Perhaps you run solely or mainly for the fitness and mental benefits -- weight loss, improved muscle tone, a more robust cardiovascular system, stress relief. But a certain subset of women run primarily to get faster. If you're one of them, and do most or all of your running on a treadmill, an easy schedule covering the full range of speed workouts can make you a faster racer.
You perform tempo runs, also called anaerobic-threshold runs or lactate-threshold runs, at the intensity level at which your muscles begin producing lactic acid faster than your system can metabolize it. According to Running Times, this corresponds to about 90 percent of your maximum heart rate, with the pace being 25 or 30 seconds per mile slower than your 5K race pace. To do a tempo tun on a treadmill, warm up easily for at least 10 minutes, then crank up the belt to the requisite speed and hold this pace for 20 minutes. If you don't have a 5K to refer to, run at a "comfortably hard" pace -- the speed at which you can just barely hold a conversation.
For some women, the treadmill is better than the track for doing speed work, because this eliminates the possibility of the erratic pacing that can wreck a workout. Short intervals are between 200 and 600 meters long -- about 0.12 to 0.38 miles. Mario Fraioli of Competitor Running suggests running these slightly faster than 5K race pace, taking a recovery jog lasting half the duration of the preceding interval and aiming for a total of 3,200 to 4,800 meters of fast work. For example, a 25:00 5K runner committed to an easy schedule could do 12 times 0.25 mile in 1:55 with a 1:00 jog. Slowing the belt drastically between fast segments does take some getting used to.
The principle underlying long intervals is essentially the same as that behind short intervals, except that with long intervals -- 800 to 1,600 meters -- you wind up doing fewer of them in order to get to the standard 3,200 to 4,800 meters of quality running. Longer intervals also go further than do short ones in reinforcing concentration and rhythm. Sample workouts of this type for a 25:00 5K runner include six times 800 meters in 3:55 with a 2:00 slow jog, three times 1,600 meters in 7:55 with a 4:00 jog, and four times 1,200 meters in 6:00 with a 3:00 jog.
Hills have been described as "speed work in disguise," and the treadmill is an excellent tool for doing "hill" sessions; not only can you set the grade precisely, but you can be assured of a perfectly nonvarying climb. Two-time Olympic marathon runner and exercise physiologist Pete Pfitzinger recommends a workout Running Times calls "The Endless Uphill." It's not a complicated run and is thus well suited to an easy treadmill schedule: Set the grade of the belt to somewhere between 4 and 8 percent -- above the latter figure, says Pfitzinger, form tends to break down -- and run for an hour at a speed that is challenging but manageable. This not only gets you fit but instills discipline and toughness.
Michael Crystal earned a Bachelor of Science in biology at Case Western Reserve University, where he was a varsity distance runner, and is a USA Track and Field-certified coach. Formerly the editor of his running club's newsletter, he has been published in "Trail Runner Magazine" and "Men's Health." He is pursuing a medical degree.