If you are experiencing a cramp in your upper abdominal area in poses with trunk flexion, as in Crow, it might not be a diaphragm cramp.  It could be a cramp in some of the smaller muscles in-between your ribs.   Often the cause of diaphragm cramping is overly strenuous cardiovascular activity.  In either case there could be several factors that can contribute to that feeling of your diaphragm cramping.  Most likely it comes from your over-using one muscle and not engaging other muscles in your body synergistically.  In yoga poses, the whole body contributes to getting into the final pose.  You may be trying to “muscle” your way into the Crow.

There are several factors at play in Bakasana.  And all of these play an equal part in the final pose.

The first is Foundation.  The hands are the base of this pose.  The hands need to press evenly into the floor with the weight equal across the base of the knuckles of all of the fingers, the length of each finger and the heel of the hand.  We first learn to do this in Adho Mukha Svanasana (AMS) or Downward Facing Dog.  Often in Down Dog, the knuckle of the index finger pops up and the weight of the body falls onto the outer wrist.  This can be painful for the wrist, but it also means that you are not engaging your pectoralis muscles (chest).  Engaging your pecs helps hug the arms towards each other which helps to press the inner edge of the hand into the floor.

If we go up the foundation from the hands, we come to the arms.  These same chest  muscles attach to your arms and they adduct your arms, or draw them towards each other, keeping them together and preventing them from buckling out.  If the pectoralis muscles are not engaged, students sometimes try to use their abs to hug their body up onto their legs.  This can cause an abdominal cramp because the abs are over working.  The triceps of the arms also need to engage as these are the muscles that straighten the arms.  In the beginning, your arms are bent, and eventually you learn to straighten the arms.

The second factor is the physics of the balance.  Think of your wrists as the fulcrum, or balance point of a seesaw.  The amount of weight on one side of the seesaw has to be equal to the weight on the other side.  Often, because of fear of falling on your face, students are afraid to lean forward enough to get their feet to lift off of the ground.  Instead they try to pull their feet up with their abs, or lift their butt high up into the air.  This can cause an abdominal cramp because it is not the job of the abs to lift the feet off of the floor.  If you tip forward enough the feet will rise off of the floor.  Of course, you have to fold your legs into your body and keep them there.  But that is the job of the hip flexors and the adductors of the legs.

The third factor is leg strength.  The legs have three jobs to do: adduct – which means draw towards each other.  This is what keeps your legs hugging against your arms.  The hamstrings also need to contract.  Contraction of the hamstrings bends the knees and draws the heels towards the buttocks.  This is what keeps you tucked into the Child’s Pose shape.  The feet need to point, which is your calf muscles working and the feet need to evert, which means that the inner edge of the foot presses outward and the outer edge of the foot lifts up.  This action also helps with adduction.  This is the opposite of a sickled foot, which is a lazy or unconscious foot.  Remember, the whole body needs to be engaged.

The fourth is the engagement of the back muscles,  They need to contract to balance the3 contraction of the abdominal muscles.  They draw the collar bones forward and decompress the abdominal area.

And finally there is core strength. There are four layers of abdominal muscles: the outer layer is the rectus abdominis, or six-pack.  Since this muscle connects to the bottom of the sternum and the top of the pubic bone, when it contracts it pulls those two body parts together.  Overuse of this muscle causes the abdominal cavity to cave into itself and I suspect that it is the primary contributor to that diaphragm cramp that students often complain about.  Sure, it does contract, but everything else has to be working, too.

The next two layers if abdominal muscles are the external and internal obliques.  These don’t play that much of a role in row because they are most active in side bending and twisting.  However, they do contract and contribute to the overall contraction of the abdominal muscles.  You cannot contract one muscle without also contracting the surrounding muscles.

But the deepest layer of abdominal muscle is the one we want to awaken and contract.  And that is the transverses abdominis.  This deeper layer of muscle has fibers that run horizontally around the center of the torso and when contracted they tighten like a corset.  They also create a lift and a sense of lightness.  This is the muscle we are contacting when we engage Uddiyana bandha, or the abdominal lock.  There are a couple of cues to engage this.  One is to think about drawing the belly button to the spine.  When you do this, see if you can feel the right and left sides of your rib cage  and the right and left sides of your frontal hip bones drawing closer together.  You can also visualize a corset around your waist and you are tightening it by pulling on the laces.  Another cue I like is that of feeling your waist area narrow as you exhale, engage the abs and make a “Ssshh” sound.  This helps you engage the transversus abdominis. In Crow, this gives you a hollow feeling in your belly and if you do this and think about drawing your navel in towards your spine. It helps you dome the upper back and lift it without that shortening and tightening sensation in the belly.

The psoas muscle also has to contract.  Although not thought of as one of the four ab muscles, it is deep inside the abdomen.  This muscle is one of the primary hip flexors, which means that it draws the thighs in towards the chest.  Interestingly enough, this muscle attaches to the last thoracic vertebrae, or T-12, which is also where the diaphragm attaches on the front of the spine.  Although, this posture has a very convex shape in the back, the back muscles, particularly the latissimus dorsi have to engage as well.  This muscle attaches at the same place, but on the outside of the spine.  When it contracts, it draws the chest forward balancing the actions of the abdominal muscles and helping to relieve that sensation of cramping.

I know this is a lot to think about, but arm balances are advanced postures which demand advanced actions by the student.  There is a great deal of finesse to practicing these postures rather than just brute strength.  Remember to practice each action precisely and “do not be attached to the fruits of your actions“.  B.G.  II.47