still worked to improve his poses, even though he was a master of the art. He gave me a somewhat surprised look, as if to say, “Of course I am!”

How to Use Your Shoulders to Deepen Uttanasana

In Uttanasana, fix the hands onto the mat and attempt to drag them forward. This contracts the anterior deltoids and draws the upper body deeper into the pose. If you can’t reach the floor, grasp the lower legs or backs of the knees and attempt to pull the hands forward. Activating the anterior deltoids with the hands fixed in place connects the upper appendicular skeleton (the arms and shoulder girdles) to the lower appendicular skeleton (the lower legs and hips). In a forward bend, engaging the anterior deltoids in this manner stretches the posterior kinetic chain, including the hamstrings.

stretching posterior kinetic chain in uttanasana
Uttanasana illustrating the anterior deltoids
 and quadriceps contracting to
stretch the posterior kinetic chain

The deltoids are large muscles on the surface of the shoulders that produce many of the major movements about this joint. They are divided into three parts—the anterior, middle, and posterior thirds. The anterior portion originates from the front part of the clavicle (collarbone) and the acromion process and inserts onto the outside of the upper humerus. The main action of the anterior deltoids is to raise the arms in front of the body.