Intensity may be one of the most important contributors to cycling performance. It's important because all the motivation, confidence, focus and emotions in the world won't help you if your body is not physiologically capable of doing what it needs for you to ride your best.
Whether you are cruising along in the peloton during a long, flat stage, ascending a Category 1 climb, or sprinting the last 100 meters of a crit, you must be at the right intensity to ride at your highest level.
What Is Intensity?
Simply put, intensity is the amount of physiological activity you experience in your body. This includes heart rate, respiration and adrenaline. Intensity is a continuum that ranges from sleep (very relaxed) to terror (very anxious). Somewhere in between those two extremes is the level of intensity at which you will ride your best in races.
The challenge with intensity is that there is no one ideal intensity for all cyclists. Depending on your physical and psychological make-up, you may ride best when very relaxed, moderately intense, or bouncing off the walls.
For example, Chris Froome needs to be relaxed during the early parts of the Alpe d'Huez stage of the Tour De France to conserve energy before the big ascents that lie ahead. Brad Wiggins must be at moderate intensity as he attacks Mont Ventoux so that he has enough energy to power up the climb and still have reserves for the final few kilometers. Robbie McEwen must be a nuclear reactor in the final sprint to the finish in Marseilles.
Experience and Perception
Intensity is made up of two components. First, there is the physical experience of intensity. This is what you actually feel in your body when you are riding. Are you calm or filled with energy? Are you relaxed or tense?
Second, there is your perception of intensity. In other words, do you perceive the intensity positively or negatively? Two riders can feel the exact same thing physiologically, but interpret those physical feelings in different ways. One may view intensity as excitement, and it will help his riding. Another may see intensity as anxiety, and it will hurt his riding.