The biggest growth in road racing the last few years has been at the 5K (3.1 mile) distance. This is partly because it's short enough to be a reasonable, enjoyable goal for recreational runners and cross- trainers. If you plan to race 5K, however, don't think you can take it lightly. After all, the world's best train over 100 miles a week for the 13 minutes (15 minutes for women) it takes them to run the distance. While debate on the award for what feels like the longest distance continues--the last mile of a marathon and the last bit of a 400- meter race are usually mentioned--the last half-mile of a 5K is a prime candidate.

That's because a 5K should be run right at your maximum aerobic capacity. This means that even in a perfectly paced race your blood lactate levels (an indicator or muscular fatigue) will rise throughout as your run become increasingly more anaerobic. Start too fast, of course, as many people do, and this unpleasantness will kick in even sooner. This makes the race all the harder, because you'll start thinking that a mile into a race is far too early to be hurting that much. Constant mental focus is also necessary in a short race like a 5K, which adds to your fatigue.

Going out sanely and more slowly than you are able, then, is crucial to running your best 5K. Even more than in most other distances, starting too quickly to build a cushion for an inevitable slowdown at the end become self-fulfilling. That is, run too fast the first mile and you are assured of slowing in the last. Most people can run a 5K about ten seconds per mile faster than a 10K. Know what you're capable of and shoot for that goal, regardless of whatever foolhardiness is going on in front of you the first mile. Doing workouts near 5K race pace is a good idea for any racer, but especially so if you want to have a feel for the proper tempo at the beginning of a 5K.

Be sure you're completely warmed up before racing a 5K. You'll be running very fast right from the start, and if you're not ready to do so, you'll go anaerobic much sooner. Jog at least a mile, do a fair amount of stretching, jog some more, do a few 100-meter accelerations at race pace about five minutes before the start, and then keep moving lightly until the gun goes off.