Understand your breath and save your Yoga Practice.
Breathing is an automatic, yet complex process. We know it needs to be a focus during our yoga practice, however misinformation or lack of understanding can easily blur the focus. If the attention isn’t clear and accurate, not only do we not achieve the health benefits we’re looking for, it can have negative effects.
To begin to understand the breath, and how we can properly regulate it during asana and pranayama, we must first understand the basic anatomy. Although free flowing, unrestricted breathing is a wave-like, full body phenomenon, let’s begin our study in the thorax.
There are approximately 46 muscles1 involved in the breathing process, the primary muscle being the diaphragm. Secondary to the diaphragm are the external intercostal muscles and in some situations, serratus anterior. When metabolic demands change, the level of recruitment of additional accessory muscles is also affected.
The diaphragm is a dome-shaped muscle that separates the abdominal and thoracic cavities of the torso. It is the most active muscle in breathing. The contractile portion of the muscle is at the edges, closer to its originating attachments at the xyphoid process, the inner cartlidge surface of ribs 7-12, the anterior surface of lumbar vertebrae 1-3, as well as the tendons of the abdominal aorta, psoas major and quadratus lumborum. The fibres travel upward inserting on a central non-contractile tendon with no boney attachment. This forms the roof of the dome and helps to give the parachute shape. Essentially, the thoracic diaphragm inserts on itself.
The diaphragm operates mostly unconsciously, but we can somewhat control the rate and amount of contraction. And, like any other muscle in the body, the diaphragm can be trained. We do this both during “active” asana and pranayama.
The External Intercostals begin at the lower border of ribs 1-11 and insert onto the upper border of ribs 2-12. Their fibres are directed obliquely downward and laterally on the back of the body and downward, forward and in on the front of the body. When they contract, they elevate the ribcage.
Serratus Anterior is a thin sheet of muscle that originates on the upper 8-9 ribs and inserts on the medial border of the scapula. One function of Serratus Anterior is to elevate the ribs when the scapulae are fixed. Therefore it becomes a primary breathing muscle when the rhomboids (also inserting on the medial scapular border) are activated to draw the scapula down and towards the spine; otherwise it’s an accessory muscle.
How it all works
When we breathe in, the diaphragm actively contracts, flattening downwards, increasing the surface area of the lungs (the elastic lungs are pulled by their attachment to the diaphragm), the external intercostal muscles contract and move the ribs up and out increasing the horizontal diameter of the rib cage. This causes a reduction in pressure and increase in volume within the lungs (and thorax), creating a vaccum, drawing air in. As the diaphragm moves down, intra abdominal pressure increases and the contents of the abdomen are pushed down and out to make space for our organs.
During a normal, quiet breath, the exhale is passive. The elastic recoil of the lungs initiates the chain of events. As they deflate, the diaphragm relaxes into its domed position and the external intercostal muscles relax, causing the ribs to move down and in, decreasing the volumen of the lungs and the pressure that forces the air out. The abdomen returns to its resting shape.
As metabolic demands increase and the body requires a deeper breath, or more oxygen, greater chest expansion is needed. This is when the trapezius muscles, sternocleidomastoids, scalenes, levator scapulae, pectoralis minor and serratus posterior superior will become active to assist in greater elevation and expansion of the ribcage. The amount of expansion required will determine the level of involvement of these key accessory muscles.
Active exhalation (sometimes called “forced”) occurs during exercise and in some breathing disorders. The abdominal muscles, serratus posterior inferior and the internal intercostal muscles then help expel air by further depressing and drawing in the ribs, decreasing the volume of the thoracic cavity, increasing its pressure and forcing air out. All of these accessory muscles can become overused, or locked in tension when disordered breathing exists.
The use of active exhalation coupled with pelvic diaphragm activation results in an ability to manage the pressure in the abdominal and thoracic cavities. This is what we are trying to do when we control it in pranayama. We will explore this in Part 2. We will also look at improper breathing and how it can become detrimental not only to your yoga practice, but to overall health.