More than ever before there is growing research recognition that human endurance is governed not only by peripheral processes (like heart rate and stroke volume) but also by central processes by which the brain makes decisions on “how much is too much” (Noakes, 2012). One reflex that comes from these central processes is termed the metaboreflex (Mcconnell, 2013) and understanding how it works, what it means and how to decrease its negative impact on the body can create massive changes in stamina with less effort that many athletes can believe is possible.
- Understand the Central Governor Theory of exercise endurance.
- Discover the role of the metaboreflex in endurance events.
- Explore the role of respiratory awareness drills and respiratory muscle strength training on exercise endurance.
- Learn basic respiratory awareness drills to immediately implement with clients.
Modern approaches to improving stamina and endurance can be incredibly effective but are often fraught with training “dangers” – the most prominent of which is the “I must do even more cardiovascular training in order to improve” mindset. However, there are profound endurance-enhancing possibilities available to be found in strength training – when the focus is on the correct muscles. While many endurance athletes recognize that strength training can be of some benefit in increasing stamina, most are unaware of the rationale and methods required to train what may be the most important “stamina” muscles of all – the muscles of respiration!
To fully understand this concept, we need to look at the development of stamina as a neurological process as well as a cardiovascular one and recognize that the brain ultimately “governs” stamina – not simply the heart and lungs. In endurance research, there has been ongoing debate around this idea for the last decade, primarily thanks to the work of Dr. Timothy Noakes. Noakes advocates what has become known as The Central Governor Theory, which basically states that your brain is what slows you down and eventually makes you quit in endurance events (Noakes, 2004). Of note is the fact that this theory is similar in nature to emerging concepts in pain neuroscience such as the Pain Neuromatrix or Threat Neuromatrix (Louw & Puentedera, 2013).
The theory contends that there is a control mechanism or suprasystem within the brain that’s constantly accumulating and analyzing all incoming data. It is observing and evaluating multiple components such as the respiratory rate, cardiovascular activity, performing ongoing chemical analyses of the blood, and monitoring sensory input from the eyes, ears, spine and extremities. As it streams this data, it compares actual versus expected measures and then manipulates motor output, posture, respiration, heart rate and a host of other responses in the body. As we approach points of “survival threat”, meaning that the Central Governor is beginning to predict injury or death, it “puts the brakes on” utilizing exhaustion as a primary tool.
The idea of the Central Governor Theory was discussed in physiology as early as the 1920’s but then cardiovascular physiology took over. The prevailing thought became, “Hey, the heart and lungs are the important thing. The heart is the rate limiter, or the lungs will make us stop the activity when they are over-stressed.” Over the last 90 years of experimentation around this concept, however, one major problem continues to rear its head. Researchers have consistently discovered that athletes can perform maximal exercise to total exhaustion and NOT exhaust either their cardiac output or lung capacity (Elliott, Skowno, & Prabhu, 2012). So what’s going on?
When evaluating stamina athletes, one of the most common findings is that shortness of breath is the primary reason that exercise cannot be continued. When we dig into the physiology behind this, what is often found is that the peripheral musculature is stronger and more resilient than the respiratory muscles themselves. When an athlete with this type of strength imbalance reaches the anaerobic threshold, the metaboloreflex activates.
Meet the Metaboreflex
The metaboloreflex is a centrally governed blood-shunting reflex that pulls blood from the peripheral musculature and sends it to the respiratory muscles with the goal of supplying more fuel and returning them more quickly to homeostasis (McConnell, 2011). When the metaboloreflex is triggered it forces the athlete to slow down by disorganizing movement, inhibiting muscular force output, and decreasing both energy production and utilization in the peripheral skeletal muscles. What this means practically in endurance training is that the stronger and more efficient an athlete’s respiratory muscles, the longer he or she may prevent the metaboloreflex from emerging (McConnell, 2013).
Building Stamina with Strength Training
While there are many approaches available to increase the strength and endurance of the respiratory muscles, the basics of strength training remain the same: you must be able to accurately contract the correct muscles, and then add progressive overload to create a strength adaptation.
So how does that work for the respiratory muscles?
In our system we teach a two-pronged approach to developing the respiratory muscles. First, the focus is on developing biomechanical awareness with a set of guided inhalation and exhalation exercises devoted to exploring the 20+ muscles responsible for respiration. Once a level of awareness and contractile competency is achieved, the next step is to focus on using external devices to increase the challenge of respiration (McConnell, 2013).
While this may sound time consuming, respiratory muscle training is a high-yield, low time-requirement approach to maximizing respiratory efficiency and decreasing metaboreflex activity during exercise (McConnell, 2013). There is a growing body of research that indicates this approach to training is equally effective as many more time-and-energy consuming protocols.
How to Begin
The first two points to focus on in building your respiratory efficiency are nasal breathing and diaphragmatic awareness exercises.
While it is beyond the scope of this article to discuss the physiology behind why nasal breathing is so important let’s simply say you need to be focusing on it! The nasal passages are the preferred entry point for air into the body in all but the most difficult exercise sessions. Here’s a simple exercise to practice with your clients:
Nasal/Mouth Contrast Breathing
- Perform this exercise either seated or supine.
- Keep the head and neck in neutral.
- Take two fast full breaths in through the nose, using a controlled exhale through the mouth.
- Next, take two fast full breaths in through the mouth, again using a controlled exhale through the mouth.
- The point of the exercise is to notice the difference in speed of air intake and relative “comfort” level with switching between the nose and mouth.
Once you are comfortable with this exercise, it’s time to move on to the diaphragm awareness/stretch exercises. The diaphragm has two distinct inspiratory mechanisms (Calais-Germain, 2006):
- In the first, the central tendon of the diaphragm which attaches to L1-3 is pulled toward the pelvis, making the abdomen bulge as diaphragm descends into abdominal cavity.
- Secondly, if the central tendon is immobilized or the abdomen is contracted the diaphragm will lift and separate the lower contour of the ribs during inhalation.
We want to make use of both of these mechanisms in our diaphragm stretch drills. Here’s how to do it:
Supine Diaphragm Stretch #1
- Perform this exercise supine, with arms overhead.
- Perform a posterior pelvic tilt.
- Inhale fully, focusing on allowing the abdomen to expand.
- Next, open your mouth and throat and create a forceful, deep exhale.
- When you think you have reached the end of your exhalation capacity, exhale even more deeply, feeling for a deep stretch in your upper lumbar and low-to-mid thoracic spine.
- Perform 3-5 repetitions of this drill each day for 1-2 weeks before moving on to stretch #2.
Supine Diaphragm Stretch #2
- Perform this exercise supine, begin with arms by your side.
- Perform a posterior pelvic tilt.
- Inhale fully as you raise your arms to the overhead position while simultaneously performing a standard bridge WITHOUT LOSING the posterior pelvic tilt.
- In the top position, open your mouth and throat and create a forceful, deep exhale.
- Once you’ve reached the end of your full exhale, maintain the exhale as you return to the ground. Try to widen your lower ribs as you do this.
- You should be feeling for a deep stretch in your upper lumbar and low-to-mid thoracic spine.
- When performed correctly this will create a “vacuum” effect in the abdomen, deeply stretching the diaphragm while allowing for abdominal relaxation.
- Perform 3-5 repetitions of this drill daily.
Once your clients have spent a few weeks working on their breathing mechanics and the above exercises it’s time to ramp up the intensity.
You may want to consider adding respiratory strength training into their program using an external device. If you are interested in learning more about this process and training progressions, you can check out the video below:
Finally, let me simply say that it would be impossible to overstate the powerful benefits that we have seen in working with breathing with thousands of clients; from those needing pain relief and rehabilitation to world champions in a variety of sports. Do yourself and your clients a huge favor and dig deeply into this topic. It will be well worth your time!
Calais-Germain, B. (2006) Anatomy of breathing. Eastland Press.
Elliott, A., Skowno, J., & Prabhu, M. Evidence of cardiac functional reserve upon exhaustion during incremental exercise to determine VO2max. British Journal of Sports Medicine 2012: 091752.
Louw, A., & Puentedera, E. (2013) Therapeutic neuroscience education. OPTP.
McConnell, A. (2011) Breath strong perform better. Human Kinetics.
McConnell, A. (2013) Respiratory muscle training: theory and practice. Elsevier.
Noakes, T. (2003) Lore of running – 4th edition. Human Kinetics.
Noakes, T. The central governor model in 2012: eight new papers deepen our understanding of the regulation of human exercise performance. British Journal of Sports Medicine 2012: 46:1-3.