Yoga Anatomy: 4 Steps to Hanumanasana (Monkey Pose)

To paraphrase the poet William Blake, you can see the world in a grain of sand. Similarly, you can learn a great deal about all asanas by carefully studying one. For this blog post, I focus on Hanumanasana (Monkey Pose or Front Splits). I use this pose in workshops to illustrate such factors as pose analysis, agonist/antagonist muscle pairs (and their synergists), physiological reflex arcs, and stretching biomechanics.

First, let’s look at the muscle-tendon unit—the muscle and its tendon—to see what lengthens in the pose. The muscle-tendon (MTU) unit is composed of several elements. These include the contractile structures (sarcomeres) and the fascial elements that surround the muscle fibers and tendons. Although these elements are often presented separately in articles on the science of stretching, in reality, they are inextricably linked to one another.

All of these elements contribute to muscle contraction and stretching. In addition, many factors contribute to the way a muscle lengthens, including the viscoelastic properties, creep (a type of deformation that has been postulated for fascial elements), neurological/psychological factors (such as muscle memory and tolerance), and extra muscular links to synergists. Individual muscle architecture or shape also plays a role. Below, I include several references from the scientific literature that discuss these factors in greater detail.

Hanumanasana, Monkey Pose, front splits, muscle memory, muscle tolerance, muscle structure

How Timing Affects Stretching

Next, there is the timing of the stretch or how long to hold it. I derive my personal approach to timing the stretch in Hanumanasana from published biomechanical studies on stretching. These studies indicate that the majority of lengthening or release of the muscle-tendon unit takes place in the first 20 seconds of the stretch. Similarly, when repeating a stretch, the lengthening of the muscle-tendon unit appears to diminish with each successive stretch, reaching its maximum at the fourth stretch, after which little additional length is gained by further stretching. (Image right: Cross-section of muscle illustrating the contractile sarcomeres with fascial elements such as the perimysium.)

We provide an illustrative curve for this process below. You can see the experimental curves in the referenced articles (1, 2.) Note that each successive lengthening of the muscle is followed by a brief recovery period in which it is released from the stretch. This is important because one two-minute stretch is not equivalent to four 30-second stretches. Accordingly, I divide my approach to Hanumanasana into four consecutive stretches—each focusing on a different muscle group. Obviously, this is only one of the many ways to approach stretching. It is, however, a method I have found beneficial for working on specific poses such as front splits.

Hanumanasana, Monkey Pose, front splits, muscles and stretching, measuring muscle stretching, efficiency of stretching

(Illustrative curves for changes in muscle length vs time in a stretch)

Practicing Monkey Pose

To begin, I analyze the positions of the major joints in Hanumanasana. For example, the back hip is extending. This means that the agonist muscles for this part of the pose are the gluteus maximus (the prime mover of hip extension). The synergists of this action are the posterior portion of the gluteus medius and minimus, the hamstrings, and the adductor magnus. Next, I use this analysis to determine which muscles are stretching. Extending the hip lengthens the hip flexors, including the psoas and its synergists. Then I apply physiological reflex arcs, including proprioceptive neuromuscular facilitation (PNF) (3,4,5) to gain length in the muscles during successive 30-second stretches.

Hanumanasana, Monkey Pose, front splits, muscle memory, agonists, synergists, PNF facilitation

(Hanumanasana (front splits) illustrating the positions of the major joints)

 Step One

  1. I focus the stretch on the prime mover of hip flexion—the psoas—for the extended back hip. This stretch also works the rectus femoris. I use two sturdy chairs for support and begin by taking the muscle out to length by engaging the back leg gluteus maximus, producing reciprocal inhibition of the psoas, and aiding it to relax into the stretch.
  2. Then I attempt to draw the back knee toward the front foot in a flexing type action, using just enough force to gently engage the psoas. I hold this for several breaths and then ease deeper into the stretch by again engaging the gluteus maximus, and limit the stretch to 30 seconds.
  3. Then I come out of the pose and stand in Tadasana (Mountain Pose) to provide a brief recovery.

​​Hanumanasana, Monkey Pose, front splits, muscle memory, agonists, synergists, PNF facilitation, cues for the pose

(Cue for engaging the back leg psoas and rectus femoris to use PNF for muscle lengthening)

Step Two

  1. Now I focus the stretch on the prime movers of hip extension for the flexed front hip. I begin by engaging the flexors of the front hip, including the psoas. I also engage the quadriceps. These muscles provide reciprocal inhibition of the gluteus maximus and hamstrings. One head of the quadriceps, the rectus femoris, also synergizes hip flexion.
  2. Then I slightly bend the knee and gently press the heel into a towel or blanket to engage the hamstrings and gluteus maximus of the front hip. I hold this action for a few breaths and then take the hamstrings and gluteus maximus out to length by engaging the hip flexors and knee extensors, again holding the total time in the stretch for a maximum of thirty seconds. Once again, I stand in Tadasana for a brief recovery (usually for about 20 seconds).

Hanumanasana, Monkey Pose, front splits, muscle memory, hip flexion, psoas, quadriceps

(Cue for engaging the front leg gluteus maximus and hamstrings to use PNF for muscle lengthening)

Step Three

I stretch the synergists of hip flexion and extension that are located more medially. For the front hip, my focus is the adductor magnus (a synergist of hip extension that is stretching). For the back hip, I focus on the adductors longus and brevis, and the pectineus (synergists of hip flexion that are stretching).

  1. I slowly build the engagement of these muscles respectively by attempting to draw the front heel and back knee towards the midline (adduction), again holding for a few breaths, then deepening the pose by relaxing more fully and engaging the back leg buttocks and front leg psoas and quads.
  2. I again use Tadasana for a brief recovery

Hanumanasana, Monkey Pose, front splits, muscle memory, hip flexion, psoas, quadriceps, practice tips

(Cue for engaging the adductor magnus (front leg) and adductors longus and brevis and pectineus for PNF )

Step Four

This is the fourth and final stretch of the series. In this step, I focus on stretching the synergists of hip flexion and extension that are located laterally or on the outside of the hips (for the back and front leg respectively). For the front hip, the synergist of extension includes the posterior part of the gluteus medius and gluteus minimus.

  1. Since both of these muscles are prime movers of hip abduction, I use this for my cue to engage them by attempting to drag the front heel away from the midline.
  2. At the same time, I engage the back hip tensor fascia lata by gently attempting to drag the knee away from the midline in the stretch.
  3. I hold this action for a few breaths and then ease deeper into the pose once again by engaging the back leg gluteus maximus and front leg psoas (and quads)—all for 30 seconds.
  4. Then again, I rest in a relaxed Tadasana.

Hanumanasana, Monkey Pose, front splits, muscle memory, engaging the the adductor muscles, front and back legs for PNF

Hanumanasana, Monkey Pose, front splits, resting muscles between practice, easing into a pose, recovery time

(Cue for engaging the abductor muscles of the front and back legs for PNF)

For a balanced stretch, I repeat the series on the other side. I allow a 48-hour recovery period after applying proprioceptive neuromuscular facilitation stretches. I never force myself into the pose, but rather use physiological reflex arcs to gently lengthen the muscles. I also use visualization and sensation of the muscles I’m stretching to focus my Drishti for a safer and more effective practice. I slow my movements as I near the endpoint of the stretch and come out of the pose carefully. This aids to prevent injury.

Remember that not all poses are suitable for all practitioners. Always practice under the direct guidance of a qualified instructor; use their assistance to determine modifications or suitability of a given pose for your individual practice. Always consult your healthcare provider and obtain medical clearance before practicing yoga or any other exercise program.

Hanumanasana, Monkey Pose, front splits, muscle memory, agonists and antagonists muscles in Hanumanasana

(Agonist (blue) and antagonist (red) muscles of the hips in Hanumanasana)


Reprinted with permission from the Daily Bandha

Photo coming soon
Author, Ray Long MD FRCSC is a board-certified orthopedic surgeon and the founder of Bandha Yoga. Ray graduated from The University of Michigan Medical School with post-graduate training at Cornell University, McGill University, The University of Montreal, and Florida Orthopedic Institute. He has studied hatha yoga for over twenty years, training extensively with B.K.S.                                                    Iyengar and other leading yoga masters.                 

Chris Macivor3d Graphic Designer / Illustrator Chris Macivor has been involved in the field of digital content creation for well over ten years. He is a graduate of Etobicoke School of the Arts, Sheridan College and Seneca College. Chris considers himself to be equally artistic and technical in nature. As such his work has spanned many genres from film and television to videogames and underwater imagery.              


1) Kato E, Vieillevoye S, Balestra C, Guissard N, Duchateau J. “Acute effect of muscle stretching on the steadiness of sustained submaximal contractions of the plantar flexor muscles.” Journal of Applied Physiology. Feb 2011;110(2):407-15. Epub 2010 Dec 2.

2) Taylor DC, Dalton JD Jr, Seaber AV, Garrett WE Jr. “Viscoelastic properties of muscle-tendon units. The biomechanical effects of stretching.” American Journal of Sports Medicine. May-Jun 1990;18(3):300-9.

3) Rees SS, Murphy AJ, Watsford ML, McLachlan KA, Coutts AJ. “Effects of proprioceptive neuromuscular facilitation stretching on stiffness and force-producing characteristics of the ankle in active women.” Journal of Strength and Conditioning Research.  May 2007;21(2):572-7.

4) Higgs F, Winter SL. “The effect of a four-week proprioceptive neuromuscular facilitation stretching program on isokinetic torque production.” Journal of Strength and Conditioning Research. August 2009;23(5):1442-7.

5)  Mahieu NN, Cools A, De Wilde B, Boon M, Witvrouw E. “Effect of proprioceptive neuromuscular facilitation stretching on the plantar flexor muscle-tendon tissue properties.” Scandinavian Journal of Medicine and Science in Sports. Aug 2009; 19(4):553-60. Epub 2008 Jun 17.

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