I still remember standing on the start line of one particular triathlon, excited, confident, and convinced I had done everything right leading up to that day. The training boxes were all checked, my numbers looked solid, and on paper I was more than ready. But once the gun went off, the race slowly unraveled—not because my body wasn’t prepared, but because my mind wasn’t. My focus scattered, my decisions got sloppy, and what should have been a strong performance turned into a painfully, and very publicly, poorly executed day.
Years later, I found myself sitting in a class hosted by Dr. Scott Frey Ph.D., of cerebralperformance.com, listening to him break down how the brain shapes our perception of effort, pain, and performance. As he spoke, I could suddenly see that disastrous race with new clarity. It wasn’t a failure of fitness; it was a failure of mental preparation and decision-making under stress. The dots connected: my brain had been the limiting factor long before my muscles ever were.
That experience fundamentally changed how I think about training, racing, and coaching. Physical preparation is essential, but it’s only part of the story. The mind—how we interpret signals, manage discomfort, and make choices in key moments—quietly drives so much of what shows up on race day.
Every athlete's journey is a rich tapestry woven together by a myriad of experiences. This mental landscape is perpetually shaped by our brain—a complex organ that filters and interprets reality, influenced by our past experiences, current conditions, and expectations for the future. Astonishingly, much of this intricate process occurs below our conscious awareness, seamlessly integrating into our physiological responses.
The brain's role in modulating neurotransmitters, hormones, and even our immune system is a testament to how our perceptions and beliefs are deeply rooted in our biological makeup. Just as circulation is the heart's domain, the mind is the brain's realm. Through the phenomenon of neuroplasticity, repeated thoughts and actions can literally rewire the brain's functionality, reinforcing the necessity of considering mental training as seriously as we do physical training.
One aspect that often surprises many is the sheer power of belief. Placebos, for instance, demonstrate how our expectations can tangibly affect outcomes, changing everything from perceived exertion to pain tolerance and even recovery. This isn't a mere psychological parlor trick; it's a profound insight into how deeply our minds influence our bodies and shape our moment-to-moment experience of effort.
For endurance athletes, this means that what we believe about our capacity, our readiness, and even our identity as “someone who can handle hard things” quietly affects every decision we make under fatigue. Acknowledging this mental component doesn’t replace physical training—it amplifies it. When belief is trained and aligned with the work we’ve done, it can turn a solid training block into a breakthrough performance, helping transform a good athlete into a great one.
One of the most fascinating points Frey makes is about the decision-making process involved in pushing our limits. The brain integrates sensory feedback and adjusts physical output, suggesting that what we perceive as our "limit" is often more a choice than a physiological barrier. This decision point is highly malleable, influenced by our mindset and mental training. We can decide to play it smart and rest, or we can choose to dig deep and push beyond what we previously thought possible.
For example, imagine a triathlete late in the run leg of an Ironman, feeling their pace start to fade and their legs grow heavy. Here, the brain is sorting through signals of rising fatigue—burning legs, heavier breathing, mounting discomfort—and this is often a place where it is safe to consciously choose to lean in, hold form, and sustain effort a bit longer. But if those sensations shift from fatigue to sharp, localized, or destabilizing pain, the message changes completely; we can push through fatigue, but we shouldn’t push through pain. That’s the nervous system speaking in a different language, signaling potential harm—and in those moments, the smartest decision is to listen and back off.
A striking example of the brain's influence is the impact of mental fatigue on physical performance. Studies indicate that even the seemingly innocuous activity of browsing social media for 30 minutes prior to a workout can lead to decreased performance. This finding underscores the connection between mind and body, highlighting the importance of mental preparation alongside physical readiness.
What’s happening here is that the brain is already “spending” some of its limited cognitive resources before the workout even begins. Scrolling through feeds, making rapid-fire micro-decisions, and processing an onslaught of emotional and sensory inputs quietly taxes the same neural systems that help you focus, tolerate discomfort, and maintain pacing under stress. By the time you start your session, your brain may already be a step closer to its perceived limits, even though your muscles are physically fresh. The result can be subtly reduced motivation, poorer pacing decisions, and an increased sense of effort at intensities that would normally feel manageable.
This has practical implications. Just as you wouldn’t show up to a key workout sleep-deprived or under-fueled, it’s wise to treat your mental state with the same respect. Creating a brief pre-session routine— practicing a few minutes of quiet breathing, reviewing the purpose of the workout, or visualizing key moments of effort—can prime the brain for performance rather than distraction. Over time, cultivating these habits not only protects you from the drag of mental fatigue but also strengthens the very circuits that support resilience, focus, and the capacity to push when it matters most.
One simple way to train this mental side is to build a short, intentional “decision-point drill” into a weekly workout. For instance, during the final intervals of a hard effort, anticipate the moment when your legs/arms, start to burn and your breathing becomes strained, and deliberately practice choosing a specific response: relax your shoulders, repeat a cue like “strong and smooth,” and hold pace for 60–90 seconds past the first urge to back off, as long as the sensations remain general fatigue rather than sharp or destabilizing pain. After the session, briefly reflect on what thoughts showed up at that decision point, how you responded, and what you want to reinforce next time. Over weeks and months, this kind of structured mental rehearsal helps rewire the brain’s default reaction to discomfort, strengthening belief in your capacity to stay engaged and focused even when effort rises.
Another tactic I often recommend is adding a short cognitive drill right after a hard workout, using a simple brain-training app or reaction-time game. Spend a few minutes completing tasks that challenge your attention, speed, and accuracy, and record metrics like how alert you feel, how quickly you respond, and how many errors you make. Over time, this creates a personal data set that shows how your decision-making shifts under fatigue and helps train your brain to stay sharp when your body is tired—exactly the scenario you face late in a race or key session.
The takeaway here is clear: the brain is the ultimate arbiter of physical output, regardless of the data and devices we may use to measure performance. Training the brain should be given as much priority as training the body. Indeed, by harnessing the mental influence and structuring mental training alongside physical routines, we can unlock new levels of athletic achievement.
While traditional training elements like physical conditioning and nutrition remain vital, the mental aspects of athletic performance are equally significant. By understanding and harnessing the power of the mind, athletes and coaches can achieve a holistic approach to performance, optimizing both the body and the mind for maximum success.