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Muscle fatigue is caused by the brain. Here are 10 ways to train your brain to delay muscle fatigue.
You know the feeling. You’re two miles into a 5K road race when you begin to feel a burning sensation in your windpipe, a growing heaviness in your legs, and an intense desire to slow down in your mind. The discomfort becomes more intense with each stride. By the time you cross the finish line you have just plain had it. You can barely stand.
What causes these intense feelings of discomfort that are always associated with fatigue during hard running (or any other form of exercise)? Sports scientists used to believe that muscle fatigue was caused primarily by acid buildup and energy depletion. But within the past several years a revolution has occurred in the scientific understanding of muscle fatigue. A growing number of experts now believe that muscle fatigue is actually caused primarily by the brain. That’s right: the brain.
The best evidence that muscle fatigue starts in the brain comes from studies involving sensors that measure electrical activity in the muscles. The amount of electrical activity in the muscles is a direct indicator of how hard the brain is driving them to perform work. In a recent French study, researchers found that an involuntary drop in performance during repeated bicycling sprints was accompanied by a comparable decline in electrical activity in the muscles. These results clearly showed that fatigue was not caused by acid buildup or any other factor within the muscles themselves. Instead, it was caused by reduced drive from the brain.
Why would your brain cause your muscles to stop working when there’s nothing actually wrong with them? Researchers speculate that it’s your brain’s way of preventing you from exercising to the point where you severely damage your muscles or other organs. For example, the muscles do become slightly more acidic during intense exercise, such as a 5K road race. If they became too acidic, however, some of your muscle cells would be destroyed.
To prevent such a disaster from occurring, your brain constantly monitors chemical and electrical signals sent from the muscles and other organs. When one or more of these signals seems to warn of impending harm, your brain produces conscious feelings of discomfort and reduces electrical output to the muscles to keep you safe. It so happens that rising acidity activates pain receptors in the muscles, serving as one of those warning signs.
So, what does all of this mean to you? The new understanding of exercise fatigue is leading to a new understanding of how to enhance athletic performance. If muscle fatigue originates in the brain, then the brain should be the primary target of our efforts to prevent fatigue. Here are 10 ways to “train your brain” for better performance.
1. Increase your pain tolerance
According to the new, brain-centered model of muscle fatigue, the feeling of fatigue itself limits performance as much as physical events in the muscles. This does not mean fatigue is an illusion. The pain and suffering of fatigue force every athlete to slow down eventually. But there is significant variation in the level of pain and suffering that ultimately causes performance to decline in individual athletes.
Beginning athletes tend to have a lower pain tolerance, because the pain of extreme muscle fatigue is unfamiliar. The brain is always somewhat overprotective in dealing with unfamiliar “threats” to the health of the organism. Thus, if you’re a beginner, your brain will force you to slow down at a lower level of fatigue than is required to make an advanced athlete slow down. But when you manage to push through a few hard workouts without suffering any permanent harm, your brain will relax a bit and allow you to push deeper into fatigue before you bonk.
Take advantage of this phenomenon by doing two or three very hard workouts each week. Your objective is to gradually increase your ability to push through the sensations of muscle fatigue. Training essentially becomes a process of recalibrating your brain’s response to fatigue.
2. Obey the hard-easy rule
Why not perform very hard workouts every day? The reason is that how hard you train is not the only thing that matters when it comes to recalibrating your brain’s response to fatigue. Your absolute performance level also matters. In other words, your workouts should serve not only to teach your brain that the pain of muscle fatigue won’t kill you, but should also to teach your brain that running at faster and faster speeds and/or for longer and longer distances won’t kill you either.
In order to perform at a high level in your hardest workouts, you must not be fatigued already from prior training when you start them. That’s why you should not try to train hard every day. Doing at least one easy workout between hard workouts will help you perform better in your hard workouts and thereby gett a stronger “brain training” effect from them.
3. Do race-intensity workouts
Brain training is essentially a matter of familiarizing your brain with the specific demands of competing. As a runner or other type of endurance athlete, you want your brain (and body) to be most familiar with race intensity. You should therefore do workouts involving race-intensity efforts throughout the training process.
In the early stages of training, expose yourself to only small doses of race-intensity running (or whatever) while focusing on building a foundation to support peak race-specific fitness later with longer, slower efforts and shorter, faster efforts. Gradually increase the amount of race-pace running you do as you draw closer to your most important race. In the final weeks of training, do some highly specific workouts that are almost as hard as the race itself will be.
4. Don’t overtrain
Hard workouts stimulate the release of cytokines, special immune system cells that coordinate the body’s response to the stress of exercise. One of these cytokines, IL-6, is known to enter the brain and cause fatigue. After a hard workout, cytokine levels remain elevated as they aid in the repair of exercise-related muscle damage.
Cytokine levels remain chronically elevated in athletes who overtrain—who do too many hard workouts and do not rest enough between hard workouts. Many athletes assume that the muscle fatigue they experience during workouts is totally different from the fatigue of incomplete muscle recovery, but they are really the same. Both are brain-based self-protective mechanisms whose function is to prevent you from doing too much.
It is important that you consistently monitor your recovery status and take measures to ensure that you do not allow yourself to enter the chronic fatigue state of overtraining.
5. Cross-Train
Cross-training is any type of exercise besides running that you do for the sake of improving your running. There are three basic types of cross-training that have been proven beneficial to runners: resistance training, flexibility and mobility training, and non-impact cardiovascular training. Each type of cross-training has a brain training dimension.
Resistance training improves communication between the brain and muscles in ways that enable you to run more efficiently and with less chance of injury. Flexibility and mobility training enhance running efficiency by training your neuromuscular system to eliminate unnecessary muscle tension from your stride. Non-impact cardiovascular training increases running efficiency and fatigue resistance by training neuromuscular patterns that are similar to but slightly different from those used in running. Your brain can then “transfer” some of these patterns back to running in ways that boost efficiency and fatigue resistance.
6. Work on your technique
The motor center of your brain stores the information that controls your muscles during running and other sports actions in a manner that is similar to how a computer stores software programs. These movement programs are highly adaptive. Many endurance athletes, and especially runners, do not adequately appreciate their capacity to modify and improve these programs by actively working on their technique.
As a runner, the best way to work on your technique is the same way athletes do in other sports, such as golf, that are recognized as technique-dominant: by imitating the best. Throughout every run you do you should consciously control you stride in one or more ways to make it more like the strides of elite runners. Concentrate on landing on the mid-foot with your foot underneath your hips, moving with prefect left-right symmetry, generating powering from the hips, minimizing ground contact time, and staying relaxed in your upper body.
7. Use protein power
Sports drinks are known to enhance performance in running and other sports by limiting dehydration and supplying extra carbohydrate fuel to the muscles. Sports drinks containing carbohydrate and protein are proven to enhance performance more than conventional sports drinks containing only carbohydrate. They appear to do so in part by lowering perceived exertion, or how hard exercise feels at any given intensity.
8. Empty your gas tank
The cytokine IL-6, mentioned above, not only causes fatigue during exercise but also helps coordinate some of the positive fitness adaptations that occur between workouts. These adaptations include improved fat burning efficiency and greater resistance to exercise-related muscle damage. The primary trigger for the release of IL-6 is depletion of muscle glycogen stores. The best way to deplete your muscle glycogen stores is to do a very long workout ending in near exhaustion. By doing this type of workout on a regular basis—once every week to ten days—you will maximize the rate at which fitness adaptations resulting from IL-6 circulation occur.
9. Visualize perfection
The motor programs for running and other sports actions that are stored in your brain can be modified even when you’re at rest. When an athlete imagines himself running, he activates the same neurons (brain cells) that become active when he actually runs. You can take advantage of this phenomenon to improve your technique by imagining yourself moving with flawless technique during brief mental rehearsals. A good time to perform these rehearsals is at night, in bed, before you go to sleep. Just five minutes per night is adequate.
10. Set higher goals
When you run a race, you cover the race distance as fast as you can. But upon finishing, how do you know you’ve actually run as fast as you could? You simply feel that you ran as fast as you could. But this feeling is not 100% reliable. For example, studies have shown that runners run faster in races against matched competition than they do in solo time trials, despite the fact that they feel they are running as fast as they can in both circumstances.
The brain always allows a safety buffer that prevents you from running truly as fast as you could and thus risking self-harm. The size of this buffer is influenced by various factors. Basically, the more motivated you are, the smaller the protective buffer you will, and the faster you will run. Competition is a motivational factor that shrinks the buffer. It is also influenced by goals. If you set an appropriate race time goal, you will be able to run races faster than you could if you ran strictly by feel without a number in mind. A race time goal is like an imaginary competitor to race against.
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