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The Science of Performance |
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Central Governor Model A review of Professor Noakes' Revolutionary Model of Performance Part 2 – Integrating Power Running into the Central Governor
Introduction In part 1 of this review we established the basis for the Central Governor Model – namely that exercise performance is controlled centrally, by the brain. At its essence the central governor model holds that the brain continually monitors all of the body’s systems and uses the data to calculate the maximum rate at which exercise can be performed while preserving and protecting the body from irreparable harm or death. In the article “Muscles Limit Performance” I built the case that muscles exert the greatest influence on performance. In that article I cited two research studies that found that distance running performance could be accurately predicted by both sprinting and jumping events. Specifically these studies found that 20m sprint times were a better predictor of 5k performance than VO2max and that the 50m sprint, 300m sprint, and plyometric leaping performance were excellent predictors of 10k run performance. In fact, plyometric leaping performance was a single better predictor of 10k performance than VO2max and was as good or better at predicting performance than lactate threshold (plyometric leaping is similar to the triple jump except that it is performed from a standing rather than running start). Using these two studies I argued that even though sprinting and jumping are anaerobic events their surprisingly potent ability to predict long distance performance indicates that whatever limits performance at sprinting and jumping must limit performance at endurance events too. I asserted that since muscle contractility is the only factor common to sprinting, jumping, and distance running that these studies support my contention that muscle contractility limits both sprinting and endurance performance. The question arises then – does the central governor invalidate my power running model of performance? If the brain centrally controls muscle fiber activation rate then doesn’t that suggest that the central governor overrides any influence that muscle contractility has on performance? Or at a minimum that muscle contractility is secondary to central control at least in terms of the primary influencer of exercise performance? Let’s explore these questions in more detail. Integration of Muscle Power and the Central Governor To answer these questions let me use the following analogy. It’s not a perfect analogy but it is close enough to make my point. Imagine that we have two motorcycles – one with a 125 cubic centimeter (cc) engine and the other with a 250 cubic centimeter (cc) engine. Both engines have governors which prevent the engines from running at excessive rpms and destroying themselves. Without a governor the 125cc engine makes a peak of 30 horsepower (hp). Due to its 125cc larger displacement the 250cc engine makes a peak of 40 horsepower (hp) without a governor. However, since both engines do have governors they are prevented from making peak horsepower. The governor on the 125cc engine is set so that horsepower peaks at 25 and on the 250cc engine the governor kicks in at 35 horsepower. The motorcycle manufacturers set the governor at very conservative levels before they deliver the motorcycles to the consumer – hence the reason the 125cc makes only 25 horsepower as delivered and the 250cc makes just 35 hp as delivered even though they are capable of 30 hp and 40 hp respectively. With a little knowledge and a few tools you can modify the governor on either bike so that either one comes much closer to reaching its peak horsepower. With some modifications of their governors, the bikes would reach about 28 hp and 38 hp respectively. Of course, if you removed the governor the 125cc bike would achieve its max of 30 hp and the 250cc bike would achieve its max of 40 hp. Despite being able to modify the governor you can not make the 125cc engine produce the same 40 hp that the 250cc engine makes. No matter what changes you make to the governor of the 125cc engine that engine will not produce 40 hp. In fact, due to its inherent design characteristics even if you removed the governor the 125cc engine is not going to produce 40 hp. With extensive engine modifications the 125cc engine will produce at most about 35 hp and then the lifespan of the engine will be severely shortened due to the immense strain it endures to produce that much horsepower. Due to its greater displacement advantage the 250cc engine will always be able to produce more horsepower than the 125cc engine. Though you can modify the governor so as to allow the engine to work closer to its current maximum, ultimately, to go significantly faster will require engine modifications. Increase the displacement of the 125cc engine, to 150cc or 200cc for example, and you instantly have more hp and a faster motorcycle. How does this relate to our bodies? The motorcycle is analogous to our bodies – our muscles are the human version of a motorcycle engine and our body’s central governor serves the same purpose as the motorcycle governor. Our muscles produce the power while the central governor ensures our muscles don’t work so hard so as to become permanently damaged. And like the governor on the motorcycle, the human central governor is set by the factory at a conservative level. And just like the motorcycle governor, with the proper knowledge and the right tools the human central governor can be re-set to a higher level. This then is the integration of the muscle power model and the central governor model. Your muscles are the engine of your body and there is a maximum amount of power they can produce. The central governor regulates power output, preventing the muscles from working at their maximum level for extended periods so as to protect the body from permanent damage or death. The central governor regulates power output so that the task at hand is completed in the quickest, most efficient manner while maintaining a reserve of physical and mental capacity. The central governor can not cause muscles to produce more power than the muscles are capable of – it can only regulate the available power output. These two physiological models – muscle power and central governor – are not in conflict and the central governor model does not invalidate the muscle power model. Instead they are complimentary, working together to maximize efficiency while maintaining homeostasis. Indeed, even Prof. Noakes addresses the issue of the integration of the muscle power model and the central governor model. Before proposing his central governor model, Prof. Noakes believed that muscle power played a primary role in performance. In the 1991 edition of his book, Lore of Running, Prof. Noakes writes, "My personal bias is that the rate of oxygen transport is not the critical factor determining exercise performance. Rather, I suggest that the best athletes have muscles with superior contractility..."(1) Even more definitively, he writes, "A muscle factor determines running performance at any distance."(2) Prof. Noakes beliefs about the role of muscle in endurance performance were modified with the introduction of the central governor model. In the updated 2003 edition of his book, Lore of Running, Prof. Noakes first introduces the running community to his newly formulated central governor model. He articulates the integration of the muscle power and central governor this way, "I interpret these findings to indicate that muscle and neural (brain) factors contribute to running performance at any distance." (3) Prof. Noakes has clearly modified his beliefs about the role of muscle power in performance and integrated the muscle power model into his central governor model . Training Implications What are the practical implications of the integration of these two models? First, in order to perform at your maximum your training will need to improve both the total power output of your muscles and re-set your central governor so that it allows greater power output prior to kicking in. To increase muscle power, recall our power formula from the “power running” series. Power = strength + contraction speed + muscular fatigue resistance + metabolic fitness We can substitute “central governor” for the term “metabolic fitness” in our power formula since they are basically the same thing, leaving us with the following: Power = strength + contraction speed + muscular fatigue resistance + central governor Improve any of the first three factors – muscle strength, muscle fiber contraction speed, muscular resistance to fatigue - and the overall power output of your muscles will increase. Using our motorcycle example, an increase in any of these three factors will result in an increase in the total horsepower of your muscles. Review the series “power running” and “muscle contractility” for recommendations on how to increase any of these three factors. Re-setting the central governor so that it allows a higher power output before it is tripped is best accomplished by training specificity and intensity. The more specific your training the more precise your central governor will be in determining the most effective power output for that activity. For example, if you are going to be competing in heat or on hills, then you should strive to train in the heat or hills. Specificity means that you should conduct some of your training at a similar distance and pace as you will be competing. Each time you do this, your central governor becomes more precise at determining the proper power output for your particular event. High intensity training also powerfully affects the central governor, re-setting it so that it allows increasingly higher power outputs before being tripped. One of the reasons that high intensity training causes immediate performance improvements, improvements that have been shown to occur in the absence of physiological changes (i.e. no changes in lactate production, mitochondrial density, heart size, capillary density, muscle fiber size, etc), is from the re-setting of the central governor at a higher level. High intensity training helps re-set the central governor so that it allows a greater mass of muscle fiber to be activated at one time, resulting in a higher total power output. Summary The muscle power model of performance and the central governor model of performance are complimentary models. Integrating these two models allows us to more accurately describe the physiological processes occurring in the body and helps us design more effective training programs. In order to improve your performance you will need to increase your power output. This is best done by increasing the power capacity of the muscle fibers and by re-setting the central governor to allow a higher power output before it is activated. References:
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