Now, please don't take this advice as me telling you not to try for a PR. If the course is flat and fast, and you're fit, by all means, figure out that PR pace and get into a groove ? and then grind it out in the final miles. Even though there will be a ton of excitement on race day—who doesn't get pumped up when they're playing good music at the start line—you need to stick to your pre-race plan, a guide that is based on your current level of fitness.
More: How to Run Fast: 3 FAQs
Don't Go Out Too Fast
Don't go out too fast. If you do, bad things will happen later in the race. In many ways this lesson is similar to the first, but it's an important one. If you've run several marathons and are shooting for a small PR, you're always better going out a bit conservatively and then grinding out the final miles to set a PR. You want to run an even pace or a negative-split race, where the second half is faster than the first half. Again, this may be subtle. For our 3:30 marathoner, he might hit 8-minute miles on the nose for 20 miles, then speed up just 5 seconds per mile for the final 6.2 miles. But, if he does that, he'll run a 30-second PR—certainly something to celebrate post-race.
This lesson is hard to put into practice, especially if you've done solid training and have completed an appropriate taper. Your legs should feel great come race day, and since your aerobic "engine" (your heart and lungs) are ready to go, it's going to take some concentration to hold back and run your pace for the first 15 to 18 miles of the race.
And maybe the biggest thing to remember within this lesson is this: Most everyone who runs the marathon will slow down in the second half of the race. This means that you must resist the urge to get sucked along with those around you, most of whom will end up slowing down later in the race.
For some racers, this is where the pace packs really help. You'll see a pace team leader holding a sign printed with their goal finish time above their heads. If you want to break 3:30, run with that 3:30 group for 18 or 20 miles, then gently start to speed up, moving through those final miles faster than the 3:30 group.