[This article originally appeared in the
issue of Northwest Runner
In last month's column, we examined a well-known model of endurance exercise. The model includes three components: maximal oxygen consumption (VO2max), lactate threshold, and running economy. For reasons discussed last month, each of these traits is considered an important determinant of success in long-distance races (i.e., events lasting anywhere from 30 minutes to 5+ hours).
"So," you ask, "what sort of training can I do to improve my VO2max, lactate threshold, and running economy as much as possible?" In the paragraphs below, we will address this question using research reports from respected scientific journals. As before, we'll consider each of the three model components in turn.
Fifteen years ago, Howard Wenger and Gordon Bell of the University of Victoria authored a paper called "The interactions of intensity, frequency and duration of exercise training in altering cardiorespiratory fitness" (Sports Medicine 3: 346-56, 1986); to this day, it remains a definitive source of data on training and VO2max. In their analysis of over 50 previously published studies, Wenger & Bell concluded that runs performed at 90-100% of VO2max pace (abbreviated vVo2max for "velocity at VO2max") bring about the largest gains in VO2max. vVO2max is defined as the slowest pace at which one reaches one's maximum oxygen consumption; for most people, it falls somewhere between one-mile race pace and two-mile race pace (Billat, Sports Medicine 22: 90-108, 1996). Thus, if your personal best two-mile time is around 12 minutes, repeat half-miles in 3:00 or so would constitute a great VO2max-building workout.
Wenger & Bell's analysis also indicates that workouts of 35-45 minutes (running time plus recovery time, if doing intervals) improve VO2max more than shorter workouts and that three or four moderate-to-hard workouts a week are an optimal training "dosage" for maximizing one's VO2max. I should mention as an aside that, for some individuals, two hard workouts per week may be plenty. The point I'd like to emphasize, however, is that you don't need to run every day to stay in really good shape. For busy people with limited time to train, a weekly regimen of three high-quality (i.e., fast) workouts and four days off -- rather than a seven-days-a-week routine -- may be the most practical way of increasing VO2max.
Further evidence for the importance of workout quality, as opposed to quantity, can be found in studies of athletes forced to reduce their training load. These studies (reviewed by Neufer, Sports Medicine 8: 302-21, 1989) have shown that a high VO2max can be maintained on as little as two or three workouts per week if the intensity of training is kept high. However, if the training intensity wanes, VO2max tends to decline as well.
So what can we make of this jumble of data? When there isn't a clear consensus in the research literature, I often use the principle of training specificity to guide my training decisions. As discussed in my December column, the body adapts very specifically to the tasks it is forced to do. The VO2max data discussed above illustrate this point nicely: to raise one's VO2max, one should train at or close to vV02max. Similarly, to develop one's lactate threshold as fully as possible, one should probably do at least some training at or slightly above lactate threshold pace (which of course will be slower than vVO2max).
Taken as a whole, the above information suggests that interval workouts at vVO2max and tempo runs at the lactate threshold are both key ingredients in the training programs of competitive distance runners. In designing a training schedule for a particular individual or team, however, the specificity-of-training principle must again be considered. In short, one's key workouts should be tailored somewhat to the pace, distance, and terrain of the race one is training for. For example, workouts at race pace are almost always a good idea regardless of what that pace happens to be, and long runs may be much more important for marathoners than for 5K specialists. Nevertheless, when pondering these important issues, we should not forget what the data tell us: "long" intervals and tempo runs are probably our best training tools for maximizing VO2max, lactate threshold, running economy, and overall fitness.