March: Speed

   You're not off the hook for speed work -- yes, even if you're 80, even if you never break a 12-minute mile. Don't try to worm out of it. While sprinters need never succumb to the tortures of a 15-mile endurance workout, distance runners have to work both worlds. Speed work benefits all running programs. Just try to argue yourself out of it.

   I don't compete. Against whom? Maybe you don't race, but that's simply because you've neglected to fill out an entry form. All runners compete against their past performances, against their former selves. Regardless of your goals and enthusiasm for running, speed work helps you improve, especially by increasing your body's lactate threshold. Ultimately, this helps you shed pounds, improve agility and stamina (especially on hills), and recover more quickly, both during intervals and after workouts.

   I'm a beginner. Only two fates await you: either you'll stop being a beginner or you'll stop running. Speed work helps you with the former. To be sure, you want to build a dependable aerobic base before you add intervals, tempo runs, or sprints to your workouts; better running coaches recommend that once you've started logging consistent 20- to 25-mile weeks, it's time to graduate from kindergarten. Begin speed work slowly, but begin.

   I don't want to hurt myself. You're not alone. As running goes, however, speed isn't destructive. Researchers say the best predictors of injury are high mileage, insufficient rest in your training, and a history of previous injury. We all know the crippling pain that follows a day of hard sprints, but you can avoid this with an extended warm-up (a languorous two-mile run is good) and by quitting intervals before you run yourself into exhaustion. If you end your workout feeling that you could have done two or three more reps, you've ended it at the right time. Distance runners shouldn't try more than two speed workouts per week. Don't increase the total distance of your fast-paced running by more than 800 meters a week, and eliminate these workouts entirely every third or fourth week.

   Speed work steals time from distance training. Quite the opposite, actually: weekly interval sets of 50 to 200 meters can shave 5 minutes or more off a marathon time, according to two new studies from the University of Nebraska and the Institute for Olympic Sports in Finland. And because speed work reduces recovery time, distance runners can vary their pace more widely to accommodate terrain and other demands of a long race or workout. One way or another, it makes you a better distance runner.

   I refuse to run with a stopwatch. So let distance be your measure. Sprinters must approach speed work with mathematical precision if they hope to get better. The rest of us can count laps around a track, steps, or charges up a hill. The goal is not to increase your speed or the distance of your sprint. Rather, it's to shorten your recovery time (and ultimately, to add more sets). Be aware that once you get hooked on speed work using general measures, running watches suddenly look useful.