Leslie Townsend

“IS FATIGUE ALL IN YOUR HEAD? In the early 1990s, in a physiology lab at the University of Cape Town in South Africa, an exercise scientist named Tim Noakes, MD, unveiled a radical new way to think about fatigue. Until then, prevailing wisdom held that fatigue occurred in the body. At a certain intensity or duration of physical effort, the demands we put on our muscles become too great and, eventually, our muscles fail. Ask any athlete, from a marathon runner to a powerlifter, and they will be familiar with the feeling. It’s not a particularly comfortable one. What at first is a manageable burn becomes worse and worse until they can no longer bear it. The runner’s pace slows to a mere shuffle; the powerlifter can’t manage to hoist the barbell up for one last rep. Try as they might, they simply run out of gas and their muscles cease to contract. Noakes, however, wasn’t convinced that fatigue occurred in the body or that muscles actually ran out of gas. He questioned why so many athletes, seemingly overwhelmed by fatigue, were suddenly able to speed up during the final stretch of a race when the end was in sight. If the muscles were truly dead, Noakes hypothesized, these finish-line spurts would be impossible. To prove his point, Noakes attached electrical sensors to athletes and then instructed them to lift weights with their legs until they simply couldn’t lift any longer. (In exercise science, this is called “inducing muscle failure.”) When the weights slammed down and each participant tapped out, reporting they could no longer contract their muscles, Noakes ran an electrical current through the sensor. Much to the surprise of everyone—especially to the participants whose legs were dead—their muscles contracted. Although the participants could not contract their muscles on their own, Noakes proved that their muscles actually had more to give. The participants felt drained, but empirically, their muscles were not. Noakes repeated similar versions of this experiment and observed the same result. Although participants reported being totally depleted and unable to contract their muscles after exercising to what they thought was failure, when electrical stimulation was applied, without fail, their muscles produced additional force. This led Noakes to conclude that contrary to popular belief, physical fatigue occurs not in the body, but in the brain. It’s not that our muscles wear out; rather, it is our brain that shuts them down when they still have a few more percentage points to give. Noakes speculates this is an innately programmed way of protecting ourselves. Physiologically, we could push our bodies to true failure (i.e., injury and organ failure), but the brain comes in and creates a perception of failure before we actually harm ourselves. The brain, Noakes remarked, is our “central governor” of fatigue. It’s our “ego” shutting us down when confronted by fear and threat. In other words, we are hardwired to retreat when the going gets tough. But like Boyle and Strecher demonstrated, it is possible to override the central governor.”
― Brad Stulberg, Peak Performance: Elevate Your Game, Avoid Burnout, and Thrive with the New Science of Success