As an avid student of yoga since the mid-90s, I have heard many yoga teachers say that boat pose, also known as navasana or paripurna (full) navasana, was a core pose.
This always confused me because, in my own body during navasana, I felt the most muscular effort at the front of my hips and in my thighs.
The diligent core strengthening I was doing did not seem to make boat pose any easier.
Fast forward to becoming a physical therapist, I realized that what was happening in navasana — or essentially any pose — was a lot more nuanced than what can be described within a yoga asana class.
This article will shed light and show how very complicated it can be to answer the questions “Is Navasana a core pose?”.
Shedding light on boat pose anatomy
It is clear from the anatomy that navasana is primarily a hip flexor, or iliopsoas, strengthening pose. More detail on that in a moment.
“Iliopsoas” is the primary mover in navasana, and is comprised of three muscles:
- Psoas major
- Psoas minor
I’ll use the term “psoas” or “hip flexors” in this post to indicate all three of these (plus rectus femoris as an additional hip flexor).
But even with that clarity comes murky waters.
What is the core?
Before deciding whether any pose is a “core” pose, we have to define “core”.
“Core” is not a medical term, and does not have a universal, clear definition. It can (and will) be used loosely — especially by fitness and movement instructors..
That said, clinicians usually consider core muscles the ones that control the pressure in the core — diaphragm, pelvic floor, abdominal wall, and multifidi. In particular, the anterior muscles (the abdominal wall) and the posterior muscles (the multifidi) are repeatedly used in research definitions of “core.”
But everything is not everything. I have heard more than one yoga instructor speak of foot arch strengthening as “core” strengthening. That is far outside of any anatomic understanding of “core”.
Isn’t psoas in the middle of the body, therefore part of the “core”?
Psoas major and psoas minor are in the trunk. They can move the spine or stabilize the spine, depending on the relationship.
Your definition of core is allowed to include psoas. However, if it does, one should understand the role of iliacus (which shares a tendon with psoas), open vs. closed chain movement, and position vs. effort. (These subjects are more in depth than can be covered in this post).
Like a photon, psoas plays more than one role in the body, depending on the position, the angle and the direction of any resistance (like gravity)
Is Navasana also a Core Pose? I feel it in my abs!
Sure, but the muscle engagement of the core is secondary to the hip flexors.
Since your torso stays neutral in navasana (though not in ardha navasana), the position and main efforts lead me to re-emphasize that the primary muscle used to sustain yourself in navasana is your iliopsoas.
Position vs. Effort
To break down what muscles are most engaged in any pose, at Yoga Anatomy Academy we look at a pose from two perspectives:
Position and effort have the potential to be the same, to overlap or to be polar opposites. This is a topic that we go into quite deeply in our anatomy mentorship.
Understanding the difference between position and effort is essential to understanding the muscular efforts of navasana.
The position of boat pose
The position of Navasana — as it is typically taught — includes a neutral spine and neutral / straight legs.
The primary joints not in “anatomic neutral” (also a subject we cover in module 1 of our Yoga Anatomy Mentorship) are the hip joints, which are at 90 degrees of flexion.
(Yes, the toes are often pointed / ankles plantarflexed, and the shoulders are often level with the horizon / flexed to about 45 degrees, but navasana would still be “navasana” without these particular joint positions.)
The position of boat pose is bilateral hip flexion at approximately 90 degrees.
Turned upside down, the position looks a lot like downward facing dog. But the efforts of downward facing dog are very different from the efforts of boat. Turned 45 degrees, the position looks like Dandasana, staff pose. Yet the efforts of staff pose are different than those of navasana.
The efforts of boat pose
Effort is where pose analysis gets interesting.
Understanding effort involves looking at the pose in relation to gravity (or other resistance) and at what muscles need to work to enter, maintain or exit a position. (This post primarily looks at maintaining or holding the pose).
The primary effort of navasana is to keep both your legs and your back from hitting the ground. Our hip flexors are in charge of that because they maintain this position of hip flexion. Hip flexor effort is why so many of us feel this pose primarily in the front of our hips.
A secondary effort of navasana is to keep your knees straight. Gravity gives our quads — the main knee extensors or straighteners — something to resist against. Quads can be working intensively, too.
Another secondary effort of navasana is trunk stabilization — keeping the spine neutral despite being at a 45 degree angle to the floor. This involves some muscles of the trunk (yes, the core), primarily rectus abdominus to prevent lumbar extension, and lumbar extensors to prevent lumbar flexion, and to control it as one leans back (eccentrics), but the predominant muscles that define this shape are not these core muscles.
If anything, gravity WANTS to take the spine into flexion here, so the abdominal wall is not fighting that. Iliopsoas is.
Boat pose requires a LOT of hip flexor effort/strength, and not nearly as much core strength.
(Ardha navasana, on the other hand…now that’s a core doozy.)
Anatomy Matters (and yoga teachers could learn more!)
The “debate” around whether navasana is a core pose is yet another reason why knowing anatomy matters.
Yoga practitioners — like myself — often feel boat pose most acutely in the hip flexors, especially if we are lifting our chests. My hope is that readers now understand exactly why.
One last question that came up in our Instagram post on Navasana “Is it ok to strengthen hip flexors?” Absolutely. Hip flexor strengthening is not a bad thing. Nor is it bad that Navasana does not target the core as much as yogis claim it does.
Let it be enough to know that navasana is a challenging pose that plays a beloved role in physically challenging classes (yes, including “core” classes).