Let the Tempo Come to You
The science of starting slowly. . . to finish ahead
The wisdom of starting a race relatively slowly and finishing fast is unquestioned, with the strategy of "negative splitting"—running the second half of the race faster than the first—yielding world marathon bests for Khalid Khannouchi and Catherine Ndereba, a course record for Cosmas Ndeti at Boston in 1994 (2:07:15), and a slew of other notable positive outcomes. Not only do negative splits typically yield better competitive results, they often mean a quicker post-race recovery, a more finely tuned sense of one’s limits at any point in a race, and a more pleasurable race experience overall (e.g., passing runners throughout the race, less physical and mental discomfort). When we speak of having run negative splits, we universally do so with satisfaction and pride.
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."