Training With a Power Meter
Very simply, look at the dial and don't surge! You have a power monitor on your stem. That monitor tells you what you're doing. You should know what you're supposed to do, in other words what watts you're supposed to stick to. Simply put, if you look at the dial and see stupid numbers, stop being stupid! Having enough gears on your bike to maintain a comfortable cadence across a range of terrain will go a long way to help you avoid surges or spikes in your watts.
The most important tool is simply increased awareness. After years of riding with power, you get accustomed to locking your eyes on the monitor whenever the terrain changes. The goal is to NEVER put out unintended watts. The goal is to make zero mistakes.
Training Without a Power Meter
Pay attention to the pressure on the soles of your feet. You're riding on the flats at 90rpm, creating X pressure on the soles of your feet. As the road starts to go up, focus on the pressure and shift up (to easier gears) to keep the cadence and pressure the same.
At the same time, watch the people around you, using them as a frame of reference. They will likely stomp on the gas and gap you—this is a good thing.
If the hill is steep enough and/or long enough, you'll run out of gears. Just settle in and get up the hill comfortably. Note that heart rate (HR) is not a great tool in this situation, as HR lags effort by about 90 seconds. If your HR raises from low Z2 to high Z3?that probably means you've been riding at a Z4 to Z5 effort the whole time and your HR is only just now catching up.
Continue to watch the people around you, specifically their body language. You'll see them come off the gas and now the gap they opened up on you stabilizes or even comes back to you a bit.
As you near the crest of the hill, focus on your feet again. Keep the pressure the same by shifting up in the gears. You're not going harder; you're simply extending your climbing effort above across the crest and into the downhill. Stay on the gas until you get up to about 34mph, then get aero and coast. As your speed bleeds off, just start pedaling again at your selected cadence and pedal pressure.
Again, watch the people around you. You'll either see them come WAY off the gas and start coasting right away—their 27 mph to your 35 mph—or pedal weakly across the crest and keep pedaling on the downhill, even trying to accelerate beyond your 34 mph. It's very, very cool to pass someone pedaling like crazy while you're aero, coasting, stretching, and recovering.
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