The Chicago Marathon is known as being one of the fastest and most competitive races in the United States and the world. And it can definitely be that way for the majority of people! Just like any race, it is important to prepare and know the course, as well as a couple of other things to keep in mind when running Chicago if you want to PR.
Your watch will be off. It may rapidly fluctuate current pace and be misleading if you are relying on that feedback for your splits. It is more effective to turn off autolap and just click the lap button at each mile marker for accurate mile splits. It's speculated that the GPS is so off due to the tall buildings, but there are lots of tall buildings in NYC and the GPS watch seems to work just fine there.
There is another way to know if you are hitting your splits. Write your 5k splits on your arm, check the clock when you cross the start line, and add that number to each 5k clock you see. There will be clocks on the course at every 5k and also the half marathon mark.
Don't go crazy the first mile. This is an absolutely beautiful mile with skyscrapers and glorious architecture. Look the fuck around you. Don't get caught up in dipping and dodging people to get to your goal race pace. Bobbing and weaving will not pay dividends. Just be in it, it's pretty rad.
There are many turns, but there are also some really long stretches. Miles 4-7 is a very long stretch through a beautiful park. This is a really nice stretch to settle into your goal race pace and pick up a pack or a pace group.
About those turns: it is really easy to run poor tangents in Chicago because of how many turns there are. The best way to run good tangents is to find that blue line on the turns and stick with it. That blue line is the shortest possible distance from start to finish. At points the blue line may disappear. This is usually because it is the middle of the street where the yellow lines are.
There are 6 bridge crossings. Theses are not steep inclines, they're very flat. But they are metal grates with carpet over them. They can get slippery if it is rainy or had been rainy prior to the start. Be cautious when crossing these bridges and stay on the carpet, not the metal grate.
Don't eat the vaseline. This is my husband's two cents because when we ran Chicago, he saw a man take the popsicle stick with vaseline and eat it. The thing is....it is Biofreeze. Yikes!
Miles 21, 22, 23 lose some spectators and can be quieter than the previous miles. It doesn't help that this is also the most difficult section of any marathon mentally and physically for most people. Keep your head in the game here. It is just you against you out there and this becomes massively obvious at this time.
The finish line: You will make a hard right up the only hill in the race, then a hard left to the finish. This hill feels like an Everest at mile 26. This hill is not the time give in, it is the time to dig in. If you burn it up that hill, you will propel yourself around the corner to the finish and it will feel epic. Burn, baby, burn.
After the race, eat all the deep dish pizza, Au Chevel burgers, and my personal favorite Chicago restaurant is The Girl and the Goat. ENJOY THE FOOD.