Running Science

by Owen Anderson

  In contrast, great running economy means minimal energy expenditure, lower rates of carbohydrate metabolism, calmer rates of glycolysis, and therefore reduced lactate production, which goes hand in hand with an advanced running velocity at lactate threshold. Overall, a runner with a fine running velocity at lactate threshold is usually also one with excellent running economy, and that is why running velocity at threshold can be such a great performance predictor. Running velocity at lactate threshold actually includes information about three important factors for running success: lactate-breakdown capacity via oxidative metabolism, the ability to clear lactate from the blood, and running economy.

  Responsiveness to Training

  Scientific research reveals that running velocity at lactate threshold is very responsive to training. In fact, it is much more reactive than O2max in most male experienced runners.9 If an athlete has been running consistently for several years, O2max may not move upward at all over the course of a single training year, but running velocity at lactate threshold might increase by 3 to 10 percent depending on the training program followed.

  Why is running velocity at lactate threshold so dynamic? “The skeletal muscles can adapt rather suddenly and strikingly to training, producing major gains in running velocity at lactate threshold,” says Marc Rogers, exercise physiologist at the University of Maryland. O2max depends to a great degree on the size of the heart’s left ventricle, which pumps oxygenated blood into the body, and that structure doesn’t change much in volume after runners have been training for some years. So O2max may not increase at all or only by a few percentage points even with increased training.10

  Scientific research strongly supports Rogers’ contention that O2max can be a rather stubborn, static variable, while running velocity at lactate threshold is extremely responsive to training. When scientists at Georgia State University and the Emory University School of Medicine followed nine elite distance runners over a 30-month period during which the athletes prepared for the 1984 Summer Olympic Games in Los Angeles, they found that O2max remained unchanged over the entire period, while running velocity at lactate threshold rose by an average of 6 percent. The upswing corresponded with either improved personal records or higher competitive rankings for the runners involved in the study.9

  Older Runners

  Another exciting aspect of running velocity at lactate threshold improvement is that it is much less limited by the aging process compared with upswings in O2max and enhancements of running economy.11, 12 Research shows that as male runners get older, one of their best opportunities for improving performance is through upgrading the running velocity at lactate threshold. While research with women has yet to be conducted, there are no indications that the results would be different. As a runner ages, maximal heart rate tends to decline by an average of one beat per year; the strength and flexibility of the left ventricle, the heart’s primary pumping chamber, also tend to diminish. These factors downgrade maximal cardiac output, a key component of O2max.

  In contrast, the muscle mitochondria that play such a large role in improving running velocity at lactate threshold and the aerobic enzymes that give running velocity at lactate threshold a boost are not necessarily reduced by the aging process. In fact, they may increase almost as much in 60-year-old athletes in response to training as they would in competitors who are 30 years younger!13

  The ability of older runners to make significant advances in running velocity at lactate threshold helps explain a fascinating piece of research carried out several years ago by researchers at Washington University in St. Louis. In that investigation, eight runners with an average age of 56 were compared with eight other runners with an average age of 25. Both groups ran 41 miles (66 km) per week and demonstrated the same 10K performance ability: average finishing time was around 41:30. As it turned out, O2max in the older competitors was almost 10 percent lower than that of the younger runners, again illustrating the poor predictive power of maximal aerobic capacity, and running economy was fairly similar in the two groups.14 So why were the older runners able to keep up with the younger competitors?

  A difference in running velocity at lactate threshold proved to be the answer. Both the older and young runners reached running velocity at lactate threshold at a velocity of approximately 230 meters per minute (about 7 minutes per mi), so it was no surprise that both groups ran their 10Ks at a pace of around 6:45 per mile (10K pace tends to be about 2.5 percent faster than running velocity at lactate threshold). The higher O2max values of the younger runners were irrelevant for predicting relative performances because the lactate-threshold speeds of the older runners occurred at a higher percentage of O2max. In fact, running velocity at lactate threshold for the older competitors settled in at 85 percent of O2max but at only 79 percent of O2max for the younger runners. As a result, the older runners were able to complete their 10Ks at about 88 to 90 percent of O2max, while the younger competitors could only handle 81 percent. If the younger runners had attempted to run their 10Ks more quickly, they would have exceeded the intensity of velocity at lactate threshold (as a percentage of O2max), and their perceived exertion would have been too great. Thus, the older runners were able to entirely compensate for the higher maximal aerobic capacities of the younger competitors.

  There’s another important lesson here. An older athlete who is serious about maintaining or raising his or her level of performance should place a strong emphasis on training that improves running velocity at lactate threshold. That’s because after the age of 40 or so, O2max begins a relentless decline that trims about 0.3 to 0.5 percent from aerobic capacity each year, even when vigorous training is sustained. The drop-off in O2max is related to the fact that the heart becomes a stiffer, less-potent pump as middle age progresses. Thus, the muscles are supplied with less oxygen-rich blood during strenuous exercise, and O2max edges downward. There’s little that can be done about this decline in oxygen availability in the blood stream, but it is possible to compensate for the loss of aerobic capacity by continuing to improve running velocity at lactate threshold. It is possible to improve or maintain race times after the age of 40 by optimizing this key variable.

  Training to increase running velocity at lactate threshold is not reserved for older runners, however. Improving running velocity at lactate threshold upgrades race times and allows competitive endurance athletes to keep pace with—and often beat—other runners who have higher maximal aerobic capacities. Appropriate, scientifically validated training techniques for increasing running velocity at lactate threshold are described in detail in chapter 27.

  Conclusion

  Conducting training that increases running velocity at lactate threshold is extremely important for the competitive runner and the athlete who wants to maximize overall fitness. This training is productive, leading to large increases in performance without corresponding changes in aerobic capacity, especially in the older runner. Important for all runners, the intense training once thought to harm muscles by producing large quantities of lactic acid is in fact exactly the kind of work necessary to optimize lactate threshold and thus promote the muscles’ ability to operate at high levels in a sustained fashion.

  Chapter 11

  Maximal Running Speed

  Maximal running speed—the highest speed that can be sustained for a 50-meter sprint carried out from a running start—is an outstanding predictor of endurance performance. It is such a powerful forecaster that if 100 endurance runners lined up according to their 10K finishing times, from fastest to slowest, and then rearranged themselves according to 50-meter sprint times, again from fastest to slowest, the two lines would look similar.

  As explained in chapter 7, this tight linkage would not occur if the runners organized themselves according to 10K performance and that highly vaunted physiological variable O2max. Runners with the highest aerobic capacities would not necessarily be fastest over the 10K, nor would those with the lowest O2max be the slowest.

  In other words
, 50-meter sprint time is superior to aerobic capacity when it comes to predicting 10K and other competitive endurance performances. Many endurance runners are unaware of this close relationship between maximal speed and endurance success. For others, it is difficult to accept the idea that maximal velocity and the stamina required to run a 10K or marathon successfully can be so closely related. This is unfortunate because it means that the objective of advancing maximal speed is not incorporated into many runners’ training programs.

  Maximal Speed and Endurance

  One of the difficulties many runners have in understanding the significance of maximal speed is that 5K, 10K, half marathon, marathon, and ultramarathon running have always been viewed as aerobic events, with almost all the required energy needed to complete these distances coming from aerobic metabolism, the use of oxygen to break down carbohydrates and fats for energy. In contrast, running 50 meters as fast as possible is thought to be anaerobic, that is, depending on the breakdown of glucose to lactate without any oxygen involvement at all. From the standpoint of energy systems, it is very difficult for runners to understand why anaerobic prowess (i.e., running very fast 50-meter sprints) would lead to success in almost entirely aerobic distance-running events.

  In addition, many popular training programs place a high value on building up mileage at moderate intensities, the kind of training believed—although incorrectly—to optimize O2max. Running fast during training and thus developing raw speed is traditionally viewed as kind of a dangerous thing to do, something that might even damage muscles or lead to a kind of muscular schizophrenia in which anaerobic development increases at the expense of much needed aerobic changes. New Zealand coach Arthur Lydiard was a proponent of such thinking, and his views on endurance training continue to have a large following around the world.

  Nonetheless, scientific research strongly supports the ideas that maximal running speed is a very reliable predictor of endurance-running success and that improving one’s maximal speed over short distances will almost automatically lead to upgraded race performances in endurance events.

  The first real intimation that maximal speed is a strong determinant of endurance performance emerged from a groundbreaking study carried out in 1990 by Noakes and his colleagues at the University of Cape Town in South Africa.1 They tested 20 experienced marathon runners and 23 well-trained ultramarathon competitors and found that peak treadmill running velocity was the best predictor of performance among the ultramarathoners and was just as good a predictor as running velocity at lactate threshold (see chapter 10) for the marathoners. Compared with peak treadmill velocity, O2max was an inferior predictor, a rather remarkable finding given that the two races under study—the marathon and ultramarathon—seem to be the kinds of events that stress aerobic capacity and endurance rather than raw running speed.

  Noakes and his fellow researchers concluded that the “factors that determine the peak treadmill running velocity . . . are not likely to be related to maximal rates of muscle oxygen utilization.”1 In other words, the best foretellers of endurance performance did not seem to be a function of aerobic capacity at all.

  Noakes’ surprising findings did not exactly take the running community by storm, but other researchers began to obtain the same sorts of results as they attempted to come to an understanding of the various factors that produce endurance success. For example, investigators from the University of Technology in Sydney, Australia, found that maximal running speed was the best predictor of competitive ability in endurance events like the 3K.2 And when Kris Berg and his colleagues at the University of Nebraska at Omaha tested 36 trained runners (20 men and 16 women), they learned that just two variables—300-meter sprint time and plyometric leaping ability—could explain nearly 78 percent of the variance in 10K performances.3 Berg and colleagues developed a mathematical equation that could predict 10K time fairly accurately using these variables alone:

  10K time = 57.22 – (5.15 × plyometric-leap distance in meters) + (.27 × 300-m time in seconds)

  Note that this best-fit, predictive equation includes near-maximal running capacity (300-m time) and plyometric leaping ability but does not incorporate any variable related to aerobic fitness such as O2max. Despite the lack of aerobic variables, the equation is able to explain most of the variation in 10K performances. The importance of optimizing maximal running velocity and neuromuscular power during 10K and 5K preparations cannot be overemphasized. It is likely that such optimization will also be beneficial for the marathon and half marathon. The researchers cautiously concluded that “it may be beneficial for distance runners to supplement aerobic training with some power and speed development.”3

  Finnish researchers Paavolainen and Rusko have also been able to document a tight bond between maximal speed and endurance performance. They divided 18 competitive endurance runners into two teams: one group trained in a conventional manner and a second group carried out explosive strength training for about one-third of the available training time.4 The two groups were monitored by Paavolainen, Rusko, and colleagues over a 9-week period. The control group athletes conducted typical endurance training, devoting just 3 percent of their training time to the explosive work.

  Meanwhile, the athletes in the explosive-training group participated in explosive strength sessions lasting from 15 to 90 minutes each and consisting of sprints (e.g., 5 to 10 reps of 20-100 m) and jumping exercises (e.g., alternative jumps, bilateral countermovement jumps, drop-and-hurdle jumps, and one-leg, five-jump drills). Sometimes the jumps were done without any additional weight; at other times, each runner held a barbell across the shoulders. The explosive-trained athletes also performed leg presses, knee extensions, and knee flexions with low resistance and close-to-maximal movement velocities (i.e., 5-20 reps per set, 30-200 reps per session, with resistance set at less than 40 percent of the 1-rep maximum).

  The use of this experimental scheme meant that during the 9-week investigation, the explosive-trained group did much less endurance-type training compared to the control athletes. The explosive-trained athletes devoted about 3 hours per week to high-speed sprints and jumps and 6 hours to traditional running workouts, while the control group spent almost every minute of their 9 training hours locked into their usual running habits. Naturally, the total volume of run training was significantly less in the explosive-trained group. In fact, the runners in this group ran about 20 to 25 fewer miles (32-40 km) per week, or about 200 fewer miles (322 km) during the 9-week period compared with the control runners. Control-group runners covered about 70 miles (121 km) of running per week, versus 45 miles (72 km) per week for the explosive-trained athletes.

  At the beginning and end of the 9-week training period, all 18 athletes ran an all-out 20-meter sprint and a 5,000-meter race as fast as possible on an indoor track. After 9 weeks, the explosive athletes had upgraded their 20-meter, maximal-effort sprint times from a running start by nearly 4 percent, while the traditionally trained athletes were no faster at all after their 630 total miles (1,014 km) of running. In the 5K event, the explosive-trained runners were 30 seconds faster than they had been initially for about a 3 percent improvement. The story was depressing on the other side: The traditional, high-mileage trainees had stagnant race times even though they had improved their average O2max values. This study provides strong evidence that explosive training advances maximal running velocity and that upgrades in maximal speed are closely coupled with improvements in endurance performances.

  False Dichotomy of Aerobic and Anaerobic

  How can advances in maximal running velocity and maximal speed improve endurance performance given that high-speed running is anaerobic and endurance running is aerobic? When runners look at endurance running solely through the traditional anaerobic-aerobic lens, it is very difficult to understand what is really happening. The trouble is that successful running involves much more than the mere presence of anaerobic and aerobic enzymes in the muscles.

  Even if it were possible to micropipette
a huge quantity of anaerobic enzymes into a runner’s leg-muscle cells, it would be unlikely the runner would be able to run any faster. The reason for this is that the nervous system is required to coordinate and direct the leg muscles in a more powerful way in order for faster running to occur. Such coordination and direction must be developed over time with the use of high-speed running and explosive drills. The nervous system’s role as director of speed development is independent of the energy-producing systems inside the muscle fibers.

  When runners change the lens through which they view endurance training and begin to examine endurance running as a function of neuromuscular characteristics, they begin to understand why maximal speed and endurance performances are tightly linked. Maximal speed improves as the nervous system learns to coordinate the muscles in ways that promote faster stride rates, shorter contact times with the ground per step, and quicker generation of substantial propulsive forces. These factors are extremely important for competitive endurance running. Shorter contact time was another key factor underlying the improvements achieved by the endurance runners in the Paavolainen and Rusko study discussed earlier. Endurance runners who develop rapid stride rates, short contact times, and ample strides will tend to do very well in their distance events, and they will outrun individuals who are significantly less explosive.

  A key goal for endurance runners is to develop the ability to run more quickly while simultaneously expanding the capacity to sustain higher speeds over extended periods. When runners do this, they will be highly successful in distance events. Since they are able to run fast, they will fare well in sprint tests, too. This explains why researchers keep finding maximal speed and distance performance to be tightly knotted together.