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Training to improve the "Big Three"

[This article originally appeared in the March 2001 issue of Northwest Runner magazine.]

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.

Unfortunately, nobody knows whether really long, moderately paced runs can bolster VO2max as much as shorter, faster runs can, although Wenger & Bell speculate that this may be the case. There are indications that long runs may offer some unique benefits to distance runners; for example, prolonged exercise bouts of two to four hours activate fast-twitch muscle fibers that aren't always used during short bouts (Gollnick et al., Pflugers Archiv 344: 1-12, 1973; Armstrong et al., Pflugers Archiv 352: 243-56, 1974; Gollnick et al., Journal of Physiology 241: 45-57, 1974; Vollestad et al., Acta Physiologica Scandinavica 122: 433-41, 1984) and "teach" the body to burn fat as a primary source of fuel (Felig & Wahren, New England Journal of Medicine 293: 1078-84, 1975). However, the impact of these long workouts on VO2max per se remains uncertain.

Lactate threshold

While workouts at or just below vVO2max seem to provide the biggest possible boost to VO2max, it's less obvious how one should go about improving one's lactate threshold. The lactate threshold, you will recall, is the exercise intensity at which lactic acid starts to accumulate in the blood; for trained runners, it is roughly equivalent to marathon race pace (Farrell et al., Medicine and Science in Sports and Exercise 11: 338-44, 1979). A number of studies have examined the relative effects of intense and moderate exercise on the threshold. Some have found that training above the threshold is most effective for raising the threshold (Sady et al., Journal of Sports Medicine 20: 41-6, 1980; Henritze et al., European Journal of Applied Physiology 54: 84-8, 1985; Weltman et al., International Journal of Sports Medicine 13: 257-63, 1992), while others indicate that such fast-paced training is no better than more moderate exertions (Poole & Gaesser, Journal of Applied Physiology 58: 1115-21, 1985; Gaesser & Wilson, International Journal of Sports Medicine 9: 417-21, 1988; Keith et al., European Journal of Applied Physiology 65: 316-23, 1992; Londeree, Medicine and Science in Sports and Exercise 29: 837-43, 1997). Additionally, in a remarkable three-year study of 44 elite cross-country skiers divided into two training groups, the "long slow distance" group improved its threshold (as a percentage of VO2max) more than the group that emphasized intense training at and above the threshold (Rusko, Journal of Sport Sciences 5: 273-86, 1987).

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).

Running economy

Running economy is a measure of how effectively the body converts oxygen into forward motion; the faster one can run for a given rate of oxygen consumption, the better. Economy doesn't always improve with endurance training (Anderson, Sports Medicine 22: 76-89, 1996; Jones & Carter, Sports Medicine 29: 373-86, 2000); in some cases, subjects are actually less economical after five to six weeks of slow, steady jogging (Ramsbottom et al., British Journal of Sports Medicine 23: 171-6, 1989; Lake & Cavanagh, Medicine and Science in Sports and Exercise 28: 860-9, 1996).

However, several longitudinal studies have shown that running economy can improve with training, and with one exception (Patton & Vogel, Medicine and Science in Sports 9: 100-3, 1977), the training that led to the improvements consisted in part of vVO2max-style intervals (Ekblom et al., Journal of Applied Physiology 24: 518-28, 1968; Franch et al., Medicine and Science in Sports and Exercise 30: 1250-6, 1998; Billat et al., Medicine and Science in Sports and Exercise 31: 156-63, 1999) or tempo runs near the lactate threshold (Sjodin et al., European Journal of Applied Physiology 49: 45-57, 1982; Franch et al., Medicine and Science in Sports and Exercise 30: 1250-6, 1998). In the investigation of Franch et al., runners who were assigned six weeks of "exhaustive distance training" (continuous runs near the threshold) or "long-interval training" (four-minute runs separated by two-minute recovery periods) improved their economy, whereas those who performed "short-interval training" (15-second sprints separated by 15-second recoveries) did not. Interestingly, the exhaustive-distance-trained and long-interval-trained runners also improved their VO2maxes by an average of 6% during the study, whereas the VO2maxes of the short-interval-trained runners only climbed 3%. Thus, it appears that the types of workouts recommended for raising VO2max and lactate threshold are also best for running economy.

Putting it all together

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.

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