As followers of my blog (now in 110 countries — waiting on you, Greenland) have surely begun to appreciate - I have a thing for breathing. Watching clients and athletes breathe, it becomes apparent that one's breathing pattern is just such an important indicator of system readiness and neutrality. Charlie Weingroff calls breathing a keyhole into the nervous system which I think is perfect. Without a normalized and balanced breathing system, movement variability suffers typically causing loss of adaptability - a rigid system - and movement patterns default to high-tension strategies (more on that later).
One of the most common breathing patterns we see is the hyperinflated pattern. Essentially, the athlete is in a state of excessive inhalation - breathing on top of breathing - with inadequate exhalation. They just can't get air out efficiently. This hyperinflated pattern of breathing can be asymmetric (typically see the left rib-cage flared more than the right) or symmetric (both rib cages flared) as described by the Postural Restoration Institute. While these differences are important, particularly to the physio, hyperinflation has consequences regardless of symmetry.
Given the anatomic link between the ribcage, diaphragm, and thoracolumbar spine it's important to think of this like an SAT analogy: Inhalation is to lumbar extension as exhalation is to lumbar flexion. In the hyperinflated state inhalation/extension >> exhalation/flexion contributing to system-wide issues in performance and loss of variability. Without access to the diaphragm (and the pelvic floor), the deep abdominals, and ultimately full spinal range (flexion), movements become rigid and "stuck": the athlete is the classic overextended, powerful but stiff dude who lacks sustainable movement (think spondy, pelvic floor dysfunction, neural tension, the list goes on and on...)
Taking it a step further: inhalation is to excitation and tension (sympathetic-dominance) as exhalation is to relaxation and inhibition (parasympathetic dominance). Inhalation yields excitation - why heart rate increases with inhalation and decreases with exhalation. The dominance of this fight-or-flight response is essential in short bouts of performance, but is pretty much awful if maintained for long periods of time as it prevents recovery and relaxation - both of which are important for system neutrality. As my dad always said, everything in moderation. With this hyperinflated state inhibition of muscles, particularly the extensors, is difficult and the athlete cannot get into and sustain a variety of movements because the nervous system is under constant threat. The increased pH of the blood due to decreased CO2 levels also contributes to a sensitive peripheral nervous system. No wonder people with persistent/chronic pain display this hyperinflated, stressed-out state - a threatened nervous system is often a painful one!
This hyperinflated state is a big culprit, in my opinion, for the high tension strategies I see so often in athletes. They just don't know how to dim or inhibit the muscles that aren't necessary for the movement. Ever walk on ice? Every muscle is tensioned to limit joint motion and decrease the risk you might fall - yeah, it's exhausting. Defaulting to these high tension strategies, when they aren't necessary, is like walking on ice. The system is rigid and movements are more taxing - everything other than max effort is typically a struggle in this state and they fatigue out early. These people always feel tight, though they probably have plenty of muscle excursion.
Clearly, exhalation needs to be emphasized for a balanced, efficient system. By emphasizing flexion-biased breathing patterns, the system can approach a balance. pH levels can be normalized and beneficial training effects can be realized without adding rigidity to the system. By facilitating ribcage over pelvis mechanics, the diaphragm and pelvic floor can return to their normal resting length and function allowing the diaphragm to act like the diaphragm. I think many of our barbell-based strength training systems lend us towards this hyperinflated state so some reset movements likely need to be thrown into programming.
So what to do about this? That's coming in a near future post but - spoiler alert - it involves forced exhalation, flexion and developmental patterns, and some recovery strategies. In the meantime here's my earlier post on diaphragmatic breathing for recovery.