This asana is often said to work the
abdominal muscles. This is true; however,
the abdominal muscles do not pull the body
into this pose—rather, they are keeping the
upper body from falling back into gravity.
The action that holds the body in this posi-
tion is hip flexion, created by the psoas major
and iliacus. If the psoas major and iliacus are
difficult to access, it is possible to overwork
the rectus femoris or tensor fasciae latae
attempting to stay up.
Just as bending the knees makes this pose
easier by shortening the length of the lower
lever arm, extending the arms overhead
makes it more difficult by lengthening the
upper lever arm.
Breathing
To maintain the stability and balance of this pose, the breath must be very restrained and
focused. To illustrate how vital this is, attempt to do navasana while taking deep belly breaths.
E5267/Kaminoff/fig7.23/417723/alw/pulled-r1Navasana with arms extended.