After the gun goes off and you get over the starting line, you would be wise to relax and just focus on getting warmed up. With all the excitement and competitive atmosphere, do not get caught up in the groups of runners that sprint off the starting line. Just focus on safe, even, splits. It should still feel "easy". You will usually get a burst of energy (and confidence) around 10 or 12 miles in. After being totally warmed up and really into the meat of the race, you might be tempted to speed up, but you need to hold back and stay the course. Around 16-17 miles in you will start to feel winded but should be able to keep up your pace. Somewhere between the 18 and 22 mile mark is where a lot of people hit the "wall". Run a smart pace, train well, and you won't hit it. You will be tired here, but this is where being tough (both physically and mentally) can carry you through the last few miles on pace!
One of the best things you can do it to utilize a pace group. Races have these set up where several reliable pace leaders will run an evenly split marathon based on a certain time. There should be plenty of info available at the race expo, on the website, and if thats not enough the morning of the race the pace leaders themselves will be holding up big signs or balloons with their expected finish time.
|Pace groups at the Chicago Marathon.|
The bigger races offer lots of pace group, some of them (like Chicago) even have an unheard of sub-3 hour marathon pace group. Smaller races might only start at 3:30. For instance, the Marine Corps Marathon here in DC has groups starting at 3:05 (the stringent men's under age 35 Boston qualifying time) up to 5:30. To be precise: 3:05, 3:15, 3:25, 3:35, 3:45, 4:00, 4:15, 4:30, 4:45, 5:00, and 5:30.
Pace groups make sure you don't go out too fast, and then have some other people to hang on to toward the end of the race when you are fading.
What time should I shoot for?
For newer marathoners, I usually suggest people think of three times. A "stretch" time, a "goal" time, and a "safe" time. Maybe your's would go 4:15, 4:20, and sub 4:30. Now, throw out the first two and aim for your "safe" time. Trust me, the amount of fade you will experience in the last 6 miles if you go out even slightly too fast for yourself will set you back far beyond what a safer goal would have been!
Why the "Negative Split"?
Without going into the physiological reasons, you will simply run a faster race if you run the first half conservative and the second half as fast or faster than the first half. A Negative Split is just that, running the second half faster than the first half.
Here is the thing: if you go out, say, even 10 seconds per mile too fast, this could result in such a fade that you are slow running or even walking the last few miles, losing over a minute per mile. So, 15 miles at 10 seconds too fast nets you 2.5 minutes. If you are losing a minute per mile (or more) your last 8 miles, this costs you at least 8 minutes.
Its always better to have too much energy the 2nd half than not enough.