This is an excerpt from the new Triathlon 2.0: Data-Driven Performance Training (Human Kinetics, 2016), written by former elite triathlete Jim Vance.

“Everyone has a plan ’til they get punched in the mouth.” — Mike Tyson

Mike Tyson was one of the most feared fighters in the history of boxing. Yet there were plenty of experts in the sport who spoke of his weaknesses and how to beat him, as though it were not that hard. Many of his opponents trained and planned to beat him by using his weaknesses against him. And much like the quote from Tyson, those plans may have been very well devised, but once the match started and they took those first few punches, dealing with the adversity of the match, it became a challenge to stick to the plan.

That’s triathlon and racing. No matter how well you plan, when you get into the big races, against the toughest competition, your resolve and steadfastness to that plan will be tested greatly. Your plan better not be good — it must be great. And it should have contingencies if the punch to the mouth was more than you expected.

There are two types of athletes: scientists and artists. Scientists use the numbers and data to train and race to their potential, while artists use the feel of their fitness to train and race to success. A few athletes, and usually the most successful, would be categorized as both, using the best of both worlds to be successful.

Many of today’s top professional triathletes get into the wind tunnel, measuring the drag of their bike position. This is a perfect example of the science side of racing helping athletes. When they use this information in a race while facing the strategic decisions of attacking at certain points, reading their opportunities and opponents to use it, it only enhances the art of racing to their advantage.

If you were to listen to an interview with two-time IRONMAN world champion Chris McCormack, he would tell you a lot about the art of racing. He does not like power meters and GPS watches.

He’s an athlete who adjusted on the fly, reading his opponents and pushing the pace, taking risks in the race and putting pressure on his competitors. Sometimes it worked for him, and sometimes it didn’t.

Unfortunately, McCormack believed so much in the art of racing that he was very resistant to science. One wonders how many IRONMAN World Championships he might have won if he were as committed to the science of training and racing as he was to the art of racing.

McCormack has spoken out about reading races and going with your gut, using your perceived exertion in the moment and having faith in your training and fitness.

I agree that athletes need to race and quit staring at the numbers. Athletes need to build trust in their perceptions, take risks and learn what they’re capable of. Chances are they are more capable than they realize of better performance. Many simply need to break the chains of the power meter zone or running at a set pace.

Our perceived exertion levels are only as reliable and good as their connection with the reality of our fitness and capabilities, though. McCormack simply doesn’t like to use the common power meter and GPS or stopwatch for running to determine this. The better he sees the skill of perceived exertion being correct for him, the better feedback he gets for himself.

But this is an acquired skill that takes months, if not years, of development and has to happen over the course of each season as well. McCormack is a guy who doesn’t balance a full-time job with training. He can conduct the sessions required to learn this skill in a much more rapid time frame than the average age grouper. He does this well, and the results are clear, but that’s not reality for many athletes in the sport.

I get the sense it is better for him to say it is all art, and not science, because then it sounds like he is the only one capable of doing it correctly. It is certainly an art and science mix, but to say one artist’s way is the only way is not something most would ever agree with.

I was coached for a period by Peter Reid during my professional IRONMAN racing days. Reid was a three-time IRONMAN world champion and probably one of the most consistent IRONMAN world championship racers ever. He was really big on athletes not getting stuck on the numbers and not letting the power meter control the athlete. I agreed, because if you really train properly, then on race day, you’re going to ask more of your body than you ever have before. And the expectation is your body should perform better than it ever has before. If you’re feeling good on race day, go with it, but be smart about it. If your race day goal is 225 watts and you’re thinking the first hour at 280 watts is easy and you can hold it, that’s probably a little too dramatic of a change.

The wind and conditions might change, so maybe you’re going much faster or slower than you predicted. It’s important to know your estimated and training tested range, from your build phase and race plan.

This is going to come down to how well you know your body as an athlete. What abilities are you confident in? If you’re confident in your run ability, you may not need to take as much risk on your bike. If you’re not confident in your run, maybe you do.

Let’s say the race is a two-loop bike course and you’re five minutes slower on the lap than what you expected on your goal watts. Now it’s looking like you’re going to be out there for 10 minutes more than you expected. You likely need to adjust your power numbers to the slower part of the range or closer to it.

What about a flat tire or mechanical issue? Should you pick up the pace and push it a little bit? My answer is no. When you try to make up time, you are changing your game plan, which inevitably leads to problems. Remember, you’ve been training for a specific pace. If you try to make up for whatever’s lost and you haven’t trained for that, your body is not going to handle that well. As much as that probably doesn’t sound like a good plan to you, the rest and recovery you get from fixing the issue can sometimes lead to a much better run split. I have seen more than a few athletes run their best splits ever after a flat, or even after they had to serve a few minutes in the penalty tent. Use the poor circumstances to your advantage, and you might be amazed at what can happen.

Elites should consider the number of matches in their matchbook. Matches are big surges and attacks from the competition. The competition is certainly going to determine your race strategy and your race specificity, so if you’re an athlete who’s going to race off the front, it’s now a much different type of strategy and specificity. Or if you’re an elite who has to hold to a position within the line of athletes and go with the moves and surges of the group, your specificity is much different, and you need to know how many big attacks or moves you can counter and how big until it affects your legs for the run.

Race day execution begins long before race day. This ultimately means knowing your goal TSS, NP and IF and the speed you will need to hold to reach your goal bike split. You can also use software programs to help plan this. Fine-tune your estimate in training. You need to understand and accept the flexibility that you can and cannot have on race day.

When it comes to the run, you’ve got to keep yourself under control early, so choose metrics that will help you monitor your performance to keep you focused on executing the pacing successfully, and use your best judgment if you feel great and want to push the watts and pace a little. But be smart. Then, on race day, execute the plan and monitor the correct metrics. It is all about execution on race day.

Jim Vance is a former triathlete and currently an international triathlon, running and cycling elite coach with TrainingBible Coaching. He is the founder and head coach of the nonprofit organization Formula Endurance, the nation’s first USA Swimming and USA Triathlon high-performance team.

As the first program to take advantage of the latest science and technology, Triathlon 2.0 examines the sport’s most popular devices, including cycling power meters, GPS trackers, and heart rate monitors. Vance, now an elite coach with TrainingBible Coaching, helps you put the numbers to work, translating data into a comprehensive program based on your performance needs and triathlon goals. Triathlon 2.0: Data-Driven Performance Training is now available in bookstores everywhere, as well as online at HumanKinetics.com.

Excerpted from Triathlon 2.0 by Jim Vance. ©2016. Reprinted with permission from Human Kinetics.

All rights reserved. No reproduction, transmission, or display is permitted without the written permission of Human Kinetics, Inc.

The views expressed in this article are the opinion of the author and not necessarily the practices of USA Triathlon. Before starting any new diet or exercise program, you should check with your physician and/or coach.