Your Strongest Core Muscle Is The One You Breathe With
Strength coaches program planks, carries and anti rotation work. Very few program the diaphragm.
Yet the diaphragm is both the main breathing muscle and part of the system that stiffens the trunk when an athlete moves.
When it is overloaded, both jobs suffer. Here is what the research shows.
The Diaphragm Is A Postural Muscle
The diaphragm forms the roof of the abdominal cavity. When it contracts with the deep abdominal muscles, it raises pressure inside the abdomen and helps stiffen the trunk.
Hodges and Gandevia (2000) recorded diaphragm activity while people made repetitive arm movements that challenged trunk stability.
During those movements, the diaphragm stayed active continuously, with its activity rising and falling at both the rhythm of the arm movement and the rhythm of breathing. It was doing two jobs at once.
Intra abdominal pressure rose during limb movement, in proportion to the forces the movement created. The researchers showed that combined activation of the diaphragm and abdominal muscles produced a sustained rise in that pressure.
For an athlete, that is every change of direction, every contact, every jump and landing. The diaphragm is working on posture and breathing at the same time.
When The Diaphragm Does Not Move Well
Kolář and colleagues (2012) used dynamic MRI to compare 18 people with chronic low back pain against 29 healthy controls, all with normal lung function.
When the limbs were loaded, the low back pain group showed smaller diaphragm movement and a higher diaphragm position than the healthy group. Their diaphragm also had a steeper slope.
The authors suggested these differences may contribute to the disorder. This was a comparison study, so it shows an association, not proof that diaphragm function causes back pain.
Still, it supports a simple point for performance staff: how the diaphragm moves under load is worth paying attention to.
The Diaphragm Fatigues, And The Legs Pay
The diaphragm can tire like any other muscle.
Johnson and colleagues (1993) tested 12 healthy, fit adults with an average VO2max of 61 mL/kg/min. After exercise to exhaustion at 95% of VO2max, the diaphragm's force response to stimulation fell by 8 to 32%, depending on lung volume.
Fatigue also appeared after exercise at 85% of VO2max, and full recovery took around 70 minutes. The authors concluded diaphragm fatigue becomes more likely and more pronounced above about 85% of VO2max.
That matters because breathing muscles compete with the legs for blood flow. Harms and colleagues (1997) studied seven trained male cyclists at maximal exercise while changing the work of breathing.
Greater work of breathing was associated with lower leg blood flow, higher leg vascular resistance and lower leg oxygen uptake. In plain terms, when breathing costs more, the working legs can get less.
For team sport athletes making repeated high intensity efforts, an efficient, well conditioned breathing system is part of keeping the legs supplied.
How To Train It
There are different ways to load the breathing muscles, and it is important to be clear about which method has which evidence.
Respiratory muscle training uses resistance devices that make breathing in, and sometimes breathing out, harder. Illi and colleagues (2012) meta analysed this method and found it improved endurance performance in healthy people.
Less fit individuals benefited more than highly trained athletes, and longer duration tests showed larger improvements. That evidence belongs to device based respiratory muscle training, not to breath holds or nasal breathing.
In Vincere Protocol, our focus is light, slow, deep nasal breathing, which teaches athletes to breathe with the diaphragm rather than the upper chest at rest and during low to moderate intensity work.
We pair that with trunk work done while breathing through the nose, so the diaphragm learns to stabilise and breathe at the same time, the way it must in competition.
Where a program wants direct strength training of the breathing muscles, device based respiratory muscle training is the method with that evidence behind it.
Putting It Into The Week
Diaphragm work does not need its own session. It fits inside what athletes already do.
In the warm up, a few minutes of slow nasal breathing lying down or in a supported position lets athletes feel the lower ribs and abdomen expand rather than the shoulders lifting.
In trunk work, athletes hold positions such as dead bugs, side planks or loaded carries while keeping steady nasal breathing. If they have to hold their breath or switch to mouth breathing to keep position, the load is too high for now.
In conditioning, staff can watch for upper chest breathing and breath holding during efforts as cues that the athlete is bracing poorly or working beyond their control.
In recovery, slow nasal breathing after sessions gives athletes another repetition of the same pattern at low intensity.
Signs Worth Watching
Coaches do not need imaging to start paying attention.
Watch whether an athlete's shoulders rise with every breath at rest. Watch whether they can talk or breathe through the nose during trunk work. Watch whether bracing under load collapses when breathing gets hard.
None of these are diagnoses. They are prompts to coach breathing alongside movement, and to refer to medical staff where pain or breathing problems are involved.
Over a preseason, the aim is simple: athletes who can hold position under load while breathing steadily, and who can keep that control late in sessions when fatigue sets in.
That is a quality every strength and conditioning coach already values. The diaphragm is simply part of how it is built.
FOR ELITE ATHLETES, THIS CAN HELP YOU
✔ Understand the diaphragm's dual role in breathing and trunk stability
✔ Recognise that the diaphragm can fatigue during very high intensity exercise
✔ Appreciate how the work of breathing can compete with the legs for blood flow
✔ Choose the right method for the goal, including device based respiratory muscle training for breathing muscle strength
Performance takeawayThe diaphragm is a core muscle. Train it like one.
This is not wellness. This is your competitive edge.
Want this in your program? Enquire about Vincere Protocol for your team.
