Tempo work is a grueling, grind of a workout. It tests not only your dedication to becoming stronger, but your desire and ability to suffer (though there is more intensity to follow). The following suggestions are ideal for testing and implementing during tempo work. Try them and I'm sure you'll find them useful on the road and helpful when it's time to hammer.
Strategy #1: Breathing
In the book, the authors have extensive descriptions and exercises for getting in touch with the flow of your breathing, so I encourage you to read it. However, for our purposes here, I'll keep it very simple: Control your breathing to stay relaxed.
When we start dealing with discomfort and pain, we tense up. If you have tense muscles and posture, then valuable energy is going to waste. It takes energy (precious ATP) to contract your muscles. Tight and tense muscles use energy, leaving less available for your legs. The ability to stay relaxed when it gets difficult is paramount.
Imagine yourself riding up a gentle grade at a moderate pace. Gradually the hill's grade increases from two percent to maybe four percent. You, being dedicated to your training, work to maintain the same pace. So if you were going 16 mph up the two percent grade, you're working harder to go 16 mph up the four percent section.
Naturally your heart rate is increasing and your legs are loading up. You know you'll have to slow down eventually, but you want to see how long you can maintain this pace. The moment you start thinking about the discomfort is when you should start employing tactics to stay relaxed.
Focus on your breathing and upper body. Your arms and shoulders need to be loose and relaxed so you're not wasting energy being tense. Then work on controlling your breathing with full and paced breaths. Suck the air deep into your lower lungs and out again. The speed of your breaths will continue to rise, but you'll immediately find that some of the pain dissipates, either because you're no longer paying attention to the pain in your legs or because they're getting more oxygen.
Eventually you'll cross the ventilatory threshold, the point at which your body can't exchange the carbon dioxide built up, and your nervous system will involuntarily cause you to pant. Up until that point you'll be able to control the air flow.
In a phenomenon that occurs during difficult moments, some individuals leave their body -- so to speak. When the pain grows and the suffering begins, their mind tries to close itself off to the stimulus of suffering and simply sends out the signals to the body to continue working.
People who can do this might start focusing on something other than cycling or focusing on something up the road as a target. If you can learn to do this, it is another way to deal with the suffering. To get started, begin by focusing heavily on your breathing.