Watching the lead runners of a big-city marathon like New York or Chicago fills one with awe, wonder, and appreciation of the purity of their athletic gifts. Many of them are graceful in their strides, and the calm effort they seem to expend as they clock sub 5-minute miles, one after the other, is a testament to their natural running ability. Their bodies seem perfectly suited to running—slightly facing forward, head held straight, powering off their midfoot. These runners have what is called good running economy. Contrast them with the tens of thousands other runners in the race, and the differences are indeed apparent. These runners look inefficient and certainly are not maximizing their energy potential.
Likewise for any endurance sporting event, whether cycling, swimming, ultramarathoning or triathlon. While we can discuss economy in virtually any sports, let’s focus on running.
Even among those with good running economy, there’s still plenty of room for improvement. That’s because running economy is influenced by various physical and metabolic factors. These include, among others, fat burning for energy, aerobic muscle fibers, foot function, and therefore footwear, gait, the regulation of stress, nutrition, and the brain.
Talk to a bunch of exercise scientists and coaches about running economy and you will often get bombarded with information, such as oxygen utilization—VO2max—in particular. But most, if not all of it, won’t be useful to athletes themselves. That’s because so much of the information on running economy is missing. We don’t know much about it scientifically, other than it may be one of the most important factors for racing faster.
Sometimes referred to as efficiency, running economy—RE—may be the only factor that is so powerful it can slice minutes off an elite marathon runner’s time, and hours from a mid or back of the pack competitor in longer events.
Ideas about RE are not new. In 1891, Nobel Prize winner Italian Dr. Angelo Mosso published what may be the first scientific study on exercise and muscle fatigue. Mosso’s initial instincts appeared quite accurate when he stated that, “fatigue of brain reduces the strength of the muscles.” England’s Dr. Archibald Hill is best known for his important work in the 1920’s measuring oxygen consumption, in particular VO2max (and another Nobel Prize winner, but for his work on brain-muscle function).
Today, scientists agree that better RE is associated with a more balanced body that results in reduced needs for oxygen. In other words, one could run the same speed with less oxygen, or run faster with the same amount.
While the measurement of oxygen utilization is important for a better understanding of exercise physiology, it is not ideally applicable for many runners seeking to perform better. The measurement of oxygen is not easily available for most people, and especially not obtainable on a regular basis, such as a daily assessment.
But alternatively, there are excellent options that can help determine that an athlete is becoming more economical. Foremost is this approach: monitoring a runner’s pace at a sub-maximal heart rate. As the pace improves at the same heart rate it assures the body is improving its aerobic function, using more fat for energy and relying less on sugar. (The same can also be measured in the laboratory as respiratory quotient).
Improving economy results in running faster with the same effort. Stated another way, with the same effort one could run faster.
No one doubts RE can be improved. Scientists, who continue to find new information about it, are still baffled by how to improve it. Many endurance athletes are looking for the magic bullet, following popular one-size-fits-all programs that could sometimes worsen economy. Clinicians and coaches who follow a truly individual approach are making accomplishments, although personalizing this is difficult in a group situation.
The Aerobic Factor
One of the most important ways to improve RE may be focusing on training the body’s aerobic muscle fibers, and much less time performing traditional track intervals, weights and other anaerobic workouts.
In 1992, Dr. Edward Coyle and colleagues at the University of Texas, found a strong correlation between the body’s aerobic muscle fibers, also referred to as slow-twitch or type 1, and exercise economy. Beginning in the 1950s and 60s, famed New Zealand coach Arthur Lydiard successfully emphasized slow-twitch training for aerobic base work. Since the late 1970s, I have been measuring improvements in RE during aerobic training as indicated by faster paces at the same heart rate, and correlating it with increased fat burning.
The idea that additional fat burning is necessary for improved endurance performance is relatively simple. If the use of fat for fuel is limited—which occurs when intensity is too high and or the aerobic fibers not well trained—more sugar must fuel the muscles. This reduces RE. But maintaining a stable blood sugar level and avoiding glycogen depletion is vital during races, and helps maintain fat burning and good RE.
Almost all types of training will increase ones VO2max and lactate threshold, even overtraining in its early stages. But this won’t always improve performance. However, increase the function of the aerobic muscle fibers and related body components, the heart, lungs, muscle circulation, fat burning—what I call the aerobic system—and the RE can improve significantly leading to faster training and race paces.
The aerobic system is an untapped source of improved performance, and only with great RE will someone perform his or her best. While laboratory testing can have value, it is more important and practical for individual’s to monitor economy regularly in the course of training.
Unfortunately, scientists have not measured large enough numbers of elite runners to make much sense of RE. But here are two specific examples of athletes who reportedly improved their RE on their way to accomplishing world records:
- Steve Scott broke the American record for the mile in 1982. Exercise physiologist Gary Krahenbuhl says that over a period of 18 weeks, Scott improved his RE by 5 percent.
- In 2003, England’s Paula Radcliffe set the marathon world record of 2:15. Previous to that, her RE increased 14 percent over a five-year period, which equated to running 40 seconds per mile faster without changing how much oxygen she took in.
The most logical way to help RE is to improve several related body components, even by modest amounts. In this case, enhance the body’s physical and chemical components as discussed below, including that of the brain, by only a relatively small percentage. Just how much improvement is needed is not known, and no doubt individual. Rather than hypothetically toss out viable percentages, I would rather discuss how one can improve RE.
There are a variety of modifiable lifestyle factors a runner can take advantage of to influence RE. Here are some of them:
- Build the aerobic system. This improves slow-twitch fiber function and fat burning, increases muscle circulation, and helps prevent injuries. One measurable result is faster running at the same sub-max effort—another is increased race pace.
- Nutritional support. Improving ones diet can influence hormone balance, red blood cell quality, water and electrolyte regulation, and the use of fat for energy. Avoid all refined carbohydrates is one of the most important factors.
- Improved gait. This can be accomplished various ways including wearing the ideal shoe for one’s foot, one that is relatively flat without unnecessary support, or going barefoot some or all the time, and to increase storage and release of energy in the lower limbs.
Others include managing muscle imbalance, minimizing or avoiding anaerobic workouts, and the right combination of endurance and strength can also be important.
Many popular ways athletes try improving RE are, unfortunately, not effective, and sometimes can worsen it. A common approach is to consciously move isolated body parts to mimic some ideal gait. Or, watch a video or read a running magazine article claiming that if you lifting-this-and-moving-that it will make one faster. But just elevating your knees, rotating the trunk more, swinging the arms and many other drills used by runners for decades is not necessarily good. An individualized approach is more likely to help RE, but a generic one often does not, and in some cases could make it worse.
Employing these types of programs can interfere with what our brains naturally want us to do.
While just running relaxed and natural, not thinking about their bodies or emulating someone else, athletes tend to automatically find their most efficient gait. This occurs because the brain figures out how to be most economical, considering the body it has to work with. Whether following an off-the-shelf program, or other generic approach, interfering with the brain may sometimes be a recipe for injury.
One reason these types of routines may not work, or worsen one’s running, has to do with addressing secondary problems rather than correcting the cause of a particular imbalance associated with reduced economy.
The assumption that training itself will improve RE is not necessarily true. In fact, some of the more common approaches employed in preparing for endurance events often reduce economy due to excess wear and tear, overtraining, inadequate rest and recovery, and reduced emphasis on aerobic function.
Another significant factor that can reduce RE is muscle imbalance. This occurs because of the impairment of one’s gait, with dysfunction in various areas such as ligaments, tendons, and joints. In this situation, the brain has to compensate by searching for the best ways to move, which will always be less economical. Muscle imbalance is also a common cause of injury.
The VO2max and Lactate Myth
Most great endurance events are performed with a relatively consistent pace at only 85 percent of VO2max. Most, if not all, of the training for this event should take place just below this level, closer to 80 percent of ones VO2max (depending on the individual), to best build the aerobic system, teach the body to obtain more energy from fat, conserve glycogen, and avoid flirting with overtraining. (By comparison, a 5- and 10 K race is performed close to ones VO2max, with much of the training at similar levels.)
Similar notions can be applied to the muscle’s production of lactic acid, and the popular concept of lactate threshold. Normally, muscles produce lactic acid during high intensity training, and this chemical ends up in the blood as lactate. But the level of lactate is more applicable to 5- and 10K distances. Great marathons, triathlons and bike road races are performed at paces with lactic acid production just above resting levels rather than high amounts, and certainly not near ones threshold.
Running economy incorporates, at least potentially, all the functions of body and brain. We may never know how important any one component may be. But we do know that these factors, from muscles and lungs to heart and brain, must work in harmony to generate energy for running a strong marathon.
This means that factors such as blood sugar regulation, circulation, breathing, red blood cell function, and others that can specifically influence RE should be looked at holistically. When doing so, it is evident that overall health is very important for RE.
While science has much to offer, the combined recommendations of clinical and coaching experiences can help improve RE. Coaches, health professionals and athletes themselves can use scientific studies as a guideline, but it is just as important, if not more, to measure the outcome of training, and quickly make modification if the right results are not quickly forthcoming. Dr. Adrian Midgley and colleagues at the Department of Sport, Health and Exercise Science, University of Hull, UK, asks whether valid, useful recommendations can be given to runners and coaches based on current scientific knowledge. They state, “Scientists should be cautious when giving training recommendations to runners and coaches based on the limited available scientific knowledge. This limited knowledge highlights that characterizing the most effective training methods for long-distance runners is still a fruitful area for future research.”
Improving RE is not hypothetical. It is reality based. One important factor that can be regularly evaluated, as part of an important and ongoing assessment process used by runners, is that of increasing pace at the same sub-max heart rate. This will help take the guesswork out of whether training is proceeding well. It is the measurement of aerobic speed, the topic of the next chapter.