Despite the rapid growth of the half-marathon and marathon in the last decade, the 5K still tops the list, with 8.3 million finishers in 2013.
Training for the 5K and marathon are actually quite similar, with 5K training being only a couple shades of gray different from your marathon prep. Both races are largely aerobic, so the majority of training for both should be at or below 85 percent of your max heart rate. Additionally, the majority of the world's best 5K runners consistently execute weekly long runs, just as marathoners do.
One of those gray shades between the marathon/half-marathon and 5K training is incorporating race pace even in the earliest stages of your training so you always stay in touch with some speed. Here are some insightful workouts and tips on how best to improve for this common race distance.
A great way to keep in touch with 5K race pace early on, without detracting from your aerobic development, is to finish two or three runs each week with eight 100-meter accelerations (ideally on a slight uphill grade to maintain and improve extension and toe-off). If these post-run strides don't appeal to you, try accelerating for 20 to 30 seconds four or five times during the final few miles of your run.
2 x 7 Minutes
Run each 7-minute rep at or slightly quicker than your goal 5K pace with 5 minutes rest between each rep. For a twist, run the 7-minute reps on a slight downhill grade (0.5 percent), with the goal of running slightly farther on the second rep compared to the first. (You'll need someone to drive you quickly back to the start after the first 7-minute run). Do this workout a couple of times in the final 4 to 5 weeks before important races, but no closer than 10 days before your most important race.
Race Short/Race Long
5K specialists will benefit from running a couple of shorter and longer races prior to their goal 5K race. For example, you can race a 1-mile race or 3K and a 10K or 10-miler. Run the longer races farther out from and the shorter races closer to your goal 5K.