The Right Stuff: The Physiology of Speed and Endurance

The Cutting-Edge Runner: How to Use the Latest Science and Technology to Run Longer, Stronger, and Faster
by Matt Fitzgerald

A state-of-the-science resource for runners - with the latest information on training, nutrition, injury prevention, and gear and gadgets that improve performance.

The science and technology of running have evolved dramatically in the past 20 years. This all-inclusive resource - based on the author's own high-level running and coaching experience and his interviews with dozens of other top runners and coaches - is an indispensable tool for runners who hope to perform at the very best of their ability.

The Cutting-Edge Runner provides:

• A comprehensive overview of how the best competitive runners train today - covering such topics as periodization, physiological testing, group training, technique work, cross-training, recovery techniques, and individual customization

• In-depth discussions of equipment and other technologies that can benefit the runner, including shoes, orthotics, heart rate monitors, altitude tents, training software, and more

• A complete "menu" of workouts for milers to marathoners

Whether he is explaining how to use hypoxic conditioning to increase oxygen consumption capacity, telling how to prepare for the mental challenge of racing, or detailing what the latest science has to say about the pros, cons, and proper usage of more than 15 nutritional supplements and drugs, Matt Fitzgerald goes straight to the most authoritative sources and provides practical ways for the average runner to adapt methods and tools used by top runners to their own running programs.

Chapter 1

What's inside the bodies of runners who are able to run fast and far? How much of what they have comes from training, and what's the best way to train to develop whatever it is they have? Exercise physiologists (scientists who study what makes our bodies move) are working hard to answer these questions in laboratories around the world. In recent years, they have learned quite a lot about the physiology of speed and endurance, and they learn more almost every day. Yet the athlete's body remains very much an open frontier in science. We won't have a complete picture for some time yet. Nevertheless, what we do know has great practical value for all runners.

You don't need to be an expert in exercise physiology to run fast, but you'll surely run faster if your training program is shaped by the most recent sports science–and if you continually keep up to date. Elite runners are usually fortunate enough to have coaches with expertise in exercise physiology who tailor their training based on the newest thinking in athletic performance. On the other hand, self-coached runners–like the rest of us–are required to make our own training decisions. To make good decisions, we need to understand the basic physiological objectives of training and the cause-effect relationships between the various types of training and these objectives.

There are two general types of exercise physiology research that you can use to improve your training. Some studies shed new light on the physiological characteristics–such as muscle fiber types and oxygen-carrying capacity–that contribute to running performance and that we should enhance in our training. Other studies give us a measurable view of how a specific training method or pattern affects one or more of these characteristics. Together, these two types of research can help you decide the proper format for your workouts and the best way to incorporate them into a training program.

If you're wondering how all this can help you run faster, consider the following practical example of exercise physiology. Studies of runners dating back to the 1960s established that faster distance runners tend to have a high aerobic capacity, or VO₂max, and superior energy economy. Aerobic capacity is the maximum rate (adjusted for weight) at which a runner can use oxygen during running. Economy is the amount of energy a runner uses while running (the less the better, of course). When you put the two together, you get one of the best predictors of running performance: namely, velocity at VO₂max–or vVO₂max. This is the slowest sustained running pace at which a runner reaches 100 percent VO₂max. For example, suppose that during a standard exercise test, it is discovered that your VO₂max is 55 liters per minute per kilogram of body weight. If this rate of oxygen consumption is first achieved at a running velocity of 10 miles per hour (mph) and shows no increase at higher running speeds, then your vVO₂max is 10 mph.

An improvement in either your VO₂max or your running economy will increase your vVO₂max (as well as the amount of time you can sustain this pace), and this in turn will improve your running performance in races. So what's the best workout to increase your vVO₂max?

This is the question that Veronique Billat, Ph.D., an exercise physiologist at the University of Paris-Evry in France, set out to answer several years ago. Specifically, she challenged herself to create workout formats that would allow runners to spend the greatest total amount of time at VO₂max and would therefore presumably produce the most powerful boosting effect on VO₂max and economy.

Billat deduced that runners seeking to maximize workout time spent at VO₂max should run at exactly vVO₂max and no faster because they would fatigue more quickly at faster speeds. (Remember, vVO₂max represents the slowest running pace at which VO₂max is reached.) Her next move was most clever. Billat knew that a runner's rate of oxygen consumption remains at or near 100 percent VO₂max for as long as 15 to 20 seconds after he or she stops running at vVO₂max, or slows down from this pace. She realized that a well-designed workout could exploit this lag phenomenon to allow runners to further increase time spent at VO₂max.

The best way to do this would be to alternate short intervals run at vVO₂max with short "floats" (jogging recoveries) at perhaps half of vVO₂max. Keeping the hard intervals short would delay fatigue by preventing neuromotor fatigue (exhaustion that results when electrical nerve signals no longer reach muscle cells easily) from getting out of hand. (More on that below.) Keeping the floats short would prevent oxygen consumption from falling very far before hard work resumed.

The workout format she settled on was highly unorthodox, consisting of 30-second bursts at vVO₂max separated by 30-second floats and repeated to failure (that is, until vVO₂max can no longer be sustained for 30 seconds). In testing this format, Billat found that some runners were able to amass more than 18 total minutes at VO₂max, almost a third of it occurring during their jogging recoveries! A group of moderately fit runners increased their VO₂max by 10 percent (that's huge) in just 8 to 10 weeks when they added twice weekly 30-30 sessions to their training. Influential running coaches and writers who pay attention to the sports science journals have since begun to promote Billat's 30-30 workout, and before long, it may become a standard-issue weapon in the competitive runner's training arsenal.

Again, you don't need to read the sports science journals yourself in order to take advantage of cutting-edge training methods such as Billat's 30-30 workout. But understanding their basic physiological underpinnings might allow you to incorporate these methods into your training more effectively, because you get the best fitness results by customizing the generally prescribed training methods to your own particular needs.

According to the latest science, there are roughly eight characteristics (the precise number depends on exactly how you choose to parse them) that make up distance-running ability. In the remainder of this chapter, I will describe them and explain which types of training have proved most effective in developing each.

CHARACTERISTIC #1: IMPACT-PROOF LEGS

Perhaps the most important early adaptation to running is an improvement in the capacity of the bones, muscles, and tendons in your legs to absorb ground impact forces without breaking down. When subjected to regular foot-to-pavement pounding, the bones of the lower extremities restructure themselves to become stronger and denser. This remodeling process is essentially a healing response to impact trauma, which works out for the best as long as you always increase running volume gradually and allow adequate recovery time. If you subject your bones to too much stress too soon, damage will outpace remodeling and a bone strain will result. Strains in the tibia (the larger of the two shin bones) are the most common injury in beginning runners. A severe bone strain can develop into a stress fracture.

Muscles and tendons adapt to impact forces in a similar injury-response fashion. The muscles, especially your calves and quadriceps, help your body absorb impact forces by contracting eccentrically–that is, by resisting their own lengthening. Eccentric contractions pull muscles in two directions simultaneously, often rupturing and damaging muscle fibers. But the damaged tissue responds by remodeling itself in such a way as to become more resistant to future eccentric rupturing.

Key tendons of the lower extremities absorb impact by stretching and recoiling. They, too, adapt to this repetitive strain with a remodeling process that increases their density, stiffness, and tensile strength (how far they can stretch without tearing).

© 2005 by Matt Fitzgerald

About the Author

Matt Fitzgerald, runner, triathlete, and coach, is a former editor and current contributor for Triathlete magazine. He writes articles for such national publications as Men's Health, Men's Fitness, Outside, Fitness Runner, and the Runner's World Web site, and serves as managing editor of the sports nutrition Web site, Pioneering Muscles.