Your Diaphragm is a Core Muscle



The first thing you did when you were born was breathe air into your lungs — and you did it perfectly. A baby’s breathing pattern, expanding its little belly with every inhalation, is a beautiful demonstration of healthy breathing technique. As life goes on, stress, poor posture, injuries, trauma, vanity, and even well-intentioned exercise programs can result in a dysfunctional diaphragm that compromises your capacity to breathe air into your lungs and to stabilize your core.

Deep and controlled breathing techniques have long been prescribed for stress management and reduction of blood pressure. Some recent studies indicate that diaphragm training potentially has other benefits. A review article in the Journal of Multidisciplinary Healthcare 2013 explains anatomically how the diaphragm is intimately connected to multiple systems within your body and its dysfunction can be implicated as a component of neck and low back pain, headaches, incontinence, gastric reflux, and sluggish lymphatic and blood flow. A 2012 study published in the Journal of Orthopedic and Sports Physical Therapy indicated that there is a close association between chronic low back pain and a sub-optimally performing diaphragm. In a 2013 study, researchers used Magnetic Resonance Imaging to compare diaphragm performance of healthy subjects to those with low back injuries and found stability and respiratory functions were compromised in the subjects with low back injuries.

Faulty posture and altered breathing patterns diminish the capability of the diaphragm to perform core stabilization and inhalation of air. Postural training and focused breathing exercises described in this post are basic techniques you can practice at home. Disciplines such as yoga, sitting meditation, qigong, tai chi, and other forms of martial arts integrate healthy diaphragmatic breathing into their practices.


When you are sitting up or standing the diaphragm muscle forms the floor of your breathing chamber spanning the circumference of the bottom of our rib cage. It is 5mm thick and shaped as an upward facing dome. Ideally, it is parallel to the pelvic floor so it can descend directly down like a piston drawing air into your lungs.

The diaphragm performs as a deep core muscle that provides stability from the inside out. It forms a lid over the top of your abdominal section connecting to a multitude of structures including the inner surfaces of the bottom five ribs, the top 3 lumbar vertebrae, and the psoas and quadratus lumborum muscles to create a complex unit that stabilizes the core. In my physical therapy practice, patients with low back pain often have tight and tender psoas muscles in the front and quadratus lumborum muscles in the back. Hip flexors tend to be shortened. The strain from these tight muscles along with abdominal weakness puts the diaphragm in a disadvantaged position; the result is shallow breathing, recruitment of neck and upper chest muscles that compensate by lifting the ribcage, and instability of the low back.


The diaphragm exercises shown in this post are performed lying on the floor so that your posture is supported while you learn the basics. This is the first hurdle in training yourself in healthy diaphragmatic function. After practicing a while you may learn to adjust your breathing pattern at other times of the day. Good times to check in are when you are sitting at a stoplight, or standing in line at the grocery store. The goal is constant diaphragmatic breathing during all of your activities.



  • Lie on the floor with your legs up on a chair or couch so that your hips and knees are at right angles. This passive position allows you to focus your attention on your breathing mechanics while allowing your body to settle into balance.
  • Place your hands on the sides of your ribcage and abdomen .
  • Expand your abdominal region and your chest as you breathe in. This expansion naturally occurs when the diaphragm descends and displaces the abdominal organs outward.
  • Allow the expansion of your ribs out to the sides to create space for the air filling up your lungs.
  • Your shoulders should not move toward your head as this indicates unnecessary contraction of the neck and upper chest muscles – a breathing pattern that can lead to fatigued and tender neck muscles.
  • Practice breathing into your abdomen in this position for 10 minutes a day to regulate your nervous system and to bring awareness to how it feels to breathe correctly.

The exercise below builds on the first exercise by adding the core stabilization component.



  • Lie in the same position as the first exercise, knees shoulder width apart
  • move your hands down to your lower abdominal area on either side of the rectus abdominis (aka your six-pack muscle).
  • Inhale deeply to expand your abdomen down into your lower abdominals so you feel pressure against your hands.
  • Maintain the lower abdominal pressure against your hands as you lift your legs off the couch
  • Hold that position for 5 breaths, expanding your chest on inhalation
  • Keep your neck relaxed.
  • Feel the stability coming from the inside out throughout your core*.

*If you find the abdominal pressure drop away from your hands, you have lost your stability from the inside. If this happens, start again but slowly take the weight off your legs to the extent that you can maintain the lower abdominal pressure against your hands. This is a skill that takes practice.

Awareness of how it feels to use the diaphragm for stabilization can go a long way, but when you get up on your feet things get a bit trickier as your upright postural alignment plays a role in how effectively your diaphragm can function.


The diaphragm is optimally positioned when it is level and parallel to the pelvic floor so it can easily descend during inhalation. If the rib cage is tipped backward, which often occurs with tight back muscles and weak abdominals, or tipped forward, which happens when sitting slouched, the diaphragm is not in an optimal position to contract normally. There are also torsional factors in the trunk from imbalanced posture left to right that can interfere with optimal diaphragm function.

Addressing all possible postural faults is beyond the scope of this post, but the fault most commonly seen in my practice is a forward tipped pelvis that results from too much sitting. Sitting allows adaptive shortening of the hip flexor muscles which in turn create a downward pull on the front of the pelvis when you are standing. A forward tipped pelvis creates stretched weakened abdominals and a relative backward tipped ribcage; this make the pelvic floor and diaphragm out of alignment – a situation that causes the diaphragm to be dysfunctional for both breathing and core stability. In our culture, just about everybody would benefit from lengthening their hip flexors.

My favorite hip flexor stretch involves a modified lunge position as shown in the picture below. This is an active stretch that demands effort when performed properly.



  • Place a cushion on the floor under the kneeling knee
  • Step forward with the opposite foot so your front knee is directly over your foot
  • Keep your body upright and tuck your pelvis so your tailbone points to the floor — this protects your low back and is accomplished by engaging your lower abdominals. Do not arch your back.
  • Shift your body forward (without bending over) until you feel a stretch in the front of your hip
  • Contract the buttock muscles in the hip of the back leg. Contraction of the buttock reflexively relaxes the hip flexors.
  • Reach with the arm on the same side as your kneeling knee up and toward your head
  • Side bend your trunk slightly away from your kneeling side
  • Hold this position for 3 minutes using diaphragmatic breathing the full duration

The diaphragm is intimately connected to your stability, respiration, nervous system, blood flow, digestion, and more. Hence, regular practice of these exercises has the potential to improve your well-being in a multitude of ways. Why not give it a try?


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s