Few runners question the wisdom of running a race at an even pace or even \"negative splitting\"—running the second half of the race faster than the first. The latter practice has produced numerous world marathon and track records over the years as well as helped recreational runners make the most of their competitive efforts. Not only are negative splits a recipe for faster times, but they lessen post-race fatigue, boost confidence, and engender a more pleasurable race experience overall - it's a lot more fun to be the passer than the pass-ee.
However, outside of the competitive milieu, our ambition to run negative splits, or otherwise finish more quickly than we start, virtually disappears. If you do your everyday six-miler at 7:30 pace, do you really care if you do the first three miles at 8:00 pace and the last three at 7:00 pace, or rip through the first mile with no warm-up in 6:30 and run 7:40's the rest of the way? Did you notice whether the last four 400-meter repeats of last week's speed workout were faster than the first four? Do any of us care about these things? Should we?
Based on scads of empirical evidence, the answer is a resounding yes. Distance running observers are quick to point out, for example, Kenyan athletes' formidable training mileage and intensity. Often ignored, however, is the well-established tendency of these runners to begin every workout—interval session, tempo run, or distance run—at a jog or even a shuffle, picking up the pace only when all physiological systems are fully attuned to the task at foot, with a smooth transition having been made from the resting state to the aerobic state. Hammering away from the get-go at whatever pace they will ultimately reach that day is simply not in these runners' training lexicon—and with good reason: It detracts from both the training benefit achieved and the maximal workload reached, to say nothing of the effect on recovery time and therefore on subsequent workouts and races.
The physiology behind running an evenly paced workout or race is straightforward. \"In very long races, economy of oxygen consumption allows you to preserve your fuel sources and prevents you from becoming glycogen-depleted,\" says John Kellogg, M.A., coach of 28:10 10,000 meter runner Weldon Johnson and other young aspirants. \"You have a ceiling of roughly 2,000 calories available from stored fuels which can be used to produce energy aerobically. You also burn approximately five calories for each liter of oxygen you consume during exercise. Do the math—you can't squander your available energy and expect to run your best race, especially if there is a chance you could run out of fuel.\"
The same principles apply to workouts. Runners left to their own devices, however, simply tend to be less diligent about pacing when not confronted with a competitive situation. \"It's crucial to approach all of your hard workouts—except pure sprint training—with some measure of caution,\" says Kellogg. On tempo workouts or other high-end aerobic efforts, Kellogg suggests allowing your effort to stabilize below your \"threshold\" before you attempt to squeeze the pace down to quicker speeds. For example, if, based on a recent race, you have calculated your anaerobic threshold to be close to 6:30 per mile, it would be wise to begin a four-mile tempo run with a 6:40 mile before easing down to 6:30 pace. Remember, a tempo run is not a time trial, but an effort carefully scripted with distinct parameters to achieve optimal results. Notes Kellogg, \"You will obviously be working harder earlier during a faster, more anaerobically oriented interval session (such as 10 x 400 or 6 x 800 with rest intervals equal to or less than the duration of the fast repeats), but you should still use the same basic strategy. Start from the slow side, find out 'what you've got' for that particular day, and try to push a little harder and get gradually faster as the workout progresses. This trains your body and mind to speed up when fatigued and enables you to recruit muscle fibers and access fuel sources in the same sequence which will ideally be used during all-out races.\"
Kellogg's 'what you've got' directive applies equally well to ordinary distance runs, particularly for marathoners immersed in high-mileage regimens that result in large day-to-day fluctuations in perceived effort at a particular pace. While training for the 2001 Boston Marathon, I reached a peak of 145 miles in a week and averaged close to 110 over a ten-week stretch. For me, this was heretofore uncharted territory, so I was careful to approach every recovery run with a measure of caution, beginning each run at perhaps 7:30 pace. During the course of the run I would discover whether 7:00 pace would be as fast as I could run comfortably or whether I'd be able to dip under 6:00 pace for the last couple of miles; the key was working with my body's constraints for that day, not against. The result was a 2 1/2 minute personal best.
The trick to harmonizing effort with speed? In a word, relaxation. \"It is of paramount importance that you learn to relax your body when running—even when running hard.\" Relaxation, notes Kellogg, is synonymous with efficiency and economy; that is, tantamount to using the fewest number of muscle motor units—a motor unit is a nerve and all the muscle cells it supplies—and the least amount of oxygen necessary to sustain a given pace. Says Kellogg, \"Running with a stabilized heart rate, breathing pattern, and perceived effort level, i.e., running in a so-called 'steady state,' also allows runners to enlist the most oxidative muscle fibers for as long as possible, thereby forestalling the inevitable spike in anaerobic energy production and the associated struggling and tying up. In simple terms, you should avoid getting in trouble early in your workouts and races and you should stay out of trouble as long as possible.\"
Kellogg likens the distribution of effort in a tempo run or high-end aerobic run to that of a motorist driving across town, timing the car's speed so as to encounter only green traffic lights. Such a practice, he points out, is efficient, fairly comfortable, conserves energy, and involves the least risk of having a wreck or getting pulled over for running red lights. Trying to drive in such a manner as to actually hit all the green lights requires finding out how long the lights remain green, ensuring a properly working automobile, and keeping enough gas in the tank to get across town. Trial and error would be necessary to quantify these variables. It's the same thing in running: competitors need to practice finding their high-end effort by feel, and must have some running background (that is, experience with different paces) in order to do an effective high-end run.
In simpler terms: Allow the tempo to come to you. By reining in your competitive impulses earlier in your runs and workouts for the express purpose of expanding their benefit, you'll find that patience pays off as strongly in training as it does in your racing.