Distance runners can find any number of ways to approach their training. Some coaches say lots of short, fast runs will make you a champion. Other coaches offer their athletes lots of long slow runs. Yet, most coaches tend to find a middle ground between these two mixing both short, faster runs with longer runs to try and meet the needs of their runners. To try and help you figure out just what your runs are for this article will examine a few basic scientific concepts underlying each of these approaches to running. By being more well-informed you will be better able to work with you coach in finding the training just right for your body.
As with any physical activity your body burns energy to run. Whether you walk to the kitchen to get a glass of water or you happen to be sprinting all out at the end of a race, your body uses stored energy to perform these actions. The types of energy your body use as a runner come from several sources in your diet. However, once the food and drink is in your body, it is processed in two major ways: 1) aerobically and 2) anaerobically. These words have picked up a lot of baggage over the years through people misusing them and applying them improperly, so to clear the air a bit we will look at each type of energy production. We will then see what that means for running.
Aerobic activity can be defined as any physical activity that uses oxygen as the main source of fuel to generate energy. This can be somewhat misleading because your body really uses sugar, water and fat to generate the energy. The term "aerobic" refers to the fact that the chemical actions your body does to convert those raw materials-sugar, water and fat-rely on the presence of oxygen to be completed. By performing aerobic activity, athletes are able to do whatever they are doing for very long periods of time. This type of activity can also be thought of as an "endless" type of work because it can go on as long as the person chooses. A good example of aerobic activity is easy jogging.
Anaerobic activity can be defined as any physical activity that does not use oxygen as the main source of fuel to generate energy. This term can also be misleading because while oxygen is used for anaerobic activity, most of the energy comes from sugar stored in your muscles and internal organs. In contrast to aerobic activity, anaerobic activity cannot be performed for "endless" periods of time. In short, running faster-like, for example, at 5k race pace-causes the body to use up its limited supplies of stored energy faster than the body can restore these supplies. This depletion process is one of the major factors of training since athletes try to lengthen the time they can run certain paces. A good example of anaerobic activity is running a mile race at top speed.
Without going too far into the science of the differences between aerobic and anaerobic activity, it is important to recognize how these "zones" affect your running. To maximize your training you must find a balance between aerobic and anaerobic efforts. For younger athletes working with a coach or knowledgeable runner helps to prevent overtraining from running too hard-or too easy-as well as allowing them to gain knowledge from the experiences of folks who have had successes and failures with the sport. In essence, learning to run the right balance of faster and slower running is the key to successful training.
You might be wondering, "So what? Why is it important to stick within these zones for various types of training?". The answer really lies in how your body uses energy. By running below an effort level called the aerobic threshold you enable your body to regenerate energy from the raw materials already in your body with oxygen. When you run above this aerobic threshold-that is running anaerobically-your body works less and less with oxygen to produce more energy. The fact is that your body is 18 times more efficient at producing energy aerobically than it is anaerobically. The term "anaerobic" consists of two roots, "an-" meaning "without" and "aerobic" which means oxygen, hence, the term "anaerobic" or "without oxygen". When you run "without oxygen" or anaerobically, you are often running less efficiently and wisely than you could unless you are doing so for a specific reason.
It is important to note that while your body has a point at which it begins to operate more anaerobically than aerobically you never operate purely with or without oxygen. In plain English, by running too fast, you will tend to use less and less oxygen, however, you are always using oxygen. The terms "aerobic" and "anaerobic", when tossed around in workouts, often simply mean that you are running slow or fast. However, there are ways to be more precise in discussing what your body is really doing when you are running "slow" and "fast". We will now take a quick look at some research that has helped runners to find out whether they are on the right side or the wrong side of that aerobic threshold.
Scientists have shown that there is really a mathematical relationship between how fast you run and how "aerobic" or "anaerobic" you are running. Depending on how much time one spends in either zone, it is easy to spot signs of poor training habits by looking at training paces. Sports scientists have been studying runners for half a century to develop training tools to help runners find the balance mentioned earlier.
Exercise physiologist Dr. Jack Daniels published a book called The Daniels Running Formula. In the Daniels Running Formula, Dr. Daniels outlines four key training zones based on his work with runners. These zones are: 1) endurance or easy 2) tempo or stamina 3) interval or max VO2 and 4) repetition or speedwork. Below is a table describing each of these zones, its benefits and its appropriate use:
Zone Heart Rate Purpose and use Easy 75% or less use for easy and long runs Tempo 87-90% use for tempo runs Interval 95-98% use for workouts to boost aerobic capacity Repetition n/a use for leg speed and building efficiency
Easy runs correlate with races of 100 kilometers or longer in terms of pace. These runs last anywhere from 5 minutes to 3 hours. Tempo runs correlate to the pace you could run for an hour all out; these runs can be anything from several 400 meter repeats with short recoveries to multiple 25 minute runs. Interval runs correlated to the pace you could run for exactly eleven minutes; in training, intervals are often best run in distances from 400m to 1600m, or, lasting anywhere from 30 seconds to 5 minutes. Lastly, repetition runs correlate to the pace you can run for 4 minutes and 30 seconds; these efforts often best relate to runs between 15 second and 2 minutes.
To put these efforts into the context of the "aerobic/anaerobic" discussion, the "Easy" runs are largely aerobic. Once you reach the next zone-tempo-you begin to reach the aerobic threshold. If you are running any faster than tempo paces and you are no longer running aerobically. These categories will help to identify how fast runs should really be. Although these four zones are widely used terms among runners and the ideas are common to most coaches, they often go by different names. What matters most is not what you call it, but how hard you run.
What Daniels offers runners most of all is a tool for calculating these paces based on race results. Below is a link for finding paces based on your own recent races that were formulated off of Daniels' research:
http://www.dissidents.com/runstuff.htm (To download the pace calculator, clink on the link and download the file VDOTer.exe).
Using this calculator, you can find out whether you are running too fast or too slow for your fitness level. Do not be discouraged if the times are not what you expected. When armed with the right knowledge an under (or over) trained athlete can find what just didn't quite make sense in their training. Hopefully, this tool will help you find out what that is.
Some key things to know about using these paces in Louisiana:
1) during the summer heart rates will be higher because of the heat
so it is often wiser to just use the paces from the tables or slow down
a little bit.
2) The paces Daniels recommends are often times considered to be a
little fast (1-2%) for most younger athletes. The main thing to using
them is to think of them as "speed limits". If, for example, someone
should run their easy runs at 7:00 pace according to the chart, running
faster than 7:00 pace will not necessarily make you faster. In fact,
Daniels says that running between these zones in a "no-man's land"
usually hurts you more than it helps you. So, while these numbers may
lead you to slow down (or speed up) just remember, this is not written
in stone, but it is based on a lot of science and has helped many people
run much faster by listening to the advice of sports scientists.
I hope this helps you learn just a little more about your running. Don't be afraid to ask questions, read books and explore these concepts. There are lots of people out there who have done what you are trying to do and can save you time and energy if you are willing to ask and learn. Best wishes and good running.
To contribute further articles to LouisianaRunning.com write to pat@louisianarunning.com